transformation.c

OpenGL的大海量资料收集

world_display(void)
{
    GLfloat pos[] = { 0.0, 0.0, 1.0, 0.0 };
    double length;
    float l[3];
    
    l[0] = at[0] - eye[0]; 
    l[1] = at[0] - eye[1]; 
    l[2] = at[0] - eye[2];
    length = normalize(l);
    
    invert(modelview, inverse);
    
    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
    
    if (world_draw) {
        glEnable(GL_LIGHTING);
        glPushMatrix();
        glMultMatrixd(inverse);
        glLightfv(GL_LIGHT0, GL_POSITION, pos);
        glPopMatrix();
        drawmodel();
        glDisable(GL_LIGHTING);
    }
    
    glPushMatrix();
    
    glMultMatrixd(inverse);
    
    glLightfv(GL_LIGHT0, GL_POSITION, pos);
    
    /* draw the axis and eye vector */
    glPushMatrix();
    glColor3ub(0, 0, 255);
    glBegin(GL_LINE_STRIP);
    glVertex3f(0.0, 0.0, 0.0);
    glVertex3f(0.0, 0.0, -1.0*length);
    glVertex3f(0.1, 0.0, -0.9*length);
    glVertex3f(-0.1, 0.0, -0.9*length);
    glVertex3f(0.0, 0.0, -1.0*length);
    glVertex3f(0.0, 0.1, -0.9*length);
    glVertex3f(0.0, -0.1, -0.9*length);
    glVertex3f(0.0, 0.0, -1.0*length);
    glEnd();
    glColor3ub(255, 255, 0);
    glRasterPos3f(0.0, 0.0, -1.1*length);
    glutBitmapCharacter(GLUT_BITMAP_HELVETICA_12, 'e');
    glColor3ub(255, 0, 0);
    glScalef(0.4, 0.4, 0.4);
    drawaxes();
    glPopMatrix();
    
    invert(projection, inverse);
    glMultMatrixd(inverse);
    
    /* draw the viewing frustum */
    glColor3f(0.2, 0.2, 0.2);
    glBegin(GL_QUADS);
    glVertex3i(1, 1, 1);
    glVertex3i(-1, 1, 1);
    glVertex3i(-1, -1, 1);
    glVertex3i(1, -1, 1);
    glEnd();
    
    glColor3ub(128, 196, 128);
    glBegin(GL_LINES);
    glVertex3i(1, 1, -1);
    glVertex3i(1, 1, 1);
    glVertex3i(-1, 1, -1);
    glVertex3i(-1, 1, 1);
    glVertex3i(-1, -1, -1);
    glVertex3i(-1, -1, 1);
    glVertex3i(1, -1, -1);
    glVertex3i(1, -1, 1);
    glEnd();
    
    glEnable(GL_BLEND);
    glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
    glColor4f(0.2, 0.2, 0.4, 0.5);
    glBegin(GL_QUADS);
    glVertex3i(1, 1, -1);
    glVertex3i(-1, 1, -1);
    glVertex3i(-1, -1, -1);
    glVertex3i(1, -1, -1);
    glEnd();
    glDisable(GL_BLEND);
    
    glPopMatrix();
    glutSwapBuffers();
}

void
world_menu(int value)
{
    switch (value) {
    case 'm':
        world_draw = !world_draw;
        break;
    }
    redisplay_all();
}

void
screen_reshape(int width, int height)
{
    glViewport(0, 0, width, height);
    glMatrixMode(GL_PROJECTION);
    glLoadIdentity();
    gluPerspective(60.0, (float)width/height, 0.5, 8.0);
    glGetDoublev(GL_PROJECTION_MATRIX, projection);
    glMatrixMode(GL_MODELVIEW);
    glLoadIdentity();
    gluLookAt(eye[0], eye[1], eye[2], at[0], at[1], at[2], up[0], up[1],up[2]);
    if (swapped) {
        glRotatef(rotation[0].value, rotation[1].value, 
            rotation[2].value, rotation[3].value);
        glTranslatef(translation[0].value, translation[1].value,
            translation[2].value);
    } else {
        glTranslatef(translation[0].value, translation[1].value,
            translation[2].value);
        glRotatef(rotation[0].value, rotation[1].value, 
            rotation[2].value, rotation[3].value);
    }
    glScalef(scale[0].value, scale[1].value, scale[2].value);
    glGetDoublev(GL_MODELVIEW_MATRIX, modelview);
    glClearColor(0.2, 0.2, 0.2, 0.0);
    glEnable(GL_DEPTH_TEST);
    glEnable(GL_LIGHTING);
    glEnable(GL_LIGHT0);
}

