Shadow model z-fighting

[squisher]

Hi, I get z-fighting when I rotate my ship around with shadows enabled:



Relevant code is:

Code: Select all

        smgr->getMeshManipulator()->setVertexColors(smgr->getMesh("bird.irrmesh"), SColor(0, 0, 0, 0));
        auto shadowNode = smgr->addAnimatedMeshSceneNode(smgr->getMesh("bird.irrmesh"), impl->node);
        shadowNode->setID(0);
        shadowNode->setMaterialFlag(irr::video::EMF_LIGHTING, false);
        shadowNode->setMaterialFlag(irr::video::EMF_ZWRITE_ENABLE, false);
        shadowNode->setMaterialFlag(irr::video::EMF_BACK_FACE_CULLING, false);
        shadowNode->setMaterialType(irr::video::EMT_TRANSPARENT_VERTEX_ALPHA);
        shadowNode->addShadowVolumeSceneNode()->setID(0);
        smgr->setShadowColor(SColor(150,0,0,0));

Here's the bird.irrmesh

Workaround is to use a copy of bird.irrmesh that's scaled by 0.99f:

Code: Select all

        auto smesh = smgr->getMeshManipulator()->createMeshCopy(smgr->getMesh("bird.irrmesh")->getMesh(0));
        smgr->getMeshManipulator()->scale(smesh, vector3df(.99f, .99f, .99f));
        smgr->getMeshManipulator()->setVertexColors(smesh, SColor(0, 0, 0, 0));
        auto mesh = smgr->getMeshManipulator()->createAnimatedMesh(smesh);
        smesh->drop();
 
        auto shadowNode = smgr->addAnimatedMeshSceneNode(mesh, impl->node);
        mesh->drop();

Had same issue in 1.7 and 1.8.

[CuteAlien]

You can try if you can work different near and far-plane values. The ratio of those 2 affects the z-fighting. Also check for model errors, like having 2 polygons in the same place accidentally.