Fix: EEVEE-Next: incorrect GGX BRDF LUT coordinates

source/blender/draw/engines/eevee_next/shaders/eevee_nodetree_lib.glsl

@@ -308,7 +308,9 @@ vec3 F_brdf_multi_scatter(vec3 f0, vec3 f90, vec2 lut)
 vec2 brdf_lut(float cos_theta, float roughness)
 {
 #ifdef EEVEE_UTILITY_TX
-  return utility_tx_sample_lut(utility_tx, vec2(cos_theta, roughness), UTIL_BSDF_LAYER).rg;
+  /* Parametrizing with `sqrt(1.0 - cos(theta))` for more precision near grazing incidence. */
+  vec2 coords = vec2(roughness, sqrt(1.0 - cos_theta));
+  return utility_tx_sample_lut(utility_tx, coords, UTIL_BSDF_LAYER).rg;
 #else
   return vec2(1.0, 0.0);
 #endif