77 lines
1.8 KiB
Plaintext
77 lines
1.8 KiB
Plaintext
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#ifdef __cplusplus
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#include <string>
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std::string shader_physics = R"("
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#version 460
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// execute 1 shader per particle. 128 executions per group
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layout (local_size_x = 128, local_size_y = 1, local_size_z = 1) in;
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// due to byte alignment, storing pos and dir as vec4 was required anyways.
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struct particle_t {
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vec4 pos;
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vec4 dir;
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};
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const int offset_size = 8192;
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const float SPEED = 1.0f;
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const float SPEED_FACTOR = 25.0f;
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const float BOUNCE_FACTOR = 0.75f;
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const float SPREAD = 4.5f;
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const float particle_lifetime = 10.0f;
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const vec2 p_min = vec2(-50, -50);
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const vec2 p_max = vec2(50, 50);
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const vec3 inital_pos = vec3(0.0f, 1.0f, 0.0f);
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const vec4 inital_dir = vec4(0.0f, 1.0f, 0.0f, 0.0f);
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const vec4 GRAVITY = vec4(0.0, -9.8, 0.0, 0.0);
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layout (std430, binding=0) buffer particle_buffer {
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particle_t particles[];
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};
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layout (std430, binding=1) buffer offset_buffer {
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vec4 offsets[offset_size];
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};
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layout(location=0) uniform float deltaSeconds;
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void resetParticle(uint i, float w) {
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particles[i].dir = inital_dir * SPEED_FACTOR + offsets[i % offset_size] * SPREAD;
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particles[i].pos = vec4(inital_pos, w);
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}
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bool checkBounds(vec2 pos) {
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return pos.x > p_min.x && pos.y > p_min.y && pos.x < p_max.x && pos.y < p_max.y;
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}
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void main() {
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uint i = gl_GlobalInvocationID.x;
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vec4 pos = particles[i].pos;
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vec4 dir = particles[i].dir;
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dir.w += deltaSeconds;
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if (dir.w > particle_lifetime) {
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resetParticle(i, pos.w);
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return;
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}
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pos += vec4(dir.xyz * SPEED * deltaSeconds, 0.0);
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dir += vec4(GRAVITY.xyz * deltaSeconds, 0.0);
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if (pos.y < 0 && checkBounds(pos.xy)) {
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dir.y = -dir.y * BOUNCE_FACTOR;
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pos.y = 0;
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}
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particles[i].dir = dir;
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particles[i].pos = pos;
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if (pos.y < -50)
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resetParticle(i, pos.w);
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}
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")";
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#endif
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