void
screen_display(void)
{
    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
    drawmodel();
    glutSwapBuffers();
}

void
screen_menu(int value)
{
    char* name = 0;
    
    switch (value) {
    case 'a':
        name = "data/al.obj";
        break;
    case 's':
        name = "data/soccerball.obj";
        break;
    case 'd':
        name = "data/dolphins.obj";
        break;
    case 'f':
        name = "data/flowers.obj";
        break;
    case 'j':
        name = "data/f-16.obj";
        break;
    case 'p':
        name = "data/porsche.obj";
        break;
    case 'r':
        name = "data/rose+vase.obj";
        break;
    }
    
    if (name) {
        pmodel = glmReadOBJ(name);
        if (!pmodel) exit(0);
        glmUnitize(pmodel);
        glmFacetNormals(pmodel);
        glmVertexNormals(pmodel, 90.0);
    }
    
    redisplay_all();
}

void
command_reshape(int width, int height)
{
    glViewport(0, 0, width, height);
    glMatrixMode(GL_PROJECTION);
    glLoadIdentity();
    gluOrtho2D(0, width, height, 0);
    glMatrixMode(GL_MODELVIEW);
    glLoadIdentity();
    glClearColor(0.0, 0.0, 0.0, 0.0);
}

void
command_display(void)
{
    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
    
    if (swapped) {
        translation[0].y = 80;
        translation[1].y = 80;
        translation[2].y = 80;
        rotation[0].y = 40;
        rotation[1].y = 40;
        rotation[2].y = 40;
        rotation[3].y = 40;
    } else {
        translation[0].y = 40;
        translation[1].y = 40;
        translation[2].y = 40;
        rotation[0].y = 80;
        rotation[1].y = 80;
        rotation[2].y = 80;
        rotation[3].y = 80;
    }
    
    glColor3ub(255, 255, 255);
    setfont("helvetica", 18);
    drawstr(30, rotation[0].y, "glRotatef(");
    drawstr(170, rotation[0].y, ",");
    drawstr(230, rotation[0].y, ","); 
    drawstr(290, rotation[0].y, ",");
    drawstr(350, rotation[0].y, ");");
    drawstr(10, translation[0].y, "glTranslatef(");
    drawstr(170, translation[0].y, ",");
    drawstr(230, translation[0].y, ","); 
    drawstr(290, translation[0].y, ");");
    drawstr(38, 120, "glScalef(");
    drawstr(170, 120, ",");
    drawstr(230, 120, ","); 
    drawstr(290, 120, ");");
    drawstr(41, 160, "glBegin(  . . .  );");
    drawstr(41, 200, " . . .");
    
    cell_draw(&translation[0]);
    cell_draw(&translation[1]);
    cell_draw(&translation[2]);
    
    cell_draw(&rotation[0]);
    cell_draw(&rotation[1]);
    cell_draw(&rotation[2]);
    cell_draw(&rotation[3]);
    
    cell_draw(&scale[0]);
    cell_draw(&scale[1]);
    cell_draw(&scale[2]);
    
    if (!selection) {
        glColor3ub(255, 255, 0);
        drawstr(10, 240,
            "Click on the arguments and move the mouse to modify values.");
    }   
    
    glutSwapBuffers();
}

int old_y;

void
command_mouse(int button, int state, int x, int y)
{
    selection = 0;
    
