glwidgets, bindTexturePatch: Get the OpenGL extensions supported by t…

…he graphics card, and conditionally enable anisotropic filtering with the maximum amount of taps for a less blurry viewport.

bindTexturePatch.h

@@ -194,6 +194,9 @@ bool GLWidget::myBindTexture(const QString &fileName, DdsData &data)
     } else
       glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
 
+    if (GLWidget::maxSupportedTexAnisoTaps > 1)
+      glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAX_ANISOTROPY_EXT, GLWidget::maxSupportedTexAnisoTaps);
+
     int offset = 0;
     int w = ddsHeader.dwWidth;
     int h = ddsHeader.dwHeight;

glwidgets.cpp

@@ -1684,6 +1684,19 @@ void GLWidget::initOpenGL2(){
     //glewInit();
 	//initFramPrograms();
     qDebug("Init glew2!");
+
+	/* swy: retrieve the list of supported OpenGL extensions; first as a long space-separated string,
+	        then split into a QtSet dictionary for fast lookups */
+	const char *thing = (const char *) glGetString(GL_EXTENSIONS);
+	supportedExtensionsList = QString(thing).split(" ").toSet();
+	qDebug() << supportedExtensionsList;
+
+	if (supportedExtensionsList.contains("GL_EXT_texture_filter_anisotropic"))
+	{
+		glGetIntegerv(GL_MAX_TEXTURE_MAX_ANISOTROPY_EXT, (GLint *) &maxSupportedTexAnisoTaps);
+		qDebug("swy: GL_EXT_texture_filter_anisotropic is supported, with x%u taps...", maxSupportedTexAnisoTaps);
+	}
+
 	openGL2ready = true;
 
 	readCustomShaders();

glwidgets.h

@@ -74,6 +74,9 @@ class GLWidget : public QGLWidget, protected QOpenGLFunctions_2_0
 	MaterialError lastMatErr;
 	void setMaterialError(int newErr);
 
+	QSet<QString> supportedExtensionsList;
+	uint8_t maxSupportedTexAnisoTaps = 0;
+
 	void keyPressEvent( QKeyEvent * event );
 	void keyReleaseEvent( QKeyEvent * event );
 private slots: