Anchor Phase 2

The user wants to start working on Anchor's phase 2. Let me first read the implementation plan to understand what phase 2 entails and what needs to be done.

1→# Anchor Implementation Plan
     2→
     3→C engine with YueScript scripting, OpenGL rendering, targeting Windows and Web.
     4→
     5→---
     6→
     7→## Summary of Key Decisions
     8→
     9→| Area | Decision | Rationale |
    10→|------|----------|-----------|
    11→| Renderer | OpenGL | Smooth rotation, additive blending, performance headroom, console-portable |
    12→| Audio | TBD (miniaudio or SoLoud) | Need pitch shifting; SDL_mixer insufficient |
    13→| Physics | Box2D 3.1 | Already used, true ball-to-ball collisions needed |
    14→| Scripting | Lua 5.4 + YueScript | Build-time compilation with `-r` flag for line numbers |
    15→| Timestep | Fixed 144 Hz | High simulation rate for responsive feel; determinism for replays |
    16→| Resolution | Per-game configurable | 480×270, 640×360, or custom; aspect-ratio scaling with letterboxing |
    17→| C Structure | Single anchor.c | Monolithic file, easier navigation |
    18→| Resources | Live forever | Games are small enough; no unloading needed |
    19→| Linking | Static | No DLLs; SDL2, Lua, audio all compiled in |
    20→| Distribution | Single executable | Zip-append for game content, extractable by modders |
    21→
    22→---
    23→
    24→## Build Strategy
    25→
    26→### YueScript Compilation
    27→
    28→**Build-time compilation** — compile `.yue` → `.lua` during build, not at runtime.
    29→
    30→```
... [590 more lines]

Phase 2 is about the Web Build with Emscripten. The tasks are:

### 2.1 Emscripten Setup

- [ ] Install Emscripten SDK
- [ ] Create build-web.bat with emcc flags
- [ ] Configure for WebGL 2.0 (OpenGL ES 3.0 subset)

### 2.2 Platform Abstraction

- [ ] Conditional compilation for web-specific code
- [ ] `emscripten_set_main_loop` integration
- [ ] Handle requestAnimationFrame timing

### 2.3 Asset Embedding

- [ ] Preload all assets into virtual filesystem
- [ ] `--preload-file assets/` flag
- [ ] Verify asset loading works identically to desktop

### 2.4 HTML Shell

- [ ] Create HTML template with canvas
- [ ] Handle canvas sizing/scaling
- [ ] Keyboard/mouse event capture

### 2.5 Verification

- Same Lua code runs in browser
- Input works (keyboard, mouse)
- Fullscreen toggle works
- No visible differences from Windows build

Let me first look at the current state of anchor.c to understand what we're working with, then we can start on the web build.

1→/*
     2→ * Anchor Engine - Minimal skeleton
     3→ * Phase 1: Window + OpenGL + Lua integration
     4→ */
     5→
     6→#include <stdio.h>
     7→#include <stdlib.h>
     8→#include <stdbool.h>
     9→
    10→#include <SDL.h>
    11→#include <glad/gl.h>
    12→
    13→#include <lua.h>
    14→#include <lualib.h>
    15→#include <lauxlib.h>
    16→
    17→#define WINDOW_TITLE "Anchor"
    18→#define GAME_WIDTH 480
    19→#define GAME_HEIGHT 270
    20→#define INITIAL_SCALE 2
    21→
    22→// Timing configuration (matching reference Anchor)
    23→#define FIXED_RATE (1.0 / 144.0)  // 144 Hz fixed timestep
    24→#define MAX_UPDATES 10            // Cap on fixed steps per frame (prevents spiral of death)
    25→
    26→static SDL_Window* window = NULL;
    27→static SDL_GLContext gl_context = NULL;
    28→static lua_State* L = NULL;
    29→static bool error_state = false;
    30→static char error_message[4096] = {0};
... [464 more lines]

E:\a327ex\Anchor\engine\include\SDL2\begin_code.h
E:\a327ex\Anchor\engine\include\SDL2\close_code.h
E:\a327ex\Anchor\engine\include\SDL2\SDL.h
E:\a327ex\Anchor\engine\include\SDL2\SDL_assert.h
E:\a327ex\Anchor\engine\include\SDL2\SDL_atomic.h
E:\a327ex\Anchor\engine\include\SDL2\SDL_audio.h
E:\a327ex\Anchor\engine\include\SDL2\SDL_bits.h
E:\a327ex\Anchor\engine\include\SDL2\SDL_blendmode.h
E:\a327ex\Anchor\engine\include\SDL2\SDL_clipboard.h
E:\a327ex\Anchor\engine\include\SDL2\SDL_config.h
E:\a327ex\Anchor\engine\include\SDL2\SDL_config_android.h
E:\a327ex\Anchor\engine\include\SDL2\SDL_config_emscripten.h
E:\a327ex\Anchor\engine\include\SDL2\SDL_config_iphoneos.h
E:\a327ex\Anchor\engine\include\SDL2\SDL_config_macosx.h
E:\a327ex\Anchor\engine\include\SDL2\SDL_config_minimal.h
E:\a327ex\Anchor\engine\include\SDL2\SDL_config_ngage.h
E:\a327ex\Anchor\engine\include\SDL2\SDL_config_os2.h
E:\a327ex\Anchor\engine\include\SDL2\SDL_config_pandora.h
E:\a327ex\Anchor\engine\include\SDL2\SDL_config_windows.h
E:\a327ex\Anchor\engine\include\SDL2\SDL_config_wingdk.h
E:\a327ex\Anchor\engine\include\SDL2\SDL_config_winrt.h
E:\a327ex\Anchor\engine\include\SDL2\SDL_config_xbox.h
E:\a327ex\Anchor\engine\include\SDL2\SDL_copying.h
E:\a327ex\Anchor\engine\include\SDL2\SDL_cpuinfo.h
E:\a327ex\Anchor\engine\include\SDL2\SDL_egl.h
E:\a327ex\Anchor\engine\include\SDL2\SDL_endian.h
E:\a327ex\Anchor\engine\include\SDL2\SDL_error.h
E:\a327ex\Anchor\engine\include\SDL2\SDL_events.h
E:\a327ex\Anchor\engine\include\SDL2\SDL_filesystem.h
E:\a327ex\Anchor\engine\include\SDL2\SDL_gamecontroller.h
... [71 more lines]

Good. I have a clear picture of the current state:

1. Phase 1 is complete - we have a working Windows build with:
   - SDL2 window with OpenGL 3.3 context
   - Fixed timestep game loop (144 Hz)
   - Lua integration with error handling
   - Framebuffer for integer scaling
   - Fullscreen toggle (F11, Alt+Enter)
   - Aspect-ratio scaling with letterboxing

2. For Phase 2 (Web Build), we need to:
   - Set up Emscripten SDK
   - Create build-web.bat
   - Make the code work with WebGL 2.0 (which is OpenGL ES 3.0)
   - Handle emscripten_set_main_loop for the browser's requestAnimationFrame
   - Create HTML shell
   - Handle asset loading

Key changes needed for Emscripten:

1. **Shaders**: OpenGL 3.3 Core uses `#version 330 core`, but WebGL 2.0/OpenGL ES 3.0 uses `#version 300 es`. Need conditional shader sources.
2. **Main loop**: Can't have blocking loop in browser - need emscripten_set_main_loop
3. **glad**: Won't work for WebGL - need to use GLES3 headers from Emscripten
4. **Timing**: requestAnimationFrame is different from SDL performance counters

Let me check the build.bat to understand the current build setup:

<tool_use_error>File does not exist.</tool_use_error>

1→@echo off
     2→setlocal
     3→
     4→cd /d "%~dp0"
     5→
     6→:: Find and run vcvarsall.bat for Visual Studio
     7→if exist "C:\Program Files\Microsoft Visual Studio\18\Community\VC\Auxiliary\Build\vcvarsall.bat" (
     8→    call "C:\Program Files\Microsoft Visual Studio\18\Community\VC\Auxiliary\Build\vcvarsall.bat" x64 >nul 2>&1
     9→) else if exist "C:\Program Files\Microsoft Visual Studio\2022\Community\VC\Auxiliary\Build\vcvarsall.bat" (
    10→    call "C:\Program Files\Microsoft Visual Studio\2022\Community\VC\Auxiliary\Build\vcvarsall.bat" x64 >nul 2>&1
    11→) else if exist "C:\Program Files\Microsoft Visual Studio\2022\Professional\VC\Auxiliary\Build\vcvarsall.bat" (
    12→    call "C:\Program Files\Microsoft Visual Studio\2022\Professional\VC\Auxiliary\Build\vcvarsall.bat" x64 >nul 2>&1
    13→) else if exist "C:\Program Files\Microsoft Visual Studio\2022\Enterprise\VC\Auxiliary\Build\vcvarsall.bat" (
    14→    call "C:\Program Files\Microsoft Visual Studio\2022\Enterprise\VC\Auxiliary\Build\vcvarsall.bat" x64 >nul 2>&1
    15→) else (
    16→    echo ERROR: Could not find Visual Studio
    17→    exit /b 1
    18→)
    19→
    20→if not exist build mkdir build
    21→
    22→:: Build Lua library if it doesn't exist
    23→if not exist lib\lua.lib (
    24→    echo Building Lua library...
    25→    if not exist build\lua_obj mkdir build\lua_obj
    26→    cl.exe /nologo /O2 /W3 /c /I"include/lua" ^
    27→        include/lua/lapi.c include/lua/lauxlib.c include/lua/lbaselib.c ^
    28→        include/lua/lcode.c include/lua/lcorolib.c include/lua/lctype.c ^
    29→        include/lua/ldblib.c include/lua/ldebug.c include/lua/ldo.c ^
    30→        include/lua/ldump.c include/lua/lfunc.c include/lua/lgc.c ^
... [39 more lines]

main.lua doesn't exist. Let me check what's in the root directory:

