NVIDIA pbuffer bug?

OpenGL
1

I have a weird problem with pbuffers on linux with nvidia hardware. When I use glReadPixels or glCopyTexImage2d, the bottom row and right column of the image is garbled.

I have a small example here:
http://www.simula.no/~thomasse/pbuffer_bug.jpg

This is taken from the NvSDK pbuffer example. The source code for this example with makefile for linux is here:
http://www.simula.no/~thomasse/simple_pbuffer.tgz

This problem occurs with all versions of the driver that supports pbuffers (including 3123), on GF2 and GF3 on various linux distributions.

Any ideas?

2

Put this question at Advanced forum. Maye the NVIDIA guys read it.

3

I’ve tried the pbuffer sample and experienced the same problem
(GeForce2 + 31.23).

Have you already submitted a bug description ?

4

This is a known issue and should be fixed in a future driver release.

5

Hi,

I downloaded you example - you forget to set PACK_ALIGNMENT to 1 before reading back the texture (Although, this will not solve the problem!) - I’m also waiting for this bug to be fixed…

EDIT:
jra101 - are you saying this is fixed for future releases or that this needs to be fixed for future releases?

– Niels

[This message has been edited by Niels Husted Kjaer (edited 10-03-2002).]

6

I’m saying it will be fixed in a future release

7

To solve this problem (temporarily) Although not perfectly. I do the following.

  glBindTexture(GL_TEXTURE_RECTANGLE_NV,m_PBufferTexObject);
  glBegin(GL_QUADS);  
  {

#ifdef linux_x86
glTexCoord2i(0, 1); glVertex2i(0,0);
glTexCoord2i(gCanvasWidth()-1, 1); glVertex2i(gCanvasWidth(),0);
glTexCoord2i(gCanvasWidth()-1, gCanvasHeight()-1); glVertex2i(gCanvasWidth(),gCanvasHeight());
glTexCoord2i(0, gCanvasHeight()-1); glVertex2i(0,gCanvasHeight());
#else
glTexCoord2f(0.0f, 0.0f); glVertex2f(0.0f,0.0f);
glTexCoord2f(gCanvasWidth(), 0.0f); glVertex2f(gCanvasWidth(),0.0f);
glTexCoord2f(gCanvasWidth(), gCanvasHeight()); glVertex2f(gCanvasWidth(),gCanvasHeight());
glTexCoord2f(0.0f, gCanvasHeight()); glVertex2f(0.0f,gCanvasHeight());
#endif
}
glEnd();
glDisable(GL_TEXTURE_RECTANGLE_NV);

Hope this helps,

Heath.

[This message has been edited by heath (edited 10-11-2002).]

8

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