89 lines
2.3 KiB
GLSL
89 lines
2.3 KiB
GLSL
#version 460
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#define FLOAT_MAX 4294967296.0f
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#define FLOAT_FACTOR 0.00000000023283064365386962890625f
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struct particle
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{
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float px, py, pz;
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float vx, vy, vz;
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float cx, cy, cz;
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float age;
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};
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layout(std430, binding = 0) buffer particles
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{
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particle p[];
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};
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layout(location = 0) uniform float dt;
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layout(location = 1) uniform vec3 resetPos;
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layout(location = 2) uniform uint maxParticles;
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layout (local_size_x = 256, local_size_y = 1, local_size_z = 1) in;
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uint hash(uvec3 seed)
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{
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uint hash;
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hash = (seed.x ^ 61u) ^ (seed.y >> 16u);
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hash *= 9u;
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hash = seed.z ^ (seed.x >> 4u);
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hash *= 0x27d4eb2du;
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hash = seed.y ^ (seed.z >> 15u);
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return hash;
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}
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uint rand(uint seed)
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{
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seed ^= (seed << 13u);
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seed ^= (seed >> 17u);
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seed ^= (seed << 5u);
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return seed;
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}
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int foreSign(uint seed)
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{
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return rand(seed) % 2 == 0 ? 1 : -1;
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}
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void main()
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{
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uint gid = gl_GlobalInvocationID.x;
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if (gid <= maxParticles)
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{
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particle part = p[gid];
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uint hash1 = hash(uvec3(uint(part.px * FLOAT_MAX), uint(part.cy * FLOAT_MAX), uint(part.vz * FLOAT_MAX)));
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uint hash2 = hash(uvec3(uint(part.vx * FLOAT_MAX), uint(part.py * FLOAT_MAX), uint(part.cz * FLOAT_MAX)));
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uint hash3 = hash(uvec3(uint(part.cx * FLOAT_MAX), uint(part.vy * FLOAT_MAX), uint(part.pz * FLOAT_MAX)));
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if (part.age < 0 || part.px > 1 || part.py > 1 || part.pz > 1 || part.px < -1 || part.py < -1 || part.pz < -1)
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{
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part.px = resetPos.x;
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part.py = resetPos.y;
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part.pz = resetPos.z;
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part.age = rand(hash(uvec3(hash1, hash2, hash3))) % (250 - 60 + 1) + 60;
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part.vx = foreSign(hash1) * float(rand(hash2)) * FLOAT_FACTOR;
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part.vy = foreSign(hash3) * float(rand(hash1)) * FLOAT_FACTOR;
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part.vz = foreSign(hash2) * float(rand(hash3)) * FLOAT_FACTOR;
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part.cx = float(rand(hash1 ^ hash2)) * FLOAT_FACTOR;
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part.cy = float(rand(hash2 ^ hash3)) * FLOAT_FACTOR;
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part.cz = float(rand(hash3 ^ hash1)) * FLOAT_FACTOR;
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}
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else
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{
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part.px += part.vx * dt;
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part.py += part.vy * dt;
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part.pz += part.vz * dt;
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part.age -= 0.01f;
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}
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p[gid] = part;
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}
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}
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