save_image_exr.cpp

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#include "save_image_exr.hpp"
#define TINYEXR_USE_STB_ZLIB 1
#define TINYEXR_USE_MINIZ 0
#include <tinyexr.h>
#include <cassert>
#include <wmtk/utils/Logger.hpp>
namespace wmtk::components::adaptive_tessellation::image {
bool save_image_exr_red_channel(
    size_t width,
    size_t height,
    const std::vector<float>& data,
    const std::filesystem::path& path)
{
    EXRHeader header;
    InitEXRHeader(&header);
 
    EXRImage image;
    InitEXRImage(&image);
 
    image.num_channels = 3;
 
    std::vector<float> images[3];
    images[0].resize(width * height);
    images[1].resize(width * height);
    images[2].resize(width * height);
 
    // Split RGBRGBRGB... into R, G and B layer
    for (int i = 0; i < width * height; i++) {
        images[0][i] = data[i];
        images[1][i] = -1.;
        images[2][i] = -1.;
    }
 
    float* image_ptr[3];
    image_ptr[0] = &(images[2].at(0)); // B
    image_ptr[1] = &(images[1].at(0)); // G
    image_ptr[2] = &(images[0].at(0)); // R
 
    image.images = (unsigned char**)image_ptr;
    image.width = width;
    image.height = height;
 
    header.num_channels = 3;
    header.channels = (EXRChannelInfo*)malloc(sizeof(EXRChannelInfo) * header.num_channels);
    // Must be (A)BGR order, since most of EXR viewers expect this channel order.
    strncpy(header.channels[0].name, "B", 255);
    header.channels[0].name[strlen("B")] = '\0';
    strncpy(header.channels[1].name, "G", 255);
    header.channels[1].name[strlen("G")] = '\0';
    strncpy(header.channels[2].name, "R", 255);
    header.channels[2].name[strlen("R")] = '\0';
 
    header.pixel_types = (int*)malloc(sizeof(int) * header.num_channels);
    header.requested_pixel_types = (int*)malloc(sizeof(int) * header.num_channels);
    for (int i = 0; i < header.num_channels; i++) {
        header.pixel_types[i] = TINYEXR_PIXELTYPE_FLOAT; // pixel type of input image
        header.requested_pixel_types[i] =
            TINYEXR_PIXELTYPE_HALF; // pixel type of output image to be stored in .EXR
    }
 
    const char* err = NULL; // or nullptr in C++11 or later.
    int ret = SaveEXRImageToFile(&image, &header, path.string().data(), &err);
    if (ret != TINYEXR_SUCCESS) {
        fprintf(stderr, "Save EXR err: %s\n", err);
        FreeEXRErrorMessage(err); // free's buffer for an error message
        return ret;
    }
    wmtk::logger().debug("Saved exr file. {} ", path);
 
    free(header.channels);
    free(header.pixel_types);
    free(header.requested_pixel_types);
    return 0;
}
 
bool save_image_exr_3channels(
    size_t width,
    size_t height,
    int r,
    int g,
    int b,
    const std::vector<float>& data_r,
    const std::vector<float>& data_g,
    const std::vector<float>& data_b,
    const std::filesystem::path& path)
{
    EXRHeader header;
    InitEXRHeader(&header);
 
    EXRImage image;
    InitEXRImage(&image);
 
    image.num_channels = 3;
 
    std::vector<float> images[3];
    images[0].resize(width * height);
    images[1].resize(width * height);
    images[2].resize(width * height);
 
    // Split RGBRGBRGB... into R, G and B layer
    for (int i = 0; i < width * height; i++) {
        images[r][i] = data_r[i];
        images[g][i] = data_g[i];
        images[b][i] = data_b[i];
    }
    wmtk::logger()
        .info("[save r {} {}, g {} {} b {} {}]", r, images[r][0], g, images[g][0], b, images[b][0]);
    float* image_ptr[3];
    image_ptr[0] = &(images[2].at(0)); // B
    image_ptr[1] = &(images[1].at(0)); // G
    image_ptr[2] = &(images[0].at(0)); // R
 
    image.images = (unsigned char**)image_ptr;
    image.width = width;
    image.height = height;
 
    header.num_channels = 3;
    header.channels = (EXRChannelInfo*)malloc(sizeof(EXRChannelInfo) * header.num_channels);
    // Must be (A)BGR order, since most of EXR viewers expect this channel order.
    strncpy(header.channels[0].name, "B", 255);
    header.channels[0].name[strlen("B")] = '\0';
    strncpy(header.channels[1].name, "G", 255);
    header.channels[1].name[strlen("G")] = '\0';
    strncpy(header.channels[2].name, "R", 255);
    header.channels[2].name[strlen("R")] = '\0';
 
    header.pixel_types = (int*)malloc(sizeof(int) * header.num_channels);
    header.requested_pixel_types = (int*)malloc(sizeof(int) * header.num_channels);
    for (int i = 0; i < header.num_channels; i++) {
        header.pixel_types[i] = TINYEXR_PIXELTYPE_FLOAT; // pixel type of input image
        header.requested_pixel_types[i] =
            TINYEXR_PIXELTYPE_HALF; // pixel type of output image to be stored in .EXR
    }
 
    const char* err = NULL; // or nullptr in C++11 or later.
    int ret = SaveEXRImageToFile(&image, &header, path.string().data(), &err);
    if (ret != TINYEXR_SUCCESS) {
        fprintf(stderr, "Save EXR err: %s\n", err);
        FreeEXRErrorMessage(err); // free's buffer for an error message
        return ret;
    }
    printf("Saved exr file 3 channels. [ %s ] \n", path.c_str());
 
    free(header.channels);
    free(header.pixel_types);
    free(header.requested_pixel_types);
    return 0;
}
} // namespace wmtk::components::adaptive_tessellation::image