    if (state == GLUT_DOWN) {
    /* mouse should only hit _one_ of the cells, so adding up all
        the hits just propagates a single hit. */
        selection += cell_hit(&translation[0], x, y);
        selection += cell_hit(&translation[1], x, y);
        selection += cell_hit(&translation[2], x, y);
        selection += cell_hit(&rotation[0], x, y);
        selection += cell_hit(&rotation[1], x, y);
        selection += cell_hit(&rotation[2], x, y);
        selection += cell_hit(&rotation[3], x, y);
        selection += cell_hit(&scale[0], x, y);
        selection += cell_hit(&scale[1], x, y);
        selection += cell_hit(&scale[2], x, y);
    }
    
    old_y = y;
    
    redisplay_all();
}

void
command_motion(int x, int y)
{
    cell_update(&translation[0], old_y-y);
    cell_update(&translation[1], old_y-y);
    cell_update(&translation[2], old_y-y);
    cell_update(&rotation[0], old_y-y);
    cell_update(&rotation[1], old_y-y);
    cell_update(&rotation[2], old_y-y);
    cell_update(&rotation[3], old_y-y);
    cell_update(&scale[0], old_y-y);
    cell_update(&scale[1], old_y-y);
    cell_update(&scale[2], old_y-y);
    
    old_y = y;
    
    redisplay_all();
}

void
command_menu(int value)
{
    main_keyboard((unsigned char)value, 0, 0);
}

void
redisplay_all(void)
{
    glutSetWindow(command);
    glutPostRedisplay();
    glutSetWindow(world);
    world_reshape(sub_width, sub_height);
    glutPostRedisplay();
    glutSetWindow(screen);
    screen_reshape(sub_width, sub_height);
    glutPostRedisplay();
}

int
main(int argc, char** argv)
{
    glutInitDisplayMode(GLUT_RGB | GLUT_DEPTH | GLUT_DOUBLE);
    glutInitWindowSize(512+GAP*3, 512+GAP*3);
    glutInitWindowPosition(50, 50);
    glutInit(&argc, argv);
    
    window = glutCreateWindow("Transformation");
    glutReshapeFunc(main_reshape);
    glutDisplayFunc(main_display);
    glutKeyboardFunc(main_keyboard);
    
    world = glutCreateSubWindow(window, GAP, GAP, 256, 256);
    glutReshapeFunc(world_reshape);
    glutDisplayFunc(world_display);
    glutKeyboardFunc(main_keyboard);
    glutCreateMenu(world_menu);
    glutAddMenuEntry("Toggle model", 'm');
    glutAttachMenu(GLUT_RIGHT_BUTTON);
    
    screen = glutCreateSubWindow(window, GAP+256+GAP, GAP, 256, 256);
    glutReshapeFunc(screen_reshape);
    glutDisplayFunc(screen_display);
    glutKeyboardFunc(main_keyboard);
    glutCreateMenu(screen_menu);
    glutAddMenuEntry("Models", 0);
    glutAddMenuEntry("", 0);
    glutAddMenuEntry("Soccerball", 's');
    glutAddMenuEntry("Al Capone", 'a');
    glutAddMenuEntry("F-16 Jet", 'j');
    glutAddMenuEntry("Dolphins", 'd');
    glutAddMenuEntry("Flowers", 'f');
    glutAddMenuEntry("Porsche", 'p');
    glutAddMenuEntry("Rose", 'r');
    glutAttachMenu(GLUT_RIGHT_BUTTON);
    
    command = glutCreateSubWindow(window, GAP+256+GAP, GAP+256+GAP, 256, 256);
    glutReshapeFunc(command_reshape);
    glutDisplayFunc(command_display);
    glutMotionFunc(command_motion);
    glutMouseFunc(command_mouse);
    glutKeyboardFunc(main_keyboard);
    glutCreateMenu(command_menu);
    glutAddMenuEntry("Projection", 0);
    glutAddMenuEntry("", 0);
    glutAddMenuEntry("[s]  Swap translate/rotate", 's');
    glutAddMenuEntry("[r]  Reset parameters", 'r');
    glutAddMenuEntry("", 0);
    glutAddMenuEntry("Quit", 27);
    glutAttachMenu(GLUT_RIGHT_BUTTON);
    
    redisplay_all();
    
    glutMainLoop();
    
    return 0;
}