openGL work and other parts

map/gl/GLHelper.h

@@ -0,0 +1,67 @@
+#ifndef MAP_HELPER_H
+#define MAP_HELPER_H
+
+#include <Indoor/geo/Point3.h>
+#include <QOpenGLFunctions>
+
+class GLHelper {
+
+public:
+
+	static QVector3D getNormal(const QVector3D& v1, const QVector3D& v2, const QVector3D& v3) {
+
+		// get two of the triangle's edges
+		const QVector4D v21 = v2-v1;
+		const QVector4D v31 = v3-v1;
+
+		const QVector3D n = QVector3D::crossProduct(v21.toVector3D(), v31.toVector3D()).normalized();
+
+		return isCCW(v1, v2, v3) ? (n) : (-n);
+
+	}
+
+	/**
+	 * is the triangle given by p1,p2,p3 CCW?
+	 * NOTE: uses OUR coordinate system (x,y,z) where z is the floor-height
+	 */
+	static bool isCCW(const Point3 p1, const Point3 p2, const Point3 p3) {
+		const QVector3D v1(p1.x, p1.z, p1.y);
+		const QVector3D v2(p2.x, p2.z, p2.y);
+		const QVector3D v3(p3.x, p3.z, p3.y);
+		return isCCW(v1, v2, v3);
+	}
+
+	/**
+	 * is the triangle given by p1,p2,p3 CCW?
+	 * NOTE: uses OpenGL coordinate system (x,z,y) (our z is the floor-height)
+	 */
+	static bool isCCW(const QVector3D& p1, const QVector3D& p2, const QVector3D& p3) {
+
+		// camera position
+		QMatrix4x4 proj; proj.lookAt(QVector3D(-1,20,-1), QVector3D(0,0,0), QVector3D(0,1,0));
+
+		// to camera space
+		QVector4D v1(p1.x(), p1.y(), p1.z(), 1);
+		QVector4D v2(p2.x(), p2.y(), p2.z(), 1);
+		QVector4D v3(p3.x(), p3.y(), p3.z(), 1);
+		v1 = proj * v1;
+		v2 = proj * v2;
+		v3 = proj * v3;
+
+		// get two of the triangle's edges
+		const QVector4D v21 = v2-v1;
+		const QVector4D v31 = v3-v1;
+
+		// check the angle between both
+		const float angle = QVector2D::dotProduct(v21.toVector2D(), v31.toVector2D());
+		return angle > 0;
+
+//		const QVector3D n = QVector3D::crossProduct(v21.toVector3D(), v31.toVector3D());
+//		return n.z() > 0;
+
+	}
+
+
+};
+
+#endif // MAP_HELPER_H