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smasherprog

ESM's

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I need some help implementing ESM's. I have searched and not found much information except for a few papers that dont help me that much because they are vague.

I believe my problem has to do with building the ESM. The articles that I read said that I have to store the linear depth to my ESM first. I have implemented a working VSM, but want to swtich to a ESM . . .

this is the code for building the ESM

struct VS_to_PS_TerrainShadow{
float4 pos : SV_Position;
float fDepth : fDepth;
};
VS_to_PS_TerrainShadow VSShadow(VsIn In){
VS_to_PS_TerrainShadow output;
float4 worldPos = mul( float4(In.pos, 1.0f), world );
output.pos = mul(worldPos, viewProj );
output.fDepth = length( lightpos.xyz - worldPos.xyz );
return output;
}

float4 PSShadow( VS_to_PS_TerrainShadow input ) : SV_Target{
return float4( input.fDepth, 0.0, 0.0f, 1.0f );
}

I then use a Gaussian blur for the intermediate step on the map

then for the shadowing term, i use

float shadowing = exp(over_darkening_factor * ( occluderdepth - receiverdepth ));

however, another question is what types of numbers are valid for over_darkening_factor? [0, 1) ?

Also, after reading http://pixelstoomany.wordpress.com/category/shadows/exponential-shadow-maps/

It seems that I can use

float shadowing = exp( k* occluderdepth) / exp( k* receiverdepth );

?

The problem I am having is that everything is in the shadow, I have a large square of black where my shadow frustum is.

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