c++ - 在 OpenGL 太阳系中创建星星

Question

我正在用 OpenGL C++ 创建一个太阳系，其中地球围绕太阳旋转。

我现在面临的唯一问题是无法在窗口上方创建星星我尝试了一切但没有帮助

现在我已经从这里删除了一些额外的代码，我希望它对你们有用，因为这些功能不是必需的，也不需要进行任何更改

                 #include "Solar.h"
        #include <stdlib.h>
        #include <glut.h>
        static GLenum spinMode = GL_TRUE;
        static GLenum singleStep = GL_FALSE;

        static float HourOfDay = 0.0;
        static float DayOfYear = 0.0;

        static float AnimateIncrement = 2.0;

        void Haxxan()
        {
        glClear(GL_COLOR_BUFFER_BIT);
        glBegin(GL_LINES);
        glColor3f(0.1,0.3,0.9);
        glVertex2f(-0.9,0.5);
        glVertex2f(-0.9,0.0);

        glVertex2f(-0.9,0.25);
        glVertex2f(-0.7,0.25);
        glEnd();
        glFlush();
        }


        /*
         * Animate() handles the animation and the redrawing of the
         *      graphics window contents.
         */
        static void Animate(void)
        {
            // Clear the redering window
            glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
        // Now Make stars Using the Vertex
        //glBegin(GL_LINES);
        //glColor3f(0.1,0.3,0.9);

        /*glVertex2f(-0.9,0.5);
        glVertex2f(-0.9,0.0);

        glVertex2f(-0.9,0.25);
        glVertex2f(-0.7,0.25);
          */
            if (spinMode) {
                // Update the animation state
                HourOfDay += AnimateIncrement;
                DayOfYear += AnimateIncrement/40.0;

                HourOfDay = HourOfDay - ((int)(HourOfDay/24))*24;
                DayOfYear = DayOfYear - ((int)(DayOfYear/365))*365;
                }

            // Clear the current matrix (Modelview)
            glLoadIdentity();

            // Back off eight units to be able to view from the origin.
            glTranslatef ( 0.0, 0.0, -8.0 );

            // Rotate the plane of the elliptic
            // (rotate the model's plane about the x axis by fifteen degrees)
            glRotatef( 15.0, 1.0, 0.0, 0.0 );

            // Draw the sun -- as a yellow, wireframe sphere
            glColor3f( 1.0, 1.0, 0.0 );
            glutWireSphere( 1.0, 15, 15 );
        // Now Draw Stars
        glColor3f(0.0,0.0,1.0);
        //glutWireSphere( 0.3, 18, 9 );
        //glLineStipple(0.1,0.1);
        glVertex2f(0.9,0.3);
        glVertex2f(0.6,0.3);

        //end stars
            // Draw the Earth
            // First position it around the sun
            //      Use DayOfYear to determine its position
            glRotatef( 360.0*DayOfYear/365.0, 0.0, 1.0, 0.0 );
            glTranslatef( 4.0, 0.0, 0.0 );
            glPushMatrix();                     // Save matrix state
            // Second, rotate the earth on its axis.
            //      Use HourOfDay to determine its rotation.
            glRotatef( 360.0*HourOfDay/24.0, 0.0, 1.0, 0.0 );
            // Third, draw the earth as a wireframe sphere.
            glColor3f( 0.2, 0.2, 1.0 );
            glutWireSphere( 0.4, 10, 10);
            glPopMatrix();                      // Restore matrix state

            // Draw the moon.
            //  Use DayOfYear to control its rotation around the earth
            glRotatef( 360.0*12.0*DayOfYear/365.0, 0.0, 1.0, 0.0 );
            glTranslatef( 0.7, 0.0, 0.0 );
            glColor3f( 0.3, 0.7, 0.3 );
            glutWireSphere( 0.1, 5, 5 );
        /* make me
        glRotatef( 360.0*12.0*DayOfYear/365.0, 0.0, 1.0, 0.0 );
            glTranslatef( 0.1, 1.0, 0.2 );
            glColor3f( 0.0, 0.7, 1.0 );
            glutWireSphere( 0.1, 3, 2 );
            */
            // Flush the pipeline, and swap the buffers
            glFlush();
            glutSwapBuffers();

            if ( singleStep ) {
                spinMode = GL_FALSE;
            }

            glutPostRedisplay();        // Request a re-draw for animation purposes

        }

        // Initialize OpenGL's rendering modes
        void OpenGLInit(void)
        {
          //  glClear(GL_COLOR_BUFFER_BIT);
        //glBegin(GL_LINES);
        //glColor3f(0.1,0.3,0.9);
        //glVertex2f(-0.9,0.5);
        //glVertex2f(-0.9,0.0);
          //  glutDisplayFunc(Haxxan);
            glShadeModel( GL_FLAT );
            glClearColor( 0.0, 0.0, 0.0, 0.0 ); 
            glClearDepth( 1.0 );
            glEnable( GL_DEPTH_TEST );
        }

        // ResizeWindow is called when the window is resized
        static void ResizeWindow(int w, int h)
        {
            float aspectRatio;
            h = (h == 0) ? 1 : h;
            w = (w == 0) ? 1 : w;
            glViewport( 0, 0, w, h );   // View port uses whole window
            aspectRatio = (float)w/(float)h;

            // Set up the projection view matrix (not very well!)
            glMatrixMode( GL_PROJECTION );
            glLoadIdentity();
            gluPerspective( 60.0, aspectRatio, 1.0, 30.0 );

