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/*
* Test GL_EXT_framebuffer_object
*
* Brian Paul
* 19 Mar 2006
*/
#include <assert.h>
#include <stdio.h>
#include <stdlib.h>
#include <math.h>
#include <GL/glew.h>
#include <GL/glut.h>
static int Win = 0;
static int Width = 400, Height = 400;
static GLuint MyFB, ColorRb, DepthRb;
static GLboolean Animate = GL_TRUE;
static GLfloat Rotation = 0.0;
static void
CheckError(int line)
{
GLenum err = glGetError();
if (err) {
printf("fbotest2: GL Error 0x%x at line %d\n", (int) err, line);
}
}
static void
Display( void )
{
GLubyte *buffer = malloc(Width * Height * 4);
GLenum status;
CheckError(__LINE__);
/* draw to user framebuffer */
glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, MyFB);
glDrawBuffer(GL_COLOR_ATTACHMENT0_EXT);
glReadBuffer(GL_COLOR_ATTACHMENT0_EXT);
status = glCheckFramebufferStatusEXT(GL_FRAMEBUFFER_EXT);
if (status != GL_FRAMEBUFFER_COMPLETE_EXT) {
printf("fbotest2: Error: Framebuffer is incomplete!!!\n");
}
CheckError(__LINE__);
glClearColor(0.5, 0.5, 1.0, 0.0);
glClear( GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT );
glEnable(GL_DEPTH_TEST);
glEnable(GL_LIGHTING);
glEnable(GL_LIGHT0);
glPushMatrix();
glRotatef(30.0, 1, 0, 0);
glRotatef(Rotation, 0, 1, 0);
glutSolidTeapot(2.0);
glPopMatrix();
/* read from user framebuffer */
glReadPixels(0, 0, Width, Height, GL_RGBA, GL_UNSIGNED_BYTE, buffer);
/* draw to window */
glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, 0);
glDisable(GL_DEPTH_TEST); /* in case window has depth buffer */
glWindowPos2iARB(0, 0);
glDrawPixels(Width, Height, GL_RGBA, GL_UNSIGNED_BYTE, buffer);
free(buffer);
glutSwapBuffers();
CheckError(__LINE__);
}
static void
Reshape( int width, int height )
{
float ar = (float) width / (float) height;
glViewport( 0, 0, width, height );
glMatrixMode( GL_PROJECTION );
glLoadIdentity();
glFrustum( -ar, ar, -1.0, 1.0, 5.0, 25.0 );
glMatrixMode( GL_MODELVIEW );
glLoadIdentity();
glTranslatef( 0.0, 0.0, -15.0 );
glBindRenderbufferEXT(GL_RENDERBUFFER_EXT, ColorRb);
glRenderbufferStorageEXT(GL_RENDERBUFFER_EXT, GL_RGB, width, height);
glBindRenderbufferEXT(GL_RENDERBUFFER_EXT, DepthRb);
glRenderbufferStorageEXT(GL_RENDERBUFFER_EXT, GL_DEPTH_COMPONENT,
width, height);
Width = width;
Height = height;
}
static void
CleanUp(void)
{
glDeleteFramebuffersEXT(1, &MyFB);
glDeleteRenderbuffersEXT(1, &ColorRb);
glDeleteRenderbuffersEXT(1, &DepthRb);
assert(!glIsFramebufferEXT(MyFB));
assert(!glIsRenderbufferEXT(ColorRb));
assert(!glIsRenderbufferEXT(DepthRb));
glutDestroyWindow(Win);
exit(0);
}
static void
Idle(void)
{
Rotation = glutGet(GLUT_ELAPSED_TIME) * 0.1;
glutPostRedisplay();
}
static void
Key( unsigned char key, int x, int y )
{
(void) x;
(void) y;
switch (key) {
case 'a':
Animate = !Animate;
if (Animate)
glutIdleFunc(Idle);
else
glutIdleFunc(NULL);
break;
case 27:
CleanUp();
break;
}
glutPostRedisplay();
}
static void
Init( void )
{
if (!glutExtensionSupported("GL_EXT_framebuffer_object")) {
printf("fbotest2: GL_EXT_framebuffer_object not found!\n");
exit(0);
}
printf("fbotest2: GL_RENDERER = %s\n", (char *) glGetString(GL_RENDERER));
glGenFramebuffersEXT(1, &MyFB);
glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, MyFB);
assert(glIsFramebufferEXT(MyFB));
/* set color buffer */
glGenRenderbuffersEXT(1, &ColorRb);
glBindRenderbufferEXT(GL_RENDERBUFFER_EXT, ColorRb);
assert(glIsRenderbufferEXT(ColorRb));
glFramebufferRenderbufferEXT(GL_FRAMEBUFFER_EXT, GL_COLOR_ATTACHMENT0_EXT,
GL_RENDERBUFFER_EXT, ColorRb);
glRenderbufferStorageEXT(GL_RENDERBUFFER_EXT, GL_RGB, Width, Height);
/* setup depth buffer */
glGenRenderbuffersEXT(1, &DepthRb);
glBindRenderbufferEXT(GL_RENDERBUFFER_EXT, DepthRb);
assert(glIsRenderbufferEXT(DepthRb));
glFramebufferRenderbufferEXT(GL_FRAMEBUFFER_EXT, GL_DEPTH_ATTACHMENT_EXT,
GL_RENDERBUFFER_EXT, DepthRb);
glRenderbufferStorageEXT(GL_RENDERBUFFER_EXT, GL_DEPTH_COMPONENT, Width, Height);
CheckError(__LINE__);
/* restore to default */
glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, 0);
CheckError(__LINE__);
}
int
main( int argc, char *argv[] )
{
glutInit( &argc, argv );
glutInitWindowPosition( 0, 0 );
glutInitWindowSize(Width, Height);
glutInitDisplayMode( GLUT_RGB | GLUT_DOUBLE );
Win = glutCreateWindow(argv[0]);
glewInit();
glutReshapeFunc( Reshape );
glutKeyboardFunc( Key );
glutDisplayFunc( Display );
if (Animate)
glutIdleFunc(Idle);
Init();
glutMainLoop();
return 0;
}
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