Add clicking to select Nodes

See: #15

resources.qrc

@@ -21,5 +21,7 @@
         <file>shaders/model.frag</file>
         <file>shaders/skybox.vert</file>
         <file>shaders/skybox.frag</file>
+        <file>shaders/picking.frag</file>
+        <file>shaders/picking.vert</file>
     </qresource>
 </RCC>

shaders/picking.frag

@@ -0,0 +1,14 @@
+#version 330
+
+uniform uint object_type;
+uniform uint object_id;
+
+out uvec3 picking_fragment;
+
+void main() {
+    // The leading 1.0 is to indicate the presence of an object
+    // in the texture, since by default, OpenGL will, clear to 0
+    // so, we need some way to tell an object was rendered at this
+    // fragment
+    picking_fragment = uvec3(1.0, object_type, object_id);
+}

shaders/picking.vert

@@ -0,0 +1,11 @@
+#version 330
+
+layout (location = 0) in vec3 in_position;
+
+uniform mat4 model;
+uniform mat4 view;
+uniform mat4 projection;
+
+void main() {
+    gl_Position = projection * view * model * vec4(in_position, 1.0);
+}

src/CMakeLists.txt

@@ -37,6 +37,7 @@ target_sources(netsimulyzer PRIVATE
         group/node/Node.h group/node/Node.cpp
         group/node/TrailBuffer.h group/node/TrailBuffer.cpp
         render/camera/Camera.h render/camera/Camera.cpp
+        render/framebuffer/PickingFramebuffer.h render/framebuffer/PickingFramebuffer.cpp
         render/helper/Floor.h render/helper/Floor.cpp
         render/Light.h
         render/material/material.h

src/render/framebuffer/PickingFramebuffer.cpp

@@ -0,0 +1,92 @@
+/*
+ * NIST-developed software is provided by NIST as a public service. You may use,
+ * copy and distribute copies of the software in any medium, provided that you
+ * keep intact this entire notice. You may improve,modify and create derivative
+ * works of the software or any portion of the software, and you may copy and
+ * distribute such modifications or works. Modified works should carry a notice
+ * stating that you changed the software and should note the date and nature of
+ * any such change. Please explicitly acknowledge the National Institute of
+ * Standards and Technology as the source of the software.
+ *
+ * NIST-developed software is expressly provided "AS IS." NIST MAKES NO
+ * WARRANTY OF ANY KIND, EXPRESS, IMPLIED, IN FACT OR ARISING BY OPERATION OF
+ * LAW, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTY OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, NON-INFRINGEMENT
+ * AND DATA ACCURACY. NIST NEITHER REPRESENTS NOR WARRANTS THAT THE
+ * OPERATION OF THE SOFTWARE WILL BE UNINTERRUPTED OR ERROR-FREE, OR THAT
+ * ANY DEFECTS WILL BE CORRECTED. NIST DOES NOT WARRANT OR MAKE ANY
+ * REPRESENTATIONS REGARDING THE USE OF THE SOFTWARE OR THE RESULTS THEREOF,
+ * INCLUDING BUT NOT LIMITED TO THE CORRECTNESS, ACCURACY, RELIABILITY,
+ * OR USEFULNESS OF THE SOFTWARE.
+ *
+ * You are solely responsible for determining the appropriateness of using and
+ * distributing the software and you assume all risks associated with its use,
+ * including but not limited to the risks and costs of program errors,
+ * compliance with applicable laws, damage to or loss of data, programs or
+ * equipment, and the unavailability or interruption of operation. This
+ * software is not intended to be used in any situation where a failure could
+ * cause risk of injury or damage to property. The software developed by NIST
+ * employees is not subject to copyright protection within the United States.
+ *
+ * Author: Evan Black <[email protected]>
+ */
+
+#include "PickingFramebuffer.h"
+#include <QOpenGLFunctions_3_3_Core>
+namespace netsimulyzer {
+
+void PickingFramebuffer::generate(int width, int height) {
+  openGl.glGenFramebuffers(1, &fbo);
+  bind(GL_FRAMEBUFFER);
+
+  openGl.glGenTextures(1, &idTexture);
+  openGl.glBindTexture(GL_TEXTURE_2D, idTexture);
+  openGl.glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB32UI, width, height, 0, GL_RGB_INTEGER, GL_UNSIGNED_INT, nullptr);
+  openGl.glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
+  openGl.glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
+  openGl.glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, idTexture, 0);
+
+  openGl.glGenTextures(1, &depthTexture);
+  openGl.glBindTexture(GL_TEXTURE_2D, depthTexture);
+  openGl.glTexImage2D(GL_TEXTURE_2D, 0, GL_DEPTH_COMPONENT, width, height, 0, GL_DEPTH_COMPONENT, GL_FLOAT, nullptr);
+  openGl.glFramebufferTexture2D(GL_FRAMEBUFFER, GL_DEPTH_ATTACHMENT, GL_TEXTURE_2D, depthTexture, 0);
+}
+
+// NOLINT(cppcoreguidelines-pro-type-member-init)
+PickingFramebuffer::PickingFramebuffer(QOpenGLFunctions_3_3_Core &openGl, int width, int height)
+    : openGl(openGl) { // NOLINT(cppcoreguidelines-pro-type-member-init)
+  generate(width, height);
+}
+
+PickingFramebuffer::~PickingFramebuffer() {
+  openGl.glDeleteTextures(1, &idTexture);
+  openGl.glDeleteTextures(1, &depthTexture);
+  openGl.glDeleteFramebuffers(1, &fbo);
+}
+
+void PickingFramebuffer::bind(GLenum mode) const {
+  openGl.glBindFramebuffer(mode, fbo);
+}
+
+void PickingFramebuffer::unbind(GLenum mode, unsigned int defaultFbo) const {
+  openGl.glBindFramebuffer(mode, defaultFbo);
+}
+
+PickingFramebuffer::PixelInfo PickingFramebuffer::read(int x, int y) const {
+  bind(GL_READ_FRAMEBUFFER);
+  openGl.glReadBuffer(GL_COLOR_ATTACHMENT0);
+
+  PixelInfo pixelInfo; // NOLINT(cppcoreguidelines-pro-type-member-init)
+  openGl.glReadPixels(x, y, 1, 1, GL_RGB_INTEGER, GL_UNSIGNED_INT, &pixelInfo);
+
+  return pixelInfo;
+}
+
+void PickingFramebuffer::resize(int width, int height) {
+  openGl.glDeleteTextures(1, &idTexture);
+  openGl.glDeleteTextures(1, &depthTexture);
+  openGl.glDeleteFramebuffers(1, &fbo);
+  generate(width, height);
+}
+
+} // namespace netsimulyzer

