44 lines
1.0 KiB
GLSL
44 lines
1.0 KiB
GLSL
uniform float inversePeriod;
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uniform vec4 particleColour;
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uniform float particleSize;
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uniform float osg_FrameTime;
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uniform float osg_DeltaFrameTime;
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varying vec4 colour;
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varying vec2 texCoord;
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void main(void)
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{
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float offset = gl_Vertex.z;
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float startTime = gl_MultiTexCoord1.x;
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texCoord = gl_MultiTexCoord0.xy;
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vec4 v_previous = gl_Vertex;
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v_previous.z = fract( (osg_FrameTime - startTime)*inversePeriod - offset);
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vec4 v_current = v_previous;
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v_current.z += (osg_DeltaFrameTime*inversePeriod);
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colour = particleColour;
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vec4 v1 = gl_ModelViewMatrix * v_current;
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vec4 v2 = gl_TextureMatrix[0] * v_previous;
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vec3 dv = v2.xyz - v1.xyz;
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vec2 dv_normalized = normalize(dv.xy);
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dv.xy += dv_normalized * particleSize;
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vec2 dp = vec2( -dv_normalized.y, dv_normalized.x ) * particleSize;
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float area = length(dv.xy);
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colour.a = 0.05+(particleSize)/area;
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v1.xyz += dv*texCoord.y;
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v1.xy += dp*texCoord.x;
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gl_Position = gl_ProjectionMatrix * v1;
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}
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