Krzysztof Narkowicz

Yes, you are on the right track. If you want to use normal maps, then you need to sample in pixel shader. You can find code for evaluating irradiance using given normal in the DXSDK samples (Samples\C++\Direct3D\IrradianceVolume/SHIrradianceEnvMap.fx).

Depth should be also interpolated using perspective correction. Without it there will be some z-buffer artifacts in places where two triangles intersect / overlap. More or less visible, depending on triangle position and size.

BTW persp corr interpolation just for zbuffer is simple - just linearly interpolate 1/z in screen space.

You could try to use histogram for better control over tonemapping. There is a nice presentation from Valve about their tonemapping with histogram aproach: http://www.valvesoft...heOrangeBox.pdf

The problem is, that you want the integral to evaluate to 1 and not to "<= 1".

I did solve it for integral = 1. I just wrote it as <= 1. Thanks for noticing.

I wrote a brdf for BRDF explorer with "Mittring" specular.

[source lang="plain"]analytic::begin parametersfloat n 1 1000 100bool normalized 1::end parameters::begin shadervec3 BRDF( vec3 L, vec3 V, vec3 N, vec3 X, vec3 Y ){ vec3 H = normalize( L + V ); float Dot = clamp( dot( N, H ), 0, 1 ); float Threshold = 0.04; float CosAngle = pow( Threshold, 1 / n ); float NormAngle = ( Dot - 1 ) / ( CosAngle - 1 ); float D = exp( -NormAngle * NormAngle ); if (normalized) { D *= 0.17287429 + 0.01388682 * n; //D *= 0.34574858 + 0.02777364 * n; } return vec3(D);}::end shader[/source]

Now when you use mine aprox, then max albedo in BRDF explorer correctly comes up as 1, but when using yours it's 2. This means, that in yours aprox sometimes outgoing energy is two times greater than incoming. I believe it's because you did integrate over full sphere, instead of just upper hemisphere.

KriScg's approximation was off by about the factor 2.

I think it's because you are using wrong treshold 0.004 (it was 0.04 in the presentation).