学步园

#include <GL/glut.h>

int setupMethod = POINTER;
int derefMethod = ARRAYELEMENT;

void setupPointers(void)
{
   static GLint vertices[] = {25, 25,
                       100, 325,
                       175, 25,
                       175, 325,
                       250, 25,
                       325, 325};
   static GLfloat colors[] = {1.0, 0.2, 0.2,
                       0.2, 0.2, 1.0,
                       0.8, 1.0, 0.2,
                       0.75, 0.75, 0.75,
                       0.35, 0.35, 0.35,
                       0.5, 0.5, 0.5};

   glEnableClientState (GL_VERTEX_ARRAY);
   glEnableClientState (GL_COLOR_ARRAY);

   glVertexPointer (2, GL_INT, 0, vertices);
   glColorPointer (3, GL_FLOAT, 0, colors);
}

void init(void)
{
   glClearColor (0.0, 0.0, 0.0, 0.0);
   glShadeModel (GL_SMOOTH);
   setupPointers ();
}

void display(void)
{
   glClear (GL_COLOR_BUFFER_BIT);

   if (derefMethod == DRAWARRAY)
      glDrawArrays (GL_TRIANGLES, 0, 6);
   else if (derefMethod == ARRAYELEMENT) {
      glBegin (GL_TRIANGLES);
      glArrayElement (2);
      glArrayElement (3);
      glArrayElement (5);
      glEnd ();
   }
   else if (derefMethod == DRAWELEMENTS) {
      GLuint indices[4] = {0, 1, 3, 4};

 //     glDrawElements (GL_POLYGON, 4, GL_UNSIGNED_INT, indices);
   }
   glFlush ();
}

void reshape (int w, int h)
{
   glViewport (0, 0, (GLsizei) w, (GLsizei) h);
   glMatrixMode (GL_PROJECTION);
   glLoadIdentity ();
   gluOrtho2D (0.0, (GLdouble) w, 0.0, (GLdouble) h);
}

int main(int argc, char** argv)
{
   glutInit(&argc, argv);
   glutInitDisplayMode (GLUT_SINGLE | GLUT_RGB);
   glutInitWindowSize (350, 350);
   glutInitWindowPosition (100, 100);
   glutCreateWindow (argv[0]);
   init ();
   glutDisplayFunc(display);
   glutReshapeFunc(reshape);

   glutMainLoop();
   return 0;
}

启用：glEnableClientState；

初始化：glVertexPointer

渲染：glDrawArrays与glArrayElement