            // Select the Modelview matrix
            glMatrixMode( GL_MODELVIEW );
        }
        // Main routine
        // Set up OpenGL, hook up callbacks, and start the main loop
        int main( int argc, char** argv )
        {
            // Need to double buffer for animation
            glutInit(&argc,argv);
            glutInitDisplayMode(GLUT_DOUBLE | GLUT_RGB | GLUT_DEPTH );

            // Create and position the graphics window
            glutInitWindowPosition( 0, 0 );
            glutInitWindowSize( 600, 360 );

            glutCreateWindow( "Solar System Demo" );

            // Initialize OpenGL.
            OpenGLInit();

            // Set up callback functions for key presses


            // Set up the callback function for resizing windows
            glutReshapeFunc( ResizeWindow );

            // Callback for graphics image redrawing
            glutDisplayFunc( Animate );

            // Start the main loop.  glutMainLoop never returns.
            glutMainLoop(  );

            return(0);
        }

Answer 1

好吧，我想通了。

我使用顶点来为 X 设置动画，就像星星一样所以我想它会起作用而且它起作用了教授很高兴所以我希望这对其他人也有帮助

  static void Animate(void)
  {
  // Clear the redering window
   glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
   if (spinMode) {
    // Update the animation state
    HourOfDay += AnimateIncrement;
    DayOfYear += AnimateIncrement/40.0;

    HourOfDay = HourOfDay - ((int)(HourOfDay/28))*24;
    DayOfYear = DayOfYear - ((int)(DayOfYear/365))*365;
    }

 // Clear the current matrix (Modelview)
 glLoadIdentity();

 // Back off eight units to be able to view from the origin.
 glTranslatef ( 0.0, 0.0, -8.0 );

 // Rotate the plane of the elliptic
 // (rotate the model's plane about the x axis by fifteen degrees)
 glRotatef( 15.0, 1.0, 0.0, 0.0 );

 // Draw the sun    -- as a yellow, wireframe sphere
 glColor3f( 1.0, 1.0, 0.0 );
 glutWireSphere( 1.0, 15, 15 );

 glBegin(GL_LINES);
 glColor3f(1.0,1.0,1.0);
 //star 1
 glVertex2f(0.4,2.5);
 glVertex2f(0.6,2.6);

 glVertex2f(0.6,2.5);
 glVertex2f(0.4,2.6);
 // star 2
 glVertex2f(0.8,1.5);
 glVertex2f(1.1,1.7);

 glVertex2f(1.1,1.5);
 glVertex2f(0.8,1.7);
 // star 3
 glVertex2f(0.8,3.5);
 glVertex2f(1.1,3.7);

 glVertex2f(1.1,3.5);
 glVertex2f(0.8,3.7);

 //star 4
 glVertex2f(2.2,1.5);
 glVertex2f(2.4,1.7);

 glVertex2f(2.4,1.5);
 glVertex2f(2.2,1.7);

 //star 5
 glVertex2f(-2.2,3.5);
 glVertex2f(-2.4,3.7);

 glVertex2f(-2.4,3.5);
 glVertex2f(-2.2,3.7);

 //star 6
 glVertex2f(-0.4,2.5);
 glVertex2f(-0.6,2.6);

 glVertex2f(-0.6,2.5);
 glVertex2f(-0.4,2.6);

 //star 7
 glVertex2f(-3.4,2.5); 
 glVertex2f(-3.6,2.6);

 glVertex2f(-3.6,2.5);
 glVertex2f(-3.4,2.6);

 //star 8
 glVertex2f(-4.4,2.5);
 glVertex2f(-4.6,2.6);

 glVertex2f(-4.6,2.5);
 glVertex2f(-4.4,2.6);

 //star 9
 glVertex2f(-4.2,3.5);
 glVertex2f(-4.4,3.7);

 glVertex2f(-4.4,3.5);
 glVertex2f(-4.2,3.7);
 glEnd();
 // Now Draw Stars
 glColor3f(0.0,0.0,1.0);
 //glutWireSphere( 0.3, 18, 9 );
 //glLineStipple(0.1,0.1);
 glVertex2f(0.9,0.3);
 glVertex2f(0.6,0.3);

 //end stars
  // Draw the Earth
 // First position it around the sun
 //     Use DayOfYear to determine its position
 glRotatef( 360.0*DayOfYear/365.0, 0.0, 1.0, 0.0 );
 glTranslatef( 4.0, 0.0, 0.0 );
 glPushMatrix();                        // Save matrix state
 // Second, rotate the earth on its axis.
 //     Use HourOfDay to determine its rotation.
 glRotatef( 360.0*HourOfDay/24.0, 0.0, 1.0, 0.0 );
 // Third, draw the earth as a wireframe sphere.
 glColor3f( 0.2, 0.2, 1.0 );
 glutWireSphere( 0.4, 10, 10);
 //glutSolidSphere(0.4,10,10);
 glPopMatrix();                     // Restore matrix state

 // Draw the moon.
 // Use DayOfYear to control its rotation around the earth
 glRotatef( 360.0*12.0*DayOfYear/365.0, 0.0, 1.0, 0.0 );
 // glRotatef( 360.0*60.0*DayOfYear/1000.0, 0.0, 1.0, 0.0 );
 glTranslatef( 0.7, 0.0, 0.0 );
 glColor3f( 0.3, 0.7, 0.3 );
 glutWireSphere( 0.1, 5, 5 );

 */
 // Flush the pipeline, and swap the buffers
 glFlush();
 glutSwapBuffers();

 if ( singleStep ) {
    spinMode = GL_FALSE;
 }

 glutPostRedisplay();       // Request a re-draw for animation purposes

 }