TSTRETCH.C

/* 
* (c) Copyright 1993, Silicon Graphics, Inc.
* 1993-1995 Microsoft Corporation
*
* ALL RIGHTS RESERVED
*
* Please refer to OpenGL/readme.txt for additional information
*
*/

#include "glos.h"

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <math.h>
#include <gl\glaux.h>

#define STEPCOUNT 40
#define FALSE 0
#define TRUE 1
#define MAX(a, b) (((a) > (b)) ? (a) : (b))
#define MIN(a, b) (((a) < (b)) ? (a) : (b))

enum {
OP_NOOP = 0,
OP_STRETCH,
OP_DRAWPOINT,
OP_DRAWIMAGE
};


typedef struct _cRec {
float x, y;
} cRec;

typedef struct _vertexRec {
float x, y;
float dX, dY;
float tX, tY;
} vertexRec;

extern void DrawImage(void );
extern void DrawPoint(void );
extern void InitVList(void );
extern void ScaleImage(int sizeX,int sizeY);
extern void SetPoint(int x,int y);
extern void Stretch(void );
static void CALLBACK Key_SPACE(void );
static GLenum CALLBACK Mouse_left(struct _AUX_EVENTREC *event);
extern void CALLBACK Animate(void );
static GLenum Args(int argc,char **argv );

GLenum doubleBuffer;
int imageSizeX, imageSizeY;
char *fileName = 0;
AUX_RGBImageRec *image;
cRec cList[50];
vertexRec vList[5];
int cCount, cIndex[2], cStep;
GLenum op = OP_NOOP;


void DrawImage(void)
{

glRasterPos2i(0, 0);
glDrawPixels(image->sizeX, image->sizeY, GL_RGB, GL_UNSIGNED_BYTE,
image->data);

auxSwapBuffers();

glRasterPos2i(0, 0);
glDrawPixels(image->sizeX, image->sizeY, GL_RGB, GL_UNSIGNED_BYTE,
image->data);
}

void DrawPoint(void)
{
int i;

glColor3f(1.0, 0.0, 1.0);
glPointSize(3.0);
glBegin(GL_POINTS);
for (i = 0; i < cCount; i++) {
glVertex2f(cList[i].x, cList[i].y);
}
glEnd();

auxSwapBuffers();
}

void InitVList(void)
{

vList[0].x = 0.0;
vList[0].y = 0.0;
vList[0].dX = 0.0;
vList[0].dY = 0.0;
vList[0].tX = 0.0;
vList[0].tY = 0.0;

vList[1].x = (float)imageSizeX;
vList[1].y = 0.0;
vList[1].dX = 0.0;
vList[1].dY = 0.0;
vList[1].tX = 1.0;
vList[1].tY = 0.0;

vList[2].x = (float)imageSizeX;
vList[2].y = (float)imageSizeY;
vList[2].dX = 0.0;
vList[2].dY = 0.0;
vList[2].tX = 1.0;
vList[2].tY = 1.0;

vList[3].x = 0.0;
vList[3].y = (float)imageSizeY;
vList[3].dX = 0.0;
vList[3].dY = 0.0;
vList[3].tX = 0.0;
vList[3].tY = 1.0;

vList[4].x = cList[0].x;
vList[4].y = cList[0].y;
vList[4].dX = (cList[1].x - cList[0].x) / STEPCOUNT;
vList[4].dY = (cList[1].y - cList[0].y) / STEPCOUNT;
vList[4].tX = cList[0].x / (float)imageSizeX;
vList[4].tY = cList[0].y / (float)imageSizeY;
}

void ScaleImage(int sizeX, int sizeY)
{
GLubyte *buf;

buf = (GLubyte *)malloc(3*sizeX*sizeY);
gluScaleImage(GL_RGB, image->sizeX, image->sizeY, GL_UNSIGNED_BYTE,
image->data, sizeX, sizeY, GL_UNSIGNED_BYTE, buf);
free(image->data);
image->data = buf;
image->sizeX = sizeX;
image->sizeY = sizeY;
}

void SetPoint(int x, int y)
{

cList[cCount].x = (float)x;
cList[cCount].y = (float)y;
cCount++;
}

void Stretch(void)
{

glBegin(GL_TRIANGLES);
glTexCoord2f(vList[0].tX, vList[0].tY);
glVertex2f(vList[0].x, vList[0].y);
glTexCoord2f(vList[1].tX, vList[1].tY);
glVertex2f(vList[1].x, vList[1].y);
glTexCoord2f(vList[4].tX, vList[4].tY);
glVertex2f(vList[4].x, vList[4].y);
glEnd();

glBegin(GL_TRIANGLES);
glTexCoord2f(vList[1].tX, vList[1].tY);
glVertex2f(vList[1].x, vList[1].y);
glTexCoord2f(vList[2].tX, vList[2].tY);
glVertex2f(vList[2].x, vList[2].y);
glTexCoord2f(vList[4].tX, vList[4].tY);
glVertex2f(vList[4].x, vList[4].y);
glEnd();

