From 03da9c5cf9fb6a0572814cd5332e5438cc21b00c Mon Sep 17 00:00:00 2001
From: ccolin <cyril.colin@etu.univ-amu.fr>
Date: Mon, 4 Jan 2021 17:37:49 +0100
Subject: [PATCH] replace the orbital cam by a free flying cam

---
 src/opengl_widget.cc | 80 +++++++++++++++++++++++++++++++++++---------
 src/opengl_widget.hh | 16 +++++++--
 2 files changed, 78 insertions(+), 18 deletions(-)

diff --git a/src/opengl_widget.cc b/src/opengl_widget.cc
index 582bf3e..92166ac 100644
--- a/src/opengl_widget.cc
+++ b/src/opengl_widget.cc
@@ -24,13 +24,21 @@ OpenGLWidget *OpenGLWidget::instance = nullptr;
 
 
 OpenGLWidget::OpenGLWidget(QWidget *parent)
-	:QOpenGLWidget(parent) {
+	:QOpenGLWidget(parent),
+	 move_timer(this) {
 	OpenGLWidget::instance = this;
 	QSurfaceFormat format;
 	format.setProfile(QSurfaceFormat::CoreProfile);
 	format.setDepthBufferSize(24);
 	format.setSamples(4);
 	setFormat(format);
+	setFocusPolicy(Qt::StrongFocus);
+	trans.translate(0, -10, -10);
+	rot.rotate(30, QVector3D(1, 0, 0));
+	rot_start = rot;
+	move_timer.setTimerType(Qt::PreciseTimer);
+	connect(&move_timer, &QTimer::timeout, this, &OpenGLWidget::move);
+	move_timer.start(16);
 }
 
 
@@ -179,9 +187,7 @@ void OpenGLWidget::paintGL() {
 	glEnable(GL_CULL_FACE);
 	glEnable(GL_DEPTH_TEST);
 	glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
-	QMatrix4x4 trans;
-	trans.translate(0, 0, -cam_dist);
-	QMatrix4x4 view = trans * rot;
+	QMatrix4x4 view = rot * trans;
 
 	glDepthMask(GL_FALSE);
 	glDepthFunc(GL_LEQUAL);
@@ -230,18 +236,62 @@ void OpenGLWidget::mouseReleaseEvent(QMouseEvent *e) {
 
 
 void OpenGLWidget::mouseMoveEvent(QMouseEvent *e) {
-	if (e->buttons() & Qt::LeftButton) {
-		QPoint delta = e->pos() - mouse_pos;
-		rot = rot_start;
-		rot.rotate(delta.x() / 5., 0, 1, 0);
-		rot.rotate(delta.y() / 5., QVector3D(1, 0, 0) * rot);
-		update();
-	}
+	if (!(e->buttons() & Qt::LeftButton)) return;
+	QPoint delta = e->pos() - mouse_pos;
+	rot = rot_start;
+	rot.rotate(delta.x() / 5., 0, 1, 0);
+	rot.rotate(delta.y() / 5., QVector3D(1, 0, 0) * rot);
+	update();
 }
 
 
-void OpenGLWidget::wheelEvent(QWheelEvent *e) {
-	cam_dist -= e->angleDelta().y() / 1000. * cam_dist;
+bool OpenGLWidget::keyEvent(QKeyEvent *e, bool press) {
+	if (e->isAutoRepeat()) return false;
+	/* would do wasd if qt had proper support for layout-independent
+	   input, but it doesnt :< */
+	switch (e->key()) {
+	case Qt::Key_Up:
+		move_forward = press;
+		break;
+	case Qt::Key_Down:
+		move_back = press;
+		break;
+	case Qt::Key_Left:
+		move_left = press;
+		break;
+	case Qt::Key_Right:
+		move_right = press;
+		break;
+	default:
+		return false;
+	}
+	update();
+	return true;
+}
+
+
+void OpenGLWidget::keyPressEvent(QKeyEvent *e) {
+	if (!keyEvent(e, true)) QOpenGLWidget::keyPressEvent(e);
+}
+
+
+void OpenGLWidget::keyReleaseEvent(QKeyEvent *e) {
+	if (!keyEvent(e, false)) QOpenGLWidget::keyReleaseEvent(e);
+}
+
+
+void OpenGLWidget::focusOutEvent(QFocusEvent *e) {
+	Q_UNUSED(e);
+	move_forward = move_back = move_left = move_right = false;
+}
+
+
+void OpenGLWidget::move() {
+	QMatrix4x4 rotation = rot.inverted();
+	if (move_forward) trans.translate(-(rotation * QVector3D(0, 0, -1)));
+	if (move_back) trans.translate(-(rotation * QVector3D(0, 0, 1)));
+	if (move_left) trans.translate(-(rotation * QVector3D(-1, 0, 0)));
+	if (move_right) trans.translate(-(rotation * QVector3D(1, 0, 0)));
 	update();
 }
 
@@ -261,9 +311,7 @@ QOpenGLShaderProgram *OpenGLWidget::getLineProgram() {
 
 
 bool OpenGLWidget::project(const QVector3D &p, QPoint &point) const {
-	QMatrix4x4 trans;
-	trans.translate(0, 0, -cam_dist);
-	QMatrix4x4 view = trans * rot;
+	QMatrix4x4 view = rot * trans;
 	QVector3D projected = proj * view * p;
 	if (projected.x() < -1 || projected.x() > 1
 		|| projected.y() < -1 || projected.y() > 1
diff --git a/src/opengl_widget.hh b/src/opengl_widget.hh
index abe226f..65c09b2 100644
--- a/src/opengl_widget.hh
+++ b/src/opengl_widget.hh
@@ -9,6 +9,7 @@
 #include <QOpenGLShaderProgram>
 #include <QOpenGLVertexArrayObject>
 #include <QOpenGLBuffer>
+#include <QTimer>
 
 #define FOV 70
 
@@ -26,8 +27,13 @@ class OpenGLWidget : public QOpenGLWidget, public QOpenGLExtraFunctions {
 	Q_OBJECT
 
 	QMatrix4x4 rot, rot_start, proj;
-	GLfloat cam_dist = 1;
+	QMatrix4x4 trans;
 	QPoint mouse_pos;
+	QTimer move_timer;
+	bool move_forward = false;
+	bool move_back = false;
+	bool move_left = false;
+	bool move_right = false;
 
 	QOpenGLShaderProgram main_program;
 	QOpenGLShaderProgram skybox_program;
@@ -39,14 +45,20 @@ class OpenGLWidget : public QOpenGLWidget, public QOpenGLExtraFunctions {
 
 	void loadSkybox();
 	void loadGround();
+	bool keyEvent(QKeyEvent *e, bool press);
 
 	const Painter *painter = nullptr;
 
+private slots:
+	void move();
+
 protected:
     virtual void mousePressEvent(QMouseEvent *e);
     virtual void mouseReleaseEvent(QMouseEvent *e);
     virtual void mouseMoveEvent(QMouseEvent *e);
-    virtual void wheelEvent(QWheelEvent *e);
+	virtual void keyPressEvent(QKeyEvent *e);
+	virtual void keyReleaseEvent(QKeyEvent *e);
+	virtual void focusOutEvent(QFocusEvent *e);
 
 public:
 	static OpenGLWidget *instance;