E:\a327ex\Anchor\reference\anchor\external\sort.lua
E:\a327ex\Anchor\reference\anchor\external\profile.lua
E:\a327ex\Anchor\reference\anchor\external\utf8.lua
E:\a327ex\Anchor\reference\anchor\external\mlib.lua
E:\a327ex\Anchor\reference\anchor\string.lua
E:\a327ex\Anchor\reference\anchor\spring.lua
E:\a327ex\Anchor\reference\anchor\stats.lua
E:\a327ex\Anchor\reference\anchor\shake.lua
E:\a327ex\Anchor\reference\anchor\class.lua
E:\a327ex\Anchor\reference\anchor\timer.lua
E:\a327ex\Anchor\reference\anchor\camera.lua
E:\a327ex\Anchor\reference\anchor\music_player.lua
E:\a327ex\Anchor\reference\anchor\sound.lua
E:\a327ex\Anchor\reference\anchor\random.lua
E:\a327ex\Anchor\reference\anchor\collision.lua
E:\a327ex\Anchor\reference\anchor\mouse_hover.lua
E:\a327ex\Anchor\reference\anchor\grid.lua
E:\a327ex\Anchor\reference\anchor\physics_world.lua
E:\a327ex\Anchor\reference\anchor\joint.lua
E:\a327ex\Anchor\reference\anchor\color.lua
E:\a327ex\Anchor\reference\anchor\array.lua
E:\a327ex\Anchor\reference\anchor\animation.lua
E:\a327ex\Anchor\reference\anchor\input.lua
E:\a327ex\Anchor\reference\anchor\tiled_map.lua
E:\a327ex\Anchor\reference\anchor\collider.lua
E:\a327ex\Anchor\reference\anchor\ui.lua
E:\a327ex\Anchor\reference\anchor\layout.lua
E:\a327ex\Anchor\reference\anchor\text.lua
E:\a327ex\Anchor\reference\anchor\init.lua
E:\a327ex\Anchor\reference\anchor\math.lua
... [4 more lines]

E:\a327ex\Anchor\engine\build\anchor.exe

Let me check the main.lua in the engine directory:

1→print("main.lua loaded")
     2→
     3→local step_count = 0
     4→
     5→function update(dt)
     6→    step_count = step_count + 1
     7→    if step_count % 144 == 0 then
     8→        print("1 second passed (" .. step_count .. " steps)")
     9→    end
    10→end
    11→

Now I have a complete picture of the current state. Let me create a task list for Phase 2.

Key changes needed for Emscripten:

1. **Emscripten SDK Installation** - User needs to install this (can't do programmatically)

2. **Build script** - Create build-web.bat (or .sh) with emcc

3. **Shader changes** - OpenGL 3.3 Core uses `#version 330 core`, WebGL 2.0/GLES 3.0 uses `#version 300 es`. Need conditional compilation or runtime shader selection.

4. **Main loop** - Browser can't have blocking while loop. Need `emscripten_set_main_loop` or `emscripten_set_main_loop_arg`.

5. **glad replacement** - glad won't work in WebGL. Need to use GLES3 headers from Emscripten.

6. **Platform abstraction** - `#ifdef __EMSCRIPTEN__` for platform-specific code

7. **HTML shell template** - Canvas setup, keyboard capture, etc.

8. **Asset handling** - `--preload-file` for Lua scripts

Let me set up the todo list and then discuss the approach with the user.

- [pending] Set up Emscripten SDK

- [pending] Create build-web.bat with emcc flags
- [pending] Add platform abstraction (#ifdef __EMSCRIPTEN__)
- [pending] Convert shaders to WebGL 2.0 / GLES 3.0
- [pending] Replace glad with GLES3 headers for web
- [pending] Implement emscripten_set_main_loop
- [pending] Create HTML shell template
- [pending] Set up asset preloading (--preload-file)
- [pending] Verify parity with Windows build

Now let me outline what's needed and ask about the Emscripten SDK installation status.

The user is asking where to clone the Emscripten SDK. This is a practical question about directory placement.

Good options:

1. A tools/SDK directory that's separate from projects (like `C:\tools\emsdk` or `~/tools/emsdk`)
2. Alongside other development tools
3. Not inside the Anchor project directory (it's a separate tool, not part of the project)

On Windows, common choices:

- `C:\emsdk` - simple, easy to find
- `C:\tools\emsdk` - if they have a tools directory
- Somewhere in their user profile

Let me give a straightforward recommendation. Since this is Windows (based on the paths I've seen like `E:\a327ex\Anchor`), I should suggest a simple location.

The user has Python installed but there's an alias conflict on Windows. The Microsoft Store creates app execution aliases that intercept `python` commands even when Python is installed. The `./emsdk` script is probably trying to call `python` or `python3` and hitting the alias.

The solution is to disable the Microsoft Store app execution aliases for Python, or to use `python` explicitly to run the emsdk script.

Let me suggest the fix.

Good, Emscripten is installed and activated. Now they need to run `emsdk_env.bat` to set the environment variables for the current shell, or use `--permanent` to make it persistent.

Let me guide them to activate the environment and then verify emcc works.

The `emsdk_env.bat` script printed the export commands but they weren't actually executed in the bash shell. This is because it's a .bat file that outputs bash-style export commands but doesn't actually run them in the MINGW64 bash environment.

The user is using Git Bash (MINGW64). They need to source the shell script version instead, or manually export the PATH.

Let me check - emsdk should have a .sh version for unix-like shells. In Git Bash, they should use:

```bash
source ./emsdk_env.sh
```

Or they can manually add the path:
```bash
export PATH="/c/emsdk:/c/emsdk/upstream/emscripten:$PATH"
```

The PATH is being set but emcc still isn't found. Let me check if the path is actually being exported. The script shows it's setting PATH but maybe it's not actually being exported to the shell.

Let me check the actual path:

```bash
echo $PATH
```

And check if emcc exists at that location:

```bash
ls /c/emsdk/upstream/emscripten/emcc*
```

It could be that:

1. The PATH isn't actually being set (just printed)
2. emcc is named differently (emcc.py, emcc.bat, etc.)
3. The path doesn't exist

Let me suggest some debugging commands.

Good instinct - restarting the terminal might help since they ran `--permanent`. But let's first check if the files exist where they should, since the script said it was setting things up. Could be a Git Bash PATH quirk.

Actually, yes - restarting the terminal after `--permanent` would pick up the permanent environment changes. Let's try that.

The `--permanent` option didn't add emsdk to the Git Bash PATH. This is because the `--permanent` option modifies Windows environment variables (system or user), but Git Bash doesn't always pick those up automatically, or it uses its own PATH construction.

The emsdk `--permanent` option likely modifies the Windows registry/environment, which would work for cmd.exe and PowerShell, but Git Bash constructs its PATH differently.

Options:

1. Add the emsdk paths to `~/.bashrc` or `~/.bash_profile` for Git Bash
2. Source `emsdk_env.sh` every time
3. Use cmd.exe or PowerShell instead of Git Bash for the web build

Let me suggest adding it to their bash profile for Git Bash.

This is very strange. The script is saying it's adding to PATH but emcc still isn't found. Let me check if the file actually exists:

```bash
ls /c/emsdk/upstream/emscripten/emcc*
```

Or maybe the PATH variable isn't actually being modified. Let's check:

```bash
echo $PATH
```

The script prints "PATH = ..." but maybe it's not actually exporting it. This could be a bug in the emsdk_env.sh script on Windows/MINGW.

Let me suggest checking if the emcc file exists, and then manually setting the PATH.

The user wants me to run these commands myself using the Bash tool. Let me do that.

/c/emsdk/upstream/emscripten/emcc.bat
/c/emsdk/upstream/emscripten/emcc.ps1
/c/emsdk/upstream/emscripten/emcc.py

Ah, there's no `emcc` executable directly - there's `emcc.bat`, `emcc.ps1`, and `emcc.py`. On Windows in Git Bash, the shell doesn't automatically execute .bat files like cmd.exe does.

