// Copyright 2016 Activision Publishing, Inc.
//
// Permission is hereby granted, free of charge, to any person obtaining
// a copy of this software and associated documentation files (the "Software"),
// to deal in the Software without restriction, including without limitation
// the rights to use, copy, modify, merge, publish, distribute, sublicense,
// and/or sell copies of the Software, and to permit persons to whom the Software
// is furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in all
// copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
// SOFTWARE.
/* clang-format off */
#[vertex]
#version 450
#VERSION_DEFINES
layout(push_constant, std430) uniform Params {
int mip_level;
uint face_id;
}
params;
layout(location = 0) out vec2 uv_interp;
/* clang-format on */
void main() {
vec2 base_arr[3] = vec2[](vec2(-1.0, -1.0), vec2(-1.0, 3.0), vec2(3.0, -1.0));
gl_Position = vec4(base_arr[gl_VertexIndex], 0.0, 1.0);
uv_interp = clamp(gl_Position.xy, vec2(0.0, 0.0), vec2(1.0, 1.0)) * 2.0; // saturate(x) * 2.0
}
/* clang-format off */
#[fragment]
#version 450
#VERSION_DEFINES
layout(push_constant, std430) uniform Params {
int mip_level;
uint face_id;
}
params;
layout(set = 0, binding = 0) uniform samplerCube source_cubemap;
layout(location = 0) in vec2 uv_interp;
layout(location = 0) out vec4 frag_color;
/* clang-format on */
#ifdef USE_HIGH_QUALITY
#define NUM_TAPS 32
#else
#define NUM_TAPS 8
#endif
#define BASE_RESOLUTION 128
#ifdef USE_HIGH_QUALITY
layout(set = 1, binding = 0, std430) buffer restrict readonly Data {
vec4[7][5][3][24] coeffs;
}
data;
#else
layout(set = 1, binding = 0, std430) buffer restrict readonly Data {
vec4[7][5][6] coeffs;
}
data;
#endif
void get_dir(out vec3 dir, in vec2 uv, in uint face) {
switch (face) {
case 0:
dir = vec3(1.0, uv[1], -uv[0]);
break;
case 1:
dir = vec3(-1.0, uv[1], uv[0]);
break;
case 2:
dir = vec3(uv[0], 1.0, -uv[1]);
break;
case 3:
dir = vec3(uv[0], -1.0, uv[1]);
break;
case 4:
dir = vec3(uv[0], uv[1], 1.0);
break;
default:
dir = vec3(-uv[0], uv[1], -1.0);
break;
}
}
void main() {
// determine dir / pos for the texel
vec3 dir, adir, frameZ;
{
vec2 uv;
uv.x = uv_interp.x;
uv.y = 1.0 - uv_interp.y;
uv = uv * 2.0 - 1.0;
get_dir(dir, uv, params.face_id);
frameZ = normalize(dir);
adir = abs(dir);
}
// determine which texel this is
// NOTE (macOS/MoltenVK): Do not rename, "level" variable name conflicts with the Metal "level(float lod)" mipmap sampling function name.