src/render/framebuffer/PickingFramebuffer.h

@@ -0,0 +1,72 @@
+/*
+ * NIST-developed software is provided by NIST as a public service. You may use,
+ * copy and distribute copies of the software in any medium, provided that you
+ * keep intact this entire notice. You may improve,modify and create derivative
+ * works of the software or any portion of the software, and you may copy and
+ * distribute such modifications or works. Modified works should carry a notice
+ * stating that you changed the software and should note the date and nature of
+ * any such change. Please explicitly acknowledge the National Institute of
+ * Standards and Technology as the source of the software.
+ *
+ * NIST-developed software is expressly provided "AS IS." NIST MAKES NO
+ * WARRANTY OF ANY KIND, EXPRESS, IMPLIED, IN FACT OR ARISING BY OPERATION OF
+ * LAW, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTY OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, NON-INFRINGEMENT
+ * AND DATA ACCURACY. NIST NEITHER REPRESENTS NOR WARRANTS THAT THE
+ * OPERATION OF THE SOFTWARE WILL BE UNINTERRUPTED OR ERROR-FREE, OR THAT
+ * ANY DEFECTS WILL BE CORRECTED. NIST DOES NOT WARRANT OR MAKE ANY
+ * REPRESENTATIONS REGARDING THE USE OF THE SOFTWARE OR THE RESULTS THEREOF,
+ * INCLUDING BUT NOT LIMITED TO THE CORRECTNESS, ACCURACY, RELIABILITY,
+ * OR USEFULNESS OF THE SOFTWARE.
+ *
+ * You are solely responsible for determining the appropriateness of using and
+ * distributing the software and you assume all risks associated with its use,
+ * including but not limited to the risks and costs of program errors,
+ * compliance with applicable laws, damage to or loss of data, programs or
+ * equipment, and the unavailability or interruption of operation. This
+ * software is not intended to be used in any situation where a failure could
+ * cause risk of injury or damage to property. The software developed by NIST
+ * employees is not subject to copyright protection within the United States.
+ *
+ * Author: Evan Black <[email protected]>
+ */
+#pragma once
+#include <QOpenGLFunctions_3_3_Core>
+
+namespace netsimulyzer {
+
+class PickingFramebuffer {
+  QOpenGLFunctions_3_3_Core &openGl;
+  unsigned int fbo;
+  unsigned int idTexture;
+  unsigned int depthTexture;
+
+  void generate(int width, int height);
+
+public:
+  struct PixelInfo {
+    unsigned int object;
+    unsigned int type;
+    unsigned int id;
+  };
+
+  PickingFramebuffer(QOpenGLFunctions_3_3_Core &openGl, int width, int height);
+  ~PickingFramebuffer();
+
+  // Disallow copying
+  PickingFramebuffer(const PickingFramebuffer &) = delete;
+  PickingFramebuffer &operator=(const PickingFramebuffer &) = delete;
+
+  void bind(GLenum mode) const;
+  void unbind(GLenum mode, unsigned int defaultFbo) const;
+
+  [[nodiscard]] PixelInfo read(int x, int y) const;
+
+  inline unsigned int getIds() {
+    return idTexture;
+  }
+
+  void resize(int width, int height);
+};
+
+} // namespace netsimulyzer

