30 lines
727 B
GLSL
30 lines
727 B
GLSL
!!FP1.0
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# Eclipse shadow shader--this shader computes a black circle centered
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# at texcoord (0.5, 0.5) and multiplies this by texture zero and the
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# diffuse color.
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# Parameters:
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# p[5] - ambient light color
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# p[20] - shadow umbra/penumbra parameters (x = scale, y = bias)
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# Compute the square of the distance from the center of the shadow
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SUB R0, f[TEX1], { 0.5, 0.5, 0, 0 };
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DP3 R1.w, R0, R0;
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# Scale and bias the squared distance to get the right shadow umbra
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# and penumbra sizes.
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MAD_SAT R0.xyz, R1.w, p[20].x, p[20].y;
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# Multiply by the diffuse term and add ambient light
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MADX_SAT R0.xyz, R0, f[COL0], p[5];
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# Mix in the texture color
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TEX R1, f[TEX0], TEX0, 2D;
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MULX R0, R0, R1;
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# Output it
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MOVX o[COLR], R0;
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END
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