int mip_level = 0;
if (params.mip_level < 0) {
// return as is
frag_color.rgb = textureLod(source_cubemap, frameZ, 0.0).rgb;
frag_color.a = 1.0;
return;
} else if (params.mip_level > 6) {
// maximum level
mip_level = 6;
} else {
mip_level = params.mip_level;
}
// GGX gather colors
vec4 color = vec4(0.0);
for (int axis = 0; axis < 3; axis++) {
const int otherAxis0 = 1 - (axis & 1) - (axis >> 1);
const int otherAxis1 = 2 - (axis >> 1);
float frameweight = (max(adir[otherAxis0], adir[otherAxis1]) - .75) / .25;
if (frameweight > 0.0) {
// determine frame
vec3 UpVector;
switch (axis) {
case 0:
UpVector = vec3(1, 0, 0);
break;
case 1:
UpVector = vec3(0, 1, 0);
break;
default:
UpVector = vec3(0, 0, 1);
break;
}
vec3 frameX = normalize(cross(UpVector, frameZ));
vec3 frameY = cross(frameZ, frameX);
// calculate parametrization for polynomial
float Nx = dir[otherAxis0];
float Ny = dir[otherAxis1];
float Nz = adir[axis];
float NmaxXY = max(abs(Ny), abs(Nx));
Nx /= NmaxXY;
Ny /= NmaxXY;
float theta;
if (Ny < Nx) {
if (Ny <= -0.999)
theta = Nx;
else
theta = Ny;
} else {
if (Ny >= 0.999)
theta = -Nx;
else
theta = -Ny;
}
float phi;
if (Nz <= -0.999)
phi = -NmaxXY;
else if (Nz >= 0.999)
phi = NmaxXY;
else
phi = Nz;
float theta2 = theta * theta;
float phi2 = phi * phi;
// sample
for (int iSuperTap = 0; iSuperTap < NUM_TAPS / 4; iSuperTap++) {
const int index = (NUM_TAPS / 4) * axis + iSuperTap;
#ifdef USE_HIGH_QUALITY
vec4 coeffsDir0[3];
vec4 coeffsDir1[3];
vec4 coeffsDir2[3];
vec4 coeffsLevel[3];
vec4 coeffsWeight[3];
for (int iCoeff = 0; iCoeff < 3; iCoeff++) {
coeffsDir0[iCoeff] = data.coeffs[mip_level][0][iCoeff][index];
coeffsDir1[iCoeff] = data.coeffs[mip_level][1][iCoeff][index];
coeffsDir2[iCoeff] = data.coeffs[mip_level][2][iCoeff][index];
coeffsLevel[iCoeff] = data.coeffs[mip_level][3][iCoeff][index];
coeffsWeight[iCoeff] = data.coeffs[mip_level][4][iCoeff][index];
}
for (int iSubTap = 0; iSubTap < 4; iSubTap++) {
// determine sample attributes (dir, weight, mip_level)
vec3 sample_dir = frameX * (coeffsDir0[0][iSubTap] + coeffsDir0[1][iSubTap] * theta2 + coeffsDir0[2][iSubTap] * phi2) + frameY * (coeffsDir1[0][iSubTap] + coeffsDir1[1][iSubTap] * theta2 + coeffsDir1[2][iSubTap] * phi2) + frameZ * (coeffsDir2[0][iSubTap] + coeffsDir2[1][iSubTap] * theta2 + coeffsDir2[2][iSubTap] * phi2);
float sample_level = coeffsLevel[0][iSubTap] + coeffsLevel[1][iSubTap] * theta2 + coeffsLevel[2][iSubTap] * phi2;
float sample_weight = coeffsWeight[0][iSubTap] + coeffsWeight[1][iSubTap] * theta2 + coeffsWeight[2][iSubTap] * phi2;
#else
vec4 coeffsDir0 = data.coeffs[mip_level][0][index];
vec4 coeffsDir1 = data.coeffs[mip_level][1][index];
vec4 coeffsDir2 = data.coeffs[mip_level][2][index];
vec4 coeffsLevel = data.coeffs[mip_level][3][index];
vec4 coeffsWeight = data.coeffs[mip_level][4][index];
for (int iSubTap = 0; iSubTap < 4; iSubTap++) {
// determine sample attributes (dir, weight, mip_level)
vec3 sample_dir = frameX * coeffsDir0[iSubTap] + frameY * coeffsDir1[iSubTap] + frameZ * coeffsDir2[iSubTap];
float sample_level = coeffsLevel[iSubTap];
float sample_weight = coeffsWeight[iSubTap];
#endif
sample_weight *= frameweight;
// adjust for jacobian
sample_dir /= max(abs(sample_dir[0]), max(abs(sample_dir[1]), abs(sample_dir[2])));
sample_level += 0.75 * log2(dot(sample_dir, sample_dir));
// sample cubemap
color.xyz += textureLod(source_cubemap, normalize(sample_dir), sample_level).xyz * sample_weight;
color.w += sample_weight;
}
}
}
}
color /= color.w;
// write color
color.xyz = max(vec3(0.0), color.xyz);
color.w = 1.0;
frag_color = color;
}
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