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/* texture.c - by David Blythe, SGI */
/* load_luminace is a simplistic routine for reading an SGI .bw image file. */
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "loadlum.h"
typedef struct _ImageRec {
unsigned short imagic;
unsigned short type;
unsigned short dim;
unsigned short xsize, ysize, zsize;
unsigned int min, max;
unsigned int wasteBytes;
char name[80];
unsigned long colorMap;
FILE *file;
unsigned char *tmp;
unsigned long rleEnd;
unsigned int *rowStart;
int *rowSize;
} ImageRec;
static void
ConvertShort(unsigned short *array, unsigned int length)
{
unsigned short b1, b2;
unsigned char *ptr;
ptr = (unsigned char *) array;
while (length--) {
b1 = *ptr++;
b2 = *ptr++;
*array++ = (b1 << 8) | (b2);
}
}
static void
ConvertUint(unsigned *array, unsigned int length)
{
unsigned int b1, b2, b3, b4;
unsigned char *ptr;
ptr = (unsigned char *) array;
while (length--) {
b1 = *ptr++;
b2 = *ptr++;
b3 = *ptr++;
b4 = *ptr++;
*array++ = (b1 << 24) | (b2 << 16) | (b3 << 8) | (b4);
}
}
static ImageRec *
ImageOpen(char *fileName)
{
union {
int testWord;
char testByte[4];
} endianTest;
ImageRec *image;
int swapFlag, x;
endianTest.testWord = 1;
if (endianTest.testByte[0] == 1)
swapFlag = 1;
else
swapFlag = 0;
image = (ImageRec *) malloc(sizeof(ImageRec));
if (image == NULL) {
fprintf(stderr, "Out of memory!\n");
exit(1);
}
if ((image->file = fopen(fileName, "rb")) == NULL) {
perror(fileName);
exit(1);
}
fread(image, 1, 12, image->file);
if (swapFlag)
ConvertShort(&image->imagic, 6);
image->tmp = (unsigned char *) malloc(image->xsize * 256);
if (image->tmp == NULL) {
fprintf(stderr, "Out of memory!\n");
exit(1);
}
if ((image->type & 0xFF00) == 0x0100) {
x = image->ysize * image->zsize * (int) sizeof(unsigned);
image->rowStart = (unsigned *) malloc(x);
image->rowSize = (int *) malloc(x);
if (image->rowStart == NULL || image->rowSize == NULL) {
fprintf(stderr, "Out of memory!\n");
exit(1);
}
image->rleEnd = 512 + (2 * x);
fseek(image->file, 512, SEEK_SET);
fread(image->rowStart, 1, x, image->file);
fread(image->rowSize, 1, x, image->file);
if (swapFlag) {
ConvertUint(image->rowStart, x / (int) sizeof(unsigned));
ConvertUint((unsigned *) image->rowSize, x / (int) sizeof(int));
}
}
return image;
}
static void
ImageClose(ImageRec * image)
{
fclose(image->file);
free(image->tmp);
free(image);
}
static void
ImageGetRow(ImageRec * image, unsigned char *buf, int y, int z)
{
unsigned char *iPtr, *oPtr, pixel;
int count;
if ((image->type & 0xFF00) == 0x0100) {
fseek(image->file, (long) image->rowStart[y + z * image->ysize], SEEK_SET);
fread(image->tmp, 1, (unsigned int) image->rowSize[y + z * image->ysize],
image->file);
iPtr = image->tmp;
oPtr = buf;
for (;;) {
pixel = *iPtr++;
count = (int) (pixel & 0x7F);
if (!count)
return;
if (pixel & 0x80) {
while (count--)
*oPtr++ = *iPtr++;
} else {
pixel = *iPtr++;
while (count--)
*oPtr++ = pixel;
}
}
} else {
fseek(image->file, 512 + (y * image->xsize) + (z * image->xsize * image->ysize),
SEEK_SET);
fread(buf, 1, image->xsize, image->file);
}
}
unsigned char *
load_luminance(char *name, int *width, int *height, int *components)
{
unsigned char *base, *lptr;
ImageRec *image;
int y;
image = ImageOpen(name);
if (!image)
return NULL;
if (image->zsize != 1)
return NULL;
*width = image->xsize;
*height = image->ysize;
*components = image->zsize;
base = (unsigned char *)
malloc(image->xsize * image->ysize * sizeof(unsigned char));
if (!base)
return NULL;
lptr = base;
for (y = 0; y < image->ysize; y++) {
ImageGetRow(image, lptr, y, 0);
lptr += image->xsize;
}
ImageClose(image);
return base;
}
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