src/render/model/ModelCache.cpp

@@ -261,6 +261,14 @@ void ModelRenderInfo::clear() {
   meshes.clear();
 }
 
+std::vector<Mesh> &ModelRenderInfo::getMeshes() {
+  return meshes;
+}
+
+std::vector<Mesh> &ModelRenderInfo::getTransparentMeshes() {
+  return transparentMeshes;
+}
+
 ModelCache::ModelCache(TextureCache &textureCache) : textureCache(textureCache) {
 }
 

src/render/model/ModelCache.h

@@ -92,6 +92,8 @@ class ModelRenderInfo : protected QOpenGLFunctions_3_3_Core {
 
   void render(Shader &s, const Model &model);
   void renderTransparent(Shader &s, const Model &model);
+  std::vector<Mesh>& getMeshes();
+  std::vector<Mesh>& getTransparentMeshes();
   void clear();
 };
 

src/render/renderer/Renderer.cpp

@@ -80,6 +80,7 @@ void Renderer::init() {
 
   initShader(modelShader, ":shader/shaders/model.vert", ":shader/shaders/model.frag");
   initShader(skyBoxShader, ":shader/shaders/skybox.vert", ":shader/shaders/skybox.frag");
+  initShader(pickingShader, ":/shader/shaders/picking.vert", ":/shader/shaders/picking.frag");
 }
 
 void Renderer::setPerspective(const glm::mat4 &perspective) {
@@ -88,6 +89,7 @@ void Renderer::setPerspective(const glm::mat4 &perspective) {
   gridShader.uniform("projection", perspective);
   modelShader.uniform("projection", perspective);
   skyBoxShader.uniform("projection", perspective);
+  pickingShader.uniform("projection", perspective);
 }
 
 void Renderer::setPointLightCount(unsigned int count) {
@@ -539,6 +541,8 @@ void Renderer::use(const Camera &cam) {
   auto noTranslationView = cam.view_matrix();
   noTranslationView[3] = {0.0f, 0.0f, 0.0f, 1.0f};
   skyBoxShader.uniform("view", noTranslationView);
+
+  pickingShader.uniform("view", cam.view_matrix());
 }
 
 void Renderer::render(const DirectionalLight &light) {
@@ -712,4 +716,22 @@ void Renderer::render(const std::vector<WiredLink> &wiredLinks) {
   glDisable(GL_LINE_SMOOTH);
 }
 
+void Renderer::renderPickingNode(unsigned int nodeId, const Model &m) {
+  auto &model = modelCache.get(m.getModelId());
+
+  pickingShader.uniform("model", m.getModelMatrix());
+  pickingShader.uniform("object_id", nodeId);
+  pickingShader.uniform("object_type", 1u);
+
+  pickingShader.bind();
+  auto &meshes = model.getMeshes();
+  for (auto &mesh : meshes) {
+    mesh.render();
+  }
+  auto &transparentMeshes = model.getTransparentMeshes();
+  for (auto &mesh : transparentMeshes) {
+    mesh.render();
+  }
+}
+
 } // namespace netsimulyzer

src/render/renderer/Renderer.h

@@ -62,6 +62,7 @@ class Renderer : protected QOpenGLFunctions_3_3_Core {
   Shader gridShader;
   Shader modelShader;
   Shader skyBoxShader;
+  Shader pickingShader;
 
   void initShader(Shader &s, const QString &vertexPath, const QString &fragmentPath);
 
