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); 
}