Terrain pssm depth shadows

[Kenshido]

Hello!

What am I doing wrong using pssm depth shadows with terrain?

Shadows settings:

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	mSceneMgr->setShadowTechnique(Ogre::SHADOWTYPE_TEXTURE_MODULATIVE_INTEGRATED);
	mSceneMgr->setShadowTextureCountPerLightType(Ogre::Light::LT_DIRECTIONAL, 3);
	mSceneMgr->setShadowTextureCount(3);
	mSceneMgr->setShadowTextureConfig(0, 512, 1024, Ogre::PF_FLOAT32_R);
	mSceneMgr->setShadowTextureConfig(1, 512, 512, Ogre::PF_FLOAT32_R);
	mSceneMgr->setShadowTextureConfig(2, 512, 512, Ogre::PF_FLOAT32_R);
	mSceneMgr->setShadowTextureSelfShadow(true);
	mSceneMgr->setShadowTextureCasterMaterial("Ogre/shadow/depth/caster");
	mSceneMgr->setShadowFarDistance(2000);
	 //shadow camera setup
	Ogre::PSSMShadowCameraSetup* pssmSetup = new Ogre::PSSMShadowCameraSetup();
	pssmSetup->calculateSplitPoints(3, mCamera->getNearClipDistance(), 2000);
	pssmSetup->setSplitPadding(mCamera->getNearClipDistance());
	Ogre::PSSMShadowCameraSetup::SplitPointList splitPointList = pssmSetup->getSplitPoints();
	splitPointList[0] = 1;
	splitPointList[1] = 100;
	splitPointList[2] = 500;
	splitPointList[3] = 2000;
	Ogre::Vector4 splitPoints;
    for (int i = 0; i < 3; ++i)   {
        splitPoints[i] = splitPointList[i];
    }
	pssmSetup->setSplitPoints(splitPointList);
	mSceneMgr->setShadowCasterRenderBackFaces(true);
	mSceneMgr->setShadowCameraSetup(Ogre::ShadowCameraSetupPtr(pssmSetup));

Terrain settings:

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	Ogre::TerrainMaterialGeneratorA::SM2Profile* matProfile =
		static_cast<Ogre::TerrainMaterialGeneratorA::SM2Profile*>(mTerrainGlobals->getDefaultMaterialGenerator()->getActiveProfile());
	if (matProfile)
	{
		matProfile->setLayerNormalMappingEnabled(false);
		matProfile->setLayerParallaxMappingEnabled(false);
		matProfile->setReceiveDynamicShadowsDepth(true);
		matProfile->setReceiveDynamicShadowsPSSM(mSettings->getPSSMSettings());
	}

Here's the result:

[dark_sylinc]

You're overwritting the split points. That's a usually bad idea.
You should be using them after calling calculateSplitPoints.

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pssmSetup->setSplitPadding(mCamera->getNearClipDistance());// Call this first
pssmSetup->calculateSplitPoints(3, mCamera->getNearClipDistance(), 2000); //Call this last.
//pssmSetup->setSplitPoints(splitPointList); //Do NOT use this function.
pssmSetup->getSplitPoints() //Get the split points if you need them

Furthermore, your shadow far distance of 2000 is too large. Shadow mapping hardly has that good precision for that. Start with low values like 50 or 100 to achieve good results and discard precision as the problem.
If it looks as it should, then start increasing incrementally the shadow distance until quality starts to degrade. The lambda parameter in calculateSplitPoints also affects the quality. You'll have to play with both settings (distance and lambda) depending on your scene.

[Kenshido]

I've shanged code to this:

