Antonis Ryakiotakis
4097f9c3c4
ATIs. This is actually a test to see if this can be enabled on ATI cards. According to various sources, newer ATI cards supporting GLSL 3.0 support gl_ClippingDistance in shaders, which is the forward compatible way to do custom clipping. This fix will bind 6 additional varying variables on ATIs, which may lead to some shaders not compiling due to limiting out of those variables, or to performance degradation. Also I do not have an ATI handy to test. Having those in mind, this commit may well be reverted later. Clipping planes are usually 4 (6 is for cube clipping), but making shaders depend on viewport state is really bad, and would lead to recompilation, so I took the worst case here to avoid that. Hopefully driver does some optimization there.
27 lines
576 B
GLSL
27 lines
576 B
GLSL
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varying vec3 varposition;
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varying vec3 varnormal;
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#ifdef CLIP_WORKAROUND
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varying float gl_ClipDistance[6];
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#endif
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void main()
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{
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vec4 co = gl_ModelViewMatrix * gl_Vertex;
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varposition = co.xyz;
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varnormal = normalize(gl_NormalMatrix * gl_Normal);
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gl_Position = gl_ProjectionMatrix * co;
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#ifdef CLIP_WORKAROUND
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int i;
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for(i = 0; i < 6; i++)
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gl_ClipDistance[i] = dot(co, gl_ClipPlane[i]);
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#else
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// Setting gl_ClipVertex is necessary to get glClipPlane working on NVIDIA
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// graphic cards, while on ATI it can cause a software fallback.
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gl_ClipVertex = co;
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#endif
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