将二维对象附加到 OpenGL 中的 3d 对象

Question

我正在尝试在我制作的 3d 立方体的侧面渲染 2d object。 立方体旋转，在此过程中它也会旋转 2d object。 如何将 2d object 连接到立方体的侧面？

我尝试了很多方法，包括将 2d object 制作成 bitmap，然后将 bitmap 作为纹理附加到立方体上。 但我觉得这不是一种专业的方式来做到这一点。

3D魔方

void DrawCube(void)
{
     glMatrixMode(GL_MODELVIEW);
    // clear the drawing buffer.
    glClear(GL_COLOR_BUFFER_BIT);
   glLoadIdentity();
        glTranslatef(0.0,0.0,-10.5);
    glRotatef(xRotated,1.0,0.0,0.0);
    // rotation about Y axis
    glRotatef(yRotated,0.0,1.0,0.0);
    // rotation about Z axis
    glRotatef(zRotated,0.0,0.0,1.0);
  glBegin(GL_QUADS);        // Draw The Cube Using quads
    glColor3f(0.0f,1.0f,0.0f);    // Color Blue
    glVertex3f( 1.0f, 1.0f,-1.0f);    // Top Right Of The Quad (Top)
    glVertex3f(-1.0f, 1.0f,-1.0f);    // Top Left Of The Quad (Top)
    glVertex3f(-1.0f, 1.0f, 1.0f);    // Bottom Left Of The Quad (Top)
    glVertex3f( 1.0f, 1.0f, 1.0f);    // Bottom Right Of The Quad (Top)
    glColor3f(1.0f,0.5f,0.0f);    // Color Orange
    glVertex3f( 1.0f,-1.0f, 1.0f);    // Top Right Of The Quad (Bottom)
    glVertex3f(-1.0f,-1.0f, 1.0f);    // Top Left Of The Quad (Bottom)
    glVertex3f(-1.0f,-1.0f,-1.0f);    // Bottom Left Of The Quad (Bottom)
    glVertex3f( 1.0f,-1.0f,-1.0f);    // Bottom Right Of The Quad (Bottom)
    glColor3f(1.0f,0.0f,0.0f);    // Color Red
    glVertex3f( 1.0f, 1.0f, 1.0f);    // Top Right Of The Quad (Front)
    glVertex3f(-1.0f, 1.0f, 1.0f);    // Top Left Of The Quad (Front)
    glVertex3f(-1.0f,-1.0f, 1.0f);    // Bottom Left Of The Quad (Front)
    glVertex3f( 1.0f,-1.0f, 1.0f);    // Bottom Right Of The Quad (Front)
    glColor3f(1.0f,1.0f,0.0f);    // Color Yellow
    glVertex3f( 1.0f,-1.0f,-1.0f);    // Top Right Of The Quad (Back)
    glVertex3f(-1.0f,-1.0f,-1.0f);    // Top Left Of The Quad (Back)
    glVertex3f(-1.0f, 1.0f,-1.0f);    // Bottom Left Of The Quad (Back)
    glVertex3f( 1.0f, 1.0f,-1.0f);    // Bottom Right Of The Quad (Back)
    glColor3f(0.0f,0.0f,1.0f);    // Color Blue
    glVertex3f(-1.0f, 1.0f, 1.0f);    // Top Right Of The Quad (Left)
    glVertex3f(-1.0f, 1.0f,-1.0f);    // Top Left Of The Quad (Left)
    glVertex3f(-1.0f,-1.0f,-1.0f);    // Bottom Left Of The Quad (Left)
    glVertex3f(-1.0f,-1.0f, 1.0f);    // Bottom Right Of The Quad (Left)
    glColor3f(1.0f,0.0f,1.0f);    // Color Violet
    glVertex3f( 1.0f, 1.0f,-1.0f);    // Top Right Of The Quad (Right)
    glVertex3f( 1.0f, 1.0f, 1.0f);    // Top Left Of The Quad (Right)
    glVertex3f( 1.0f,-1.0f, 1.0f);    // Bottom Left Of The Quad (Right)
    glVertex3f( 1.0f,-1.0f,-1.0f);    // Bottom Right Of The Quad (Right)
  glEnd();            // End Drawing The Cube
glFlush();
}

样品 2D Object

void Rectangle(double bottomLeftVertexX, double bottomLeftVertexY, double topRightVertexX, double topRightVertexY)
{
    double x1 = bottomLeftVertexX;
    double y1 = bottomLeftVertexY;
    double x2 = topRightVertexX;
    double y2 = topRightVertexY;


    glBegin(GL_POLYGON);
        glVertex2f(x1, y1);
        glVertex2f(x2, y1);
        glVertex2f(x2, y2);
        glVertex2f(x1, y2);
    glEnd();
}

Rectangle(20.0, 15.0, 40.0, 47.0);