add option to draw trajectories

shaders/line.frag

@@ -0,0 +1,5 @@
+uniform vec3 color;
+
+void main() {
+	gl_FragColor = vec4(color, 1);
+}

shaders/line.vert

@@ -0,0 +1,8 @@
+attribute vec3 in_pos;
+
+uniform mat4 proj;
+uniform mat4 view;
+
+void main() {
+	gl_Position = proj * view * vec4(in_pos, 1.0);
+}

shaders/shaders_resources.qrc

@@ -5,5 +5,7 @@
 	<file>main.frag</file>
 	<file>skybox.vert</file>
 	<file>skybox.frag</file>
+	<file>line.vert</file>
+	<file>line.frag</file>
   </qresource>
 </RCC>

src/drone_controller.cc

@@ -44,6 +44,38 @@ DroneController::DroneController(const QJsonObject &json)
 }
 
 
+void DroneController::drawTrajectory(QOpenGLExtraFunctions *f, const Drone &d) const {
+	OpenGLWidget::instance->getLineProgram()->bind();
+	OpenGLWidget::instance->getLineProgram()->setUniformValue("color", 1, 0, .532);
+	size_t trajectory_len = 1;
+	for (const Waypoint &wp : d.getWaypoints()) {
+		if (wp.frame > frame) break;
+		trajectory_len++;
+	}
+	GLfloat trajectory[trajectory_len * 3] = {0};
+	size_t i = 0;
+	for (const Waypoint &wp : d.getWaypoints()) {
+		if (wp.frame > frame) break;
+		trajectory[i] = wp.pos.x();
+		trajectory[i + 1] = wp.pos.y();
+		trajectory[i + 2] = wp.pos.z();
+		i += 3;
+	}
+	trajectory[i] = d.getPos().x();
+	trajectory[i + 1] = d.getPos().y();
+	trajectory[i + 2] = d.getPos().z();
+	f->glEnableVertexAttribArray(0);
+	f->glBindBuffer(GL_ARRAY_BUFFER, 0);
+	f->glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 0, trajectory);
+	glLineWidth(2);
+	f->glDisable(GL_CULL_FACE);
+	f->glDrawArrays(GL_LINE_STRIP, 0, trajectory_len);
+	f->glEnable(GL_CULL_FACE);
+	OpenGLWidget::instance->getLineProgram()->release();
+	OpenGLWidget::instance->getMainProgram()->bind();
+}
+
+
 void DroneController::draw(QOpenGLExtraFunctions *f) const {
 	const QVector<QPair<int, int>> &col = collisions[frame];
 	for (const Drone &d : drones) {
@@ -60,6 +92,9 @@ void DroneController::draw(QOpenGLExtraFunctions *f) const {
 			sphere->draw(f, mat);
 		}
 		OpenGLWidget::instance->getMainProgram()->setUniformValue("highlight", false);
+		if (draw_trajectories) {
+			drawTrajectory(f, d);
+		}
 	}
 }
 
@@ -155,3 +190,9 @@ void DroneController::displaySpheres(double sphere_radius) {
 bool DroneController::collides(const Drone &a, const Drone &b, double sqDist) {
 	return (b.getPos() - a.getPos()).lengthSquared() < sqDist;
 }
+
+
+void DroneController::setDrawTrajectories(bool enable) {
+	draw_trajectories = enable;
+	OpenGLWidget::instance->update();
+}

src/drone_controller.hh

@@ -23,12 +23,15 @@ class DroneController : public QObject, public Painter {
 	double sphere_radius = 0;
 	QTimer sphere_timer;
 	QMap<int, QVector<QPair<int, int>>> collisions;
+	bool draw_trajectories = false;
 
 	static OpenGLMesh *sphere;
 	static const unsigned char sphere_neutral[];
 
 	static bool collides(const Drone &a, const Drone &b, double radius);
 
+	void drawTrajectory(QOpenGLExtraFunctions *f, const Drone &d) const;
+
 public:
 	DroneController(const QJsonObject &json);
 	int getDuration() const;
@@ -51,6 +54,7 @@ public slots:
 	void seek(int frame);
 	void computeCollisions(double sphere_radius);
 	void displaySpheres(double sphere_radius);
+	void setDrawTrajectories(bool enable);
 };
 
 

src/main_window.cc

@@ -89,6 +89,8 @@ void MainWindow::open(const QString &path) {
 			dc, &DroneController::computeCollisions);
 	connect(settings_pane, &SettingsPane::sphereRadiusChanged,
 			dc, &DroneController::displaySpheres);
+	connect(settings_pane, &SettingsPane::toggledTrajectories,
+			dc, &DroneController::setDrawTrajectories);
 	settings_pane->setEnabled(true);
 
 	glw.setPainter(dc);

src/opengl_mesh.cc

@@ -32,4 +32,5 @@ void OpenGLMesh::draw(QOpenGLExtraFunctions *f, const QMatrix4x4 &mat) const {
 	if (tex) tex->bind();
 	f->glDrawArrays(GL_TRIANGLES, 0, nverts);
 	if (tex) tex->release();
+	f->glBindVertexArray(0);
 }

src/opengl_widget.cc

@@ -144,6 +144,20 @@ void OpenGLWidget::initializeGL() {
 	main_program.setUniformValue("tex", 0);
 	main_program.release();
 
+	if (!line_program.addShaderFromSourceFile(QOpenGLShader::Vertex, ":/shaders/line.vert")) {
+		qFatal("Error compiling line.vert: %s", line_program.log().toLocal8Bit().constData());
+	}
+	if (!line_program.addShaderFromSourceFile(QOpenGLShader::Fragment, ":/shaders/line.frag")) {
+		qFatal("Error compiling line.frag: %s", line_program.log().toLocal8Bit().constData());
+	}
+	line_program.bindAttributeLocation("in_pos", 0);
+	if (!line_program.link()) {
+		qFatal("Error linking the line shader program: %s", line_program.log().toLocal8Bit().constData());
+	}
+	line_program.bind();
+	line_program.setUniformValue("color", 0, 0, 0);
+	line_program.release();
+
 	loadSkybox();
 	loadGround();
 
@@ -183,6 +197,11 @@ void OpenGLWidget::paintGL() {
 	glDepthMask(GL_TRUE);
 	glDepthFunc(GL_LESS);
 
+	line_program.bind();
+	line_program.setUniformValue("proj", proj);
+	line_program.setUniformValue("view", view);
+	line_program.release();
+
 	main_program.bind();
 	main_program.setUniformValue("proj", proj);
 	main_program.setUniformValue("view", view);
@@ -232,3 +251,7 @@ void OpenGLWidget::setPainter(const Painter *p) {
 QOpenGLShaderProgram *OpenGLWidget::getMainProgram() {
 	return &main_program;
 }
+
+QOpenGLShaderProgram *OpenGLWidget::getLineProgram() {
+	return &line_program;
+}

src/opengl_widget.hh

@@ -28,6 +28,7 @@ class OpenGLWidget : public QOpenGLWidget, public QOpenGLExtraFunctions {
 
 	QOpenGLShaderProgram main_program;
 	QOpenGLShaderProgram skybox_program;
+	QOpenGLShaderProgram line_program;
 	GLuint skybox_tex;
 	GLuint skybox_vao;
 	GLuint skybox_vbo;
@@ -56,6 +57,7 @@ public:
 	void paintGL() override;
 	void setPainter(const Painter *p);
 	QOpenGLShaderProgram *getMainProgram();
+	QOpenGLShaderProgram *getLineProgram();
 
 signals:
 	void initialized();