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/*
* Test GL_EXT_framebuffer_object
*
* Brian Paul
* 7 Feb 2005
*/
#define GL_GLEXT_PROTOTYPES
#include <assert.h>
#include <stdio.h>
#include <stdlib.h>
#include <math.h>
#include <GL/glut.h>
static int Width = 400, Height = 400;
static GLuint MyFB, MyRB;
static void
CheckError(int line)
{
GLenum err = glGetError();
if (err) {
printf("GL Error 0x%x at line %d\n", (int) err, line);
}
}
static void
Display( void )
{
GLubyte *buffer = malloc(Width * Height * 4);
GLenum status;
/* draw to user framebuffer */
glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, MyFB);
glDrawBuffer(GL_COLOR_ATTACHMENT1_EXT);
glReadBuffer(GL_COLOR_ATTACHMENT1_EXT);
status = glCheckFramebufferStatusEXT(GL_FRAMEBUFFER_EXT);
if (status != GL_FRAMEBUFFER_COMPLETE_EXT) {
printf("Framebuffer incomplete!!!\n");
}
glClearColor(0.5, 0.5, 1.0, 0.0);
glClear( GL_COLOR_BUFFER_BIT );
glBegin(GL_POLYGON);
glColor3f(1, 0, 0);
glVertex2f(-1, -1);
glColor3f(0, 1, 0);
glVertex2f(1, -1);
glColor3f(0, 0, 1);
glVertex2f(0, 1);
glEnd();
/* read from user framebuffer */
glReadPixels(0, 0, Width, Height, GL_RGBA, GL_UNSIGNED_BYTE, buffer);
/* draw to window */
glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, 0);
glWindowPos2iARB(0, 0);
glDrawPixels(Width, Height, GL_RGBA, GL_UNSIGNED_BYTE, buffer);
free(buffer);
glutSwapBuffers();
CheckError(__LINE__);
}
static void
Reshape( int width, int height )
{
#if 0
float ar = (float) width / (float) height;
#endif
glViewport( 0, 0, width, height );
glMatrixMode( GL_PROJECTION );
glLoadIdentity();
#if 0
glFrustum( -ar, ar, -1.0, 1.0, 5.0, 25.0 );
#else
glOrtho(-1.0, 1.0, -1.0, 1.0, 5.0, 25.0 );
#endif
glMatrixMode( GL_MODELVIEW );
glLoadIdentity();
glTranslatef( 0.0, 0.0, -15.0 );
Width = width;
Height = height;
glRenderbufferStorageEXT(GL_RENDERBUFFER_EXT, GL_RGB, Width, Height);
}
static void
CleanUp(void)
{
glDeleteFramebuffersEXT(1, &MyFB);
glDeleteRenderbuffersEXT(1, &MyRB);
assert(!glIsFramebufferEXT(MyFB));
assert(!glIsRenderbufferEXT(MyRB));
exit(0);
}
static void
Key( unsigned char key, int x, int y )
{
(void) x;
(void) y;
switch (key) {
case 27:
CleanUp();
break;
}
glutPostRedisplay();
}
static void
Init( void )
{
GLint i;
if (!glutExtensionSupported("GL_EXT_framebuffer_object")) {
printf("GL_EXT_framebuffer_object not found!\n");
/*exit(0);*/
}
printf("GL_RENDERER = %s\n", (char *) glGetString(GL_RENDERER));
glGenFramebuffersEXT(1, &MyFB);
assert(MyFB);
assert(!glIsFramebufferEXT(MyFB));
glDeleteFramebuffersEXT(1, &MyFB);
assert(!glIsFramebufferEXT(MyFB));
/* Note, continue to use MyFB below */
glGenRenderbuffersEXT(1, &MyRB);
assert(MyRB);
assert(!glIsRenderbufferEXT(MyRB));
glDeleteRenderbuffersEXT(1, &MyRB);
assert(!glIsRenderbufferEXT(MyRB));
MyRB = 42; /* an arbitrary ID */
glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, MyFB);
assert(glIsFramebufferEXT(MyFB));
glBindRenderbufferEXT(GL_RENDERBUFFER_EXT, MyRB);
assert(glIsRenderbufferEXT(MyRB));
glGetIntegerv(GL_RENDERBUFFER_BINDING_EXT, &i);
assert(i == MyRB);
glGetIntegerv(GL_FRAMEBUFFER_BINDING_EXT, &i);
assert(i == MyFB);
CheckError(__LINE__);
glFramebufferRenderbufferEXT(GL_FRAMEBUFFER_EXT, GL_COLOR_ATTACHMENT1_EXT,
GL_RENDERBUFFER_EXT, MyRB);
glRenderbufferStorageEXT(GL_RENDERBUFFER_EXT, GL_RGB, Width, Height);
CheckError(__LINE__);
{
GLint r, g, b, a;
glGetRenderbufferParameterivEXT(GL_RENDERBUFFER_EXT,
GL_RENDERBUFFER_RED_SIZE_EXT, &r);
glGetRenderbufferParameterivEXT(GL_RENDERBUFFER_EXT,
GL_RENDERBUFFER_GREEN_SIZE_EXT, &g);
glGetRenderbufferParameterivEXT(GL_RENDERBUFFER_EXT,
GL_RENDERBUFFER_BLUE_SIZE_EXT, &b);
glGetRenderbufferParameterivEXT(GL_RENDERBUFFER_EXT,
GL_RENDERBUFFER_ALPHA_SIZE_EXT, &a);
CheckError(__LINE__);
printf("renderbuffer RGBA sizes = %d %d %d %d\n", r, g, b, a);
glGetIntegerv(GL_RED_BITS, &r);
glGetIntegerv(GL_GREEN_BITS, &g);
glGetIntegerv(GL_BLUE_BITS, &b);
glGetIntegerv(GL_ALPHA_BITS, &a);
printf("Visual RGBA sizes = %d %d %d %d\n", r, g, b, a);
}
/* 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 );
glutCreateWindow(argv[0]);
glutReshapeFunc( Reshape );
glutKeyboardFunc( Key );
glutDisplayFunc( Display );
Init();
glutMainLoop();
return 0;
}
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