# DX11 [DX11] problem with depth buffer getting no writes

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Tasche    222
i already posted this on beginners forum, seems to me in is pout of place there... since i wrote to a couple of forum mods, and the thread hasnt been moved, ill repost here...
link to the old post: [url="http://www.gamedev.net/topic/607898-directx-11-depth-buffer-problem/"]http://www.gamedev.n...buffer-problem/[/url] if any mod would be so kind as to delete that

hi im kinda new to these forums so not sure if this is the correct board for posting this, but i have a problem with my depth buffer not working (properly)...

i have set it up like this (following the code from [url="http://www.rastertek.com/dx11tut03.html"]http://www.rastertek.../dx11tut03.html[/url]):

[code]
// Initialize the description of the depth buffer.
D3D11_TEXTURE2D_DESC dbDesc;
ZeroMemory(&dbDesc, sizeof(dbDesc));

// Set up the description of the depth buffer.
dbDesc.Width = SCREEN_WIDTH;
dbDesc.Height = SCREEN_HEIGHT;
dbDesc.MipLevels = 1;
dbDesc.ArraySize = 1;
dbDesc.Format = DXGI_FORMAT_D24_UNORM_S8_UINT;
dbDesc.SampleDesc.Count = 1;
dbDesc.SampleDesc.Quality = 0;
dbDesc.Usage = D3D11_USAGE_DEFAULT;
dbDesc.BindFlags = D3D11_BIND_DEPTH_STENCIL;
dbDesc.CPUAccessFlags = 0;
dbDesc.MiscFlags = 0;

// Create the texture for the depth buffer using the filled out description.
hr = m_mainPtrs.m_pDev->CreateTexture2D(&dbDesc, NULL, &m_depthStencilBuffer);
if (FAILED(hr)) {SHOWERRORMSG("Creating depth stencil buffer target failed"); return FALSE;}

// Initialize the description of the stencil state.
D3D11_DEPTH_STENCIL_DESC dsDesc;
ZeroMemory(&dsDesc, sizeof(dsDesc));

// Set up the description of the stencil state.
dsDesc.DepthEnable = true;
dsDesc.DepthFunc = D3D11_COMPARISON_LESS;

dsDesc.StencilEnable = false;

// Stencil operations if pixel is front-facing.
dsDesc.FrontFace.StencilFailOp = D3D11_STENCIL_OP_KEEP;
dsDesc.FrontFace.StencilDepthFailOp = D3D11_STENCIL_OP_INCR;
dsDesc.FrontFace.StencilPassOp = D3D11_STENCIL_OP_KEEP;
dsDesc.FrontFace.StencilFunc = D3D11_COMPARISON_ALWAYS;

// Stencil operations if pixel is back-facing.
dsDesc.BackFace.StencilFailOp = D3D11_STENCIL_OP_KEEP;
dsDesc.BackFace.StencilDepthFailOp = D3D11_STENCIL_OP_DECR;
dsDesc.BackFace.StencilPassOp = D3D11_STENCIL_OP_KEEP;
dsDesc.BackFace.StencilFunc = D3D11_COMPARISON_ALWAYS;

// Create the depth stencil state.
hr = m_mainPtrs.m_pDev->CreateDepthStencilState(&dsDesc, &m_depthStencilState);
if (FAILED(hr)) {SHOWERRORMSG("Creating depth stencil state description failed"); return FALSE;}

// Set the depth stencil state.
m_mainPtrs.m_pDevCon->OMSetDepthStencilState(m_depthStencilState, 1);

// Initailze the depth stencil view.
D3D11_DEPTH_STENCIL_VIEW_DESC dsvDesc;
ZeroMemory(&dsvDesc, sizeof(dsvDesc));

// Set up the depth stencil view description.
dsvDesc.Format = DXGI_FORMAT_D24_UNORM_S8_UINT;
dsvDesc.ViewDimension = D3D11_DSV_DIMENSION_TEXTURE2D;
dsvDesc.Texture2D.MipSlice = 0;

// Create the depth stencil view.
hr = m_mainPtrs.m_pDev->CreateDepthStencilView(m_depthStencilBuffer, &dsvDesc, &m_mainPtrs.m_depthStencilView);
if (FAILED(hr)) {SHOWERRORMSG("Creating depth stencil view description failed"); return FALSE;}

// Bind the render target view and depth stencil buffer to the output render pipeline.
m_mainPtrs.m_pDevCon->OMSetRenderTargets(1, &m_mainPtrs.m_pBackbuffer, m_mainPtrs.m_depthStencilView);
[/code]
of course i clear the depth buffer with
[code]
mptrs.m_pDevCon->ClearDepthStencilView(mptrs.m_depthStencilView, D3D11_CLEAR_DEPTH|D3D11_CLEAR_STENCIL, 1.0f, 0);
[/code]

now strange enough, depth testing isnt working... the code compiles correctly, i also checked if the used DXGI_FORMAT_D24_UNORM_S8_UINT format is supported for D3D11_FORMAT_SUPPORT_DEPTH_STENCIL, and it is. Further i tried clearing only the depth stencil, turning stencil test off and various depth functions.

