shaders = ({ agent: ` const PI: f32 = 3.141592653589793; const TWO_PI: f32 = 6.283185307179586; struct Uniforms { time: f32, sensor_angle: f32, sensor_distance: f32, rotation_angle: f32, step_distance: f32, decay_rate: f32, deposit_amount: f32, blur_strength: f32, } struct Agent { pos: vec2f, heading: f32, _pad: f32, species_mask: vec4f, } @group(0) @binding(0) var uniforms: Uniforms; @group(0) @binding(1) var agentsIn: array; @group(0) @binding(2) var agentsOut: array; @group(0) @binding(3) var trailCounts: array>; @group(0) @binding(4) var trails_in: texture_2d; @group(0) @binding(6) var interaction_texture: texture_2d; fn grid_index_from_agent_pos(pos: vec2u) -> u32 { return (pos.x % ${S}) + (pos.y % ${S}) * ${S}; } // On generating random numbers, with help of y= [(a+x)sin(bx)] mod 1", W.J.J. Rey, // 22nd European Meeting of Statisticians 1998 fn rand11(n: f32) -> f32 { return fract(sin(n) * 43758.5453123); } fn rand22(n: vec2f) -> f32 { return fract(sin(dot(n, vec2f(12.9898, 4.1414))) * 43758.5453); } fn hash11(_p: f32) -> f32 { var p = fract(_p * .1031); p *= p + 33.33; p *= p + p; return fract(p); } fn hash12(p: vec2f) -> f32 { var p3 = fract(vec3f(p.xyx) * .1031); p3 += dot(p3, p3.yzx + 33.33); return fract((p3.x + p3.y) * p3.z); } fn hash13(_p3: vec3f) -> f32 { var p3 = fract(_p3 * .1031); p3 += dot(p3, p3.zyx + 31.32); return fract((p3.x + p3.y) * p3.z); } fn shft(x: f32, size: f32) -> f32 { return x + select(0.0, size, x < 0) + select(0.0, -size, x >= size); } fn next_agent_state(agent: Agent, texSize: vec2u) -> Agent { let p = agent.pos; let a = agent.heading; let sa = uniforms.sensor_angle; let sd = uniforms.sensor_distance; let ra = uniforms.rotation_angle; let step_dist = uniforms.step_distance; let xc = p.x + cos(a) * sd; let yc = p.y + sin(a) * sd; let xl = p.x + cos(a - sa) * sd; let yl = p.y + sin(a - sa) * sd; let xr = p.x + cos(a + sa) * sd; let yr = p.y + sin(a + sa) * sd; // good enough var C = textureLoad(trails_in, vec2u(u32(xc % ${S}), u32(yc % ${S})), 0).r; var L = textureLoad(trails_in, vec2u(u32(xl % ${S}), u32(yl % ${S})), 0).r; var R = textureLoad(trails_in, vec2u(u32(xr % ${S}), u32(yr % ${S})), 0).r; C += textureLoad(interaction_texture, vec2u(u32(xc % ${S}), u32(yc % ${S})), 0).r; L += textureLoad(interaction_texture, vec2u(u32(xl % ${S}), u32(yl % ${S})), 0).r; R += textureLoad(interaction_texture, vec2u(u32(xr % ${S}), u32(yr % ${S})), 0).r; // note // behaviors 1 & 4 actually look cooler when p was incorrectly passed to the rand fn as an int with no fract() var d = 0.0; if (C > L && C > R) { d = 0.0; } else if (C < L && C < R) { d = select(-1.0, 1.0, hash13(vec3f(p.x / ${S}, p.y / ${S}, uniforms.time)) > 0.5); } else if (L < R) { d = 1.0; } else if (R < L) { d = -1.0; } var rnd = hash13(vec3f(p.x / ${S}, p.y / ${S}, uniforms.time)) * (0.01 * TWO_PI) * select(-1.0, 1.0, hash11(uniforms.time) > 0.5); let da = ra * d; var next_angle = shft(a + da + rnd, TWO_PI); var next_pos = vec2f( p.x + cos(next_angle) * step_dist, p.y + sin(next_angle) * step_dist, ); // TODO optimize if (next_pos.x < 0.0) { next_pos.x = 0.0; next_angle += PI; } else if (next_pos.y < 0.0) { next_pos.y = 0.0; next_angle += PI; } else if (next_pos.x >= f32(texSize.x)) { next_pos.x = f32(texSize.x - 1); next_angle += PI; } else if (next_pos.y >= f32(texSize.y)) { next_pos.y = f32(texSize.y - 1); next_angle += PI; } return Agent(next_pos, next_angle % TWO_PI, 0, vec4f(0)); } @compute @workgroup_size(64, 1, 1) fn cs( @builtin(global_invocation_id) gid: vec3u, @builtin(local_invocation_id) lid: vec3u, ) { let agent_index = gid.x; if (agent_index > arrayLength(&agentsIn)) { return; } let agent = agentsIn[agent_index]; let texSize = textureDimensions(trails_in); let next_agent = next_agent_state(agent, texSize); agentsOut[agent_index].pos = next_agent.pos; agentsOut[agent_index].heading = next_agent.heading; // add to trail counts let trail_index = grid_index_from_agent_pos(vec2u(u32(next_agent.pos.x), u32(next_agent.pos.y))); atomicAdd(&trailCounts[trail_index], 1); } `, trailCombine: ` struct Uniforms { time: f32, sensor_angle: f32, sensor_distance: f32, rotation_angle: f32, step_distance: f32, decay_rate: f32, deposit_amount: f32, blur_strength: f32, } @group(0) @binding(0) var uniforms: Uniforms; @group(0) @binding(3) var trailCounts: array>; @group(0) @binding(4) var inputTexture: texture_2d; @group(0) @binding(5) var outputTexture: texture_storage_2d; @group(0) @binding(6) var externalTexture: texture_2d; const tileSize: vec2u = vec2u(16, 16); const blurRadius: i32 = 1; const count: f32 = pow(f32(blurRadius) * 2 + 1, 2); @compute @workgroup_size(16, 16, 1) fn cs(@builtin(global_invocation_id) global_id: vec3u) { let texSize: vec2u = textureDimensions(inputTexture).xy; let tileNW: vec2u = (global_id.xy / tileSize) * tileSize; let localPos: vec2u = global_id.xy % tileSize; let texPos: vec2u = tileNW + localPos; let index = texPos.x + texPos.y * texSize.x; if (texPos.x < texSize.x && texPos.y < texSize.y) { var colorSum: vec4f = vec4f(0.0, 0.0, 0.0, 0.0); let externalColor = textureLoad(externalTexture, texPos, 0); if (externalColor.a > 0.0) { colorSum = vec4f(0.5); } for (var y = -blurRadius; y <= blurRadius; y++) { for (var x = -blurRadius; x <= blurRadius; x++) { let samplePos = vec2i(texPos) + vec2i(x, y); if ( samplePos.x >= 0 && samplePos.x < i32(texSize.x) && samplePos.y >= 0 && samplePos.y < i32(texSize.y) ) { colorSum = colorSum + textureLoad(inputTexture, samplePos, 0); } } } let blurred: vec4f = colorSum / count; let count = f32(atomicLoad(&trailCounts[index])) * uniforms.deposit_amount; var color = blurred - vec4f(uniforms.decay_rate) + count; color = clamp(color, vec4f(0), vec4f(1)); textureStore(outputTexture, texPos, color); } // reset atomicStore(&trailCounts[index], 0); } ` })