Initial revision
This commit is contained in:
jtg
273
progs/samples/rgbtoppm.c
Normal file
273
progs/samples/rgbtoppm.c
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/* texture.c - by David Blythe, SGI */
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/* texload is a simplistic routine for reading an SGI .rgb image file. */
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <GL/glut.h>
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typedef struct _ImageRec {
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unsigned short imagic;
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unsigned short type;
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unsigned short dim;
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unsigned short xsize, ysize, zsize;
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unsigned int min, max;
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unsigned int wasteBytes;
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char name[80];
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unsigned long colorMap;
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FILE *file;
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unsigned char *tmp;
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unsigned long rleEnd;
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unsigned int *rowStart;
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int *rowSize;
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} ImageRec;
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void
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rgbtorgb(unsigned char *r,unsigned char *g,unsigned char *b,unsigned char *l,int n) {
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while(n--) {
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l[0] = r[0];
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l[1] = g[0];
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l[2] = b[0];
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l += 3; r++; g++; b++;
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}
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}
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static void
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ConvertShort(unsigned short *array, unsigned int length) {
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unsigned short b1, b2;
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unsigned char *ptr;
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ptr = (unsigned char *)array;
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while (length--) {
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b1 = *ptr++;
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b2 = *ptr++;
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*array++ = (b1 << 8) | (b2);
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}
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}
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static void
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ConvertUint(unsigned *array, unsigned int length) {
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unsigned int b1, b2, b3, b4;
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unsigned char *ptr;
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ptr = (unsigned char *)array;
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while (length--) {
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b1 = *ptr++;
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b2 = *ptr++;
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b3 = *ptr++;
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b4 = *ptr++;
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*array++ = (b1 << 24) | (b2 << 16) | (b3 << 8) | (b4);
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}
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}
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static ImageRec *ImageOpen(char *fileName)
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{
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union {
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int testWord;
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char testByte[4];
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} endianTest;
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ImageRec *image;
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int swapFlag;
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int x;
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endianTest.testWord = 1;
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if (endianTest.testByte[0] == 1) {
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swapFlag = 1;
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} else {
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swapFlag = 0;
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}
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image = (ImageRec *)malloc(sizeof(ImageRec));
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if (image == NULL) {
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fprintf(stderr, "Out of memory!\n");
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exit(1);
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}
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if ((image->file = fopen(fileName, "rb")) == NULL) {
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return NULL;
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}
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fread(image, 1, 12, image->file);
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if (swapFlag) {
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ConvertShort(&image->imagic, 6);
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}
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image->tmp = (unsigned char *)malloc(image->xsize*256);
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if (image->tmp == NULL) {
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fprintf(stderr, "\nOut of memory!\n");
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exit(1);
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}
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if ((image->type & 0xFF00) == 0x0100) {
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x = image->ysize * image->zsize * (int) sizeof(unsigned);
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image->rowStart = (unsigned *)malloc(x);
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image->rowSize = (int *)malloc(x);
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if (image->rowStart == NULL || image->rowSize == NULL) {
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fprintf(stderr, "\nOut of memory!\n");
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exit(1);
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}
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image->rleEnd = 512 + (2 * x);
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fseek(image->file, 512, SEEK_SET);
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fread(image->rowStart, 1, x, image->file);
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fread(image->rowSize, 1, x, image->file);
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if (swapFlag) {
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ConvertUint(image->rowStart, x/(int) sizeof(unsigned));
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ConvertUint((unsigned *)image->rowSize, x/(int) sizeof(int));
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}
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}
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return image;
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}
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static void
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ImageClose(ImageRec *image) {
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fclose(image->file);
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free(image->tmp);
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free(image);
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}
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static void
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ImageGetRow(ImageRec *image, unsigned char *buf, int y, int z) {
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unsigned char *iPtr, *oPtr, pixel;
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int count;
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if ((image->type & 0xFF00) == 0x0100) {
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fseek(image->file, (long) image->rowStart[y+z*image->ysize], SEEK_SET);
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fread(image->tmp, 1, (unsigned int)image->rowSize[y+z*image->ysize],
