openGL_glOriginalGray

#define FILENAME_IN "../../bmp/ãÓÉPäx1.bmp"

#include <stdio.h>
#include <GLUT/glut.h>
#include "bmpLoadSave.h"

//ä÷êîÇÃÉvÉçÉgÉ^ÉCÉvêÈåæ
void init();
void display();
void resize(int w, int h);
void keyboard(unsigned char key, int x, int y);
//ïœêî
//âÊëúÇÃÉTÉCÉY
int imgWidth, imgHeight;
GLubyte image[MAX_HEIGHT * MAX_WIDTH];
//ÉEÉCÉìÉhÉEÇÃÉTÉCÉY
int width  = 800;
int height = 600;
//ï\é¶âÊëúÇÃç∂è„énì_
int px0 = 10;
int py0 = 10;
//ç∂â∫
int qx0, qy0;

int main(int argc, char** argv)
{
    glutInit(&argc, argv);

    //ï\é¶ÉÇÅ[Éh
    glutInitDisplayMode(GLUT_RGBA);
    //ï\é¶ÉEÉBÉìÉhÉEÇÃÉTÉCÉY
    glutInitWindowSize(width, height);
    //ç∂è„ÇÃà íu
    glutInitWindowPosition(100, 100);
    //ÉEÉBÉìÉhÉEçÏê¨
    glutCreateWindow("GL_OriginalGray");
    //ÉEÉBÉìÉhÉEÇÃÉTÉCÉYïœçX
    glutReshapeFunc(resize);
    //ÉLÅ[É{Å[ÉhÇÃóòóp
    glutKeyboardFunc(keyboard);
    //ï\é¶
    glutDisplayFunc(display);
    //èâä˙ê›íË
    init();
    //ÉCÉxÉìÉgèàóùÉãÅ[ÉvÇ…ì¸ÇÈ
    glutMainLoop();
    return 0;
}

void init(void)
{
    //îwåiêF
    glClearColor(0.2, 0.2, 0.2, 1.0);
    //ÉÇÉmÉNÉçâÊëúÇÃéÊìæ
    loadGrayData(image, &imgWidth, &imgHeight, FILENAME_IN);
}

void display(void)
{
    //ÉJÉâÅ[ÉoÉbÉtÉ@ÇÃÉNÉäÉA
    glClear(GL_COLOR_BUFFER_BIT);

    //ç∂â∫ÇÃà íu
    qx0 = px0;
    qy0 = height - imgHeight- py0;
    if(qy0 < 0) qy0 = 0;
    glRasterPos2i(qx0, qy0);
    glPixelStorei(GL_UNPACK_ALIGNMENT, 1);
    glDrawPixels(imgWidth, imgHeight, GL_LUMINANCE, GL_UNSIGNED_BYTE, image);
    //èIóπ
    glFlush();
}

void resize(int w, int h)
{
    //ÉrÉÖÅ[É|Å[Égïœä∑
    glViewport(0, 0, w, h);
    //ÉvÉçÉWÉFÉNÉVÉáÉìçsóÒÇÃéwíËÇ∆èâä˙âª
    glMatrixMode(GL_PROJECTION);
    glLoadIdentity();
    //ê≥ìäâeçsóÒÇÃê›íËÅiìäâeïœä∑Åj
    gluOrtho2D(0.0, w, 0.0, h);

    width = w;
    height = h;
}

void keyboard(unsigned char key, int x, int y)
{
    switch((unsigned char)key)
    {
        case 27://Esc
            exit(0);
            break;

        default:
            break;
    }
}