90 lines
2.4 KiB
WebGPU Shading Language
90 lines
2.4 KiB
WebGPU Shading Language
struct Particle {
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pos : vec2<f32>,
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vel : vec2<f32>,
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};
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struct SimParams {
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deltaT : f32,
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rule1Distance : f32,
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rule2Distance : f32,
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rule3Distance : f32,
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rule1Scale : f32,
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rule2Scale : f32,
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rule3Scale : f32,
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};
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struct Particles {
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particles : array<Particle>,
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};
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@binding(0) @group(0) var<uniform> params : SimParams;
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@binding(1) @group(0) var<storage, read> particlesA : Particles;
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@binding(2) @group(0) var<storage, read_write> particlesB : Particles;
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// https://github.com/austinEng/Project6-Vulkan-Flocking/blob/master/data/shaders/computeparticles/particle.comp
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@compute @workgroup_size(64)
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fn main(@builtin(global_invocation_id) GlobalInvocationID : vec3<u32>) {
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var index : u32 = GlobalInvocationID.x;
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if (index >= arrayLength(&particlesA.particles)) {
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return;
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}
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var vPos = particlesA.particles[index].pos;
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var vVel = particlesA.particles[index].vel;
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var cMass = vec2<f32>(0.0, 0.0);
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var cVel = vec2<f32>(0.0, 0.0);
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var colVel = vec2<f32>(0.0, 0.0);
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var cMassCount : u32 = 0u;
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var cVelCount : u32 = 0u;
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var pos : vec2<f32>;
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var vel : vec2<f32>;
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for (var i : u32 = 0u; i < arrayLength(&particlesA.particles); i = i + 1u) {
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if (i == index) {
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continue;
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}
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pos = particlesA.particles[i].pos.xy;
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vel = particlesA.particles[i].vel.xy;
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if (distance(pos, vPos) < params.rule1Distance) {
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cMass = cMass + pos;
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cMassCount = cMassCount + 1u;
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}
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if (distance(pos, vPos) < params.rule2Distance) {
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colVel = colVel - (pos - vPos);
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}
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if (distance(pos, vPos) < params.rule3Distance) {
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cVel = cVel + vel;
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cVelCount = cVelCount + 1u;
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}
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}
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if (cMassCount > 0u) {
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var temp = f32(cMassCount);
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cMass = (cMass / vec2<f32>(temp, temp)) - vPos;
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}
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if (cVelCount > 0u) {
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var temp = f32(cVelCount);
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cVel = cVel / vec2<f32>(temp, temp);
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}
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vVel = vVel + (cMass * params.rule1Scale) + (colVel * params.rule2Scale) +
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(cVel * params.rule3Scale);
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// clamp velocity for a more pleasing simulation
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vVel = normalize(vVel) * clamp(length(vVel), 0.0, 0.1);
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// kinematic update
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vPos = vPos + (vVel * params.deltaT);
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// Wrap around boundary
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if (vPos.x < -1.0) {
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vPos.x = 1.0;
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}
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if (vPos.x > 1.0) {
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vPos.x = -1.0;
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}
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if (vPos.y < -1.0) {
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vPos.y = 1.0;
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}
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if (vPos.y > 1.0) {
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vPos.y = -1.0;
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}
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// Write back
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particlesB.particles[index].pos = vPos;
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particlesB.particles[index].vel = vVel;
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}
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