Reverting my changes from r4569 as they also break stuff by now. Will continue...

Reverting my changes from r4569 as they also break stuff by now. Will continue the discussion in http://irrlicht.sourceforge.net/forum/viewtopic.php?f=7&t=48940

git-svn-id: svn://svn.code.sf.net/p/irrlicht/code/trunk@4575 dfc29bdd-3216-0410-991c-e03cc46cb475

include/EMaterialTypes.h

@@ -101,7 +101,7 @@ namespace video
 		EMT_TRANSPARENT_ALPHA_CHANNEL,
 
 		//! Makes the material transparent based on the texture alpha channel.
-		/** If the alpha channel value is greater than a certain value (default 127), a
+		/** If the alpha channel value is greater than 127, a
 		pixel is written to the target, otherwise not. This
 		material does not use alpha blending and is a lot faster
 		than EMT_TRANSPARENT_ALPHA_CHANNEL. It is ideal for drawing
@@ -109,12 +109,7 @@ namespace video
 		blurry but sharp. Only first texture is used. If you are
 		using this material with small textures and 3d object, it
 		is a good idea to load the texture in 32 bit mode
-		(video::IVideoDriver::setTextureCreationFlag()). 
-		By changing SMaterial::MaterialTypeParam you can control the value which is used 
-		to seperate transparent and opaque pixels. The range is 0-1 (corresponding to 0-255 values
-		for the alpha-channel test). 0 is special and like 0.5 interpreted as 127 
-		(if you really want no transparency at all use a very small value above 0)
-		*/
+		(video::IVideoDriver::setTextureCreationFlag()). */
 		EMT_TRANSPARENT_ALPHA_CHANNEL_REF,
 
 		//! Makes the material transparent based on the vertex alpha value.

source/Irrlicht/CD3D8MaterialRenderer.h

@@ -350,9 +350,7 @@ public:
 	{
 		services->setBasicRenderStates(material, lastMaterial, resetAllRenderstates);
 
-		if (material.MaterialType != lastMaterial.MaterialType 
-			|| material.MaterialTypeParam != lastMaterial.MaterialTypeParam 
-			|| resetAllRenderstates)
+		if (material.MaterialType != lastMaterial.MaterialType || resetAllRenderstates)
 		{
 			setTextureColorStage(pID3DDevice, 0,
 				D3DTA_TEXTURE, D3DTOP_MODULATE, D3DTA_CURRENT);
@@ -362,7 +360,8 @@ public:
 
 			pID3DDevice->SetRenderState(D3DRS_ALPHABLENDENABLE, FALSE);
 
-			pID3DDevice->SetRenderState(D3DRS_ALPHAREF, material.MaterialTypeParam == 0 ? 127 : material.MaterialTypeParam * 255.f);
+			// 127 is required by EMT_TRANSPARENT_ALPHA_CHANNEL_REF
+			pID3DDevice->SetRenderState(D3DRS_ALPHAREF, 127);
 			pID3DDevice->SetRenderState(D3DRS_ALPHAFUNC, D3DCMP_GREATEREQUAL);
 			pID3DDevice->SetRenderState(D3DRS_ALPHATESTENABLE, TRUE);
 		}

source/Irrlicht/CD3D9MaterialRenderer.h

@@ -381,9 +381,7 @@ public:
 	{
 		services->setBasicRenderStates(material, lastMaterial, resetAllRenderstates);
 
-		if (material.MaterialType != lastMaterial.MaterialType 
-			||	material.MaterialTypeParam != lastMaterial.MaterialTypeParam 
-			|| resetAllRenderstates)
+		if (material.MaterialType != lastMaterial.MaterialType || resetAllRenderstates)
 		{
 			setTextureColorStage(pID3DDevice, 0,
 				D3DTA_TEXTURE, D3DTOP_MODULATE, D3DTA_CURRENT);
@@ -393,7 +391,8 @@ public:
 
 			pID3DDevice->SetRenderState(D3DRS_ALPHABLENDENABLE, FALSE);
 
-			pID3DDevice->SetRenderState(D3DRS_ALPHAREF, material.MaterialTypeParam == 0 ? 127 : material.MaterialTypeParam * 255.f);
+			// 127 is required by EMT_TRANSPARENT_ALPHA_CHANNEL_REF
+			pID3DDevice->SetRenderState(D3DRS_ALPHAREF, 127);
 			pID3DDevice->SetRenderState(D3DRS_ALPHAFUNC, D3DCMP_GREATEREQUAL);
 			pID3DDevice->SetRenderState(D3DRS_ALPHATESTENABLE, TRUE);
 		}

source/Irrlicht/COpenGLMaterialRenderer.h

@@ -495,12 +495,10 @@ public:
 		Driver->disableTextures(1);
 		Driver->setBasicRenderStates(material, lastMaterial, resetAllRenderstates);
 
-		if (material.MaterialType != lastMaterial.MaterialType 
-			|| material.MaterialTypeParam != lastMaterial.MaterialTypeParam
-			|| resetAllRenderstates)
+		if (material.MaterialType != lastMaterial.MaterialType || resetAllRenderstates)
 		{
 			Driver->getBridgeCalls()->setAlphaTest(true);
-			Driver->getBridgeCalls()->setAlphaFunc(GL_GREATER, material.MaterialTypeParam == 0 ? 0.5 : material.MaterialTypeParam);
+			Driver->getBridgeCalls()->setAlphaFunc(GL_GREATER, 0.5f);
 			glTexEnvi(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_MODULATE);
 		}
 	}
@@ -508,7 +506,7 @@ public:
 	virtual void OnSetBaseMaterial(const SMaterial& material) _IRR_OVERRIDE_
 	{
 		Driver->getBridgeCalls()->setAlphaTest(true);
-		Driver->getBridgeCalls()->setAlphaFunc(GL_GREATER, material.MaterialTypeParam == 0 ? 0.5 : material.MaterialTypeParam);
+		Driver->getBridgeCalls()->setAlphaFunc(GL_GREATER, 0.5f);
 	}
 
 	virtual void OnUnsetMaterial() _IRR_OVERRIDE_