95 lines
2.8 KiB
C
95 lines
2.8 KiB
C
// quick and dirty bitmap loader...for 24 bit bitmaps with 1 plane only.
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// See http://www.dcs.ed.ac.uk/~mxr/gfx/2d/BMP.txt for more info.
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#include <stdio.h>
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#include <stdint.h>
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#include <stdlib.h>
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#include "loadbmp.h"
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int ImageLoad(char *filename, Image *image) {
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FILE *file;
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size_t size; // size of the image in bytes.
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size_t i; // standard counter.
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int32_t sizeX, sizeY; // width/height of the image - must be 4 bytes to match the file format
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int16_t planes; // number of planes in image (must be 1)
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int16_t bpp; // number of bits per pixel (must be 24)
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char temp; // temporary color storage for bgr-rgb conversion.
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// make sure the file is there.
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if ((file = fopen(filename, "rb"))==NULL) {
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printf("File Not Found : %s\n",filename);
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return 0;
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}
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// seek through the bmp header, up to the width/height:
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fseek(file, 10, SEEK_CUR);
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uint32_t offset;
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fread(&offset, 4, 1, file);
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fseek(file, 4, SEEK_CUR);
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// read the width
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if ((i = fread(&sizeX, 4, 1, file)) != 1) {
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printf("Error reading width from %s.\n", filename);
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return 0;
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}
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image->sizeX = sizeX;
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printf("Width of %s: %d\n", filename, sizeX);
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// read the height
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if ((i = fread(&sizeY, 4, 1, file)) != 1) {
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printf("Error reading height from %s.\n", filename);
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return 0;
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}
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image->sizeY = sizeY;
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printf("Height of %s: %d\n", filename, sizeY);
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// calculate the size (assuming 24 bits or 3 bytes per pixel).
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size = image->sizeX * image->sizeY * 3;
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// read the planes
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if ((fread(&planes, 2, 1, file)) != 1) {
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printf("Error reading planes from %s.\n", filename);
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return 0;
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}
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if (planes != 1) {
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printf("Planes from %s is not 1: %u\n", filename, planes);
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return 0;
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}
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// read the bpp
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if ((i = fread(&bpp, 2, 1, file)) != 1) {
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printf("Error reading bpp from %s.\n", filename);
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return 0;
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}
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if (bpp != 24) {
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printf("Bpp from %s is not 24: %u\n", filename, bpp);
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return 0;
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}
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// seek past the rest of the bitmap header.
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fseek(file, offset, SEEK_SET);
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// read the data.
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image->data = (char *) malloc(size);
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if (image->data == NULL) {
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printf("Error allocating memory for color-corrected image data");
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return 0;
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}
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if ((i = fread(image->data, size, 1, file)) != 1) {
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printf("Error reading image data from %s.\n", filename);
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return 0;
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}
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for (i=0;i<size;i+=3) { // reverse all of the colors. (bgr -> rgb)
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temp = image->data[i];
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image->data[i] = image->data[i+2];
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image->data[i+2] = temp;
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}
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// we're done.
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return 1;
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}
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