Add a new flag for controlling zbuffer writing to SMaterial.

In 4774 we tried fixing zwriting for shader materials as those are ignored in SMaterial::isTransparent.
This affected too many existing projects and made it hard to still write to zbuffer in some situations where it was necessary. So trying now another approach which brings back old functionality mostly, but allows users to have more fine-control with a new flag. Using an enum instead of bool for the new flag as it's foreseeable that more options might be necessary for this in the future.
Note: Several tests are currently failing, but they did that before, so that has to be debugged on it's own.


git-svn-id: svn://svn.code.sf.net/p/irrlicht/code/trunk@5076 dfc29bdd-3216-0410-991c-e03cc46cb475

include/SMaterial.h

@@ -246,6 +246,16 @@ namespace video
 		0
 	};
 
+	//! Fine-tuning for SMaterial.ZWriteFineControl 
+	enum E_ZWRITE_FINE_CONTROL
+	{
+		//! Default. Only write zbuffer when When SMaterial::ZBuffer is true and SMaterial::isTransparent() returns false.
+		EZI_ONLY_NON_TRANSPARENT,
+		//! Writing will just be based on SMaterial::ZBuffer value, transparency is ignored.
+		//! Needed mostly for certain shader materials as SMaterial::isTransparent will always return false for those.
+		EZI_ZBUFFER_FLAG
+	};
+
 
 	//! Maximum number of texture an SMaterial can have.
 	const u32 MATERIAL_MAX_TEXTURES = _IRR_MATERIAL_MAX_TEXTURES_;
@@ -264,7 +274,8 @@ namespace video
 			PolygonOffsetFactor(0), PolygonOffsetDirection(EPO_FRONT),
 			Wireframe(false), PointCloud(false), GouraudShading(true),
 			Lighting(true), ZWriteEnable(true), BackfaceCulling(true), FrontfaceCulling(false),
-			FogEnable(false), NormalizeNormals(false), UseMipMaps(true)
+			FogEnable(false), NormalizeNormals(false), UseMipMaps(true), 
+			ZWriteFineControl(EZI_ONLY_NON_TRANSPARENT)
 		{ }
 
 		//! Copy constructor
@@ -318,6 +329,7 @@ namespace video
 			PolygonOffsetFactor = other.PolygonOffsetFactor;
 			PolygonOffsetDirection = other.PolygonOffsetDirection;
 			UseMipMaps = other.UseMipMaps;
+			ZWriteFineControl = other.ZWriteFineControl;
 
 			return *this;
 		}
@@ -475,6 +487,11 @@ namespace video
 		/** Sometimes, disabling mipmap usage can be useful. Default: true */
 		bool UseMipMaps:1;
 
+		//! Give more control how the ZWriteEnable flag is interpreted
+		/** Note that there is also the global flag AllowZWriteOnTransparent
+		which when set acts like all materials have set EZI_ALLOW_ON_TRANSPARENT. */
+		E_ZWRITE_FINE_CONTROL ZWriteFineControl;
+
 		//! Gets the texture transformation matrix for level i
 		/** \param i The desired level. Must not be larger than MATERIAL_MAX_TEXTURES.
 		\return Texture matrix for texture level i. */
@@ -695,7 +712,9 @@ namespace video
 				BlendFactor != b.BlendFactor ||
 				PolygonOffsetFactor != b.PolygonOffsetFactor ||
 				PolygonOffsetDirection != b.PolygonOffsetDirection ||
-				UseMipMaps != b.UseMipMaps;
+				UseMipMaps != b.UseMipMaps ||
+				ZWriteFineControl != b.ZWriteFineControl;
+				;
 			for (u32 i=0; (i<MATERIAL_MAX_TEXTURES) && !different; ++i)
 			{
 				different |= (TextureLayer[i] != b.TextureLayer[i]);

source/Irrlicht/CD3D9Driver.cpp

@@ -2130,15 +2130,13 @@ void CD3D9Driver::setBasicRenderStates(const SMaterial& material, const SMateria
 	}
 
 	// zwrite
-//	if (resetAllRenderstates || (lastmaterial.ZWriteEnable != material.ZWriteEnable))
-	{
-		if (material.ZWriteEnable && (AllowZWriteOnTransparent || (!material.isTransparent() &&
- 			!MaterialRenderers[material.MaterialType].Renderer->isTransparent())))
+	if (getWriteZBuffer(material))
 	{
 		pID3DDevice->SetRenderState( D3DRS_ZWRITEENABLE, TRUE);
 	}
 	else
-			pID3DDevice->SetRenderState( D3DRS_ZWRITEENABLE, FALSE);
+	{
+		pID3DDevice->SetRenderState(D3DRS_ZWRITEENABLE, FALSE);
 	}
 
 	// back face culling

source/Irrlicht/CNullDriver.h

@@ -725,6 +725,26 @@ namespace video
 			return (f32) getAverage ( p[(y * pitch) + x] );
 		}
 
+		inline bool getWriteZBuffer(const SMaterial&material) const
+		{
+			if (material.ZWriteEnable)
+			{
+				if (!AllowZWriteOnTransparent)
+				{
+					switch (material.ZWriteFineControl)
+					{
+					case EZI_ONLY_NON_TRANSPARENT:
+						return !material.isTransparent();
+					case EZI_ZBUFFER_FLAG:
+						return true;
+					}
+				}
+				else
+					return true;
+			}
+			return false;
+		}
+
 		struct SSurface
 		{
 			video::ITexture* Surface;

source/Irrlicht/COpenGLDriver.cpp

@@ -2964,8 +2964,7 @@ void COpenGLDriver::setBasicRenderStates(const SMaterial& material, const SMater
 	}
 
 	// ZWrite
-	if (material.ZWriteEnable && (AllowZWriteOnTransparent || (material.BlendOperation == EBO_NONE &&
-		!MaterialRenderers[material.MaterialType].Renderer->isTransparent())))
+	if (getWriteZBuffer(material))
 	{
 		BridgeCalls->setDepthMask(true);
 	}

source/Irrlicht/CSoftwareDriver2.cpp

@@ -178,8 +178,7 @@ void CBurningVideoDriver::setCurrentShader()
 
 	bool zMaterialTest = Material.org.ZBuffer != ECFN_DISABLED &&
 						Material.org.ZWriteEnable &&
-							( AllowZWriteOnTransparent || (!Material.org.isTransparent() &&
-							!MaterialRenderers[Material.org.MaterialType].Renderer->isTransparent()) );
+						getWriteZBuffer(Material.org);
 
 	EBurningFFShader shader = zMaterialTest ? ETR_TEXTURE_GOURAUD : ETR_TEXTURE_GOURAUD_NOZ;