the different depth functions also dont give results as expected;
i draw two intersecting objects, always one of them is completely obscuring the other, dependent on the depth comparison function (1 means obscures 2, - means nothing is drawn , obj1 is sent to the pipeline first):
depth buffer cleared to 1.0f:
[code]
LESS LEQ ALWAYS NEVER GRTR GREQ EQ
Obj1 1 2 2 _ _ _ _
Obj2 2 1 1
[/code]

depth buffer cleared to 0.0f:
[code]
LESS LEQ ALWAYS NEVER GRTR GREQ EQ
Obj1 1 2 2 _ _ _ 2
Obj2 2 1 1 1
[/code]

EDIT: hm seems that monospace copy & paste didnt quite pan out on those tables^^, but well you get what is should be where i think

it looks like the whole geometry is collapsed to the near clipping plane. can it be that a projection matrix collapses geometry to the near clipping plane (i use D3DPerspectivesomething to calculate my projection matrix)? never thought about that... and if so why does the LESS depth func act different? obj1 is still getting sent to pipeline first, so it should be below obj2, but its not.

also, obj1 should be partly behind obj2 (since their geometry intersects) however always one is completely drawn above the other....

ive been sitting at this for hours! pls help!!!

system: Windows7 (obviously with dx11)
compiler: VS 10 express

EDIT: update: by passing the vertex shaders output position to the pixel shader i tried drawing the actual depth values in color. the pixelshader now just returns
[code]
float4((depthvalue-0.9)*10.0f,0,0,1)
[/code]
, where depthvalue is position.z/position.w. the subtraction by 0.9 and multiplication by 10 is just so the range 0.9 to 1 gets a better resolution.
i can see clearly that my depth values are calculated correctly, they simply aren't written to the depthbuffer properly :///

[code]

cbuffer pfConst
{
matrix matView;
matrix matProj;
}

cbuffer poConst
{
matrix matWorld;
}

struct VIn
{
float4 position : Position;
float3 normal : Normal;
float2 tex : TexCoord0;
float4 tangent : Tangent0;
};

struct PIn
{
float4 position : SV_POSITION;
float2 tex : TEXCOORD0;
float3 lightDirSurf : TEXCOORD1;
float4 lightParam : TEXCOORD2;
};

sampler texSamp;
Texture2D <float4> colorTex;

{
PIn output;
input.position.w = 1.0f;
float4 worldPos = mul(input.position,matWorld);
float4 viewPos = mul(worldPos,matView);
output.position = mul(viewPos,matProj);
output.tex = input.tex; //ignore this
output.lightDirSurf = float4(0.0,0.0,0.0,0.0); //ignore this
output.lightParam = output.position; //ignore this
// output.lightParam = float4(lightDist, LightPos.w, 0.0f, 0.0f); //used this texccord for debugging depth
return output;
}

{
float4 color = colorTex.Sample( texSamp, input.tex );
// float depthValue;
// float4 color;
// depthValue = input.lightParam.z / input.lightParam.w;
// color = float4((depthValue-0.9)*10.0f, 0.0f, 0.0f, 1.0f);

return color;
}
[/code]
here are 2 screenshots (ignore the ugly texture in the textured.jpg, its drawn as expected)
[url="http://imageshack.us/g/200/depthq.jpg/"]http://imageshack.us/g/200/depthq.jpg/[/url]
brighter red areas are drawn in front of darker red areas, as seen in textured.jpg,though they should actually be hidden by the black heightfield geometry. depth.jpg was taken with exactly the same setting as textured.jpg, only changed the comments in the pixel shader i can see clearly that my depth values are calculated correctly, they simply aren't written to the depthbuffer properly :///

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Tasche    222
actually, from what i found out so far, the title should be: all my geometry is doing 0.0f depthbuffer writes, regardless of the z and w coordinate output by the vertex shader.

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MJP    19755
Are you setting the viewport correctly?

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Tasche    222
[quote name='MJP' timestamp='1312743136' post='4845857']
Are you setting the viewport correctly?
[/quote]

.....
for *$§%$%&"\$% sake
how could i forget that

of course, that solved it, thanks

EDIT: seriously, i spent like 8hrs searching for my problem... then again, now i know everything about depth buffering there is to know^^, even know all enums pertaining to depth in some way by heart =)

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MJP    19755
Well then at least at least now you're an expert on depth buffers.

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