129 lines
4.0 KiB
GLSL
129 lines
4.0 KiB
GLSL
#version 430
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layout(points) in;
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layout(points) out;
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layout(max_vertices = 40) out;
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// All that we get from vertex shader
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in vec3 position_pass[];
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in vec3 velocity_pass[];
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in vec3 color_pass[];
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in float lifetime_pass[];
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in float size_pass[];
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in float type_pass[];
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// All that we send further
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out vec3 position_out;
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out vec3 velocity_out;
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out vec3 color_out;
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out float lifetime_out;
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out float size_out;
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out float type_out;
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uniform vec3 spawn_position; // Position where new particles are spawned
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uniform vec3 spawn_gravity; // Gravity vector for particles - updates velocity of particles
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uniform vec3 spawn_velocity_min; // Velocity of new particle - from min to (min+range)
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uniform vec3 spawn_velocity_range;
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uniform vec3 spawn_color;
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uniform float spawn_size;
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uniform float spawn_lifetime_min, spawn_lifetime_range; // Life of new particle - from min to (min+range)
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uniform float delta; // Time passed since last frame
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uniform vec3 random_seed; // Seed number for our random number function
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vec3 local_seed;
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uniform int number_to_generate; // How many particles will be generated next time, if greater than zero, particles are generated
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float random_zero_to_one() {
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uint n = floatBitsToUint(local_seed.y * 214013.0 + local_seed.x * 2531011.0 + local_seed.z * 141251.0);
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n = n * (n * n * 15731u + 789221u);
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n = (n >> 9u) | 0x3F800000u;
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float fRes = 2.0 - uintBitsToFloat(n);
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local_seed = vec3(local_seed.x + 147158.0 * fRes, local_seed.y*fRes + 415161.0 * fRes, local_seed.z + 324154.0*fRes);
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return fRes;
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}
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void main() {
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local_seed = random_seed;
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// gl_Position doesn't matter now, as rendering is discarded
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position_out = position_pass[0];
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velocity_out = velocity_pass[0];
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if(type_pass[0] != 0.0) position_out += velocity_out * delta;
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if(type_pass[0] != 0.0) velocity_out += spawn_gravity * delta;
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color_out = color_pass[0];
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lifetime_out = lifetime_pass[0] - delta;
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size_out = size_pass[0];
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type_out = type_pass[0];
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if(type_out == 0.0) {
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// This is the emitter particle
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EmitVertex();
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EndPrimitive();
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for(int i = 0; i < number_to_generate; i++)
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{
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position_out = spawn_position;
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velocity_out = spawn_velocity_min + vec3(
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spawn_velocity_range.x * random_zero_to_one(),
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spawn_velocity_range.y * random_zero_to_one(),
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spawn_velocity_range.z * random_zero_to_one()
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);
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color_out = spawn_color;
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lifetime_out = spawn_lifetime_min + spawn_lifetime_range * random_zero_to_one();
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size_out = spawn_size;
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type_out = 1.0;
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EmitVertex();
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EndPrimitive();
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}
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} else if (lifetime_out > 0.0) {
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// This is a normal particle which is still alive
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EmitVertex();
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EndPrimitive();
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} else if (type_out == 1.0) {
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// The lifetime is over -- transform this particle in a new one or discard
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for(int i = 0; i < 15; i++) {
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// Keep the position
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velocity_out = (spawn_velocity_min + vec3(
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spawn_velocity_range.x * random_zero_to_one(),
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spawn_velocity_range.y * random_zero_to_one(),
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spawn_velocity_range.z * random_zero_to_one()
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)) * 0.75;
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color_out = vec3(1.0, 0, 0);
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lifetime_out = spawn_lifetime_min + spawn_lifetime_range * random_zero_to_one();
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size_out = spawn_size * 2.0;
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type_out = 2.0;
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EmitVertex();
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EndPrimitive();
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}
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} else if (type_out == 2.0) {
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// The lifetime is over -- transform this particle in a new one or discard
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for(int i = 0; i < 10; i++) {
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// Keep the position
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velocity_out = (spawn_velocity_min + vec3(
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spawn_velocity_range.x * random_zero_to_one(),
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spawn_velocity_range.y * random_zero_to_one(),
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spawn_velocity_range.z * random_zero_to_one()
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)) * 0.5;
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color_out = vec3(0.0, 1.0, 0);
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lifetime_out = (spawn_lifetime_min + spawn_lifetime_range * random_zero_to_one()) * 0.3;
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size_out = spawn_size * 0.75;
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type_out = 3.0;
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EmitVertex();
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EndPrimitive();
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}
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}
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} |