81 lines
3.3 KiB
GLSL
81 lines
3.3 KiB
GLSL
uniform int dt;
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uniform mat4 previous_frame_sourcematrix;
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uniform mat4 sourcematrix;
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uniform int level;
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uniform float size_increase_factor;
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#if __VERSION__ >= 330
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layout (location = 4) in vec3 particle_position_initial;
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layout (location = 5) in float lifetime_initial;
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layout (location = 6) in vec3 particle_velocity_initial;
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layout (location = 7) in float size_initial;
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layout (location = 0) in vec3 particle_position;
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layout (location = 1) in float lifetime;
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layout (location = 2) in vec3 particle_velocity;
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layout (location = 3) in float size;
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#else
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in vec3 particle_position_initial;
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in float lifetime_initial;
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in vec3 particle_velocity_initial;
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in float size_initial;
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in vec3 particle_position;
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in float lifetime;
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in vec3 particle_velocity;
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in float size;
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#endif
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out vec3 new_particle_position;
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out float new_lifetime;
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out vec3 new_particle_velocity;
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out float new_size;
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void main(void)
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{
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float updated_lifetime = lifetime + (float(dt)/lifetime_initial);
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if (updated_lifetime > 1.)
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{
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if (gl_VertexID < level)
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{
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float dt_from_last_frame = fract(updated_lifetime) * lifetime_initial;
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float coeff = dt_from_last_frame / dt;
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vec4 previous_frame_position = previous_frame_sourcematrix * vec4(particle_position_initial, 1.0);
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vec4 current_frame_position = sourcematrix * vec4(particle_position_initial, 1.0);
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vec4 updated_initialposition = mix(current_frame_position,
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previous_frame_position,
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coeff);
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vec4 updated_initial_velocity = mix(sourcematrix * vec4(particle_velocity_initial, 0.0),
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previous_frame_sourcematrix * vec4(particle_velocity_initial, 0.0),
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coeff);
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//+ (current_frame_position - previous_frame_position) / dt;
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//To be accurate, emitter speed should be added.
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//But the simple formula ( (current_frame_position - previous_frame_position) / dt ) with a constant speed
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//between 2 frames creates visual artifacts when the framerate is low, and a more accurate formula would need
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//more complex computations.
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new_particle_position = updated_initialposition.xyz + dt_from_last_frame * updated_initial_velocity.xyz;
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new_particle_velocity = updated_initial_velocity.xyz;
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new_lifetime = fract(updated_lifetime);
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new_size = mix(size_initial, size_initial * size_increase_factor, fract(updated_lifetime));
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}
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else
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{
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new_lifetime = fract(updated_lifetime);
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new_size = 0;
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}
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}
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else
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{
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new_particle_position = particle_position + particle_velocity.xyz * float(dt);
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new_particle_velocity = particle_velocity;
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new_lifetime = updated_lifetime;
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new_size = (size == 0) ? 0. : mix(size_initial, size_initial * size_increase_factor, updated_lifetime);
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}
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gl_Position = vec4(0.);
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}
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