3535670ff1
Global scope arrays can incur suboptimal per-shader-thread memory allocations, resulting in excessive usage of limited local memory resources. These changes ensure that any arrays are limited to the closest scope in which they are required and thus will get correctly optimized by the compiler. A number of constants have also been replaced with Macro's as these can result in better runtime performance for complex shader code. Authored by Apple: Michael Parkin-White Ref T96261 Reviewed By: fclem Maniphest Tasks: T96261 Differential Revision: https://developer.blender.org/D16825
113 lines
3.3 KiB
GLSL
113 lines
3.3 KiB
GLSL
|
|
#pragma BLENDER_REQUIRE(bsdf_common_lib.glsl)
|
|
|
|
/* ---------------------------------------------------------------------- */
|
|
/** \name Utiltex
|
|
*
|
|
* Utiltex is a sampler2DArray that stores a number of useful small utilitary textures and lookup
|
|
* tables.
|
|
* \{ */
|
|
|
|
#if !defined(USE_GPU_SHADER_CREATE_INFO)
|
|
|
|
uniform sampler2DArray utilTex;
|
|
|
|
#endif
|
|
|
|
#define LUT_SIZE 64
|
|
|
|
#define LTC_MAT_LAYER 0
|
|
#define LTC_BRDF_LAYER 1
|
|
#define BRDF_LUT_LAYER 1
|
|
#define NOISE_LAYER 2
|
|
#define LTC_DISK_LAYER 3 /* UNUSED */
|
|
|
|
/* Layers 4 to 20 are for BTDF Lut. */
|
|
#define lut_btdf_layer_first 4.0
|
|
#define lut_btdf_layer_count 16.0
|
|
|
|
/**
|
|
* Reminder: The 4 noise values are based of 3 uncorrelated blue noises:
|
|
* x : Uniformly distributed value [0..1] (noise 1).
|
|
* y : Uniformly distributed value [0..1] (noise 2).
|
|
* z,w : Uniformly distributed point on the unit circle [-1..1] (noise 3).
|
|
*/
|
|
#define texelfetch_noise_tex(coord) texelFetch(utilTex, ivec3(ivec2(coord) % LUT_SIZE, 2.0), 0)
|
|
|
|
/* Return texture coordinates to sample Surface LUT. */
|
|
vec2 lut_coords(float cos_theta, float roughness)
|
|
{
|
|
vec2 coords = vec2(roughness, sqrt(1.0 - cos_theta));
|
|
/* scale and bias coordinates, for correct filtered lookup */
|
|
return coords * (LUT_SIZE - 1.0) / LUT_SIZE + 0.5 / LUT_SIZE;
|
|
}
|
|
|
|
/* Returns the GGX split-sum precomputed in LUT. */
|
|
vec2 brdf_lut(float cos_theta, float roughness)
|
|
{
|
|
return textureLod(utilTex, vec3(lut_coords(cos_theta, roughness), BRDF_LUT_LAYER), 0.0).rg;
|
|
}
|
|
|
|
/* Return texture coordinates to sample Surface LUT. */
|
|
vec3 lut_coords_btdf(float cos_theta, float roughness, float ior)
|
|
{
|
|
/* ior is sin of critical angle. */
|
|
float critical_cos = sqrt(1.0 - ior * ior);
|
|
|
|
vec3 coords;
|
|
coords.x = sqr(ior);
|
|
coords.y = cos_theta;
|
|
coords.y -= critical_cos;
|
|
coords.y /= (coords.y > 0.0) ? (1.0 - critical_cos) : critical_cos;
|
|
coords.y = coords.y * 0.5 + 0.5;
|
|
coords.z = roughness;
|
|
|
|
coords = saturate(coords);
|
|
|
|
/* scale and bias coordinates, for correct filtered lookup */
|
|
coords.xy = coords.xy * (LUT_SIZE - 1.0) / LUT_SIZE + 0.5 / LUT_SIZE;
|
|
|
|
return coords;
|
|
}
|
|
|
|
/* Returns GGX BTDF in first component and fresnel in second. */
|
|
vec2 btdf_lut(float cos_theta, float roughness, float ior)
|
|
{
|
|
if (ior <= 1e-5) {
|
|
return vec2(0.0);
|
|
}
|
|
|
|
if (ior >= 1.0) {
|
|
vec2 split_sum = brdf_lut(cos_theta, roughness);
|
|
float f0 = f0_from_ior(ior);
|
|
/* Baked IOR for GGX BRDF. */
|
|
const float specular = 1.0;
|
|
const float eta_brdf = (2.0 / (1.0 - sqrt(0.08 * specular))) - 1.0;
|
|
/* Avoid harsh transition coming from ior == 1. */
|
|
float f90 = fast_sqrt(saturate(f0 / (f0_from_ior(eta_brdf) * 0.25)));
|
|
float fresnel = F_brdf_single_scatter(vec3(f0), vec3(f90), split_sum).r;
|
|
/* Setting the BTDF to one is not really important since it is only used for multiscatter
|
|
* and it's already quite close to ground truth. */
|
|
float btdf = 1.0;
|
|
return vec2(btdf, fresnel);
|
|
}
|
|
|
|
vec3 coords = lut_coords_btdf(cos_theta, roughness, ior);
|
|
|
|
float layer = coords.z * lut_btdf_layer_count;
|
|
float layer_floored = floor(layer);
|
|
|
|
coords.z = lut_btdf_layer_first + layer_floored;
|
|
vec2 btdf_low = textureLod(utilTex, coords, 0.0).rg;
|
|
|
|
coords.z += 1.0;
|
|
vec2 btdf_high = textureLod(utilTex, coords, 0.0).rg;
|
|
|
|
/* Manual trilinear interpolation. */
|
|
vec2 btdf = mix(btdf_low, btdf_high, layer - layer_floored);
|
|
|
|
return btdf;
|
|
}
|
|
|
|
/** \} */
|