1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
|
#include <GL/glut.h>
#include <GL/gl.h>
#include <math.h>
static void display(void)
{
static float a = 0;
int const win_w = glutGet(GLUT_WINDOW_WIDTH);
int const win_h = glutGet(GLUT_WINDOW_HEIGHT);
float const win_a = (float)win_w/(float)win_h;
glDrawBuffer(GL_BACK);
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
glViewport(0, 0, win_w, win_h);
glMatrixMode(GL_PROJECTION);
glLoadIdentity();
glFrustum(-win_a, win_a, -1, 1, 1, 5);
glMatrixMode(GL_MODELVIEW);
glLoadIdentity();
glTranslatef(0,0,-3);
glRotatef( a = fmodf(a + 1, 360) , 0,1,0);
glutWireTeapot(1);
glFlush();
glDrawBuffer(GL_FRONT);
glReadBuffer(GL_BACK);
glCopyPixels(0, 0, win_w, win_h, GL_COLOR);
glFinish();
}
int main(int argc, char *argv[])
{
glutInit(&argc, argv);
glutInitDisplayMode(GLUT_DOUBLE | GLUT_RGBA | GLUT_DEPTH);
glutCreateWindow("Test copy back->front instead of buffer swap");
glutDisplayFunc(display);
glutIdleFunc(glutPostRedisplay);
glutMainLoop();
return 0;
}
|
