67 lines
1.4 KiB
Text
67 lines
1.4 KiB
Text
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#version 450
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#extension GL_ARB_separate_shader_objects : enable
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#extension GL_ARB_shading_language_420pack : enable
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struct Particle
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{
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vec4 pos;
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vec4 col;
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vec4 vel;
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};
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// Binding 0 : Position storage buffer
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layout(std140, binding = 0) buffer Pos
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{
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Particle particles[ ];
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};
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layout (local_size_x = 16, local_size_y = 16) in;
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layout (binding = 1) uniform UBO
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{
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float deltaT;
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float destX;
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float destY;
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int particleCount;
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} ubo;
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vec3 attraction(vec3 pos, vec3 attractPos)
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{
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vec3 delta = attractPos - pos;
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const float damp = 0.5;
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float dDampedDot = dot(delta, delta) + damp;
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float invDist = 1.0f / sqrt(dDampedDot);
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float invDistCubed = invDist*invDist*invDist;
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return delta * invDistCubed * 0.00035;
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}
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void main()
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{
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// Current SSBO index
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uint index = gl_GlobalInvocationID.x;
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// Don't try to write beyond particle count
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if (index >= ubo.particleCount)
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return;
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// Read position and velocity
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vec3 vPos = particles[index].pos.xyz;
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vec3 vVel = particles[index].vel.xyz;
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vec3 destPos = vec3(ubo.destX, ubo.destY, 0.0);
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// Calculate new velocity depending on attraction point
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vVel += attraction(vPos, destPos.xyz);
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// Move by velocity
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vPos += vVel * ubo.deltaT;
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if ((vPos.x < -1.0) || (vPos.x > 1.0))
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vVel.x -= vVel.x;
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// Write back
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particles[index].pos.xyz = vPos;
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particles[index].vel.xyz = vVel;
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}
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