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	mSceneMgr->setShadowTechnique(Ogre::SHADOWTYPE_TEXTURE_MODULATIVE_INTEGRATED);
	mSceneMgr->setShadowTextureCountPerLightType(Ogre::Light::LT_DIRECTIONAL, 3);
	mSceneMgr->setShadowTextureCount(3);
	mSceneMgr->setShadowTextureConfig(0, 512, 512, Ogre::PF_FLOAT32_R);
	mSceneMgr->setShadowTextureConfig(1, 512, 512, Ogre::PF_FLOAT32_R);
	mSceneMgr->setShadowTextureConfig(2, 512, 512, Ogre::PF_FLOAT32_R);
	mSceneMgr->setShadowTextureSelfShadow(true);
	mSceneMgr->setShadowTextureCasterMaterial("Ogre/shadow/depth/caster");
	mSceneMgr->setShadowFarDistance(100);
	 //shadow camera setup
	Ogre::PSSMShadowCameraSetup* pssmSetup = new Ogre::PSSMShadowCameraSetup();
	pssmSetup->calculateSplitPoints(3, mCamera->getNearClipDistance(), 100, 0.8f);
	pssmSetup->setSplitPadding(mCamera->getNearClipDistance());
	Ogre::PSSMShadowCameraSetup::SplitPointList splitPointList = pssmSetup->getSplitPoints();
	Ogre::Vector4 splitPoints;
    for (int i = 0; i < 3; ++i)   {
        splitPoints[i] = splitPointList[i];
    }
	//pssmSetup->setSplitPoints(splitPointList);
	mSceneMgr->setShadowCasterRenderBackFaces(true);
	mSceneMgr->setShadowCameraSetup(Ogre::ShadowCameraSetupPtr(pssmSetup));

and nothing's happened:

[Kenshido]

I don't understand, how caster works.

For example, how this stone:

can create this depth texture?

If I understand correctly, close polygons should cause close depth values?

The second question:

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	// Calculate the position of vertex in light space
	outp.lightSpacePos0 = mul(texWorldViewProjMatrix0, pos);
	outp.lightSpacePos1 = mul(texWorldViewProjMatrix1, pos);
	outp.lightSpacePos2 = mul(texWorldViewProjMatrix2, pos);

	// make linear
	outp.lightSpacePos0.z = (outp.lightSpacePos0.z - depthRange0.x) * depthRange0.w;
	outp.lightSpacePos1.z = (outp.lightSpacePos1.z - depthRange1.x) * depthRange1.w;
	outp.lightSpacePos2.z = (outp.lightSpacePos2.z - depthRange2.x) * depthRange2.w;

All lightSpacePos.z has always negative values, is this correct?

[stasclick]

What am I doing wrong using pssm depth shadows with terrain?

Maybe this can help. I had the same problem, it helps me:

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VS_OUT main_caster_vp(...)
{
    ...
    outp.depth = (outp.pos.z - depthRange.x) * depthRange.w;
    return outp;
}
float4 main_caster_fp(
   VS_OUT In, ...)
{
    return float4(In.depth.xxx, 1);
}

[Kenshido]

Maybe this can help. I had the same problem, it helps me:

Unfortunately, ogre's shader for depth shadows already uses this code...

[Kenshido]

The code, where comparison of depths (caster and object) processed:

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float calcDepthShadow(sampler2D shadowMap, float4 uv, float invShadowMapSize)
{
	// 4-sample PCF
	
	float shadow = 0.0;
	float offset = (NUM_SHADOW_SAMPLES_1D/2 - 0.5) * SHADOW_FILTER_SCALE;
	for (float y = -offset; y <= offset; y += SHADOW_FILTER_SCALE)
		for (float x = -offset; x <= offset; x += SHADOW_FILTER_SCALE)
		{
			float depth = tex2Dproj(shadowMap, offsetSample(uv, float2(x, y), invShadowMapSize)).x;
			if (depth >= 1 || depth >= uv.z)
				shadow += 1.0;
		}

	shadow /= SHADOW_SAMPLES;
	return shadow;
}

Where uv.z is lightSpacePos.z
I created pixel shader, whitch shows uv.z and depth values as texture.

uv.z:

uv.z is always negative and has very close values, so I used this code for representation: (uv.z + 0.3) * 10;

Why uv.z from lightSpacePos0, lightSpacePos1 and lightSpacePos2 has different values?

depth:

Strange separation of trunk depth I can explan by different scene_depth (because of stone, placed behind of part of tree) (im I right?)
But I can't explain, why trunk's depth is the same from bottom to top? My light source has this direction:

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Ogre::Vector3 lightdir(0.5, -0.35, 0.5);

So, depth values from bottom should shoud have bigger values, then from top of trunk.

[Kenshido]

I've finally implemented depth shadows with terrain and PagedGeometry. Not PSSM, but CSM from this sample

[Lax]

Hi Kenshido,

I'm also trying to integrate CSM shadows for terrain and pagedgeometry but without success. I do not know how to apply CSM for Ogre terrain.
Could you help me out? Could you show some code what needs to be done?

Thanks in advance
Regards
Lax