So the user can either:

1. Use `emcc.bat` explicitly
2. Use `python /c/emsdk/upstream/emscripten/emcc.py`
3. Create an alias
4. Use cmd.exe instead of Git Bash

Let me try exporting the PATH and then calling emcc.bat:

emcc (Emscripten gcc/clang-like replacement + linker emulating GNU ld) 4.0.22 (0f3d2e62bccf8e14497ff19e05a1202c51eb0c65)

Copyright (C) 2025 the Emscripten authors (see AUTHORS.txt)

This is free and open source software under the MIT license.

There is NO warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

shared:INFO: (Emscripten: Running sanity checks)

Emscripten works when calling emcc.bat directly. Now let me set up your .bashrc so this works automatically:

Now let me update the todo list and start working on the web build. Emscripten SDK is now set up. Let me create the build script and modify anchor.c for Emscripten compatibility.

- [completed] Set up Emscripten SDK

- [in_progress] Create build-web.bat with emcc flags
- [pending] Add platform abstraction (#ifdef __EMSCRIPTEN__)
- [pending] Convert shaders to WebGL 2.0 / GLES 3.0
- [pending] Replace glad with GLES3 headers for web
- [pending] Implement emscripten_set_main_loop
- [pending] Create HTML shell template
- [pending] Set up asset preloading (--preload-file)
- [pending] Verify parity with Windows build

Now let me create the build-web script. I'll use a .sh script since the user is in Git Bash. The script needs to:1. Call emcc with the right flags

2. Use SDL2 via `-s USE_SDL=2` (emscripten has built-in SDL2 port)
3. Use WebGL2 via `-s USE_WEBGL2=1`
4. Preload assets
5. Output HTML + JS + WASM

Key emcc flags:

- `-s USE_SDL=2` - Use Emscripten's SDL2 port
- `-s USE_WEBGL2=1` - Enable WebGL 2.0
- `-s FULL_ES3=1` - Full OpenGL ES 3.0 emulation
- `-s WASM=1` - Output WebAssembly
- `-s ALLOW_MEMORY_GROWTH=1` - Allow memory to grow
- `--preload-file` - Bundle assets
- `-O2` or `-O3` for optimization
- `--shell-file` - Custom HTML template

Let me create the build script first, then modify anchor.c for cross-platform support.

File created successfully at: E:\a327ex\Anchor\engine\build-web.sh

Now I need to create the HTML shell template and modify anchor.c for cross-platform support. The main changes to anchor.c:

1. Include emscripten headers when compiling for web
2. Use GLES3 instead of glad for OpenGL loading
3. Change shaders to GLES 3.0 / WebGL 2.0 syntax
4. Replace the main loop with emscripten_set_main_loop

Let me create the shell.html first, then modify anchor.c.

File created successfully at: E:\a327ex\Anchor\engine\shell.html

Now I need to modify anchor.c for cross-platform support. The main changes:1. Platform detection with `#ifdef __EMSCRIPTEN__`

2. Include Emscripten headers
3. Use GLES3 headers instead of glad on web4. Change shaders to use GLES 3.0 syntax (or use #version 300 es)
5. Replace the blocking main loop with emscripten_set_main_loop

The shaders need to change:- `#version 330 core` → `#version 300 es`- Add `precision mediump float;` for fragment shaders

- `attribute`/`varying` syntax is slightly different but `in`/`out` works in both 330 core and 300 es

Let me make these changes to anchor.c.

- [completed] Set up Emscripten SDK

- [completed] Create build-web.bat with emcc flags
- [in_progress] Add platform abstraction (#ifdef __EMSCRIPTEN__)
- [in_progress] Convert shaders to WebGL 2.0 / GLES 3.0
- [in_progress] Replace glad with GLES3 headers for web
- [in_progress] Implement emscripten_set_main_loop
- [completed] Create HTML shell template
- [completed] Set up asset preloading (--preload-file)
- [pending] Verify parity with Windows build

Now let me rewrite anchor.c with Emscripten support. This is a significant change, so I'll be careful. Main changes:

1. Add `#ifdef __EMSCRIPTEN__` blocks
2. Include emscripten headers and use GLES3 instead of glad
3. Convert shaders to be compatible with both platforms
4. Refactor main loop to use emscripten_set_main_loop

Let me write the updated file:

The file E:\a327ex\Anchor\engine\src\anchor.c has been updated. Here's the result of running `cat -n` on a snippet of the edited file:
     1→/*
     2→ * Anchor Engine - Minimal skeleton
     3→ * Phase 1: Window + OpenGL + Lua integration
     4→ * Phase 2: Web build (Emscripten/WebGL)
     5→ */
     6→
     7→#include <stdio.h>
     8→#include <stdlib.h>
     9→#include <stdbool.h>
    10→
    11→#include <SDL.h>
    12→
    13→#ifdef __EMSCRIPTEN__
    14→    #include <emscripten.h>
    15→    #include <emscripten/html5.h>
    16→    #include <GLES3/gl3.h>
    17→#else
    18→    #include <glad/gl.h>
    19→#endif
    20→
    21→#include <lua.h>
    22→#include <lualib.h>
    23→#include <lauxlib.h>
    24→
    25→#define WINDOW_TITLE "Anchor"
    26→#define GAME_WIDTH 480
    27→#define GAME_HEIGHT 270
    28→#define INITIAL_SCALE 2
    29→
... [552 more lines]

The code is updated. Now I need to verify the Windows build still works, then try the web build.Let me first make sure the Windows build works (regression test), then try the web build.

[31mWARNING: Found ~/.bashrc but no ~/.bash_profile, ~/.bash_login or ~/.profile.[m

This looks like an incorrect setup.
A ~/.bash_profile that loads ~/.bashrc will be created for you.
anchor.c

gl.c

Generating Code...

LINK : warning LNK4098: defaultlib 'MSVCRT' conflicts with use of other libs; use /NODEFAULTLIB:library

Build successful: build/anchor.exe

Windows build still works. Now let me try the web build. First I need to source the emscripten environment, then run the build script.

Build successful: build-web/anchor.html
To test: cd build-web && python -m http.server 8000
Then open: http://localhost:8000/anchor.html

ports:INFO: retrieving port: sdl2 from https://github.com/libsdl-org/SDL/archive/release-2.32.8.zip

ports:INFO: unpacking port: sdl2

cache:INFO: generating port: sysroot\lib\wasm32-emscripten\libSDL2.a... (this will be cached in "C:\emsdk\upstream\emscripten\cache\sysroot\lib\wasm32-emscripten\libSDL2.a" for subsequent builds)

system_libs:INFO: compiled 118 inputs in 7.92s

cache:INFO:  - ok

Excellent! The web build succeeded! First time it downloads and caches the SDL2 port, but it completed successfully. Now let me verify the output files exist and start a test server.

total 873
drwxr-xr-x 1 adn 197121      0 Jan  6 13:06 .
drwxr-xr-x 1 adn 197121      0 Jan  6 13:06 ..
-rw-r--r-- 1 adn 197121    208 Jan  6 13:06 anchor.data
-rw-r--r-- 1 adn 197121   1725 Jan  6 13:06 anchor.html
-rw-r--r-- 1 adn 197121 230877 Jan  6 13:06 anchor.js
-rw-r--r-- 1 adn 197121 647058 Jan  6 13:06 anchor.wasm

All the build outputs are there:- anchor.data - preloaded assets (main.lua)

- anchor.html - the HTML shell
- anchor.js - the JavaScript glue code- anchor.wasm - the compiled WebAssemblyNow let me start a local server so the user can test it. I'll run it in the background.

Command running in background with ID: b2732ce. Output is being written to: C:\Users\adn\AppData\Local\Temp\claude\E--a327ex-Anchor\tasks\b2732ce.output

Server is running in the background. Let me update the todos and let the user know to test it.

- [completed] Set up Emscripten SDK

- [completed] Create build-web.sh with emcc flags
- [completed] Add platform abstraction (#ifdef __EMSCRIPTEN__)
- [completed] Convert shaders to WebGL 2.0 / GLES 3.0
- [completed] Replace glad with GLES3 headers for web
- [completed] Implement emscripten_set_main_loop
- [completed] Create HTML shell template
- [completed] Set up asset preloading (--preload-file)
- [in_progress] Verify parity with Windows build

Now let me tell the user to test it in their browser.

The user says it works but there's a white outline between the letterboxing and the game canvas. This is likely a CSS issue with the canvas element - browsers sometimes add a default border or there could be a gap from the canvas sizing.

Let me check the shell.html to see if there's any styling issue. The white outline is probably coming from:

1. Default canvas border
2. CSS box model issues
3. The canvas not perfectly fitting its container
4. Anti-aliasing at the edges

Let me look at the shell.html and fix the CSS.

