Using Frame Buffer

glGenFramebuffersEXT function address hasn't been initialized properly (hence it's NULL address). Are you using something like Glew, or are you getting the address yourself? (Since the program compiles, I assume glGenFramebuffersEXT has been defined somewhere)

~zix

I load it myself. The code is following:

#include <GL/gl.h>#undef GL_GLEXT_PROTOTYPES#include <GL/glext.h>#include <GL/glut.h>#include <GL/wglext.h>#include <glh_genext.h>PFNGLGENFRAMEBUFFERSEXTPROC glGenFramebuffersEXT = (PFNGLGENFRAMEBUFFERSEXTPROC)wglGetProcAddress("glGenFramebuffersEXT");PFNGLBINDFRAMEBUFFEREXTPROC glBindFramebufferEXT = (PFNGLBINDFRAMEBUFFEREXTPROC)wglGetProcAddress("BindFramebufferEXT");PFNGLGENRENDERBUFFERSEXTPROC glGenRenderbuffersEXT = (PFNGLGENRENDERBUFFERSEXTPROC)wglGetProcAddress("GenRenderbuffersEXT");PFNGLBINDRENDERBUFFEREXTPROC glBindRenderbufferEXT = (PFNGLBINDRENDERBUFFEREXTPROC)wglGetProcAddress("BindRenderbufferEXT");PFNGLRENDERBUFFERSTORAGEEXTPROC glRenderbufferStorageEXT = (PFNGLRENDERBUFFERSTORAGEEXTPROC)wglGetProcAddress("RenderbufferStorageEXT");PFNGLFRAMEBUFFERRENDERBUFFEREXTPROC glFramebufferRenderbufferEXT = (PFNGLFRAMEBUFFERRENDERBUFFEREXTPROC)wglGetProcAddress("FramebufferRenderbufferEXT");

And I can't figure out what's wrong here...

Thanks for assistance.
Looks like I overcame this problem, using one free library. But I will appreciate if you give me some idea why my code was not working.
But I has another problem, while getting into this example. I try to run a simple app (here is the part of it with everything linked to rendering and frame buffers)

void render2texture (){    glClearColor ( 1.0, 0.0, 0.0, 1.0 );    glEnable(GL_TEXTURE_2D);    glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, fbo);    glPushAttrib(GL_VIEWPORT_BIT);    glViewport(0,0,512,512);        glClear( GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT );        glColor3d (1.0, 1.0, 1.0);          glutSolidTeapot(1);        glutSwapBuffers();    glPopAttrib();    glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, 0);}void display(){    render2texture();    glClearColor ( 0.0, 0.0, 0.0, 1.0 );    glClear( GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT );    //glColor3d (1.0, 1.0, 1.0);      glGenTextures(1, &img);    glBindTexture(GL_TEXTURE_2D, img);    glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA8,  512, 512, 0, GL_RGBA, GL_UNSIGNED_BYTE, NULL);    glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);    glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR_MIPMAP_LINEAR);    glTexEnvf(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_MODULATE);    glGenerateMipmapEXT(GL_TEXTURE_2D);    glColor3d (0.5, 0.5, 0.5);     glBegin( GL_QUADS );		glTexCoord2f(0, 0);		glVertex2f(-1, -1);		glTexCoord2f(0, 1);		glVertex2f(-1,  1);		glTexCoord2f(1, 1);		glVertex2f( 1,  1);		glTexCoord2f(1, 0);		glVertex2f( 1, -1);    glEnd();    glutSwapBuffers();}void init(){       glEnable(GL_TEXTURE_2D);    glClearColor ( 0.0, 0.0, 0.0, 1.0 );    initExtensions();    glGenFramebuffersEXT(1, &fbo);    glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, fbo);    GLuint depthbuffer;    glGenRenderbuffersEXT(1, &depthbuffer);    glBindRenderbufferEXT(GL_RENDERBUFFER_EXT, depthbuffer);    glRenderbufferStorageEXT(GL_RENDERBUFFER_EXT, GL_DEPTH_COMPONENT, 512, 512);    glFramebufferRenderbufferEXT(GL_FRAMEBUFFER_EXT, GL_DEPTH_ATTACHMENT_EXT, GL_RENDERBUFFER_EXT, depthbuffer);    glGenTextures(1, &img);    glBindTexture(GL_TEXTURE_2D, img);    glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA8,  512, 512, 0, GL_RGBA, GL_UNSIGNED_BYTE, NULL);    glFramebufferTexture2DEXT(GL_FRAMEBUFFER_EXT, GL_COLOR_ATTACHMENT0_EXT, GL_TEXTURE_2D, img, 0);    GLenum status = glCheckFramebufferStatusEXT(GL_FRAMEBUFFER_EXT);}void reshape(int w, int h){    glViewport(0,0,w,h);    glMatrixMode(GL_PROJECTION);    glLoadIdentity();    gluPerspective ( 60.0, (GLfloat)w/(GLfloat)h, 1.0, 60.0 );    glMatrixMode(GL_MODELVIEW);    glLoadIdentity();    gluLookAt (0, 0, 10, 0, 0, 0, 0, 1, 0);}

So I want to render to texture blue teapot on red background and then apply it to the quad. I checked if what I want to render into framebuffer renders fine in the screen - that's it. All other code I use from sample.
But the app shows only a black quad (obviously, nothing, because it is on the black background :)). When I disable GL_TEXTURE_2D I can see the gray quad. So the problem is in texture generating/mapping - but I can't find it.
Thanks for everything that could help,
Peter.

Does your framebuffer status equal GL_FRAMEBUFFER_COMPLETE ?

Quote:

Original post by stanlo Does your framebuffer status equal GL_FRAMEBUFFER_COMPLETE ?

No. My video card is GeForce 5600 FX, so it should support this extension.

Oops, its value is GL_FRAMEBUFFER_UNSUPPORTED_EXT...
I thought that GeForce 5600 FX supports RTT via frame buffers - but where can be a problem here?

I think your extension loader isn't working because your missing the prefix 'gl', ie: you have "GenRenderbuffersEXT", and you need "glGenRenderbuffersEXT".

My source looks like


It points out if it has any troubling loading of the extensions via my logging function (Which I find handy in debugging it on other computers, as well).

Hope I could help,
~Zix

[Edited by - zix99 on March 27, 2007 2:37:20 PM]

Quote:

Original post by Garret So the problem is in texture generating/mapping - but I can't find it. Thanks for everything that could help, Peter.

The problem is that you generate and then attach a texture in the init function and then each time you run through the display function you setup a new texture and fill it with nothing and then draw that texture on the quad.

In short; the program is doing what you asked it to.

Thanks for both of you!