@@ -89,6 +90,8 @@ class Renderer : protected QOpenGLFunctions_3_3_Core {
   void startTransparent();
   void endTransparent();
 
+  void renderPickingNode(unsigned int nodeId, const Model &m);
+
   void use(const Camera &cam);
   void render(const DirectionalLight &light);
   void render(const PointLight &light);

src/window/scene/SceneWidget.cpp

@@ -209,6 +209,10 @@ void SceneWidget::initializeGL() {
 
   updatePerspective();
 
+  // picking FBO
+  pickingFbo = std::make_unique<PickingFramebuffer>(openGl, width(), height());
+  pickingFbo->unbind(GL_FRAMEBUFFER, defaultFramebufferObject());
+
   // Cheap hack to get Qt to repaint at a reasonable rate
   // Seems to only work with the old connect syntax
   QObject::connect(&timer, SIGNAL(timeout()), this, SLOT(update()));
@@ -225,9 +229,25 @@ void SceneWidget::paintGL() {
       handleUndoEvents();
   }
 
-  glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT); // NOLINT(hicpp-signed-bitwise)
+  // Picking
+  pickingFbo->bind(GL_FRAMEBUFFER);
+  glClearColor(0.0f, 0.0f, 0.0f, 0.0f);
+  glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
+
+  for (auto &[key, node] : nodes) {
+    if (!node.visible())
+      continue;
+    renderer.renderPickingNode(node.getNs3Model().id, node.getModel());
+  }
+
+  glBindFramebuffer(GL_FRAMEBUFFER, defaultFramebufferObject());
+  // end Picking
+
   camera.move(static_cast<float>(frameTimer.elapsed()));
   renderer.use(camera);
+
+  glClearColor(1.0f, 1.0f, 1.0f, 1.0f);
+  glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
   if (renderSkybox)
     renderer.render(*skyBox);
 
@@ -318,6 +338,7 @@ void SceneWidget::paintGL() {
 void SceneWidget::resizeGL(int w, int h) {
   updatePerspective();
   glViewport(0, 0, w, h);
+  pickingFbo->resize(w, h);
 }
 
 void SceneWidget::keyPressEvent(QKeyEvent *event) {
@@ -332,6 +353,21 @@ void SceneWidget::keyReleaseEvent(QKeyEvent *event) {
 
 void SceneWidget::mousePressEvent(QMouseEvent *event) {
   QWidget::mousePressEvent(event);
+
+  makeCurrent();
+
+  // OpenGL starts from the bottom left,
+  // Qt Starts at the top left,
+  // so adjust the Y coordinate accordingly
+  const auto selected = pickingFbo->read(event->x(), height() - event->y());
+  pickingFbo->unbind(GL_READ_FRAMEBUFFER, defaultFramebufferObject());
+  doneCurrent();
+
+  if (selected.object && selected.type == 1u) {
+    emit nodeSelected(selected.id);
+    return;
+  }
+
   if (!camera.mouseControlsEnabled())
     return;
 

src/window/scene/SceneWidget.h

@@ -49,6 +49,7 @@
 #include "../../settings/SettingsManager.h"
 #include "../../util/undo-events.h"
 #include "src/group/link/WiredLink.h"
+#include "src/render/framebuffer/PickingFramebuffer.h"
 #include "src/render/helper/CoordinateGrid.h"
 #include "src/render/helper/SkyBox.h"
 #include <QApplication>
@@ -93,6 +94,8 @@ class SceneWidget : public QOpenGLWidget, protected QOpenGLFunctions_3_3_Core {
   bool renderBuildingOutlines = settings.get<bool>(SettingsManager::Key::RenderBuildingOutlines).value();
   bool renderMotionTrails = settings.get<bool>(SettingsManager::Key::RenderMotionTrails).value();
 
+  std::unique_ptr<PickingFramebuffer> pickingFbo;
+
   DirectionalLight mainLight;
   std::unique_ptr<SkyBox> skyBox;
   std::unique_ptr<Floor> floor;
@@ -242,5 +245,6 @@ class SceneWidget : public QOpenGLWidget, protected QOpenGLFunctions_3_3_Core {
   void timeChanged(parser::nanoseconds simulationTime, parser::nanoseconds increment);
   void paused();
   void playing();
+  void nodeSelected(unsigned int nodeId);
 };
 } // namespace netsimulyzer