www.pudn.com > blendpot.rar > BLENDPOT.C

/* 
 * Transparent pots using glBlendFunc() from Chapter 10. 
 * 
 * Written by Michael Sweet. 
 */ 
 
/* 
 * Include necessary headers. 
 */ 
 
#include  
 
 
/* 
 * Globals... 
 */ 
 
int Width;  /* Width of window */ 
int Height; /* Height of window */ 
 
 
/* 
 * Functions... 
 */ 
 
void Redraw(void); 
void Resize(int width, int height); 
 
 
/* 
 * 'main()' - Open a window and display two teapots. 
 */ 
 
int                /* O - Exit status */ 
main(int  argc,    /* I - Number of command-line arguments */ 
     char *argv[]) /* I - Command-line arguments */ 
    { 
    glutInit(&argc, argv); 
    glutInitDisplayMode(GLUT_RGB | GLUT_DEPTH); 
    glutInitWindowSize(792, 573); 
    glutCreateWindow("Transparent Teapots"); 
    glutReshapeFunc(Resize); 
    glutDisplayFunc(Redraw); 
    glutMainLoop(); 
    return (0); 
    } 
 
 
/* 
 * 'Redraw()' - Clear the window... 
 */ 
 
void 
Redraw(void) 
    { 
    static GLfloat red_light[4]  = { 1.0, 0.0, 0.0, 1.0 }; 
    static GLfloat red_pos[4]    = { 1.0, 1.0, 1.0, 0.0 }; 
    static GLfloat blue_light[4] = { 0.0, 0.0, 1.0, 1.0 }; 
    static GLfloat blue_pos[4]   = { -1.0, -1.0, -1.0, 0.0 }; 
 
    /* Clear the window to black */ 
    glClearColor(0.0, 0.0, 0.0, 1.0); 
    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT); 
 
    /* Enable drawing features that we need... */ 
    glEnable(GL_DEPTH_TEST); 
    glEnable(GL_LIGHTING); 
    glEnable(GL_LIGHT0); 
    glEnable(GL_LIGHT1); 
 
    glShadeModel(GL_SMOOTH); 
 
    /* 
     * Draw two teapots in different colors... 
     * 
     * We have positioned two lights in this scene.  The first is red and 
     * located above, to the right, and behind the viewer.  The second is blue 
     * and located below, to the left, and in front of the viewer. 
     */ 
 
    glLightfv(GL_LIGHT0, GL_DIFFUSE, red_light); 
    glLightfv(GL_LIGHT0, GL_POSITION, red_pos); 
 
    glLightfv(GL_LIGHT1, GL_DIFFUSE, blue_light); 
    glLightfv(GL_LIGHT1, GL_POSITION, blue_pos); 
 
    glEnable(GL_COLOR_MATERIAL); 
    glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA); 
 
    glPushMatrix(); 
    glTranslatef(0.0, 0.0, -15.0); 
    glRotatef(-45.0, 0.0, 1.0, 0.0); 
 
    glDisable(GL_BLEND); 
    glColor3f(1.0, 1.0, 0.0); 
    glutSolidTeapot(1.0); 
    glPopMatrix(); 
 
    glPushMatrix(); 
    glTranslatef(0.0, 0.0, -10.0); 
    glRotatef(45.0, 0.0, 1.0, 0.0); 
 
    glEnable(GL_BLEND); 
    glColor4f(1.0, 1.0, 1.0, 0.25); 
    glutSolidTeapot(1.0); 
    glPopMatrix(); 
 
    glFinish(); 
    } 
 
 
/* 
 * 'Resize()' - Resize the window... 
 */ 
 
void 
Resize(int width,  /* I - Width of window */ 
       int height) /* I - Height of window */ 
    { 
    /* Save the new width and height */ 
    Width  = width; 
    Height = height; 
 
    /* Reset the viewport... */ 
    glViewport(0, 0, width, height); 
 
    glMatrixMode(GL_PROJECTION); 
    glLoadIdentity(); 
    gluPerspective(22.5, (float)width / (float)height, 0.1, 1000.0); 
    glMatrixMode(GL_MODELVIEW); 
    }