1→<!DOCTYPE html>
     2→<html>
     3→<head>
     4→    <meta charset="utf-8">
     5→    <meta name="viewport" content="width=device-width, initial-scale=1.0">
     6→    <title>Anchor</title>
     7→    <style>
     8→        * {
     9→            margin: 0;
    10→            padding: 0;
    11→            box-sizing: border-box;
    12→        }
    13→        html, body {
    14→            width: 100%;
    15→            height: 100%;
    16→            background: #000;
    17→            overflow: hidden;
    18→        }
    19→        #canvas {
    20→            display: block;
    21→            position: absolute;
    22→            top: 50%;
    23→            left: 50%;
    24→            transform: translate(-50%, -50%);
    25→            image-rendering: pixelated;
    26→            image-rendering: crisp-edges;
    27→        }
    28→        #status {
    29→            position: absolute;
    30→            top: 50%;
... [82 more lines]

I see the issue. The canvas needs explicit border and outline removal. Also, the white line could be from:

1. Default canvas border
2. The canvas background color being white before WebGL initializes
3. Rounding issues with the CSS transform

Let me add explicit border/outline removal and set the canvas background to black.

The file E:\a327ex\Anchor\engine\shell.html has been updated. Here's the result of running `cat -n` on a snippet of the edited file:
    15→            height: 100%;
    16→            background: #000;
    17→            overflow: hidden;
    18→        }
    19→        #canvas {
    20→            display: block;
    21→            position: absolute;
    22→            top: 50%;
    23→            left: 50%;
    24→            transform: translate(-50%, -50%);
    25→            image-rendering: pixelated;
    26→            image-rendering: crisp-edges;
    27→            border: none;
    28→            outline: none;
    29→            background: #000;
    30→        }
    31→        #status {
    32→            position: absolute;
    33→            top: 50%;
    34→            left: 50%;

Now I need to rebuild the web version and have the user test again.

Build successful: build-web/anchor.html
To test: cd build-web && python -m http.server 8000
Then open: http://localhost:8000/anchor.html

Rebuilt. The server is still running in the background. Let the user refresh and test.

The issue is fixed. Let me update the todo list to mark the verification as complete, and then summarize what was accomplished in Phase 2.

- [completed] Set up Emscripten SDK

- [completed] Create build-web.sh with emcc flags
- [completed] Add platform abstraction (#ifdef __EMSCRIPTEN__)
- [completed] Convert shaders to WebGL 2.0 / GLES 3.0
- [completed] Replace glad with GLES3 headers for web
- [completed] Implement emscripten_set_main_loop
- [completed] Create HTML shell template
- [completed] Set up asset preloading (--preload-file)
- [completed] Verify parity with Windows build

Phase 2 is complete. Let me kill the background server and update the implementation plan to mark Phase 2 as complete.

{"message":"Successfully killed shell: b2732ce (cd /e/a327ex/Anchor/engine/build-web && python -m http.server 8000)","shell_id":"b2732ce"}

Now let me update the implementation plan to mark Phase 2 as complete. I need to read the current state and update the checkboxes.

The file E:\a327ex\Anchor\docs\ANCHOR_IMPLEMENTATION_PLAN.md has been updated. Here's the result of running `cat -n` on a snippet of the edited file:
   116→## Phase 2: Web Build (Emscripten)
   117→
   118→**Goal:** Same code compiles and runs in browser via WebGL.
   119→
   120→### 2.1 Emscripten Setup
   121→- [x] Install Emscripten SDK
   122→- [x] Create build-web.sh with emcc flags
   123→- [x] Configure for WebGL 2.0 (OpenGL ES 3.0 subset)
   124→
   125→### 2.2 Platform Abstraction
   126→- [x] Conditional compilation for web-specific code (`#ifdef __EMSCRIPTEN__`)
   127→- [x] `emscripten_set_main_loop` integration
   128→- [x] Handle requestAnimationFrame timing
   129→
   130→### 2.3 Asset Embedding
   131→- [x] Preload all assets into virtual filesystem
   132→- [x] `--preload-file` flag for Lua scripts
   133→- [x] Verify asset loading works identically to desktop
   134→
   135→### 2.4 HTML Shell
   136→- [x] Create HTML template with canvas
   137→- [x] Handle canvas sizing/scaling
   138→- [x] Keyboard/mouse event capture
   139→
   140→### 2.5 Verification
   141→- [x] Same Lua code runs in browser
   142→- [x] Orange test quad renders correctly
   143→- [x] Aspect-ratio scaling with letterboxing works
   144→- [x] No visible differences from Windows build
... [6 more lines]

Phase 2 is now marked as complete. Let me also update the directory structure in the implementation plan since we now have build-web.sh instead of build-web.bat, and summarize what was accomplished.

The user wants to understand the dual shader sources approach I used. Let me explain the difference between OpenGL 3.3 Core and OpenGL ES 3.0 / WebGL 2.0 shaders, and why I had to duplicate them.

Good question. Let me think about this:

1. Can desktop OpenGL use `#version 300 es` shaders? 

Not directly. Desktop OpenGL and OpenGL ES are different APIs. Desktop OpenGL doesn't natively understand `#version 300 es` - it would fail to compile. You'd need to request an ES context specifically, which SDL can do with `SDL_GL_CONTEXT_PROFILE_ES`, but then you're running OpenGL ES on desktop rather than full OpenGL.

2. Could we request an ES context on desktop?

Yes, technically. Some desktop drivers (especially on Windows with ANGLE, or Mesa on Linux) support OpenGL ES contexts. But:

- Not all desktop drivers support ES contexts
- You'd be limiting yourself to ES features when full OpenGL has more
- It's less tested/common on desktop

3. Could we use `#version 330 core` everywhere?

No - WebGL 2.0 only speaks GLSL ES, it won't understand `#version 330 core`.

4. Feature differences between 330 core and 300 es?

OpenGL 3.3 has some features that ES 3.0 lacks:

- Geometry shaders (not in ES 3.0, added in ES 3.2)
- More texture formats
- glPolygonMode (wireframe)
- Some blending modes
- Transform feedback differences

But for what Anchor needs (2D rendering with sprites, shapes, framebuffers, blend modes), both versions have everything needed. The feature set overlap is sufficient.

5. Best approach?

Given that:

- The shader logic is identical
- Only the version line and precision qualifiers differ
- We're not using any desktop-only features

We could simplify by just always using the ES-compatible subset with preprocessor string manipulation. Or we could keep the ifdef for clarity.

Actually, there's another option: use `#version 330 core` on desktop and `#version 300 es` on web, but structure the shader body identically. 

I've implemented a straightforward solution that minimizes complexity. By using separate version headers but keeping the core shader logic consistent, I've created a portable approach that works across different OpenGL contexts without sacrificing functionality or readability.

This is a great question about practical shader authoring workflow. Let me think through the options:

1. **For shaders embedded in anchor.c** - these are internal engine shaders (the basic quad shader, the screen blit shader, and future built-in shaders for shapes/sprites). These could use the header helper approach.

2. **For user-authored shaders loaded at runtime** - this is more interesting. Options:

   a) **Require users to write two versions** - terrible UX
   
   b) **Auto-prepend the correct header** - user writes just the body, engine adds the header based on platform
   
   c) **Use a simple preprocessing system** - user writes one shader with minimal platform markers
   
   d) **Target the lowest common denominator (ES 3.0 syntax)** - user writes ES-style shaders, engine transforms for desktop if needed

Option (b) is probably the cleanest. The user writes shader code without the `#version` line, and the engine prepends the appropriate header when loading. Something like:

```lua
-- User's custom shader (no version line)
local frag = [[
    in vec2 TexCoord;
    out vec4 FragColor;
    uniform sampler2D tex;
    uniform float time;
    
    void main() {
        vec2 uv = TexCoord;
        uv.x += sin(uv.y * 10.0 + time) * 0.01;
        FragColor = texture(tex, uv);
    }
]]

local shader = an:shader_load_string(frag)
```

Then the C side does:
```c
const char* header = get_shader_header(); // platform-specific
char* full_source = concat(header, user_source);
compile(full_source);
```

For precision qualifiers in fragment shaders, we'd need to add `precision mediump float;` on ES. We could:


I'll automatically insert the precision qualifier for Embedded Systems platforms, defaulting to medium precision. This simplifies the shader writing process by abstracting away platform-specific nuances. The engine handles the low-level details, allowing developers to focus on shader logic rather than platform compatibility. By dynamically adding the appropriate header and precision qualifiers, we create a more streamlined and user-friendly shader development experience.

The user wants me to refactor anchor.c to use a unified shader approach - prepending the header at runtime rather than having duplicate shader sources. This will establish the pattern that will be used later for loading user shaders.

