在 OpenGL 中绘制一个实心立方体

Question

I am trying to draw a solid cube in open GL to serve as a background of an interface button. The problem is, it is not being drawn on the screen at all. I have a class OGWindow that handles the drawing and a main class/method. I invoke all of the necessary methods from OGWindow in the main class. What am I doing wrong here?

This is my main class:

OGWindow    theWindow;

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

glutInit(&argc, argv);
glutInitDisplayMode(GLUT_RGB | GLUT_DOUBLE | GLUT_DEPTH);   
glutInitWindowSize( 1000, 600 );
glutInitWindowPosition(0, 0);
glutCreateWindow("OpenGL Demo");
glEnable(GL_DEPTH_TEST);    // enable the depth buffer test

glutDisplayFunc(DrawGLScene);
glutReshapeFunc(ReSizeGLScene);
glutMouseFunc(mouseClick);
glutMotionFunc(mouseMotion);
glutPassiveMotionFunc(mousePassiveMotion);
glutIdleFunc(Idle);
theWindow.initGL(); 

glutMainLoop();
}

void DrawGLScene(void) {
   theWindow.myDrawGLScene();
}

This is my OGWindow class:

void OGWindow::initGL(void) {


glClearColor(1.0, 1.0, 1.0, 1.0);

squareX = 1.0;
squareY = 1.0;

squareWidth = 40.0;
squareHeight = 40.0;
squareColour = RED;

squareDraggingP = false;
}


void OGWindow::MyReSizeGLScene(int fwidth, int fheight) 
{
// Store window size  in class variables so it can be accessed in myDrawGLScene() if necessary
wWidth = fwidth;
wHeight = fheight;

// Calculate aspect ration of the OpenGL window
aspect_ratio = (float) fwidth / fheight;

// Set camera so it can see a square area of space running from 0 to 10 
// in both X and Y directions, plus a bit of space around it.
Ymin = 0;
Xmin = 0;

Ymax = 600;
// Choose Xmax so that the aspect ration of the projection
// = the aspect ratio of the viewport
//Xmax = (aspect_ratio * (Ymax -Ymin)) + Xmin;
Xmax = 1000;

glMatrixMode(GL_PROJECTION);        // Select The Projection Stack
glLoadIdentity();
glOrtho(Xmin, Xmax, Ymin, Ymax, -1.0, 1.0);

glViewport(0, 0, wWidth, wHeight);      // Viewport fills the window
}


void OGWindow::myDrawGLScene(GLvoid)        // Here's Where We Do All The Drawing
{
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT); // clear the drawing area

glMatrixMode(GL_MODELVIEW);
glLoadIdentity();

OGWindow::myDrawModel();
glColor3f(0.0, 0.0, 0.0);
drawToolbar();
drawCreateButton();

glutSwapBuffers(); // Needed if we're running an animation
glFlush();
}

And this is the method that is suppose to draw a solid cube in the scene:

void OGWindow::drawCreateButton(GLvoid){
glPushMatrix();
glColor3f(0.0, 1.0, 0.0);
    glTranslatef(10.0,30.0,0.0);
    glutSolidCube(4);
glPopMatrix();
 }

Answer 1

Sorry if i'm not answering your question, but it seems you're not using modern OpenGL, functions like glMatrixMode(GL_PROJECTION); and a lot more in your code should be avoided in modern applications.

Instead of glVertex() and glColor() you should use a VBO and a shader.

Here's a modern OpenGL tutorial wich is easy to follow: OpenGL tutorial for beginners