Enable seamless filtering for cubemaps on OpenGL by default and add a new driver feature flag to disable it.

git-svn-id: svn://svn.code.sf.net/p/irrlicht/code/trunk@5661 dfc29bdd-3216-0410-991c-e03cc46cb475

include/EDriverFeatures.h

@@ -139,6 +139,9 @@ namespace video
 		//! Support for cube map textures.
 		EVDF_TEXTURE_CUBEMAP,
 
+		//! Support for filtering across different faces of the cubemap
+		EVDF_TEXTURE_CUBEMAP_SEAMLESS,
+
 		//! Only used for counting the elements of this enum
 		EVDF_COUNT
 	};

source/Irrlicht/COpenGLDriver.cpp

@@ -2022,6 +2022,19 @@ ITexture* COpenGLDriver::createDeviceDependentTextureCubemap(const io::path& nam
 	return texture;
 }
 
+void COpenGLDriver::disableFeature(E_VIDEO_DRIVER_FEATURE feature, bool flag)
+{
+	CNullDriver::disableFeature(feature, flag);
+
+	if ( feature == EVDF_TEXTURE_CUBEMAP_SEAMLESS )
+	{
+		if ( queryFeature(feature) )
+			glEnable(GL_TEXTURE_CUBE_MAP_SEAMLESS);
+		else if (COpenGLExtensionHandler::queryFeature(feature))
+			glDisable(GL_TEXTURE_CUBE_MAP_SEAMLESS);
+	}
+}
+
 //! Sets a material. All 3d drawing functions draw geometry now using this material.
 void COpenGLDriver::setMaterial(const SMaterial& material)
 {

source/Irrlicht/COpenGLDriver.h

@@ -131,6 +131,9 @@ namespace video
 			return FeatureEnabled[feature] && COpenGLExtensionHandler::queryFeature(feature);
 		}
 
+		//! Disable a feature of the driver.
+		virtual void disableFeature(E_VIDEO_DRIVER_FEATURE feature, bool flag=true) _IRR_OVERRIDE_;
+
 		//! Sets a material. All 3d drawing functions draw geometry now
 		//! using this material.
 		//! \param material: Material to be used from now on.

source/Irrlicht/COpenGLExtensionHandler.cpp

@@ -747,6 +747,10 @@ void COpenGLExtensionHandler::initExtensions(bool stencilBuffer)
 		os::Printer::log("Free render buffer memory (kB)", core::stringc(val[0]));
 	}
 #endif
+
+	if (queryFeature(EVDF_TEXTURE_CUBEMAP_SEAMLESS))
+		glEnable(GL_TEXTURE_CUBE_MAP_SEAMLESS);
+
 #endif
 }
 
@@ -824,6 +828,8 @@ bool COpenGLExtensionHandler::queryFeature(E_VIDEO_DRIVER_FEATURE feature) const
 		return FeatureAvailable[IRR_EXT_texture_compression_s3tc];
 	case EVDF_TEXTURE_CUBEMAP:
 		return (Version >= 130) || FeatureAvailable[IRR_ARB_texture_cube_map] || FeatureAvailable[IRR_EXT_texture_cube_map];
+	case EVDF_TEXTURE_CUBEMAP_SEAMLESS:
+		return FeatureAvailable[IRR_ARB_seamless_cube_map];
 	default:
 		return false;
 	};