From 5ff9894925b110e700cd186f4485edc97d744b94 Mon Sep 17 00:00:00 2001
From: Richard Davey <rich@photonstorm.com>
Date: Thu, 17 Sep 2020 18:08:07 +0100
Subject: [PATCH] MeshCamera now supports orbit and pan modes

---
 src/gameobjects/mesh/MeshCamera.js | 175 ++++++++++++++++++++++++++---
 1 file changed, 158 insertions(+), 17 deletions(-)

diff --git a/src/gameobjects/mesh/MeshCamera.js b/src/gameobjects/mesh/MeshCamera.js
index 089266ea1..2030ed55c 100644
--- a/src/gameobjects/mesh/MeshCamera.js
+++ b/src/gameobjects/mesh/MeshCamera.js
@@ -8,6 +8,7 @@ var Class = require('../../utils/Class');
 var DegToRad = require('../../math/DegToRad');
 var Matrix4 = require('../../math/Matrix4');
 var Vector3 = require('../../math/Vector3');
+var Vector4 = require('../../math/Vector4');
 
 /**
  * @classdesc
@@ -31,24 +32,116 @@ var MeshCamera = new Class({
         this._near = near;
         this._far = far;
 
-        this._position = new Vector3(x, y, z);
-        this._target = new Vector3();
+        this.position = new Vector3();
+        this.rotation = new Vector3();
 
-        this.orientation = Vector3.DOWN;
+        this.forward = new Vector4();
+        this.up = new Vector4(); //  What the up direction is, invert to get bottom
+        this.right = new Vector4();	//  What the right direction is, invert to get left
 
+        this.matView = new Matrix4();
         this.viewMatrix = new Matrix4();
         this.projectionMatrix = new Matrix4();
+
+        this.mode = MeshCamera.MODE_ORBIT;
+    },
+
+    panX: function (v)
+    {
+        this.updateViewMatrix();
+
+        this.position.addScale(this.right, v);
+    },
+
+    panY: function (v)
+    {
+        this.updateViewMatrix();
+
+        this.position.y += this.up.y * v;
+
+        if (this.mode === MeshCamera.MODE_ORBIT)
+        {
+            //  Can only move up and down the y axix in orbit mode
+            return;
+        }
+
+        this.position.x += this.up.x * v;
+        this.position.z += this.up.z * v;
+    },
+
+    panZ: function (v)
+    {
+        this.updateViewMatrix();
+
+        if (this.mode === MeshCamera.MODE_ORBIT)
+        {
+            //  orbit mode does translate after rotate, so only need to set Z, the rotate will handle the rest.
+            this.position.z += v;
+        }
+        else
+        {
+            //  In freemode to move forward, we need to move based on our forward which is relative to our current rotation
+            this.position.addScale(this.forward, v);
+        }
+    },
+
+    //  To have different modes of movements, this function handles the view matrix update for the transform object.
+    updateViewMatrix: function ()
+    {
+        var d = Math.PI / 180;
+        var matView = this.matView;
+        var rotation = this.rotation;
+
+        matView.identity();
+
+        //  Optimize camera transform update, no need for scale nor rotateZ
+        if (this.mode === MeshCamera.MODE_FREE)
+        {
+            matView.translate(this.position);
+            matView.rotateX(rotation.x * d);
+            matView.rotateY(rotation.y * d);
+        }
+        else
+        {
+            matView.rotateX(rotation.x * d);
+            matView.rotateY(rotation.y * d);
+            matView.translate(this.position);
+        }
+
+        this.updateDirection();
+
+        this.viewMatrix.copy(matView);
+        this.viewMatrix.invert();
+
+        this.dirty = true;
     },
 
     update: function (width, height)
     {
         this.aspectRatio = width / height;
 
-        this.viewMatrix.lookAt(this._position, this._target, this.orientation);
+        this.updateViewMatrix();
 
         this.projectionMatrix.perspective(DegToRad(this._fov), this.aspectRatio, this._near, this._far);
     },
 
+    updateDirection: function ()
+    {
+        var matView = this.matView;
+
+        this.forward.set(0, 0, 1, 0).transformMat4(matView);
+        this.up.set(0, 1, 0, 0).transformMat4(matView);
+        this.right.set(1, 0, 0, 0).transformMat4(matView);
+    },
+
+    reset: function ()
+    {
+        this.position.set();
+        this.rotation.set();
+
+        this.updateViewMatrix();
+    },
+
     fov: {
 
         get: function ()
@@ -107,13 +200,13 @@ var MeshCamera = new Class({
 
         get: function ()
         {
-            return this._position.x;
+            return this.position.x;
         },
 
         set: function (value)
         {
-            this._position.x = value;
-            this.dirty = true;
+            this.position.x = value;
+            this.updateViewMatrix();
         }
 
     },
@@ -122,13 +215,13 @@ var MeshCamera = new Class({
 
         get: function ()
         {
-            return this._position.y;
+            return this.position.y;
         },
 
         set: function (value)
         {
-            this._position.y = value;
-            this.dirty = true;
+            this.position.y = value;
+            this.updateViewMatrix();
         }
 
     },
@@ -137,25 +230,73 @@ var MeshCamera = new Class({
 
         get: function ()
         {
-            return this._position.z;
+            return this.position.z;
         },
 
         set: function (value)
         {
-            this._position.z = value;
-            this.dirty = true;
+            this.position.z = value;
+            this.updateViewMatrix();
+        }
+
+    },
+
+    rotationX: {
+
+        get: function ()
+        {
+            return this.rotation.x;
+        },
+
+        set: function (value)
+        {
+            this.rotation.x = value;
+            this.updateViewMatrix();
+        }
+
+    },
+
+    rotationY: {
+
+        get: function ()
+        {
+            return this.rotation.y;
+        },
+
+        set: function (value)
+        {
+            this.rotation.y = value;
+            this.updateViewMatrix();
+        }
+
+    },
+
+    rotationZ: {
+
+        get: function ()
+        {
+            return this.rotation.z;
+        },
+
+        set: function (value)
+        {
+            this.rotation.z = value;
+            this.updateViewMatrix();
         }
 
     },
 
     destroy: function ()
     {
-        this._position = null;
-        this._target = null;
-        this.viewMatrix = null;
-        this.projectionMatrix = null;
+        //  TODO - Needed?
     }
 
 });
 
+// Allows free movement of position and rotation
+MeshCamera.MODE_FREE = 0;
+
+// Movement is locked to rotate around the origin
+MeshCamera.MODE_ORBIT = 1;
+
 module.exports = MeshCamera;