Hi
I'm working on shadow mapping for my Game engine and I have a big problem.It makes me crazy and I can't find it for last week of debugging.

The problem is my shadow maps work when objects are fix.But after moving the light or other objects it doesn't work any more.When I want to debug it by PIX it shows the correct image in PIX. Also after resetting the device(for device lost)It shows the correct image before moving the light or other objects.After a while this shadow complettly disappears.
It seems vertex shader for deph pass uses incorrect matrix but I can't find the problem.
P.S:I'm using deferred shading.
[source lang="cpp"]float4x4 WorldViewProjection;



struct VertexShaderInput
{
float4 Position : POSITION0;

};

struct VertexShaderOutput
{
float4 Position : POSITION0;
float2 Depth : TEXCOORD0;
};

VertexShaderOutput VertexShaderFunction(VertexShaderInput input)
{
VertexShaderOutput output;

//float4 worldPosition = mul(World,input.Position);
//float4x4 worldview = mul(World, View);
//worldview = mul(worldview, Projection);
//output.Position = mul(input.Position,worldview);
output.Position = mul( WorldViewProjection,input.Position);


//output.Depth = worldPosition-SpotlightPosition;
output.Depth.x = output.Position.z;
output.Depth.y = output.Position.w;

return output;
}
struct PixelShaderOutput
{
float4 Depth : COLOR0;
};

PixelShaderOutput PixelShaderFunction(VertexShaderOutput input): COLOR0
{

PixelShaderOutput output;
//float4 l=input.Depth-SpotlightPosition;
//input.Depth/=input.Depth.w;
//output.Depth =float4(0,0,0,0); //output Depth

output.Depth =input.Depth.x/input.Depth.y; //output Depth


return output;
}

technique buildPass
{
pass Pass1
{
VertexShader = compile vs_2_0 VertexShaderFunction();
PixelShader = compile ps_2_0 PixelShaderFunction();

}
}
[/source]




First image is the image befor rotating the car.
[attachment=12619:first.JPG]


second image is what I see after rotating the car.
[attachment=12620:second.JPG]

Third pic is what I see in PIX
[attachment=12621:pic_from_pix.jpg]

Sounds like you're not clearing (setting all values to a clip-far value) your shadow map before rendering.

I clear it correctly.There should be some thing wrong with matrix but I can't find it.Because PIX doesnt show any error.

Sounds like you're not clearing (setting all values to a clip-far value) your shadow map before rendering.

Finally I found it. The problem was Zbuffer.It couldn't clear the Zbuffer.
From MSDN:
IDirect3DDevice9::Clear will fail if you:
1-Try to clear either the depth buffer or the stencil buffer of a render target that does not have an attached depth buffer.
2-Try to clear the stencil buffer when the depth buffer does not contain stencil data.

Mine was case 2.