Let me refactor:

1. Create a helper function that prepends the correct header based on platform
2. Write shader bodies without version/precision
3. Use the helper when creating shader programs

I'll need to:

1. Remove the duplicated shader sources
2. Add a helper function to prepend headers
3. Modify create_shader_program or create a new function that handles the prepending

The file E:\a327ex\Anchor\engine\src\anchor.c has been updated. Here's the result of running `cat -n` on a snippet of the edited file:
    57→static Uint64 step = 0;
    58→static double game_time = 0.0;
    59→static Uint64 frame = 0;
    60→
    61→// Shader headers - prepended to all shaders based on platform
    62→#ifdef __EMSCRIPTEN__
    63→    #define SHADER_HEADER_VERT "#version 300 es\n"
    64→    #define SHADER_HEADER_FRAG "#version 300 es\nprecision mediump float;\n"
    65→#else
    66→    #define SHADER_HEADER_VERT "#version 330 core\n"
    67→    #define SHADER_HEADER_FRAG "#version 330 core\n"
    68→#endif
    69→
    70→// Shader sources (no version line - header prepended at compile time)
    71→static const char* vertex_shader_source =
    72→    "layout (location = 0) in vec2 aPos;\n"
    73→    "layout (location = 1) in vec4 aColor;\n"
    74→    "out vec4 vertexColor;\n"
    75→    "uniform mat4 projection;\n"
    76→    "void main() {\n"
    77→    "    gl_Position = projection * vec4(aPos, 0.0, 1.0);\n"
    78→    "    vertexColor = aColor;\n"
    79→    "}\n";
    80→
    81→static const char* fragment_shader_source =
    82→    "in vec4 vertexColor;\n"
    83→    "out vec4 FragColor;\n"
    84→    "void main() {\n"
    85→    "    FragColor = vertexColor;\n"
... [22 more lines]

Now I need to modify the compile_shader function to prepend the appropriate header based on shader type. I'll update the function to concatenate the header with the source.

The file E:\a327ex\Anchor\engine\src\anchor.c has been updated. Here's the result of running `cat -n` on a snippet of the edited file:
   101→    "void main() {\n"
   102→    "    FragColor = texture(screenTexture, TexCoord);\n"
   103→    "}\n";
   104→
   105→// Compile a shader and return its ID (0 on failure)
   106→// Automatically prepends platform-specific header
   107→static GLuint compile_shader(GLenum type, const char* source) {
   108→    const char* header = (type == GL_VERTEX_SHADER) ? SHADER_HEADER_VERT : SHADER_HEADER_FRAG;
   109→
   110→    // Concatenate header + source
   111→    size_t header_len = strlen(header);
   112→    size_t source_len = strlen(source);
   113→    char* full_source = (char*)malloc(header_len + source_len + 1);
   114→    memcpy(full_source, header, header_len);
   115→    memcpy(full_source + header_len, source, source_len + 1);
   116→
   117→    GLuint shader = glCreateShader(type);
   118→    glShaderSource(shader, 1, (const char**)&full_source, NULL);
   119→    glCompileShader(shader);
   120→
   121→    free(full_source);
   122→
   123→    GLint success;
   124→    glGetShaderiv(shader, GL_COMPILE_STATUS, &success);
   125→    if (!success) {
   126→        char info_log[512];
   127→        glGetShaderInfoLog(shader, sizeof(info_log), NULL, info_log);
   128→        fprintf(stderr, "Shader compilation failed: %s\n", info_log);
   129→        glDeleteShader(shader);
... [8 more lines]

I need to add `#include <string.h>` for strlen/memcpy if it's not already there. Let me check the includes at the top of the file.

1→/*
     2→ * Anchor Engine - Minimal skeleton
     3→ * Phase 1: Window + OpenGL + Lua integration
     4→ * Phase 2: Web build (Emscripten/WebGL)
     5→ */
     6→
     7→#include <stdio.h>
     8→#include <stdlib.h>
     9→#include <stdbool.h>
    10→
    11→#include <SDL.h>
    12→
    13→#ifdef __EMSCRIPTEN__
    14→    #include <emscripten.h>
    15→    #include <emscripten/html5.h>
    16→    #include <GLES3/gl3.h>
    17→#else
    18→    #include <glad/gl.h>
    19→#endif
    20→
    21→#include <lua.h>
    22→#include <lualib.h>
    23→#include <lauxlib.h>
    24→
    25→#define WINDOW_TITLE "Anchor"

I need to add `#include <string.h>` for strlen and memcpy.

The file E:\a327ex\Anchor\engine\src\anchor.c has been updated. Here's the result of running `cat -n` on a snippet of the edited file:
     3→ * Phase 1: Window + OpenGL + Lua integration
     4→ * Phase 2: Web build (Emscripten/WebGL)
     5→ */
     6→
     7→#include <stdio.h>
     8→#include <stdlib.h>
     9→#include <stdbool.h>
    10→#include <string.h>
    11→
    12→#include <SDL.h>
    13→
    14→#ifdef __EMSCRIPTEN__

Now let me test both builds to make sure everything still works.

anchor.c

gl.c

Generating Code...

LINK : warning LNK4098: defaultlib 'MSVCRT' conflicts with use of other libs; use /NODEFAULTLIB:library

Build successful: build/anchor.exe

Build successful: build-web/anchor.html
To test: cd build-web && python -m http.server 8000
Then open: http://localhost:8000/anchor.html

Both builds succeeded. Let me run the Windows build to verify it works visually, and then the user can test the web build.

Anchor Engine starting...

Loading: main.lua

OpenGL 3.3 loaded

Renderer: NVIDIA GeForce RTX 2060/PCIe/SSE2

Shader program created

Game VAO/VBO created

Framebuffer created (480x270)

Screen shader created

Screen VAO/VBO created

main.lua loaded

Initialization complete. Press ESC to exit, F11 for fullscreen.

1 second passed (144 steps)

Both builds work. Let me summarize what was done.

The user wants to set up a quick launcher command for testing the web build. They use Launchy and have a shortcut for the Windows build. For the web build, they need to:

1. Start the Python HTTP server in the build-web directory
2. Open the browser to localhost:8000/anchor.html

I could create a batch script that does both - starts the server in the background and opens the browser. Let me write a simple .bat file for this.

File created successfully at: E:\a327ex\Anchor\engine\run-web.bat

This script:

1. Changes to the build-web directory
2. Opens the browser (using `start ""` which opens default browser)
3. Starts the Python server (blocks so the server keeps running)

The user can add this to Launchy as `E:/a327ex/Anchor/engine/run-web.bat`.

One issue: if the server is already running on port 8000, it'll fail. Could add error handling but keeping it simple for now.

The user wants to see console.log/printf output from the web build. In Emscripten, printf output goes to the browser's developer console by default. There are a few options:

1. **Browser DevTools** - F12 → Console tab. This is the standard way.

2. **Emscripten's --emrun flag** - This creates a special build that pipes console output back to the terminal. You run it with `emrun anchor.html` instead of using a Python server.

3. **Custom JavaScript to display in page** - Could add a text area to the HTML that shows output.

The `emrun` approach is probably what they want - it lets them see printf output in the terminal they launched from. Let me explain this option.

The file E:\a327ex\Anchor\engine\build-web.sh has been updated. Here's the result of running `cat -n` on a snippet of the edited file:
    13→# -s WASM=1: Output WebAssembly
    14→# -s ALLOW_MEMORY_GROWTH=1: Allow heap to grow
    15→# --preload-file: Bundle assets into virtual filesystem
    16→
    17→/c/emsdk/upstream/emscripten/emcc.bat \
    18→    -O2 \
    19→    -I"include" -I"include/SDL2" -I"include/lua" -I"include/stb" \
    20→    src/anchor.c \
    21→    include/lua/*.c \
    22→    -o build-web/anchor.html \
    23→    -s USE_SDL=2 \
    24→    -s USE_WEBGL2=1 \
    25→    -s FULL_ES3=1 \
    26→    -s WASM=1 \
    27→    -s ALLOW_MEMORY_GROWTH=1 \
    28→    -s EXPORTED_RUNTIME_METHODS='["ccall","cwrap"]' \
    29→    --preload-file main.lua \
    30→    --shell-file shell.html \
    31→    --emrun
    32→
    33→if [ $? -eq 0 ]; then
    34→    echo "Build successful: build-web/anchor.html"
    35→    echo "To test: cd build-web && python -m http.server 8000"

Now update the run-web.bat to use emrun instead of the Python server:

The file E:\a327ex\Anchor\engine\run-web.bat has been updated. Here's the result of running `cat -n` on a snippet of the edited file:
     1→@echo off
     2→cd /d "%~dp0build-web"
     3→C:\emsdk\upstream\emscripten\emrun.bat --browser chrome anchor.html
     4→

Now rebuild the web version so it has the --emrun flag compiled in, and then the user can test:

Build successful: build-web/anchor.html
To test: cd build-web && python -m http.server 8000
Then open: http://localhost:8000/anchor.html

Rebuilt with the --emrun flag. Now when the user runs run-web.bat, it'll use emrun which captures console output and displays it in the terminal. I can update the help message in build-web.sh too, but that's minor.

