42 lines
1.2 KiB
C++
42 lines
1.2 KiB
C++
#define STRINGIFY(A) #A
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// vertex shader
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const char *vertexShader = STRINGIFY(
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uniform float pointRadius; // point size in world space
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uniform float pointScale; // scale to calculate size in pixels
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uniform float densityScale;
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uniform float densityOffset;
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void main()
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{
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// calculate window-space point size
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vec3 posEye = vec3(gl_ModelViewMatrix * vec4(gl_Vertex.xyz, 1.0));
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float dist = length(posEye);
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gl_PointSize = pointRadius * (pointScale / dist);
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gl_TexCoord[0] = gl_MultiTexCoord0;
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gl_Position = gl_ModelViewProjectionMatrix * vec4(gl_Vertex.xyz, 1.0);
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gl_FrontColor = gl_Color;
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}
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);
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// pixel shader for rendering points as shaded spheres
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const char *spherePixelShader = STRINGIFY(
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void main()
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{
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const vec3 lightDir = vec3(0.577, 0.577, 0.577);
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// calculate normal from texture coordinates
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vec3 N;
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N.xy = gl_TexCoord[0].xy*vec2(2.0, -2.0) + vec2(-1.0, 1.0);
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float mag = dot(N.xy, N.xy);
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if (mag > 1.0) discard; // kill pixels outside circle
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N.z = sqrt(1.0-mag);
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// calculate lighting
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float diffuse = max(0.0, dot(lightDir, N));
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gl_FragColor = gl_Color * diffuse;
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}
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);
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