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#type compute
#version 430 core
layout(local_size_x = 256) in;
struct Particle
{
vec4 position; // xyz = position, w = lifetime
vec4 velocity; // xyz = velocity, w = mass
vec4 color; // rgba = color
};
layout(std430, binding = 0) buffer ParticleBuffer
{
Particle particles[];
} particleBuffer;
uniform float u_DeltaTime;
uniform vec3 u_Gravity;
uniform vec3 u_EmitterPosition;
uniform float u_EmissionRate;
uniform float u_ParticleLifetime;
uniform float u_Time;
void main()
{
uint index = gl_GlobalInvocationID.x;
if (index >= particles.length())
return;
Particle particle = particleBuffer.particles[index];
particle.position.w -= u_DeltaTime;
if (particle.position.w <= 0.0)
{
particle.position.xyz = u_EmitterPosition;
particle.position.w = u_ParticleLifetime;
float angle = fract(sin(dot(vec2(index, u_Time), vec2(12.9898, 78.233))) * 43758.5453) * 2.0 * 3.14159;
float speed = 2.0 + fract(sin(dot(vec2(index + 1, u_Time), vec2(12.9898, 78.233))) * 43758.5453) * 3.0;
particle.velocity.xyz = vec3(cos(angle) * speed, 5.0, sin(angle) * speed);
particle.velocity.w = 1.0;
particle.color = vec4(1.0, 0.5 + 0.5 * fract(sin(index * 123.456) * 43758.5453), 0.2, 1.0);
}
else
{
particle.velocity.xyz += u_Gravity * u_DeltaTime;
particle.position.xyz += particle.velocity.xyz * u_DeltaTime;
float lifeRatio = particle.position.w / u_ParticleLifetime;
particle.color.a = lifeRatio;
}
particleBuffer.particles[index] = particle;
}
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