☆OpenGL_bitmap_texture2_cat☆

#include <stdio.h>
#include <stdlib.h>
#include <GLUT/glut.h>


/* keep the picture data*/
#define  IMGFILE  "cat.bmp"
#define  CHANNEL  3  // color(R, G, B)
int width;           // width of picture
int height;          // height of picture
GLuint texture;      // texture number
GLubyte* image;      // keep the BMP data


void loadImage(const char* filepath);  // read BMP

float shiftX,shiftY;
float mouseX,mouseY;
float x,y;
float a;
float g_pressed = 0;

void display(void)
{


    /*diaplay the picture */
    glEnable(GL_TEXTURE_2D);
    glClear(GL_COLOR_BUFFER_BIT);
    glBindTexture(GL_TEXTURE_2D, texture);

    glTranslated(-0.5,-0.5,0);

    glBegin(GL_QUADS);


    glTexCoord2f(1.0, 0.0);  glVertex2f(1.0, 0.0);//position
    glTexCoord2f(1.0, 1.0);  glVertex2f(1.0, 1.0);
    glTexCoord2f(0.0, 1.0);  glVertex2f(0.0, 1.0);
    glTexCoord2f(0.0, 0.0);  glVertex2f(0.0, 0.0);

    //glClear(GL_COLOR_BUFFER_BIT);

    glDisable(GL_TEXTURE_2D);

    glEnd();


    //glColor3d(0.0, 0.0, 0.0);//color


    glTranslated(0.5,0.5,0);
    glTranslatef(shiftX,shiftY,0);

    x=0.1;
    y=0.1;

    glBegin(GL_LINE_LOOP);

    glVertex2d(-x+shiftX, -y+shiftY);//position
    glVertex2d(x+shiftX, -y+shiftY);
    glVertex2d(x+shiftX, y+shiftY);
    glVertex2d(-x+shiftX, y+shiftY);

    //glPushMatrix();
    //glTranslatef(shiftX,shiftY,0);
    // glTranslatef(0.5,0.5,0);
    //glPopMatrix();
    glEnd();


    glutSwapBuffers();



    //glFlush();

}



void myInit(void)
{
    /* necessary setting for before create window*/
    glutInitWindowSize(800, 600);                  // setting for window size
    glutInitWindowPosition(0, 0);              // window position
    glutInitDisplayMode(GLUT_RGBA | GLUT_DOUBLE);  // setting display mode
    glutCreateWindow("OpenGL");                    // create window
    glClearColor (0.0, 0.0, 0.0, 1.0);             // window back color


    glutDisplayFunc(display);
    //create texture
    loadImage(IMGFILE);
    glPixelStorei(GL_UNPACK_ALIGNMENT, 8);
    glGenTextures(1, &texture);
    glBindTexture(GL_TEXTURE_2D, texture);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
    glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB,
                 width, height, 0, GL_RGB,
                 GL_UNSIGNED_BYTE, image);
    free(image);
}

void keyboard(unsigned char key, int x, int y)  //keyboard setting
{
    switch (key) {
        case 'q':
        case 'Q':
        case '\033':
            exit(0);
        default:
            break;
    }
}


void mouse(int btn, int state, int x, int y)  //mouze setting
{


    if(btn == GLUT_LEFT_BUTTON == state == GLUT_DOWN)  //when press the left button
    {

        mouseX = x;
        mouseY = y;
        g_pressed = 1;
    }
    else if(btn == GLUT_LEFT_BUTTON == state ==GLUT_UP)  //when take off the left button
    {
        g_pressed = 0;

    }
}

void motion(int x, int y)  //controll the motion by the mouse
{
    {

        shiftX = (float)((x - mouseX)/6000);
        shiftY = (float)(-(y - mouseY)/6000);

        glutPostRedisplay();

    }

    printf("X = %d : Y = %d\n" , x , y);  //diplay the position of coordinate
    printf("ShiftX = %f : ShiftY = %f\n" , shiftX , shiftY);  //display the amount of the shift
    printf("mouseX = %f : mouseY = %f \n" , mouseX , mouseY);  //display the mouseX and mouseY

}

int main(int argc, char* argv[])
{

    glutInit(&argc, argv);
    //glutInitDisplayMode(GLUT_RGBA);
    //glutCreateWindow(argv[0]);
    myInit();
    glutDisplayFunc(display);  //when need to set about display function
    glutKeyboardFunc(keyboard);  //when need keyboard function
    glutMouseFunc(mouse);  //when need mouse function
    glutMotionFunc(motion);  //when need mouse motion function


    glutMainLoop();

    return 0;
}



void loadImage(const char* filepath)
{
    int i;
    int size;  // size of picture (width , height, color)
    FILE* fp;

     /* read file */
    fp = fopen(filepath, "rb");  //read binary
    if (fp == NULL)
    {
        fprintf(stderr, "%sfail loading\n", filepath);
        exit(EXIT_FAILURE);
    }

    /* get width and height  */
    fseek(fp, 18, SEEK_SET);  //move fp to place where has been put width of picture
    fread(&width, 4, 1, fp);
    fread(&height, 4, 1, fp);

    /* read data of picture */
    fseek(fp, 54, SEEK_SET);  //move fp to place where has been put dataof the picture
    size = width * height * CHANNEL;
    image = (GLubyte* ) malloc(size);
    if (image == NULL)
    {
        fprintf(stderr, "fail to keep the memory\n");
        exit(EXIT_FAILURE);
    }

    for (i = 0; i < size; ++i)
        fread(&image[i], sizeof(GLubyte), 1, fp);

    /* exit */
    fclose(fp);
}