Function writePPM

layersvt/screenshot.cpp:528–563

Writes image to a PPM file.

// Writes image to a PPM file.
bool writePPM(const char *filename, const char *pixels, uint32_t width, uint32_t height, uint32_t numChannels, uint32_t rowPitch) {
    PROFILE("writePPM");

    std::ofstream file(filename, ios::binary);
    if (!file.is_open()) {
        return false;
    }

    file << "P6\n";
    file << width << "\n";
    file << height << "\n";
    file << 255 << "\n";

    if (3 == numChannels) {
        for (uint32_t y = 0; y < height; y++) {
            file.write(pixels, 3 * width);
            pixels += rowPitch;
        }
    } else if (4 == numChannels) {
        std::vector<unsigned char> tempRowBuffer;
        tempRowBuffer.resize(3 * width + 1);
        for (uint32_t y = 0; y < height; y++) {
            const uint32_t *srcRow = reinterpret_cast<const uint32_t *>(pixels);
            unsigned char *destRow = tempRowBuffer.data();

            for (uint32_t x = 0; x < width; x++) {
                *reinterpret_cast<uint32_t *>(destRow) = *srcRow++;
                destRow += 3;
            }
            file.write(reinterpret_cast<const char *>(tempRowBuffer.data()), 3 * width);
            pixels += rowPitch;
        }
    }
    file.close();
    return true;
}

static VkFormat determineOutputFormat(VkFormat format, ColorSpaceFormat userColorSpaceFormat, uint32_t numChannels) {
    // Initial dest format is undefined as we will look for one