# Weird rendering issue (rows of pixels are drawn weird)

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cakefrost    137

SOLVED thanks to Endurion.

My backbuffer and actual window size were different, so I used AdjustWindowRect to figure out what my actual window size should be.

Hi Guys, this is a very weird problem for me to try and explain (there is a picture below). I am rendering a scene using a Sprite (LPD3DXSPRITE) and things at particular rows on my screen are causing weird issues (there's like 3-4 of these rows, all displaying similar behavior).  This is ONLY happening in windowed mode (1024 x 768).

In the screenshot below, each tile is 64x64, and they are rendered adjacent to each other. If you look at the "2" in the picture, you can see the 2 pixels high row that is a blurred mess. The two side by side comparisons ("1" and "3") are trying to illustrate that it is always in the same place relative to the screen. It is NOT related to the texture being rendered, but purely off the position in the screen.

I am not entirely sure which code to add here, so I will just add some things that might seem important (below the image)

I am mostly just looking for help in determining where to even debug.

EDIT: I think I might have tracked down the problem area. I was looking how I create the window (CreateWindowEx). And apparently I am padding the width/height by 6 and 32 respectively.. I dont know why I was, but changing these will change the characteristics of the bug. Looking more into it.

Potentially SOLVED.

.

// Render call

// sprite is a LPD3DXSPRITE
// texture is a LPDIRECT3DTEXTURE9
// frame is a RECT (and is correctly being set to the proper dimensions)
// position is a D3DXVECTOR3 (with values set to what I'd expect)
sprite->Draw(texture, frame, NULL, &position, 0xffffffff);


.

// D3D Present Parameters

if(window.isWindowed()) {
d3dpp.Windowed					= TRUE;
}
else {
d3dpp.Windowed					= FALSE;
}
d3dpp.BackBufferWidth				= window.getScreenWidth();
d3dpp.BackBufferHeight				= window.getScreenHeight();
d3dpp.BackBufferFormat				= D3DFMT_X8R8G8B8;
d3dpp.BackBufferCount				= 1;
d3dpp.MultiSampleType				= D3DMULTISAMPLE_NONE;
d3dpp.MultiSampleQuality			= 0;
d3dpp.hDeviceWindow					= window.getHandle();
d3dpp.AutoDepthStencilFormat		= D3DFMT_D16;
d3dpp.EnableAutoDepthStencil		= TRUE;
d3dpp.PresentationInterval			= D3DPRESENT_INTERVAL_DEFAULT;
d3dpp.Flags							= 0;
d3dpp.FullScreen_RefreshRateInHz	= D3DPRESENT_RATE_DEFAULT;


.

// Creating devices
// I do check if the device/sprite creation is successful, but I am omitting the error handling for brevity

D3DDEVTYPE_HAL,
window.getHandle(),
D3DCREATE_SOFTWARE_VERTEXPROCESSING,
&d3dpp,
&d3ddev);

d3ddev->SetRenderState(D3DRS_ZENABLE, D3DZB_TRUE);
d3ddev->SetRenderState(D3DRS_ALPHAREF, (DWORD)0x00000001);
d3ddev->SetRenderState(D3DRS_ALPHATESTENABLE, TRUE);
d3ddev->SetRenderState(D3DRS_ALPHAFUNC, D3DCMP_GREATEREQUAL);

D3DXCreateSprite(d3ddev, &sprite);



Edited by jarrett.baugh

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Endurion    5411

This is pretty sure a problem with your backbuffer size not matching the windows' client area size.

Do you use AdjustClientRect(Ex) to calculate the required windows size to offset for the border and caption?

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cakefrost    137

Thanks for the idea. I think you're right, however I couldn't find anything on AdjustClientRect (or with the Ex), but I am using GetClientRect for detecting mouse controls, and it'd make sense I'd want to do something similar for this.

Did you mean AdjustWindowRect? Because AdjustWindowRect looks like that can be VERY useful, thanks a bunch!