Irrlicht Engine

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btTriangleMesh * ConvertTerrainToBulletTriangleMesh(
    irr::scene::ITerrainSceneNode* terrain,
    const irr::core::vector3df& Scaling)
      {
         //mesh converting

            btVector3 vertices[3];
            irr::u32 j,k,index,numVertices,numIndices;
            irr::u16* mb_indices16;
			irr::u32* mb_indices32;
			video::E_INDEX_TYPE indicesType;
            btTriangleMesh *triangleMesh;

            irr::scene::ITerrainSceneNode *pTerrain = terrain;


			scene::CDynamicMeshBuffer* buffer = 0;

			numVertices = terrain->getMesh()->getMeshBuffer(0)->getVertexCount();
			if (numVertices <= 65536)
			{
				//small enough for 16bit buffers
				buffer = new scene::CDynamicMeshBuffer(video::EVT_2TCOORDS, video::EIT_16BIT);
			}
			else
			{
				//we need 32bit buffers
				buffer = new scene::CDynamicMeshBuffer(video::EVT_2TCOORDS, video::EIT_32BIT);
			}

            pTerrain->getMeshBufferForLOD(*buffer, 0);

            numVertices = buffer->getVertexCount();
            numIndices = buffer->getIndexCount();
			indicesType = buffer->getIndexType();

			if (indicesType == video::EIT_16BIT)
			{
				mb_indices16 = buffer->getIndices();

				irr::video::S3DVertex2TCoords* mb_vertices = (irr::video::S3DVertex2TCoords*)buffer->getVertices();
				btTriangleMesh *pTriMesh = new btTriangleMesh();
				irr::core::vector3df scaling = Scaling;

				for(j = 0; j < numIndices; j += 3)
				{ 
					//index into irrlicht data
					for (k = 0; k < 3; k++)
					{
						index = mb_indices16[j+k];

						// we apply scaling factor directly to verticies
						vertices[k] = btVector3(mb_vertices[index].Pos.X*scaling.X,
						mb_vertices[index].Pos.Y*scaling.Y,
						mb_vertices[index].Pos.Z*scaling.Z);
					}

					pTriMesh->addTriangle(vertices[0], vertices[1], vertices[2]);
				}

				triangleMesh = pTriMesh;
			}
			else if (indicesType == video::EIT_32BIT)
			{
				mb_indices32 = (u32*)buffer->getIndices();

				irr::video::S3DVertex2TCoords* mb_vertices = (irr::video::S3DVertex2TCoords*)buffer->getVertices();
				btTriangleMesh *pTriMesh = new btTriangleMesh();
				irr::core::vector3df scaling = Scaling;

				for(j = 0; j < numIndices; j += 3)
				{ 
					//index into irrlicht data
					for (k = 0; k < 3; k++)
					{
						index = mb_indices32[j+k];

						// we apply scaling factor directly to verticies
						vertices[k] = btVector3(mb_vertices[index].Pos.X*scaling.X,
						mb_vertices[index].Pos.Y*scaling.Y,
						mb_vertices[index].Pos.Z*scaling.Z);
					}

					pTriMesh->addTriangle(vertices[0], vertices[1], vertices[2]);
				}

				triangleMesh = pTriMesh;
			}
			else
			{
				// bad indices type!
				buffer->drop();

				return NULL;
			}

			buffer->drop();

			return  triangleMesh;
      }