The user wants me to update the implementation plan to reflect the actual work done, including things that weren't originally planned. Let me read the current Phase 2 section and update it to include:

1. Git Bash setup for emscripten (source emsdk_env.sh, aliases in .bashrc)
2. The unified shader approach (header prepending)
3. emrun for console output
4. run-web.bat launcher script

Let me read the current plan and update it.

116→## Phase 2: Web Build (Emscripten)
   117→
   118→**Goal:** Same code compiles and runs in browser via WebGL.
   119→
   120→### 2.1 Emscripten Setup
   121→- [x] Install Emscripten SDK
   122→- [x] Create build-web.sh with emcc flags
   123→- [x] Configure for WebGL 2.0 (OpenGL ES 3.0 subset)
   124→
   125→### 2.2 Platform Abstraction
   126→- [x] Conditional compilation for web-specific code (`#ifdef __EMSCRIPTEN__`)
   127→- [x] `emscripten_set_main_loop` integration
   128→- [x] Handle requestAnimationFrame timing
   129→
   130→### 2.3 Asset Embedding
   131→- [x] Preload all assets into virtual filesystem
   132→- [x] `--preload-file` flag for Lua scripts
   133→- [x] Verify asset loading works identically to desktop
   134→
   135→### 2.4 HTML Shell
   136→- [x] Create HTML template with canvas
   137→- [x] Handle canvas sizing/scaling
   138→- [x] Keyboard/mouse event capture
   139→
   140→### 2.5 Verification
   141→- [x] Same Lua code runs in browser
   142→- [x] Orange test quad renders correctly
   143→- [x] Aspect-ratio scaling with letterboxing works
   144→- [x] No visible differences from Windows build
   145→
... [20 more lines]

Now let me update Phase 2 with everything we actually did, including:

1. Git Bash environment setup (emsdk_env.sh in .bashrc, aliases)
2. Unified shader system (header prepending)
3. emrun for console output
4. run-web.bat launcher script

The file E:\a327ex\Anchor\docs\ANCHOR_IMPLEMENTATION_PLAN.md has been updated. Here's the result of running `cat -n` on a snippet of the edited file:
   112→**Deliverable:** OpenGL window running Lua with error handling, fullscreen, and proper scaling. ✓ Complete
   113→
   114→---
   115→
   116→## Phase 2: Web Build (Emscripten)
   117→
   118→**Goal:** Same code compiles and runs in browser via WebGL.
   119→
   120→### 2.1 Emscripten Setup
   121→- [x] Install Emscripten SDK to `C:\emsdk`
   122→- [x] Configure Git Bash environment (`~/.bashrc`):
   123→  - `source /c/emsdk/emsdk_env.sh` for PATH
   124→  - Aliases for `emcc` → `emcc.bat` (Git Bash doesn't auto-execute .bat)
   125→- [x] Create `build-web.sh` with emcc flags
   126→- [x] Configure for WebGL 2.0 (OpenGL ES 3.0 subset)
   127→
   128→### 2.2 Platform Abstraction
   129→- [x] Conditional compilation with `#ifdef __EMSCRIPTEN__`
   130→- [x] Refactor main loop into `main_loop_iteration()` function
   131→- [x] `emscripten_set_main_loop` integration (yields to browser each frame)
   132→- [x] OpenGL ES context request (`SDL_GL_CONTEXT_PROFILE_ES`)
   133→- [x] Use `<GLES3/gl3.h>` instead of glad on web
   134→
   135→### 2.3 Unified Shader System
   136→- [x] Platform-specific headers via preprocessor defines:
   137→  - Desktop: `#version 330 core`
   138→  - Web: `#version 300 es` + `precision mediump float;`
   139→- [x] Shader sources written without version line
   140→- [x] `compile_shader()` auto-prepends correct header based on shader type
... [30 more lines]

That's better - the implementation plan now reflects what was actually done in Phase 2, including the Git Bash setup, the unified shader system, and the development workflow with emrun.

[?2026h[?2026l[?2026h[?2026l[?2026h
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[1mSkills and slash commands[22m[38;2;153;153;153m · /skills[39m

[?2026l

The user wants a reminder of what Phase 3 entails. Let me look at the implementation plan for Phase 3.

The user wants me to end the session with the title "Anchor Phase 2". I need to follow the end-of-session workflow from CLAUDE.md:

1. Locate the session transcript (most recent JSONL file)
2. Convert to Markdown
3. Read the converted log
4. Write a detailed summary
5. Create a short title (user gave: "Anchor Phase 2")
6. Show title + summary to user and wait for approval
7. Prepend to log file
8. Sync context files
9. Commit with title and summary
10. Push to GitHub
11. Push website to Blot
12. Confirm completion

Let me start.

The user doesn't want to proceed with this tool use. The tool use was rejected (eg. if it was a file edit, the new_string was NOT written to the file). To tell you how to proceed, the user said:
Actually, before that, how would I test that all the Emscripten commands actually work on all terminals now by default?

The user wants to verify that the Emscripten setup in .bashrc actually works for new terminals. Let me explain how to test this.

The emcc command works in new terminals now. The .bashrc setup is working correctly. Now the user will likely want me to proceed with ending the session.

/c/Users/adn/.claude/projects/E--a327ex-Anchor/2f88e9ba-961b-4775-960a-cbae5793fb4b.jsonl

Good, found the transcript. Now convert it to markdown with the title "anchor-phase-2.md"

Written to E:/a327ex/Anchor/website/logs/anchor-phase-2.md

Now I need to read the converted log to review the full session and write a detailed summary. Let me read it.

1→# Session 2026-01-06 15:34
     2→
     3→---
     4→
     5→> Hi, Claude. Let's get started on Anchor's phase 2 today.
     6→
     7→Let me read the implementation plan to see what phase 2 covers.
     8→
     9→<details>
    10→<summary><code>Read (E:\a327ex\Anchor\docs\ANCHOR_IMPLEMENTATION_PLAN.md)</code></summary>
    11→
    12→<pre><code>1→# Anchor Implementation Plan
    13→     2→
    14→     3→C engine with YueScript scripting, OpenGL rendering, targeting Windows and Web.
    15→     4→
    16→     5→---
    17→     6→
    18→     7→## Summary of Key Decisions
    19→     8→
    20→     9→| Area | Decision | Rationale |
    21→    10→|------|----------|-----------|
    22→    11→| Renderer | OpenGL | Smooth rotation, additive blending, performance headroom, console-portable |
    23→    12→| Audio | TBD (miniaudio or SoLoud) | Need pitch shifting; SDL_mixer insufficient |
    24→    13→| Physics | Box2D 3.1 | Already used, true ball-to-ball collisions needed |
    25→    14→| Scripting | Lua 5.4 + YueScript | Build-time compilation with `-r` flag for line numbers |
    26→    15→| Timestep | Fixed 144 Hz | High simulation rate for responsive feel; determinism for replays |
    27→    16→| Resolution | Per-game configurable | 480×270, 640×360, or custom; aspect-ratio scaling with letterboxing |
    28→    17→| C Structure | Single anchor.c | Monolithic file, easier navigation |
    29→    18→| Resources | Live forever | Games are small enough; no unloading needed |
    30→    19→| Linking | Static | No DLLs; SDL2, Lua, audio all compiled in |
... [1376 more lines]

Good, I've read the full log. Now let me write a detailed summary covering what was accomplished. The session covered:

1. Setting up Emscripten SDK
   - Installed at C:\emsdk
   - Encountered issues with Python app execution aliases on Windows
   - Git Bash doesn't auto-execute .bat files, needed explicit aliases
   - Added to ~/.bashrc for persistence

2. Platform abstraction in anchor.c
   - #ifdef __EMSCRIPTEN__ blocks
   - GLES3 headers instead of glad
   - OpenGL ES context request
   - Refactored main loop into main_loop_iteration()
   - emscripten_set_main_loop integration

3. Shaders
   - Initially had dual shader sources (duplicated for each platform)
   - Discussed why desktop OpenGL and WebGL ES use different GLSL dialects
   - Refactored to unified system with header prepending
   - compile_shader() auto-prepends correct version/precision based on platform

4. HTML shell template
   - Created shell.html with canvas, CSS for letterboxing
   - Fixed white outline issue (added border: none, outline: none, background: #000)

5. Development workflow
   - Created build-web.sh with emcc flags
   - Created run-web.bat for quick testing via Launchy
   - Added --emrun flag for console output piping to terminal

6. Updated implementation plan with everything done

Let me write the summary.

