#ok-file-formats A few file format decoders. No external dependencies.

• PNG - Reads any PNG file.
• JPG - Reads most JPEG files. Baseline only, no progressive support.
• WAV - Reads WAV or CAF files. PCM format only.
• FNT - Reads AngelCode BMFont files.
• CSV - Reads Comma-Separated Values files.
• MO - Reads gettext MO files.

The files do not depend on one another, and there are no dependencies on external libraries. If all you need is to read a PNG file, just grab ok_png.h and ok_png.c and you're good to go.

This example decodes a PNG from a stdio file and uploads the data to OpenGL. The color format is optimized for iOS devices.

#include "ok_png.h"

static int file_input_func(void *user_data, unsigned char *buffer, const int count) {
    FILE *fp = (FILE *)user_data;
    if (buffer && count > 0) {
        return (int)fread(buffer, 1, count, fp);
    }
    else if (fseek(fp, count, SEEK_CUR) == 0) {
        return count;
    }
    else {
        return 0;
    }
}

GLuint load_texture(const char *file_name, const bool flip_y) {
#if GL_APPLE_texture_format_BGRA8888 && GL_BGRA_EXT
    GLenum glFormat = GL_BGRA_EXT;
    ok_color_format ok_format = OK_COLOR_FORMAT_BGRA_PRE;
#else
    GLenum glFormat = GL_RGBA;
    ok_color_format ok_format = OK_COLOR_FORMAT_RGBA_PRE;
#endif
    FILE *fp = fopen(file_name, "rb");
    ok_image *image = ok_png_read(fp, file_input_func, ok_format, flip_y);
    fclose(fp);
    
    GLuint textureId = 0;
    if (!image->data) {
        printf("Error: %s\n", image->error_message);
    }
    else {
        glGenTextures(1, &textureId);
        glBindTexture(GL_TEXTURE_2D, textureId);
        glPixelStorei(GL_UNPACK_ALIGNMENT, 1);
        glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, image->width, image->height, 0,
                     glFormat, GL_UNSIGNED_BYTE, image->data);
        glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
        glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
        glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
        glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
    }
    ok_image_free(image);
    return textureId;
}

• Reads any PNG file.
• All color formats, all bit depths, all transparency types.
• Complex formats like interlacing and multiple IDAT chunks.
• Reads Apple's proprietary CgBI chunk for iOS devices.
• Ignores gAMA chunks.
• Option to get the image dimensions without decoding.
• Options to premultiply alpha and flip the image vertically.
• Tested against the PngSuite.

• Reads most JPEG files.
• Baseline only (no progressive JPEGs)
• Interprets EXIF orientation tags.
• Option to get the image dimensions without decoding.
• Option to flip the image vertically.
• Tested with several JPEG files against IJG's jpeg-8d library.

• Reads WAV or CAF files.
• PCM format only.

• Reads AngelCode BMFont files.
• Binary format, version 3, from AngelCode Bitmap Font Generator v1.10 or newer.

• Reads Comma-Separated Values files.
• Properly handles escaped fields.

• Reads gettext MO files.
• Provides utility functions to convert UTF-8 to 32-bit Unicode.

ZLIB