Objects have to be rendered in the right order for alpha blending to work

src/pulsaranimationwidget.cpp

@@ -73,11 +73,12 @@ PulsarAnimationWidget::~PulsarAnimationWidget()
 
 void PulsarAnimationWidget::initializeGL()
 {
-	glShadeModel(GL_SMOOTH);
 	glClearColor(0.0, 0.0, 0.0, 0.0);
 	glClearDepth(1.0f);
-	glEnable(GL_DEPTH_TEST);
 	glDepthFunc(GL_LEQUAL);
+	glEnable(GL_DEPTH_TEST);
+
+	glShadeModel(GL_SMOOTH);
 	glHint(GL_PERSPECTIVE_CORRECTION_HINT, GL_NICEST);
 
 	GLfloat LightAmbient[] = { 0.3f, 0.3f, 0.3f, 1.0f };
@@ -98,8 +99,8 @@ void PulsarAnimationWidget::initializeGL()
 	glEnable(GL_LIGHT0);
 	glEnable(GL_LIGHTING);
 
-	glEnable(GL_BLEND);
 	glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
+	glEnable(GL_BLEND);
 
 	m_quadricPulsarOrbitPlane = gluNewQuadric();
 	m_quadricPulsar = gluNewQuadric();
@@ -135,19 +136,6 @@ void PulsarAnimationWidget::paintGL()
 			  0.0, 0.0, 0.0,
 			  0.0, 1.0, 0.0);
 
-	if(m_cameraInteraction) {
-		static GLfloat pulsarOrbitAmbientDiffuse[] = { 1.0, 1.0, 1.0, 0.25 };
-		glMaterialfv(GL_FRONT, GL_AMBIENT_AND_DIFFUSE, pulsarOrbitAmbientDiffuse);
-
-		glPushMatrix();
-			glRotatef(90.0f, 1.0f, 0.0f, 0.0f);
-			gluDisk(m_quadricPulsarOrbitPlane,
-					m_pulsarOrbitRadius * 0.9f,
-					m_pulsarOrbitRadius * 1.1f,
-					64, 1);
-		glPopMatrix();
-	}
-
 	// TODO: should be located elsewhere
 	static GLfloat no_mat[] = { 0.0, 0.0, 0.0, 1.0 };
 	static GLfloat mat_diffuse[] = { 0.5, 0.5, 0.5, 1.0 };
@@ -198,6 +186,19 @@ void PulsarAnimationWidget::paintGL()
 			gluCylinder(m_quadricPulsarCone2, 0.5f, 0.0f, 3.0f, 32, 32);
 		glPopMatrix();
 	glPopMatrix();
+
+	if(m_cameraInteraction) {
+		static GLfloat pulsarOrbitAmbientDiffuse[] = { 1.0, 1.0, 1.0, 0.33 };
+		glMaterialfv(GL_FRONT, GL_AMBIENT_AND_DIFFUSE, pulsarOrbitAmbientDiffuse);
+
+		glPushMatrix();
+			glRotatef(90.0f, 1.0f, 0.0f, 0.0f);
+			gluDisk(m_quadricPulsarOrbitPlane,
+					m_pulsarOrbitRadius * 0.9f,
+					m_pulsarOrbitRadius * 1.1f,
+					64, 1);
+		glPopMatrix();
+	}
 }
 
 void PulsarAnimationWidget::runAnimation()