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| author | Kory Postma <postmako@gmail.com> | 2023-05-24 15:00:47 -0500 |
|---|---|---|
| committer | Kory Postma <postmako@gmail.com> | 2023-05-27 18:01:44 -0500 |
| commit | c8cac39446a3826752fa9122750cb59cd07058ec (patch) | |
| tree | b83606db33a594107e8595ccc21699d925a1e271 /core/io/image.cpp | |
| parent | 2eec9a67d564b11326f44c5ef8b6b6f9aec251b9 (diff) | |
| download | redot-engine-c8cac39446a3826752fa9122750cb59cd07058ec.tar.gz | |
Grayscale fix for Image::premultiply_alpha() and Image::convert(FORMAT_L8) while using REC.709, with added test case
Diffstat (limited to 'core/io/image.cpp')
| -rw-r--r-- | core/io/image.cpp | 13 |
1 files changed, 7 insertions, 6 deletions
diff --git a/core/io/image.cpp b/core/io/image.cpp index 8111ca447c..9bb987b670 100644 --- a/core/io/image.cpp +++ b/core/io/image.cpp @@ -468,7 +468,7 @@ int Image::get_mipmap_count() const { //using template generates perfectly optimized code due to constant expression reduction and unused variable removal present in all compilers template <uint32_t read_bytes, bool read_alpha, uint32_t write_bytes, bool write_alpha, bool read_gray, bool write_gray> static void _convert(int p_width, int p_height, const uint8_t *p_src, uint8_t *p_dst) { - uint32_t max_bytes = MAX(read_bytes, write_bytes); + constexpr uint32_t max_bytes = MAX(read_bytes, write_bytes); for (int y = 0; y < p_height; y++) { for (int x = 0; x < p_width; x++) { @@ -492,8 +492,9 @@ static void _convert(int p_width, int p_height, const uint8_t *p_src, uint8_t *p } if constexpr (write_gray) { - //TODO: not correct grayscale, should use fixed point version of actual weights - wofs[0] = uint8_t((uint16_t(rgba[0]) + uint16_t(rgba[1]) + uint16_t(rgba[2])) / 3); + // REC.709 + const uint8_t luminance = (13938U * rgba[0] + 46869U * rgba[1] + 4729U * rgba[2] + 32768U) >> 16U; + wofs[0] = luminance; } else { for (uint32_t i = 0; i < write_bytes; i++) { wofs[i] = rgba[i]; @@ -3718,9 +3719,9 @@ void Image::premultiply_alpha() { for (int j = 0; j < width; j++) { uint8_t *ptr = &data_ptr[(i * width + j) * 4]; - ptr[0] = (uint16_t(ptr[0]) * uint16_t(ptr[3])) >> 8; - ptr[1] = (uint16_t(ptr[1]) * uint16_t(ptr[3])) >> 8; - ptr[2] = (uint16_t(ptr[2]) * uint16_t(ptr[3])) >> 8; + ptr[0] = (uint16_t(ptr[0]) * uint16_t(ptr[3]) + 255U) >> 8; + ptr[1] = (uint16_t(ptr[1]) * uint16_t(ptr[3]) + 255U) >> 8; + ptr[2] = (uint16_t(ptr[2]) * uint16_t(ptr[3]) + 255U) >> 8; } } } |