106 lines
2.4 KiB
Python
106 lines
2.4 KiB
Python
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/*
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* Copyright 2014 Stanlo Slasinski. All rights reserved.
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* License: http://www.opensource.org/licenses/BSD-2-Clause
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*/
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#include "bgfx_compute.sh"
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#include "uniforms.sh"
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BUFFER_WR(prevPositionBuffer, vec4, 0);
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BUFFER_WR(curPositionBuffer, vec4, 1);
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uint rotl(uint _x, uint _r)
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{
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return (_x << _r) | (_x >> (32u - _r) );
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}
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uint hash(uint _key, uint _seed)
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{
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uint c1 = 0xcc9e2d51u;
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uint c2 = 0x1b873593u;
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uint k1 = _key;
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uint h1 = _seed;
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k1 *= c1;
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k1 = rotl(k1, 15u);
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k1 *= c2;
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h1 ^= k1;
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h1 = rotl(h1, 13u);
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h1 = h1 * 5u + 0xe6546b64u;
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k1 *= c1;
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k1 = rotl(k1, 15u);
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k1 *= c2;
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h1 ^= k1;
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h1 ^= h1 >> uint(16u);
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h1 *= 0x85ebca6bu;
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h1 ^= h1 >> 13u;
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h1 *= 0xc2b2ae35u;
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h1 ^= h1 >> 16u;
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return h1;
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}
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vec3 randomPointOnSphere(uint _id, uint _seed)
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{
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uvec2 u = uvec2(
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hash(_id, _seed + 0u),
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hash(_id, _seed + 1u)
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);
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vec2 v = uintBitsToFloat( (u >> 9u) | 0x3f800000u) - 1.0;
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float lambda = v.x * 3.14159 * 2.0;
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float phi = acos(2.0 * v.y - 1.0) - 3.14159 / 2.0;
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vec3 p;
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p.x = cos(lambda) * cos(phi);
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p.y = sin(phi);
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p.z = sin(lambda) * cos(phi);
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return p;
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}
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NUM_THREADS(512, 1, 1)
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void main()
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{
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uint key = gl_GlobalInvocationID.x;
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vec3 position;
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if (u_initialShape == 0u)
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{
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position = vec3_splat(0.0);
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}
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else if (u_initialShape == 1u)
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{
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position = 20.0 * randomPointOnSphere(gl_GlobalInvocationID.x, u_baseSeed * 7u);
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}
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else if (u_initialShape == 2u)
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{
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uvec3 u = uvec3(
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hash(gl_GlobalInvocationID.x, u_baseSeed * 7u + 0u),
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hash(gl_GlobalInvocationID.x, u_baseSeed * 7u + 1u),
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hash(gl_GlobalInvocationID.x, u_baseSeed * 7u + 2u)
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);
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position = 20.0 * (uintBitsToFloat((u >> 9u) | uvec3(0x40000000, 0x40000000, 0x40000000) ) - 3.0);
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}
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else
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{
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uvec3 u = uvec3(
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hash(gl_GlobalInvocationID.x, u_baseSeed * 7u + 0u),
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hash(gl_GlobalInvocationID.x, u_baseSeed * 7u + 1u),
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hash(gl_GlobalInvocationID.x, u_baseSeed * 7u + 2u)
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);
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vec3 v = 3.14159 * 2.0 * (uintBitsToFloat( (u >> 9u) | uvec3(0x3f800000u, 0x3f800000u, 0x3f800000u) ) - 1.0);
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position.x = 20.0 * cos(v.x) + 3.0 * cos(v.y) * cos(v.x);
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position.y = 3.0 * sin(v.y);
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position.z = 20.0 * sin(v.x) + 3.0 * cos(v.y) * sin(v.x);
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}
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vec3 velocity = u_initialSpeed * randomPointOnSphere(gl_GlobalInvocationID.x, u_baseSeed * 7u + 3u);
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prevPositionBuffer[gl_GlobalInvocationID.x] = vec4(position - velocity * u_timeStep, 0.0);
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curPositionBuffer[ gl_GlobalInvocationID.x] = vec4(position, 0.0);
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}
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