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Broken Rendertarget? Appears to be black?

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#1   Members   -  Reputation: 109


Posted 17 April 2013 - 12:04 PM


I'm having a problem where my rendertargets are not working when ran on an NVIDIA gpu. Basically what happens is I store the native drawing surface as a backbuffersurface. switch to a newly created texture/rendertarget surface, clear it to literally any color, and draw a model to it. When I save the surface as a texture it shows up black.

Creating the texture:




The HR function is from one of Frank Luna's books, and is as follows:


#if defined(DEBUG) | defined(_DEBUG)
	#ifndef HR
	#define HR(x)                                      \
	{                                                  \
		HRESULT hr = x;                                \
		if(FAILED(hr))                                 \
		{                                              \
			DXTrace(__FILE__, __LINE__, hr, #x, TRUE); \
		}                                              \

	#ifndef HR
	#define HR(x) x;


Now here I am using it:


	HR(gd3dDevice->GetRenderTarget(0, &mBackBufferSurface));

	//Draw the scene:
	gd3dDevice->SetRenderTarget(0, mRenderBufferSurface);
	gd3dDevice->Clear(0, 0, D3DCLEAR_TARGET | D3DCLEAR_ZBUFFER, 0xFFFF0000, 1.0f, 0);

	gd3dDevice->SetRenderState( D3DRS_ALPHABLENDENABLE, FALSE );

	m_Sun->Render(gd3dDevice, mView, mProj);


	HR(D3DXSaveTextureToFile("scene.tga", D3DXIFF_TGA, mRenderBuffer, NULL));

	//Continue rendering more objects to other targets... Present later


The result is black from saving the texture to a file, and the same with saving the surface to a file as well. But, when I save the mBackBufferSurface to a file, that works fine. This is why I believe there is a problem with my rendertargets.

Any ideas what could be causing this?


Edited by TheOrangeDay, 17 April 2013 - 12:09 PM.

#2   Crossbones+   -  Reputation: 8202


Posted 17 April 2013 - 12:33 PM

Check all return values with that HR macro. Also: Direct3D Programming Tip #5: Use The Debug Runtime. If something fails you usually get detailed information this way.

I suspect a rendertarget vs zbuffer mismatch.

#3   Crossbones+   -  Reputation: 2833


Posted 17 April 2013 - 12:43 PM

I am not sure that you can save D3DFMT_A16B16G16R16 as TGA, if and what conversions are done by D3DXSaveTextureToFile function in such case.

Also (not sure) D3DXSaveTextureToFile reads from texture to be able to save it, but from i can see in your code you have its surface still bound at time you call D3DXSaveTextureToFile so it might be an issue there. Try to switch to other RT and then save.

#4   Crossbones+   -  Reputation: 12035


Posted 17 April 2013 - 05:28 PM



This function supports saving to all D3DXIMAGE_FILEFORMAT formats except Portable Pixmap (.ppm) and Targa/Truevision Graphics Adapter (.tga).


It sucks, but writing a TGA is so trivial anyway that it doesn't suck that much.

It appears that the gentleman thought C++ was extremely difficult and he was overjoyed that the machine was absorbing it; he understood that good C++ is difficult but the best C++ is well-nigh unintelligible.

#5   Members   -  Reputation: 109


Posted 17 April 2013 - 08:46 PM

The targa files work. don't worry about that.


I fixed the problem. It appears that in Frank Luna's source code (I am also using his class for setting up the window), he set the back buffer width and height to 0 in the CreateDevice parameters. I adjusted them so they reflected my window size, and everything was fixed.


Thanks everyone!

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