22 lines
471 B
C
22 lines
471 B
C
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float fresnel_dielectric(vector Incoming, normal Normal, float eta)
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{
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/* compute fresnel reflectance without explicitly computing
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the refracted direction */
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float c = fabs(dot(Incoming, Normal));
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float g = eta * eta - 1 + c * c;
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float result;
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if(g > 0) {
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g = sqrt(g);
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float A =(g - c)/(g + c);
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float B =(c *(g + c)- 1)/(c *(g - c)+ 1);
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result = 0.5 * A * A *(1 + B * B);
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}
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else
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result = 1.0; /* TIR (no refracted component) */
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return result;
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}
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