palreader.c

/*
 * palreader.c
 * Reads Fallout 2 .pal files
 *
 * Copyright (c) 2012, Paul Chote
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met: 
 *
 * 1. Redistributions of source code must retain the above copyright notice, this
 *    list of conditions and the following disclaimer. 
 * 2. Redistributions in binary form must reproduce the above copyright notice,
 *    this list of conditions and the following disclaimer in the documentation
 *    and/or other materials provided with the distribution. 
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR
 * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 *  LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#include <stdlib.h>
#include <png.h>

#include "palreader.h"

palreader *palreader_from_data(uint8_t *data)
{
    palreader *reader = malloc(sizeof(palreader));
    if (!reader)
        return NULL;

    reader->brightness = PALTYPE_NOON;

    // Copy (r,g,b) triplets
    memcpy(reader->data, data, 256*3*sizeof(uint8_t));

    // Remaining data defines a cube to map arbitrary
    // RGB -> palette index, followed by up to 3
    // undefined additional tables
    // Ignore these for now
    return reader;
}

void palreader_free(palreader *reader)
{
    free(reader);
}

// Based on code from http://www.lemoda.net/c/write-png/
int palreader_export_png(palreader *reader, uint8_t *data, uint16_t width, uint16_t height, const char *path)
{
    int status = -1;
    FILE *fp = fopen(path, "wb");
    if (!fp)
        goto fopen_failed;

    png_structp png_ptr = png_create_write_struct(PNG_LIBPNG_VER_STRING, NULL, NULL, NULL);
    if (png_ptr == NULL)
        goto png_create_write_struct_failed;

    png_infop info_ptr = png_create_info_struct(png_ptr);
    if (info_ptr == NULL)
        goto png_create_info_struct_failed;

    // Set up error handling
    if (setjmp(png_jmpbuf(png_ptr)))
        goto png_failure;

    // Set image attributes.
    png_set_IHDR(png_ptr, info_ptr, width, height, 8,
                 PNG_COLOR_TYPE_RGB, PNG_INTERLACE_NONE,
                 PNG_COMPRESSION_TYPE_DEFAULT, PNG_FILTER_TYPE_DEFAULT);

    // Initialize rows of PNG
    png_byte **row_pointers = png_malloc(png_ptr, height*sizeof(png_byte *));
    for (size_t y = 0; y < height; y++)
    {
        png_byte *row = png_malloc(png_ptr, 3*width*sizeof(uint8_t));
        row_pointers[y] = row;
        for (size_t x = 0; x < width; x++)
        {
            uint8_t index = data[y*width + x];
            for (size_t i = 0; i < 3; i++)
                *row++ = reader->data[3*index + i]*reader->brightness;
        }
    }

    // Write to file
    png_init_io(png_ptr, fp);
    png_set_rows(png_ptr, info_ptr, row_pointers);
    png_write_png(png_ptr, info_ptr, PNG_TRANSFORM_IDENTITY, NULL);

    // Cleanup
    status = 0;
    for (size_t y = 0; y < height; y++)
        png_free(png_ptr, row_pointers[y]);

    png_free(png_ptr, row_pointers);

png_failure:
png_create_info_struct_failed:
    png_destroy_write_struct (&png_ptr, &info_ptr);
png_create_write_struct_failed:
    fclose (fp);
fopen_failed:
    return status;
}