81 lines
2.5 KiB
WebGPU Shading Language
81 lines
2.5 KiB
WebGPU Shading Language
struct Agent {
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position: vec2<f32>,
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angle: f32,
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}
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struct Settings {
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size: vec2<f32>,
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deltaTime : f32,
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time : f32,
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trailWeight : f32,
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moveRate : f32,
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turnRate : f32,
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sensorAngle : f32,
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sensorOffsetDst : f32,
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};
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@group(0) @binding(0) var<uniform> settings : Settings;
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@group(0) @binding(1) var<storage, read_write> agents : array<Agent>;
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@group(0) @binding(2) var TrailMapIn : texture_2d<f32>;
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@group(0) @binding(3) var TrailMapOut : texture_storage_2d<rgba16float, write>;
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@compute @workgroup_size(8, 8)
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fn main(@builtin(global_invocation_id) global_id : vec3<u32>) {
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let id = global_id.x;
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if (id >= arrayLength(&agents)) {
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return;
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}
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var agent = agents[id];
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let random = f32(hash(id + u32(settings.time * 10000 + agent.position.y * 10 + agent.position.x))) / 4294967295.0;
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let weightForward : f32 = sense(agent, 0.);
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let weightLeft : f32 = sense(agent, settings.sensorAngle);
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let weightRight : f32 = sense(agent, -settings.sensorAngle);
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if (weightForward < weightLeft && weightForward < weightRight) {
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agent.angle += (random - 0.5) * 2. * settings.turnRate;
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} else if (weightLeft < weightRight) {
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agent.angle -= random * settings.turnRate;
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} else if (weightRight < weightLeft) {
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agent.angle += random * settings.turnRate;
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}
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let direction = vec2(cos(agent.angle), sin(agent.angle));
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var newPos = agent.position + direction / normalize(settings.size) * settings.moveRate;
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newPos = clamp(newPos, vec2<f32>(0, 0), vec2<f32>(1, 1));
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if (newPos.x == 0. || newPos.x == 1. || newPos.y == 0. || newPos.y == 1.) {
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agent.angle += 3.14159265359 + random - 0.5;
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}
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textureStore(
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TrailMapOut,
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vec2<i32>(newPos * settings.size),
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vec4(vec3<f32>(1.) * settings.trailWeight * 0.02, 1.)
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);
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agent.position = newPos;
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agents[id] = agent;
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}
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fn hash(state0 : u32) -> u32 {
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// Hash function www.cs.ubc.ca/~rbridson/docs/schechter-sca08-turbulence.pdf
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var state : u32 = state0;
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state = state ^ 2747636419u;
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state = state * 2654435769u;
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state = state ^ (state >> 16u);
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state = state * 2654435769u;
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state = state ^ (state >> 16u);
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state = state * 2654435769u;
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return state;
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}
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fn sense(agent : Agent, sensorAngleOffset : f32) -> f32 {
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let sensorAngle : f32 = agent.angle + sensorAngleOffset;
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let sensorDir : vec2<f32> = vec2(cos(sensorAngle), sin(sensorAngle)) / normalize(settings.size);
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let sensorPos : vec2<f32> = agent.position + sensorDir * settings.sensorOffsetDst;
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return textureLoad(TrailMapIn, vec2<i32>(sensorPos * settings.size), 0).x;
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}
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