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#ifndef __RAS_PREWITT2DFILTER
#define __RAS_PREWITT2DFILTER
char * PrewittFragmentShader=STRINGIFY(
uniform sampler2D bgl_RenderedTexture;
uniform vec2 bgl_TextureCoordinateOffset[9];
void main(void)
{
vec4 sample[9];
for (int i = 0; i < 9; i++)
{
sample[i] = texture2D(bgl_RenderedTexture,
gl_TexCoord[0].st + bgl_TextureCoordinateOffset[i]);
}
vec4 horizEdge = sample[2] + sample[5] + sample[8] -
(sample[0] + sample[3] + sample[6]);
vec4 vertEdge = sample[0] + sample[1] + sample[2] -
(sample[6] + sample[7] + sample[8]);
gl_FragColor.rgb = sqrt((horizEdge.rgb * horizEdge.rgb) +
(vertEdge.rgb * vertEdge.rgb));
gl_FragColor.a = 1.0;
}
);
#endif
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