Add support for MAX_COMBINED_TEXTURES, which allows more texture support than...

Add support for MAX_COMBINED_TEXTURES, which allows more texture support than with the original fixed pipeline texture check under OpenGL. Now, more than 4 textures should also work with newer gfx cards and drivers, which often only support 4 fixed pipeline textures.
Moreover, now you can also set more than the maximal texture layers defined in IrrCompileConfig, simply by calling setTexture in the driver. The MAX_MATERIAL_TEXTURES thus only defines how many textures and configurations are stored in material properties. Currently only used under OpenGL.

git-svn-id: svn://svn.code.sf.net/p/irrlicht/code/trunk@4200 dfc29bdd-3216-0410-991c-e03cc46cb475

source/Irrlicht/COpenGLDriver.cpp

@@ -2421,7 +2421,7 @@ void COpenGLDriver::drawPixel(u32 x, u32 y, const SColor &color)
 
 bool COpenGLDriver::setActiveTexture(u32 stage, const video::ITexture* texture)
 {
-	if (stage >= MaxTextureUnits)
+	if (stage >= MaxSupportedTextures)
 		return false;
 
 	if (CurrentTexture[stage]==texture)
@@ -2460,7 +2460,7 @@ bool COpenGLDriver::setActiveTexture(u32 stage, const video::ITexture* texture)
 bool COpenGLDriver::disableTextures(u32 fromStage)
 {
 	bool result=true;
-	for (u32 i=fromStage; i<MaxTextureUnits; ++i)
+	for (u32 i=fromStage; i<MaxSupportedTextures; ++i)
 		result &= setActiveTexture(i, 0);
 	return result;
 }

source/Irrlicht/COpenGLExtensionHandler.cpp

@@ -567,14 +567,30 @@ void COpenGLExtensionHandler::initExtensions(bool stencilBuffer)
 	#endif
 #endif // _IRR_WINDOWS_API_
 
-	GLint num;
+	GLint num=0;
 	// set some properties
 #if defined(GL_ARB_multitexture) || defined(GL_VERSION_1_3)
 	if (Version>102 || FeatureAvailable[IRR_ARB_multitexture])
 	{
+#if defined(GL_MAX_TEXTURE_UNITS)
 		glGetIntegerv(GL_MAX_TEXTURE_UNITS, &num);
+#elif defined(GL_MAX_TEXTURE_UNITS_ARB)
+		glGetIntegerv(GL_MAX_TEXTURE_UNITS_ARB, &num);
+#endif
 		MaxSupportedTextures=static_cast<u8>(num);
 	}
+#endif
+#if defined(GL_ARB_vertex_shader) || defined(GL_VERSION_2_0)
+	if (Version>=200 || FeatureAvailable[IRR_ARB_vertex_shader])
+	{
+		num=0;
+#if defined(GL_MAX_COMBINED_TEXTURE_IMAGE_UNITS)
+		glGetIntegerv(GL_MAX_COMBINED_TEXTURE_IMAGE_UNITS, &num);
+#elif defined(GL_MAX_COMBINED_TEXTURE_IMAGE_UNITS_ARB)
+		glGetIntegerv(GL_MAX_COMBINED_TEXTURE_IMAGE_UNITS_ARB, &num);
+#endif
+		MaxSupportedTextures=core::max_(MaxSupportedTextures,static_cast<u8>(num));
+	}
 #endif
 	glGetIntegerv(GL_MAX_LIGHTS, &num);
 	MaxLights=static_cast<u8>(num);