How to mix static shadow with dynamic shadow

[liudingjun]

hello, while I was playing GEAR of WAR, I noticed that this game did a very good job on mix static shadow with dynamic shadow. The static shadow are pre-computed in the light map or RNM, and dynamic shadow cast from the the chracters.
When the character enter some dark area, I could not see those area become more darker. When the character enter some bright area, I could see that those area become dark but consistant with other dark area.
How do they do that?
Maybe I could bake two different light maps, one is much dark without this light, and other one is much bright with this light.
In the game run time, I choose different lightmap based on the value from character shadow map. If the current pixel is in the shadow of the character, the dark light map will be selected. Otherwise, I pick the bright one.
This solution should works fine. But it will increase a lots of texture memory, and the situation will become more complex when more than one light exist.
So Is there anybody have some idea to solve this problem?
Thanks a lots!

[Radikalizm]

This actually sounds like a regular HDR lighting pipeline with tonemapping, based on your description (although I'm not sure that's what you mean)

Do you have any videos showing the effect?

[liudingjun]

hi, I think some body may have the same problem with mine.
You could check the following link here : http://forum.unity3d.com/threads/32385- ... ic-shadows

Just as you see from the above image, the cube is a moving characters in the game scene. The whole scene (not include the white cube) painted with the light maps. Here the shadow effect cast by the cube is very different from those which picked from pre-computed lightmaps. Of course, the shadow from the cube is real time. That means, I may use Dynamic Shadow Map to create the cube shadow map. Right now, I am looking for a way to make both of them (light map shadow and dynamic real time shadow) look the same. Any body have some ideas?
3Q You!

[Mel]

Something quite curious would be to have "premade" shadow volumes that rendered the same as the realtime stencil shadows, but without the need to precalculate them.

[ACE247]

So you could recalculate when a node is moving and then store its dynamic shadow as static in the lightmap but then you have to remove your previous shadow from the lightmap once you've moved again.... Why not just load the whole lightmap as an additive onto the dynamic shadow buffer. and then set the whole buffers color for the shadows the same. (Im not the best with this kinda stuff, but is that feasible?)

[fmx]

How difficult is it to edit the colour calculations in the shader to make the shadows match?
The only difference seems to be that the cube shadows look more transparent, just make the dynamic shadows darker (less luminance and more alpha)
That is all you have to do IMO

edit:
on second thought, I can see the dynamic shadow is bleeding "over" the static shadow so that wont work

[Mel]

I have a suggestion for the dynamic/static shadow blending. Basically, If you use lightmapping, you can multiply the shadowmap by the lightmap, and calculate the luminance of the result to blend it with the ambient lighting. This, obviously, overrides the lightmap color, but almost blends perfectly the shadowmap with the lightmap.

Code: Select all

 
lightmapColor*=shadowmapValue;
colorIntensity = (lightmapColor.r+lightmapColor.g+lightmapColor.b)/3.0;
lightCol = (1-colorIntensity)*ambient+(colorIntensity)*lightmapColor;