Martin Slachta
73 lines
1.8 KiB
Plaintext
73 lines
1.8 KiB
Plaintext
#version 450
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struct Particle {
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vec4 position;
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vec4 velocity;
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vec4 gradient_pos;
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};
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layout(std140, binding = 0) buffer ParticleBuffer {
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Particle particles[];
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};
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layout (local_size_x = 256) in;
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vec2 attraction(vec2 pos, vec2 attractPos)
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{
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vec2 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 * 0.0035;
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}
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vec2 repulsion(vec2 pos, vec2 attractPos)
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{
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vec2 delta = attractPos - pos;
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float targetDistance = sqrt(dot(delta, delta));
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return delta * (1.0 / (targetDistance * targetDistance * targetDistance)) * -0.000035;
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}
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void main()
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{
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uint particle_count = 1000;
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float dest_x = 0.0f;
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float dest_y = 0.0f;
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float delta_time = 0.001;
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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 >= particle_count)
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return;
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// Read position and velocity
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vec2 vVel = particles[index].velocity.xy;
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vec2 vPos = particles[index].position.xy;
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vec2 destPos = vec2(dest_x, dest_y);
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vec2 delta = destPos - vPos;
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float targetDistance = sqrt(dot(delta, delta));
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vVel += repulsion(vPos, destPos.xy) * 0.05;
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// Move by velocity
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vPos += vVel * delta_time;
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// collide with boundary
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if ((vPos.x < -1.0) || (vPos.x > 1.0) || (vPos.y < -1.0) || (vPos.y > 1.0))
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vVel = (-vVel * 0.1) + attraction(vPos, destPos) * 12;
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else
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particles[index].position.xy = vPos;
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// Write back
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particles[index].velocity.xy = vVel;
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particles[index].gradient_pos.x += 0.02 * delta_time;
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if (particles[index].gradient_pos.x > 1.0)
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particles[index].gradient_pos.x -= 1.0;
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particles[index].position = vec4(0.0, index, index, 1.0f);
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}
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