71 lines
2.5 KiB
Plaintext
71 lines
2.5 KiB
Plaintext
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#version 430 core
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//Uniform block containing positions and masses of the attractors
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layout (std140, binding = 0) uniform attractor_block
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{
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vec4 attractor[8]; //xyz = position, w = strength
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};
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//Process particles in blocks of 128
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layout (local_size_x = 1024) in;
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//buffers containing the positions and velocities of the particles
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layout (rgba32f, binding = 0) uniform imageBuffer velocity_buffer;
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layout (rgba32f, binding = 1) uniform imageBuffer start_position_buffer;
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layout (rgba32f, binding = 2) uniform imageBuffer end_position_buffer;
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//Delta time
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uniform float dt;
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uniform vec3 nearTopLeft;
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uniform vec3 nearBottomRight;
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uniform vec3 farTopLeft;
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uniform vec3 farBottomRight;
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bool insideFrustrum(vec4 point) {
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//float zRelative = ((point.z - nearBottomRight.z) / (nearBottomRight.z - farBottomRight.z));
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//bool moreLeft = (point.x >= (nearTopLeft.x + (nearTopLeft.x - farTopLeft.x) * zRelative)); // left plane
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//bool lessRight = (point.x <= (nearBottomRight.x + (nearBottomRight.x - farBottomRight.x) * zRelative)); // left plane
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//bool moreBottom = (point.y >= (nearBottomRight.y + (nearBottomRight.y - farBottomRight.y) * zRelative)); //top plane
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//bool lessTop = (point.y <= (nearTopLeft.y + (nearTopLeft.y - farTopLeft.y) * zRelative)); //bottom plane
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//return ( (zRelative >= -1.0f) && moreLeft && lessRight && lessTop && moreBottom);
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return ((point.x < farBottomRight.x) && (point.x > farTopLeft.x) && (point.y < farTopLeft.y) && (point.y > farBottomRight.y) && (point.z > -1.0));
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}
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vec4 scaleToZZero(vec4 v){
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vec4 newV = v / (1 + v.z);
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return newV;
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}
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void main(void)
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{
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//read the current position and velocity from the buffers
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vec4 vel = imageLoad(velocity_buffer, int(gl_GlobalInvocationID.x));
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vec4 pos = imageLoad(start_position_buffer, int(gl_GlobalInvocationID.x));
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int i;
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bool inFrustrum = true;
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float dt2 = dt * dt;
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while( inFrustrum && pos.z < 0.0f){
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//update position using current velocity * time
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pos.xyz += vel.xyz * dt;
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//for each attractor... BOTTLENECK
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for(i = 0; i < 8; i++)
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{
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if(attractor[i].w > 0){
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//calculate force and update velocity accordingly
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vec3 dir = (attractor[i].xyz - pos.xyz);
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float dist = dot(dir, dir);
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vel.xyz += (dt2 * attractor[i].w * cross(dir, vel.xyz) / (pow(dist, 2)));
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}
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}
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inFrustrum = insideFrustrum(pos);
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}
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pos = scaleToZZero(pos);
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//store the new position back into the buffers
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imageStore(end_position_buffer, int(gl_GlobalInvocationID.x), pos);
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}
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