[C++] Texture::GetPixels() for buffer texture

[Rastar]

When I try to get the pixels of a Buffer's color texture, I get an exception. The texture is fine and can e.g. be set to a texture slot, so I guess the data isn't actually retrieved from the GPU? Is there a way to do this?

[macklebee]

Does the example for GetPixels() work for you? Perhaps showing example code of what you are trying will result in help.

[Rastar]

Yes, that works. But I am trying to get the content of a render buffer

 

Texture* tex = Texture::Create(width, height);
Buffer* buffer = Buffer::Create(width, height, 1, 0);
buffer->SetColorTexture(tex);
buffer->Enable();
buffer->Clear();
world->Render();
buffer->Disable();
Context::SetCurrent(context);
tex = buffer->GetColorTexture();
const char* pixelBuf = new char[tex->GetMipmapSize(0)];
tex->GetPixels(pixelBuf);

 

A call to mat->SetTexture(tex) works, probably because the texture handle is being passed, but the above call to GetPixels() doesn't. As I said, I assume the texture isn't actually retrieved from the GPU to the main memory.

[NightQuest]

Forgive me if I'm wrong, but I think your problem may be the const

const char* pixelBuf = new char[tex->GetMipmapSize(0)];
tex->GetPixels(pixelBuf);

When I did this, I had to cast it

GLubyte* tPixels = new GLubyte[tex->GetMipmapSize(0)];
tex->GetPixels(reinterpret_cast<const char*>(tPixels));

 

I have no idea why it's passed as a const char* since it's obviously modified; if anything, it should be passed as a char* const.