EBB Combat Juice Part 2 (Plants)

Opus 4.5

Summary

Comprehensive implementation of the decorative plant system (1.16 from IMPLEMENTATION_PLAN.md), including physics-based sway reactions, death probability mechanics, and visual death effects.

Plant System Foundation:

Plant class with velocity/acceleration-based sway physics (not spring-based) using math.damping for framerate-independent decay
Two force types matching super emoji box reference:
- Moving force: gentle (accel=80, max_v=4), triggered by ball/weapon passing through plant's ghost collider
- Direct force: snappy (accel=200, max_v=6), triggered by ball hitting ground near plants
Ghost colliders (sensors) with {sensor: true, offset_y: -@h/2} for detecting pass-through
get_rotation! method to capture current sway state including ambient sine-wave motion

Plant Spawning System:

8 predefined plant group templates copied from super emoji box reference
Each group has validated plant sizes/offsets tested one by one (seedling, sheaf, tulip, blossom, four_leaf_clover)
Groups track horizontal extents for overlap prevention
Spawns 2-3 groups per arena with gap-filling algorithm
Front/back layer separation for visual depth (ball appears "between" plants)

Force Application Mechanics:

Direct force: plants push AWAY from impact point (direction = -math.sign(dx)), closer plants get more force (75) vs farther (25)
Added vy parameter to scale force based on incoming ball's vertical velocity
Weapon velocity calculated from angular velocity: weapon_vx = -av * offset * sin(angle)
Sensor events fire both directions - identify ball vs plant by checking weapon_visual_offset property

Death Probability System:

@force_count tracks total forces applied to each plant
@force_threshold = 5 forces needed before death becomes possible
Strong forces (intensity > 150) trigger death probability check: math.remap(@force_count, threshold, threshold+10, 0, 100)
@dying flag prevents multiple dying plants from same plant

Dying Plant Visual Effect:

Captures exact plant state at death (position, rotation, scale, image, layer)
Spawns at visual center (@y - @h/2) to rotate around center not base
Physics: initial velocity based on force direction + upward bump, linear damping (0.92), accumulating gravity
Rotation velocity based on intensity and direction, also damped
Blinking effect using timer\during_step with accelerating frequency before final death

Critical Bug Fixes:

@dead = true vs @\kill!: direct assignment doesn't propagate to children, so colliders/timers weren't being cleaned up. Changed ALL instances to use @\kill!
Floor hit detection: was checking normal_y < -0.5 (ceiling), fixed to normal_y > 0.5 (floor in screen coordinates)
during_step parameter order: 5th param is step_method, need nil before after callback
Dying plants initially added to @plants container causing iteration errors - moved to @effects

Framework Additions:

math.damping(p, t, dt, v) function added to anchor/math.yue for framerate-independent decay
Physics sensor registration: an\physics_sensor 'weapon_hitbox', 'plant_ghost'

Debug Keys Added:

F/G: direct force right/left
D/A: moving force right/left
K: kill random plant (for testing death effect)