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EEVEE: Fix incorrect fresnel function. 

The optimized version was not correct. Also it is not showing any benefit
over the non optimized version.
This commit is contained in:
Clément Foucault 2021-02-13 18:49:42 +01:00
parent 7f7e683099
commit 06492fd619
Notes: blender-bot 2023-02-14 03:34:17 +01:00 
Referenced by issue #86795, EEVEE Render Glitch
1 changed files with 8 additions and 16 deletions
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24
source/blender/draw/engines/eevee/shaders/bsdf_common_lib.glsl
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@ -24,6 +24,7 @@ float ior_from_f0(float f0)
return (-f - 1.0) / (f - 1.0);
}
/* Simplified form of F_eta(eta, 1.0). */
float f0_from_ior(float eta)
{
float A = (eta - 1.0) / (eta + 1.0);
@ -56,30 +57,21 @@ float F_eta(float eta, float cos_theta)
* the refracted direction */
float c = abs(cos_theta);
float g = eta * eta - 1.0 + c * c;
float result;
if (g > 0.0) {
g = sqrt(g);
vec2 g_c = vec2(g) + vec2(c, -c);
float A = g_c.y / g_c.x;
A *= A;
g_c *= c;
float B = (g_c.y - 1.0) / (g_c.x + 1.0);
B *= B;
result = 0.5 * A * (1.0 + B);
float A = (g - c) / (g + c);
float B = (c * (g + c) - 1.0) / (c * (g - c) + 1.0);
return 0.5 * A * A * (1.0 + B * B);
}
else {
result = 1.0; /* TIR (no refracted component) */
}
return result;
/* Total internal reflections. */
return 1.0;
}
/* Fresnel color blend base on fresnel factor */
vec3 F_color_blend(float eta, float fresnel, vec3 f0_color)
{
float f0 = F_eta(eta, 1.0);
float fac = saturate((fresnel - f0) / max(1e-8, 1.0 - f0));
float f0 = f0_from_ior(eta);
float fac = saturate((fresnel - f0) / (1.0 - f0));
return mix(f0_color, vec3(1.0), fac);
}