42 lines
No EOL
1.1 KiB
GLSL
42 lines
No EOL
1.1 KiB
GLSL
#version 120
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attribute vec2 in_vertex;
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attribute vec3 in_position;
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attribute vec3 in_velocity;
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uniform float age;
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uniform float size;
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uniform float maxVelocity;
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uniform float halfAge;
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uniform vec3 explCenter;
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varying float decay;
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varying vec3 velocity;
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varying vec2 vertex;
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varying float explCenterDist;
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// TODO: rotate to face the user!
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void main()
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{
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// add a bit variation to the decay compution by adding part of the initial
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// position to the age
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float ageMod = age + mod(20.0*in_position.z + 10.0*in_position.x + in_position.y, 0.5);
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//decay = min(1.0, age+5.0*length(velocity)) / halfAge;
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//decay = max(decay*decay, sqrt(decay));
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decay = ageMod / halfAge;
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// faster particles are smaller
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float scaleBySpeed = (1.0 - 0.95*length(in_velocity)/maxVelocity);
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float finalSize = size * scaleBySpeed;
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vec2 base = in_vertex;
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vec3 p = finalSize*vec3(base, 0.0);
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vec3 offset = (0.2*age + log(1.0+age*5.0)) * in_velocity + in_position;
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p += offset;
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gl_Position = vec4(p, 1.0);
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vertex = base.xy;
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velocity = in_velocity;
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explCenterDist = length(explCenter-offset);
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} |