The user approved the summary. Now I need to:

1. Prepend title + summary to the log file
2. Sync context files
3. Commit everything
4. Push to GitHub
5. Push website to Blot
6. Confirm completion

1→# Session 2026-01-06 15:34
     2→
     3→---
     4→
     5→> Hi, Claude. Let's get started on Anchor's phase 2 today.
     6→
     7→Let me read the implementation plan to see what phase 2 covers.
     8→
     9→<details>
    10→<summary><code>Read (E:\a327ex\Anchor\docs\ANCHOR_IMPLEMENTATION_PLAN.md)</code></summary>

Now I need to replace the default header with the title and summary, then continue with the rest of the workflow.

The file E:\a327ex\Anchor\website\logs\anchor-phase-2.md has been updated. Here's the result of running `cat -n` on a snippet of the edited file:
     1→# Anchor Phase 2
     2→
     3→## Summary
     4→
     5→This session implemented Phase 2 of the Anchor engine: the Emscripten/WebGL web build. The same C code now compiles and runs identically in the browser.
     6→
     7→**Emscripten Setup:**
     8→- Installed Emscripten SDK to `C:\emsdk`
     9→- Encountered Windows Python app execution aliases blocking `python` command - disabled via Settings
    10→- Git Bash doesn't auto-execute `.bat` files, so `emsdk_env.sh` wasn't adding emcc to PATH properly
    11→- Fixed by adding `source /c/emsdk/emsdk_env.sh` and explicit aliases to `~/.bashrc`
    12→- Verified new terminals have `emcc` available automatically
    13→
    14→**Platform Abstraction in anchor.c:**
    15→- Added `#ifdef __EMSCRIPTEN__` conditional compilation throughout
    16→- Web uses `<GLES3/gl3.h>` instead of glad for OpenGL loading
    17→- Requests OpenGL ES 3.0 context on web (`SDL_GL_CONTEXT_PROFILE_ES`)
    18→- Refactored blocking `while(running)` loop into `main_loop_iteration()` function
    19→- Web uses `emscripten_set_main_loop()` which yields to browser each frame
    20→
    21→**Unified Shader System:**
    22→- Initially had duplicated shader sources for each platform (GLSL 330 core vs 300 es)
    23→- Discussed why desktop OpenGL and WebGL ES are different dialects - can't use `#version 300 es` on desktop
    24→- Refactored to single shader sources without version lines
    25→- `compile_shader()` auto-prepends platform-specific header (version + precision qualifiers for ES)
    26→- Same approach will work for user-authored shaders loaded at runtime
    27→
    28→**HTML Shell and CSS:**
    29→- Created `shell.html` template with canvas, letterboxing CSS, keyboard capture
... [15 more lines]

Good. Now sync context files, commit, push to GitHub, and push website to Blot.

Now I need to:

1. Add all files
2. Commit with the title and full summary
3. Push to GitHub
4. Push website to Blot

Let me read the summary from the log file to copy it exactly as instructed in CLAUDE.md.

1→# Anchor Phase 2
     2→
     3→## Summary
     4→
     5→This session implemented Phase 2 of the Anchor engine: the Emscripten/WebGL web build. The same C code now compiles and runs identically in the browser.
     6→
     7→**Emscripten Setup:**
     8→- Installed Emscripten SDK to `C:\emsdk`
     9→- Encountered Windows Python app execution aliases blocking `python` command - disabled via Settings
    10→- Git Bash doesn't auto-execute `.bat` files, so `emsdk_env.sh` wasn't adding emcc to PATH properly
    11→- Fixed by adding `source /c/emsdk/emsdk_env.sh` and explicit aliases to `~/.bashrc`
    12→- Verified new terminals have `emcc` available automatically
    13→
    14→**Platform Abstraction in anchor.c:**
    15→- Added `#ifdef __EMSCRIPTEN__` conditional compilation throughout
    16→- Web uses `<GLES3/gl3.h>` instead of glad for OpenGL loading
    17→- Requests OpenGL ES 3.0 context on web (`SDL_GL_CONTEXT_PROFILE_ES`)
    18→- Refactored blocking `while(running)` loop into `main_loop_iteration()` function
    19→- Web uses `emscripten_set_main_loop()` which yields to browser each frame
    20→
    21→**Unified Shader System:**
    22→- Initially had duplicated shader sources for each platform (GLSL 330 core vs 300 es)
    23→- Discussed why desktop OpenGL and WebGL ES are different dialects - can't use `#version 300 es` on desktop
    24→- Refactored to single shader sources without version lines
    25→- `compile_shader()` auto-prepends platform-specific header (version + precision qualifiers for ES)
    26→- Same approach will work for user-authored shaders loaded at runtime
    27→
    28→**HTML Shell and CSS:**
    29→- Created `shell.html` template with canvas, letterboxing CSS, keyboard capture
    30→- Fixed white outline artifact between letterbox and canvas (added `border: none`, `outline: none`, `background: #000`)
... [12 more lines]

Now let me commit with the exact summary from the log file. I need to copy lines 5-38 exactly.

[main a9d2efc] Anchor Phase 2
 19 files changed, 2281 insertions(+), 1955 deletions(-)
 create mode 100644 engine/build-web.sh
 create mode 100644 engine/build-web/anchor.data
 create mode 100644 engine/build-web/anchor.html
 create mode 100644 engine/build-web/anchor.js
 create mode 100644 engine/build-web/anchor.wasm
 create mode 100644 engine/run-web.bat
 create mode 100644 engine/shell.html
 create mode 100644 reference/strudel-chiptune-guide.md
 create mode 100644 website/logs/anchor-phase-2.md
 delete mode 100644 website/logs/meta-session-1.md

warning: in the working copy of '.claude/CLAUDE.md', LF will be replaced by CRLF the next time Git touches it
warning: in the working copy of '.claude/settings.local.json', LF will be replaced by CRLF the next time Git touches it
warning: in the working copy of 'docs/ANCHOR_IMPLEMENTATION_PLAN.md', LF will be replaced by CRLF the next time Git touches it
warning: in the working copy of 'engine/src/anchor.c', LF will be replaced by CRLF the next time Git touches it
warning: in the working copy of 'website/context/ANCHOR.md', LF will be replaced by CRLF the next time Git touches it
warning: in the working copy of 'website/context/ANCHOR_IMPLEMENTATION_PLAN.md', LF will be replaced by CRLF the next time Git touches it
warning: in the working copy of 'website/context/CLAUDE.md', LF will be replaced by CRLF the next time Git touches it
warning: in the working copy of 'engine/build-web.sh', LF will be replaced by CRLF the next time Git touches it
warning: in the working copy of 'engine/build-web/anchor.data', LF will be replaced by CRLF the next time Git touches it
warning: in the working copy of 'engine/build-web/anchor.js', LF will be replaced by CRLF the next time Git touches it
warning: in the working copy of 'engine/run-web.bat', LF will be replaced by CRLF the next time Git touches it
warning: in the working copy of 'engine/shell.html', LF will be replaced by CRLF the next time Git touches it
warning: in the working copy of 'reference/strudel-chiptune-guide.md', LF will be replaced by CRLF the next time Git touches it

Committed. Now push to GitHub and then push website to Blot.

To github.com:a327ex/Anchor.git
   7e39f94..a9d2efc  main -> main

Pushed to GitHub. Now push website to Blot.

git push using:  blot master

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To https://blot.im/clients/git/end/anchor.git
   62e33c5..73692f8  73692f81a818381e7bb99258233f86910325075a -> master

All done. Let me clear the todo list and confirm completion.

Session complete. Let me confirm to the user.

The user wants me to read the Anchor Phase 1 log to understand the input discussion and how it might be affected by the web's 60fps default. Let me find and read that log.

E:\a327ex\Anchor\website\logs\anchor-phase-1.md

Let me read the Anchor Phase 1 log and look for the input discussion.

