Implement MousePicker

client/src/main/java/core/engine/Engine.java

@@ -9,6 +9,7 @@ import core.engine.model.TexturedModel;
 import core.engine.renderer.MasterRenderer;
 import core.engine.terrain.Terrain;
 import core.engine.textures.ModelTexture;
+import core.engine.toolbox.MousePicker;
 import org.lwjgl.BufferUtils;
 import org.lwjgl.Version;
 import org.lwjgl.glfw.*;
@@ -134,7 +135,8 @@ public class Engine {
         // Run the rendering loop until the user has attempted to close
         // the window or has pressed the ESCAPE key.
         MasterRenderer renderer = new MasterRenderer();
-        input(camera, renderer);
+        MousePicker mousePicker = new MousePicker(camera, renderer.getProjectionMatrix());
+        input(camera, renderer, mousePicker);
         while ( !glfwWindowShouldClose(window) ) {
             renderer.processTerrain(terrain);
             //renderer.processEntity(hexagonEntity);
@@ -148,7 +150,7 @@ public class Engine {
         loader.cleanUp();
     }
 
-    private void input(Camera camera, MasterRenderer masterRenderer) {
+    private void input(Camera camera, MasterRenderer masterRenderer, MousePicker mousePicker) {
 
         GLFWScrollCallback glfwScrollCallback = new GLFWScrollCallback() {
             @Override
@@ -172,6 +174,16 @@ public class Engine {
                     // Middle mouse button released
                     isMouseWheelPressed = false;
                 }
+
+                if(button == GLFW_MOUSE_BUTTON_LEFT && action == GLFW_PRESS) {
+                    //Track mouse position
+                    DoubleBuffer posX = BufferUtils.createDoubleBuffer(1);
+                    DoubleBuffer posY = BufferUtils.createDoubleBuffer(1);
+                    glfwGetCursorPos(window, posX, posY);
+                    System.out.println(posX.get(0) + "|" + posY.get(0));
+                    mousePicker.update((float) posX.get(0), (float) posY.get(0));
+                    System.out.println(mousePicker.getCurrentRay());
+                }
             }
         };
 
@@ -235,6 +247,8 @@ public class Engine {
             }
         });
 
+
+
     }
 
 }

client/src/main/java/core/engine/renderer/MasterRenderer.java

@@ -110,4 +110,8 @@ public class MasterRenderer {
             glPolygonMode(GL_FRONT_AND_BACK, GL_FILL);
         }
     }
+
+    public Matrix4f getProjectionMatrix() {
+        return projectionMatrix;
+    }
 }

client/src/main/java/core/engine/toolbox/MousePicker.java

@@ -0,0 +1,60 @@
+package core.engine.toolbox;
+
+import core.engine.Engine;
+import core.engine.entity.Camera;
+import org.lwjgl.system.windows.MOUSEINPUT;
+import utils.MatrixGraphicUtils;
+import utils.vectors.Matrix4f;
+import utils.vectors.Vector2f;
+import utils.vectors.Vector3f;
+import utils.vectors.Vector4f;
+
+public class MousePicker {
+
+    private Vector3f currentRay;
+    private Matrix4f projectionMatrix;
+    private Matrix4f viewMatrix;
+    private Camera camera;
+
+    public MousePicker(Camera camera, Matrix4f projectionMatrix) {
+        this.camera = camera;
+        this.projectionMatrix = projectionMatrix;
+        this.viewMatrix = MatrixGraphicUtils.createViewMatrix(camera);
+    }
+
+    public Vector3f getCurrentRay() {
+        return currentRay;
+    }
+
+    public void update(float mouseX, float mouseY) {
+        this.viewMatrix = MatrixGraphicUtils.createViewMatrix(camera);
+        this.currentRay = calculateMouseRay(mouseX, mouseY);
+    }
+
+    public Vector3f calculateMouseRay(float mouseX, float mouseY) {
+        Vector2f normalizedDeviceCoords = getNormalizedDeviceCoords(mouseX, mouseY);
+        Vector4f clipCoords = new Vector4f(normalizedDeviceCoords.x, normalizedDeviceCoords.y, -1f, 1f);
+        Vector4f eyeCoords = toEyeCoords(clipCoords);
+        return toWorldCoords(eyeCoords);
+    }
+
+    private Vector2f getNormalizedDeviceCoords(float mouseX, float mouseY) {
+        float x = (2f* mouseX) / Engine.WINDOW_WIDTH -1;
+        float y = (2f * mouseY) / Engine.WINDOW_HEIGHT -1;
+        return new Vector2f(x, y);
+    }
+
+    private Vector4f toEyeCoords(Vector4f clipCoords) {
+        Matrix4f invertedProjectionMatrix = Matrix4f.invert(projectionMatrix, null);
+        Vector4f eyeCoords = Matrix4f.transform(invertedProjectionMatrix, clipCoords, null);
+        return new Vector4f(eyeCoords.x, eyeCoords.y, -1f, 0f);
+    }
+
+    private Vector3f toWorldCoords (Vector4f eyeCoords) {
+        Matrix4f invertedViewMatrix = Matrix4f.invert(viewMatrix, null);
+        Vector4f rayWorld = Matrix4f.transform(invertedViewMatrix, eyeCoords, null);
+        Vector3f worldCoords =  new Vector3f(rayWorld.x, rayWorld.y, rayWorld.z);
+        worldCoords.normalise();
+        return worldCoords;
+    }
+}