50 lines
1.9 KiB
GLSL
50 lines
1.9 KiB
GLSL
uniform int dt;
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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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uniform float track_x;
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uniform float track_z;
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uniform float track_x_len;
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uniform float track_z_len;
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uniform samplerBuffer heightmap;
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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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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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bool reset = false;
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float i_as_float = clamp(256. * (particle_position.x - track_x) / track_x_len, 0., 255.);
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float j_as_float = clamp(256. * (particle_position.z - track_z) / track_z_len, 0., 255.);
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int i = int(i_as_float);
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int j = int(j_as_float);
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float h = particle_position.y - texelFetch(heightmap, i * 256 + j).r;
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reset = h < 0.;
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vec4 initialposition = sourcematrix * vec4(particle_position_initial, 1.0);
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vec4 adjusted_initial_velocity = sourcematrix * vec4(particle_position_initial + particle_velocity_initial, 1.0) - initialposition;
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float adjusted_lifetime = lifetime + (float(dt)/lifetime_initial);
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reset = reset || (adjusted_lifetime > 1.) && (gl_VertexID <= level);
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reset = reset || (lifetime < 0.);
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new_particle_position = !reset ? particle_position + particle_velocity.xyz * float(dt) : initialposition.xyz;
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new_lifetime = !reset ? adjusted_lifetime : 0.;
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new_particle_velocity = !reset ? particle_velocity : adjusted_initial_velocity.xyz;
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new_size = !reset ? mix(size_initial, size_initial * size_increase_factor, adjusted_lifetime) : size_initial;
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gl_Position = vec4(0.);
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}
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