From fbb51563c9bc39a12425a7e6b285087231b927cf Mon Sep 17 00:00:00 2001
From: Anakin <Battlefrontler@t-online.de>
Date: Mon, 30 Jan 2017 00:02:32 +0100
Subject: [PATCH] fixed backface culling bug, todo: connect headligh

---
 QtMeshViewer/Form Files/SettingsWindow.ui |  3 ---
 QtMeshViewer/Header/GeometryEngine.h      |  2 +-
 QtMeshViewer/Header/OglViewerWidget.h     |  1 +
 QtMeshViewer/Source/GeometryEngine.cpp    |  6 +-----
 QtMeshViewer/Source/OglViewerWidget.cpp   | 19 ++++++++++++-------
 5 files changed, 15 insertions(+), 16 deletions(-)

diff --git a/QtMeshViewer/Form Files/SettingsWindow.ui b/QtMeshViewer/Form Files/SettingsWindow.ui
index 4dd2cf2..454d889 100644
--- a/QtMeshViewer/Form Files/SettingsWindow.ui	
+++ b/QtMeshViewer/Form Files/SettingsWindow.ui	
@@ -530,9 +530,6 @@
         <property name="text">
          <string>Backface Culling</string>
         </property>
-        <property name="checked">
-         <bool>true</bool>
-        </property>
        </widget>
       </item>
      </layout>
diff --git a/QtMeshViewer/Header/GeometryEngine.h b/QtMeshViewer/Header/GeometryEngine.h
index b2556b2..7464662 100644
--- a/QtMeshViewer/Header/GeometryEngine.h
+++ b/QtMeshViewer/Header/GeometryEngine.h
@@ -36,7 +36,7 @@ private:
 	void clearData();
 
 public:
-	void drawGeometry(QOpenGLShaderProgram *program, bool wireframe);
+	void drawGeometry(QOpenGLShaderProgram *program);
 	void loadFile(QString filePath);
 
 // signals
diff --git a/QtMeshViewer/Header/OglViewerWidget.h b/QtMeshViewer/Header/OglViewerWidget.h
index 0eb3398..0a61d1a 100644
--- a/QtMeshViewer/Header/OglViewerWidget.h
+++ b/QtMeshViewer/Header/OglViewerWidget.h
@@ -27,6 +27,7 @@ private:
 
 	bool m_wireframe = false;
 	bool m_lightOn = false;
+	bool m_backfaceCulling = false;
 
 	struct {
 		QVector4D position = { 1,1,1,0 };
diff --git a/QtMeshViewer/Source/GeometryEngine.cpp b/QtMeshViewer/Source/GeometryEngine.cpp
index b8c41f6..331eaae 100644
--- a/QtMeshViewer/Source/GeometryEngine.cpp
+++ b/QtMeshViewer/Source/GeometryEngine.cpp
@@ -51,7 +51,7 @@ void GeometryEngine::clearData()
 	m_drawList.clear();
 }
 
-void GeometryEngine::drawGeometry(QOpenGLShaderProgram *program, bool wireframe)
+void GeometryEngine::drawGeometry(QOpenGLShaderProgram *program)
 {
 	if (!m_arrayBuf.isCreated() || !m_indexBuf.isCreated())
 		return;
@@ -133,12 +133,8 @@ void GeometryEngine::drawGeometry(QOpenGLShaderProgram *program, bool wireframe)
 		program->setUniformValue("materialSpecularColor", specularColor);
 
 		// Draw cube geometry using indices from VBO 1
-		if (wireframe)
-			glPolygonMode(GL_FRONT_AND_BACK, GL_LINE);
-
 		glDrawElements(GL_TRIANGLES, it.size, GL_UNSIGNED_INT, (void*)(it.offset * sizeof(GLuint)));
 
-		glPolygonMode(GL_FRONT_AND_BACK, GL_FILL);
 	}
 }
 
diff --git a/QtMeshViewer/Source/OglViewerWidget.cpp b/QtMeshViewer/Source/OglViewerWidget.cpp
index 85bf2f6..7e2f3d7 100644
--- a/QtMeshViewer/Source/OglViewerWidget.cpp
+++ b/QtMeshViewer/Source/OglViewerWidget.cpp
@@ -94,7 +94,7 @@ void OglViewerWidget::initializeGL()
 
 	//TODO: does not work
 	// Enable back face culling
-	glEnable(GL_CULL_FACE);
+	//glEnable(GL_CULL_FACE);
 
 	// Enable transparency
 	glEnable(GL_BLEND);
@@ -164,7 +164,16 @@ void OglViewerWidget::paintGL()
 	m_program.setUniformValue("cameraPosition", rotateBack * (-m_translation));
 
 	// Draw cube geometry
-	m_dataEngine->drawGeometry(&m_program, m_wireframe);
+	if (m_backfaceCulling)
+		glEnable(GL_CULL_FACE);
+
+	if (m_wireframe)
+		glPolygonMode(GL_FRONT_AND_BACK, GL_LINE);
+
+	m_dataEngine->drawGeometry(&m_program);
+
+	glDisable(GL_CULL_FACE);
+	glPolygonMode(GL_FRONT_AND_BACK, GL_FILL);
 }
 
 // Inputs ///////////////////////////////////////////////////////////////
@@ -410,11 +419,7 @@ void OglViewerWidget::setAmbCoef(double value)
 
 void OglViewerWidget::setBackfaceCulling(bool value)
 {
-	if (value)
-		glCullFace(GL_FRONT_AND_BACK);
-	else if(!value)
-		glCullFace(GL_FRONT);
-
+	m_backfaceCulling = value;
 	update();
 }