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image->file);
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iPtr = image->tmp;
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oPtr = buf;
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for (;;) {
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pixel = *iPtr++;
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count = (int)(pixel & 0x7F);
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if (!count) {
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return;
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}
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if (pixel & 0x80) {
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while (count--) {
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*oPtr++ = *iPtr++;
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}
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} else {
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pixel = *iPtr++;
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while (count--) {
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*oPtr++ = pixel;
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}
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}
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}
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} else {
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fseek(image->file, 512+(y*image->xsize)+(z*image->xsize*image->ysize),
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SEEK_SET);
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fread(buf, 1, image->xsize, image->file);
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}
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}
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GLubyte *
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read_alpha_texture(char *name, int *width, int *height)
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{
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unsigned char *base, *lptr;
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ImageRec *image;
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int y;
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image = ImageOpen(name);
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if(!image) {
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return NULL;
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}
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(*width)=image->xsize;
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(*height)=image->ysize;
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if (image->zsize != 1) {
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ImageClose(image);
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return NULL;
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}
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base = (unsigned char *)malloc(image->xsize*image->ysize*sizeof(unsigned char));
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lptr = base;
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for(y=0; y<image->ysize; y++) {
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ImageGetRow(image,lptr,y,0);
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lptr += image->xsize;
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}
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ImageClose(image);
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return (unsigned char *) base;
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}
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GLubyte *
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read_rgb_texture(char *name, int *width, int *height)
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{
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unsigned char *base, *ptr;
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unsigned char *rbuf, *gbuf, *bbuf, *abuf;
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ImageRec *image;
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int y;
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image = ImageOpen(name);
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if(!image)
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return NULL;
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(*width)=image->xsize;
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(*height)=image->ysize;
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if (image->zsize != 3 && image->zsize != 4) {
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ImageClose(image);
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return NULL;
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}
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base = (unsigned char*)malloc(image->xsize*image->ysize*sizeof(unsigned int)*3);
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rbuf = (unsigned char *)malloc(image->xsize*sizeof(unsigned char));
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gbuf = (unsigned char *)malloc(image->xsize*sizeof(unsigned char));
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bbuf = (unsigned char *)malloc(image->xsize*sizeof(unsigned char));
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abuf = (unsigned char *)malloc(image->xsize*sizeof(unsigned char));
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if(!base || !rbuf || !gbuf || !bbuf || !abuf) {
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if (base) free(base);
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if (rbuf) free(rbuf);
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if (gbuf) free(gbuf);
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if (bbuf) free(bbuf);
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if (abuf) free(abuf);
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return NULL;
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}
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ptr = base;
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for(y=0; y<image->ysize; y++) {
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if(image->zsize == 4) {
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ImageGetRow(image,rbuf,y,0);
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ImageGetRow(image,gbuf,y,1);
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ImageGetRow(image,bbuf,y,2);
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ImageGetRow(image,abuf,y,3); /* Discard. */
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rgbtorgb(rbuf,gbuf,bbuf,ptr,image->xsize);
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ptr += (image->xsize * 3);
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} else {
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ImageGetRow(image,rbuf,y,0);
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ImageGetRow(image,gbuf,y,1);
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ImageGetRow(image,bbuf,y,2);
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rgbtorgb(rbuf,gbuf,bbuf,ptr,image->xsize);
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ptr += (image->xsize * 3);
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}
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}
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ImageClose(image);
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free(rbuf);
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free(gbuf);
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free(bbuf);
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free(abuf);
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return (GLubyte *) base;
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}
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int main(int argc, char **argv)
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{
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int width, height;
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GLubyte *data;
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if (argc != 2)
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{
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fprintf(stderr, "usage: %s <filename>\n", argv[0]);
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return 1;
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}
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data = read_rgb_texture(argv[1], &width, &height);
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printf("P6\n%d %d\n255\n", width, height);
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fwrite(data, width * 3, height, stdout);
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return 0;
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}
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