glBegin(GL_TRIANGLES);
glTexCoord2f(vList[2].tX, vList[2].tY);
glVertex2f(vList[2].x, vList[2].y);
glTexCoord2f(vList[3].tX, vList[3].tY);
glVertex2f(vList[3].x, vList[3].y);
glTexCoord2f(vList[4].tX, vList[4].tY);
glVertex2f(vList[4].x, vList[4].y);
glEnd();

glBegin(GL_TRIANGLES);
glTexCoord2f(vList[3].tX, vList[3].tY);
glVertex2f(vList[3].x, vList[3].y);
glTexCoord2f(vList[0].tX, vList[0].tY);
glVertex2f(vList[0].x, vList[0].y);
glTexCoord2f(vList[4].tX, vList[4].tY);
glVertex2f(vList[4].x, vList[4].y);
glEnd();

auxSwapBuffers();

if (++cStep < STEPCOUNT) {
vList[4].x += vList[4].dX;
vList[4].y += vList[4].dY;
} else {
cIndex[0] = cIndex[1];
cIndex[1] = cIndex[1] + 1;
if (cIndex[1] == cCount) {
cIndex[1] = 0;
}
vList[4].dX = (cList[cIndex[1]].x - cList[cIndex[0]].x) / STEPCOUNT;
vList[4].dY = (cList[cIndex[1]].y - cList[cIndex[0]].y) / STEPCOUNT;
cStep = 0;
}
}

static void CALLBACK Key_SPACE(void)
{
if (cCount > 1) {
InitVList();
cIndex[0] = 0;
cIndex[1] = 1;
cStep = 0;
glEnable(GL_TEXTURE_2D);
op = OP_STRETCH;
}
}

static GLenum CALLBACK Mouse_left(AUX_EVENTREC *event)
{
GLint mouseX;
GLint mouseY;

mouseX = event->data[AUX_MOUSEX];
mouseY = event->data[AUX_MOUSEY];
if (op == OP_STRETCH) {
glDisable(GL_TEXTURE_2D);
cCount = 0;
op = OP_DRAWIMAGE;
} else {
SetPoint(mouseX, imageSizeY-mouseY);
op = OP_DRAWPOINT;
}
return GL_TRUE;
}

void CALLBACK Animate(void)
{

switch (op) {
case OP_STRETCH:
Stretch();
break;
case OP_DRAWPOINT:
DrawPoint();
break;
case OP_DRAWIMAGE:
DrawImage();
break;
}
}

static GLenum Args(int argc, char **argv)
{
GLint i;

doubleBuffer = GL_FALSE;


for (i = 1; i < argc; i++) {
if (strcmp(argv[i], "-sb") == 0) {
doubleBuffer = GL_FALSE;
} else if (strcmp(argv[i], "-db") == 0) {
doubleBuffer = GL_TRUE;
} else if (strcmp(argv[i], "-f") == 0) {
if (i+1 >= argc || argv[i+1][0] == '-') {
//printf("-f (No file name).\n");
return GL_FALSE;
} else {
fileName = argv[++i];
}
} else {
//printf("%s (Bad option).\n", argv[i]);
return GL_FALSE;
}
}
return GL_TRUE;
}

void main(int argc, char **argv)
{
GLenum type;

if (Args(argc, argv) == GL_FALSE) {
auxQuit();
}

if (fileName == 0) {
//printf("No image file.\n");
auxQuit();
}

image = auxRGBImageLoad(fileName);

imageSizeX = (int)pow(2.0, (float)((int)(log(image->sizeX)/log(2.0))));
imageSizeY = (int)pow(2.0, (float)((int)(log(image->sizeY)/log(2.0))));

auxInitPosition(0, 0, imageSizeX, imageSizeY);

type = AUX_RGB;
type |= (doubleBuffer) ? AUX_DOUBLE : AUX_SINGLE;

auxInitDisplayMode(type);

if (auxInitWindow("Stretch") == GL_FALSE) {
auxQuit();
}

glViewport(0, 0, imageSizeX, imageSizeY);
gluOrtho2D(0, imageSizeX, 0, imageSizeY);
glClearColor(0.0, 0.0, 0.0, 0.0);

glPixelStorei(GL_UNPACK_ALIGNMENT, 1);
glPixelStorei(GL_PACK_ALIGNMENT, 1);

ScaleImage(imageSizeX, imageSizeY);

glTexEnvi(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_DECAL);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
glTexImage2D(GL_TEXTURE_2D, 0, 3, image->sizeX, image->sizeY, 0,
GL_RGB, GL_UNSIGNED_BYTE, (unsigned char *)image->data);

cCount = 0;
cIndex[0] = 0;
cIndex[1] = 0;
cStep = 0;
op = OP_DRAWIMAGE;

auxKeyFunc(AUX_SPACE, Key_SPACE);
auxMouseFunc(AUX_LEFTBUTTON, AUX_MOUSEDOWN, Mouse_left);
auxIdleFunc(Animate);
auxMainLoop(NULL);
}