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optimize srgb -> linear preparation by using lookup table

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This commit is contained in:
MaxGraey
2021-07-13 18:33:15 +03:00
parent ad5002c79c
commit cc9a887386
1 changed files with 16 additions and 6 deletions
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22
codecs/visdif/visdif.cpp
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@@ -5,12 +5,21 @@
using namespace emscripten; using namespace emscripten;
using namespace butteraugli; using namespace butteraugli;
#define GAMMA 2.2
static double SrgbToLinear[256];
inline void gammaLookupTable() {
for (int i = 1; i < 256; ++i) {
SrgbToLinear[i] = pow(i / 255.0, GAMMA);
}
}
// Turns an interleaved RGBA buffer into 4 planes for each color channel // Turns an interleaved RGBA buffer into 4 planes for each color channel
void planarize(std::vector<ImageF>& img, void planarize(std::vector<ImageF>& img,
const uint8_t* rgba, const uint8_t* rgba,
int width, int width,
int height, int height) {
float gamma = 2.2) {
assert(img.size() == 0); assert(img.size() == 0);
img.push_back(ImageF(width, height)); img.push_back(ImageF(width, height));
img.push_back(ImageF(width, height)); img.push_back(ImageF(width, height));
@@ -22,10 +31,10 @@ void planarize(std::vector<ImageF>& img,
float* const row_b = img[2].Row(y); float* const row_b = img[2].Row(y);
float* const row_a = img[3].Row(y); float* const row_a = img[3].Row(y);
for (int x = 0; x < width; x++) { for (int x = 0; x < width; x++) {
row_r[x] = 255.0 * pow(rgba[(y * width + x) * 4 + 0] / 255.0, gamma); row_r[x] = static_cast<float>(255.0 * SrgbToLinear[rgba[(y * width + x) * 4 + 0]]);
row_g[x] = 255.0 * pow(rgba[(y * width + x) * 4 + 1] / 255.0, gamma); row_g[x] = static_cast<float>(255.0 * SrgbToLinear[rgba[(y * width + x) * 4 + 1]]);
row_b[x] = 255.0 * pow(rgba[(y * width + x) * 4 + 2] / 255.0, gamma); row_b[x] = static_cast<float>(255.0 * SrgbToLinear[rgba[(y * width + x) * 4 + 2]]);
row_a[x] = 255.0 * pow(rgba[(y * width + x) * 4 + 3] / 255.0, gamma); row_a[x] = static_cast<float>(255.0 * SrgbToLinear[rgba[(y * width + x) * 4 + 3]]);
} }
} }
} }
@@ -37,6 +46,7 @@ class VisDiff {
public: public:
VisDiff(std::string ref_img, int width, int height) { VisDiff(std::string ref_img, int width, int height) {
gammaLookupTable();
planarize(this->ref_img, (uint8_t*)ref_img.c_str(), width, height); planarize(this->ref_img, (uint8_t*)ref_img.c_str(), width, height);
this->width = width; this->width = width;
this->height = height; this->height = height;