Axiom.Core.SceneManager.DeriveShadowCasterPass C# (CSharp) Method

		protected virtual Pass DeriveShadowCasterPass( Pass pass )
		{
			if ( this.IsShadowTechniqueTextureBased )
			{
				Pass retPass;
				if ( pass.Parent.ShadowCasterMaterial != null )
				{
					retPass = pass.Parent.ShadowCasterMaterial.GetBestTechnique().GetPass( 0 );
				}
				else
				{
					retPass = ( this.shadowTextureCustomCasterPass != null ? this.shadowTextureCustomCasterPass : this.shadowCasterPlainBlackPass );
				}

				// Special case alpha-blended passes
				if ( ( pass.SourceBlendFactor == SceneBlendFactor.SourceAlpha &&
					   pass.DestinationBlendFactor == SceneBlendFactor.OneMinusSourceAlpha )
					|| pass.AlphaRejectFunction != CompareFunction.AlwaysPass )
				{
					// Alpha blended passes must retain their transparency
					retPass.SetAlphaRejectSettings( pass.AlphaRejectFunction, pass.AlphaRejectValue );
					retPass.SetSceneBlending( pass.SourceBlendFactor, pass.DestinationBlendFactor );
					retPass.Parent.Parent.TransparencyCastsShadows = true;

					// So we allow the texture units, but override the color functions
					// Copy texture state, shift up one since 0 is shadow texture
					int origPassTUCount = pass.TextureUnitStageCount;
					for ( int t = 0; t < origPassTUCount; ++t )
					{
						TextureUnitState tex;
						if ( retPass.TextureUnitStageCount <= t )
						{
							tex = retPass.CreateTextureUnitState();
						}
						else
						{
							tex = retPass.GetTextureUnitState( t );
						}
						// copy base state
						pass.GetTextureUnitState( t ).CopyTo( tex );
						// override colour function
						tex.SetColorOperationEx( LayerBlendOperationEx.Source1, LayerBlendSource.Manual, LayerBlendSource.Current, this.IsShadowTechniqueAdditive ? ColorEx.Black : shadowColor );
					}
					// Remove any extras
					while ( retPass.TextureUnitStageCount > origPassTUCount )
					{
						retPass.RemoveTextureUnitState( origPassTUCount );
					}
				}
				else
				{
					// reset
					retPass.SetSceneBlending( SceneBlendType.Replace );
					retPass.AlphaRejectFunction = CompareFunction.AlwaysPass;
					while ( retPass.TextureUnitStageCount > 0 )
					{
						retPass.RemoveTextureUnitState( 0 );
					}
				}

				// Propogate culling modes
				retPass.CullingMode = pass.CullingMode;
				retPass.ManualCullingMode = pass.ManualCullingMode;

				// Does incoming pass have a custom shadow caster program?
				if ( pass.ShadowCasterVertexProgramName != "" )
				{
					retPass.SetVertexProgram( pass.ShadowCasterVertexProgramName, false );
					GpuProgram prg = retPass.VertexProgram;
					// Load this program if not done already
					if ( !prg.IsLoaded )
					{
						prg.Load();
					}
					// Copy params
					retPass.VertexProgramParameters = pass.ShadowCasterVertexProgramParameters;
					// Also have to hack the light autoparams, that is done later
				}
				else
				{
					// reset vp?
					if ( retPass == this.shadowTextureCustomCasterPass )
					{
						if ( retPass.VertexProgramName != this.shadowTextureCustomCasterVertexProgram )
						{
							this.shadowTextureCustomCasterPass.SetVertexProgram( this.shadowTextureCustomCasterVertexProgram );
							if ( retPass.HasVertexProgram )
							{
								retPass.VertexProgramParameters = this.shadowTextureCustomCasterVPParams;
							}
						}
					}
					else
					{
						// Standard shadow caster pass, reset to no vp
						retPass.SetVertexProgram( "" );
					}
				}

				return retPass;
			}
			else
			{
				return pass;
			}
		}