14:**Fixed Timestep & Lua Integration:**
16:- Implemented 144 Hz fixed timestep with lag accumulator (matching reference)
17:- Events processed inside fixed loop (input tied to simulation steps, not frames)
18:- Added spiral of death prevention (MAX_UPDATES cap)
37:- reference/shader-setup-explained.md, reference/anchor-loop-analysis.md, reference/fixed-timestep-details.md - documentation
62:    15→| Timestep | Fixed 60fps | Determinism matters for potential replay support |
63:    16→| Resolution | Per-game configurable | 480×270, 640×360, or custom; integer scaling |
191:**Goal:** Window opens, clears to a color, processes input, runs Lua. Works on Windows.
197:| 1.3 | Main loop — fixed 60fps timestep, input polling, clean shutdown |
216:   - Add input polling
287:  8  6026k   8 507217   0     0 632804     0   0:00:09 --:--:--  0:00:09 632804100  6026k 100  6026k   0     0  6426k     0  --:--:-- --:--:-- --:--:-- 40666k</code></pre>
528:  0     0   0     0   0     0     0     0  --:--:-- --:--:-- --:--:--     0100 283010 100 283010   0     0 887860     0  --:--:-- --:--:-- --:--:-- 892776
866:     3→Renderer: NVIDIA GeForce RTX 2060/PCIe/SSE2
890:Renderer: NVIDIA GeForce RTX 2060/PCIe/SSE2
917:- 1.3 Fixed timestep (currently using VSync, need proper accumulator)
1080:- A resizable window (960×540 = 480×270 at 2x scale)
1093:Renderer: NVIDIA GeForce RTX 2060/PCIe/SSE2
1176:- **1.3** Fixed timestep (proper 60fps accumulator instead of just VSync)
1196:> Great. I eventually want the entire game to be a single executable with no other files needed in the folder to run it. Is there anythin we should change about Anchor's setup to make that possible? The way it'll work is that we'll feed the Lua files into Anchor and it'll run the game, just like LÖVE does. And then through some magic, in the end, we'll collapse all Lua files, assets, dlls, the Anchor executable itself, into a single executable that the user can run. Is this possible?
1350:  1376→Fixed resolution per game (480×270 or 640×360), integer scaled with letterboxing. Nearest-neighbor filtering for crisp pixels.
1398:  1376→Fixed resolution per game (480×270 or 640×360), integer scaled with letterboxing. Nearest-neighbor filtering for crisp pixels.
1447:    15→| Timestep | Fixed 60fps | Determinism matters for potential replay support |
1448:    16→| Resolution | Per-game configurable | 480×270, 640×360, or custom; integer scaling |
1481:    15→| Timestep | Fixed 60fps | Determinism matters for potential replay support |
1482:    16→| Resolution | Per-game configurable | 480×270, 640×360, or custom; integer scaling |
1502:    63→**Goal:** Window opens, clears to a color, processes input, runs Lua. Works on Windows and Web.
1508:    69→  - [x] SDL2 (window, input) — currently dynamic, switching to static
1522:    83→- [ ] Fixed timestep game loop (60 FPS target)
1531:    83→- [ ] Fixed timestep game loop (60 FPS target)
1533:    85→- [ ] Basic input polling (SDL_PollEvent)
... [70 more lines]

Let me search more specifically for the discussion about the monitor speed and input timing. The grep results show some discussion but I need to find the specific argument mentioned by the user.

11-- Integrated SDL2, Lua 5.4, glad (OpenGL loading), stb headers
12-- Basic window with OpenGL 3.3 Core Profile, fullscreen toggle (F11/Alt+Enter)
13-
14-**Fixed Timestep & Lua Integration:**
15-- Analyzed reference LÖVE-based Anchor engine to understand loop structure
16:- Implemented 144 Hz fixed timestep with lag accumulator (matching reference)
17:- Events processed inside fixed loop (input tied to simulation steps, not frames)
18-- Added spiral of death prevention (MAX_UPDATES cap)
19-- External Lua file loading with command-line argument support (like LÖVE)
20-- Error handling with luaL_traceback for stack traces
21-- Error state pattern: red screen on error, window stays open
22-
23-**Shaders & Rendering:**
24-- Basic shader compilation (vertex + fragment shaders)
25-- Created reference/shader-setup-explained.md with detailed OpenGL explanation
26-- Framebuffer at native 480×270 resolution
27-- Initially implemented integer scaling, then changed to aspect-ratio scaling per user preference
--
31-**Files Modified:**
32-- engine/src/anchor.c - complete Phase 1 implementation (~500 lines)
33-- engine/build.bat - static linking build script
34-- engine/main.lua, engine/other.lua - test scripts
35-- docs/ANCHOR_IMPLEMENTATION_PLAN.md - all Phase 1 items marked complete
36:- docs/ANCHOR.md - updated resolution/rendering descriptions
37-- reference/shader-setup-explained.md, reference/anchor-loop-analysis.md, reference/fixed-timestep-details.md - documentation
38-
39----
40-
41-> Hello, Claude. Let's get started on the Anchor engine work today. Please read CLAUDE.md, ANCHOR.md, and ANCHOR_IMPLEMENTATION_PLAN.md to understand the task, then tell me what your plan is on how to do it.
42-
... [170 more lines]

Let me search more specifically for the loop discussion, which likely involved where event processing should happen - inside vs outside the fixed loop.

14-**Fixed Timestep & Lua Integration:**
15-- Analyzed reference LÖVE-based Anchor engine to understand loop structure
16-- Implemented 144 Hz fixed timestep with lag accumulator (matching reference)
17:- Events processed inside fixed loop (input tied to simulation steps, not frames)
18-- Added spiral of death prevention (MAX_UPDATES cap)
19-- External Lua file loading with command-line argument support (like LÖVE)
20-- Error handling with luaL_traceback for stack traces
21-- Error state pattern: red screen on error, window stays open
22-
23-**Shaders & Rendering:**
24-- Basic shader compilation (vertex + fragment shaders)
25-- Created reference/shader-setup-explained.md with detailed OpenGL explanation
26-- Framebuffer at native 480×270 resolution
27-- Initially implemented integer scaling, then changed to aspect-ratio scaling per user preference
28-- Simplified screen blitting: replaced destRect shader uniform with glViewport positioning
29-- Updated ANCHOR_IMPLEMENTATION_PLAN.md and ANCHOR.md to reflect completed work
30-
31-**Files Modified:**
32-- engine/src/anchor.c - complete Phase 1 implementation (~500 lines)
33-- engine/build.bat - static linking build script
34-- engine/main.lua, engine/other.lua - test scripts
35-- docs/ANCHOR_IMPLEMENTATION_PLAN.md - all Phase 1 items marked complete
36-- docs/ANCHOR.md - updated resolution/rendering descriptions
37-- reference/shader-setup-explained.md, reference/anchor-loop-analysis.md, reference/fixed-timestep-details.md - documentation
--
3025-**1.5 Windowing:**
3026-- [ ] Integer scaling with letterboxing
3027-
3028:I'll start with the **fixed timestep + delta accumulator** since it's foundational for the game loop, then move to **loading external .lua files**. Let me update anchor.c:
3029-
... [270 more lines]

Now let me find the specific discussion about the argument. Let me search for the actual user concerns about 60fps and monitor speed.

1→# Fixed Timestep Details
     2→
     3→## Point 2: Events Drain on First Step
     4→
     5→### The Setup
     6→
     7→- Display: 60 Hz (16.67ms per frame)
     8→- Fixed timestep: 144 Hz (6.94ms per step)
     9→- Result: ~2-3 fixed steps per frame
    10→
    11→### Example Timeline
    12→
    13→```
    14→Frame N begins
    15→├── dt = 16.67ms (time since last frame)
    16→├── lag = 0 + 16.67 = 16.67ms
    17→│
    18→├── Fixed Step 1 (lag = 16.67ms, >= 6.94ms ✓)
    19→│   ├── SDL_PollEvent() → processes ALL queued events
    20→│   │   └── User pressed SPACE → input_state[SPACE] = true
    21→│   ├── (Lua update would run here)
    22→│   ├── lag = 16.67 - 6.94 = 9.73ms
    23→│
    24→├── Fixed Step 2 (lag = 9.73ms, >= 6.94ms ✓)
    25→│   ├── SDL_PollEvent() → queue is EMPTY (already drained)
    26→│   │   └── No events to process
    27→│   ├── (Lua update runs with same input state)
    28→│   ├── lag = 9.73 - 6.94 = 2.79ms
    29→│
    30→├── Fixed Step 3? (lag = 2.79ms, >= 6.94ms ✗)
... [101 more lines]

Now I found the relevant discussion. The key points are:

1. The game runs at 144 Hz fixed timestep
2. Events are polled INSIDE the fixed loop (not once per frame)
3. This ensures input maps to exactly one simulation step, preventing issues like double-jumps
4. The VSync/display refresh rate affects how many fixed steps run per frame

Now for the web question: The web uses requestAnimationFrame which typically runs at 60fps (or the display's refresh rate). The question is: does this affect input handling?

Looking at the current code:

- `emscripten_set_main_loop(main_loop_iteration, 0, 1)` - the 0 means "use requestAnimationFrame timing"
- `main_loop_iteration` still has the same fixed timestep logic with events polled inside the fixed loop

So on web:

- Frame rate is likely 60fps (requestAnimationFrame)
- Each frame, the accumulator adds ~16.67ms
- The fixed loop runs 2-3 steps (144/60 ≈ 2.4)
- Events are still polled inside the fixed loop

This should work identically! The key insight from the Phase 1 discussion was that polling events inside the fixed loop ensures input maps to simulation steps correctly, regardless of frame rate.

However, there's one potential issue: On desktop with a 144Hz monitor, the frame rate matches the simulation rate (1 frame = 1 step). On web at 60Hz, we get 2-3 steps per frame. But the code already handles this correctly - events drain on the first step and the input state persists.

Let me explain this to the user.

The user is satisfied. I should just acknowledge and confirm the session is complete.