From c64a530be4e3d33dc163866c4b9f1341650c8e12 Mon Sep 17 00:00:00 2001
From: ZappoMan <bradh@konamoxt.com>
Date: Sun, 9 Feb 2014 16:24:38 -0800
Subject: [PATCH] first cut at lookAt

---
 interface/src/Camera.cpp | 16 +++++++++++++++-
 interface/src/Camera.h   | 26 ++++++++++++++++++++++++++
 2 files changed, 41 insertions(+), 1 deletion(-)

diff --git a/interface/src/Camera.cpp b/interface/src/Camera.cpp
index 87725967b9..6dd327a3c3 100644
--- a/interface/src/Camera.cpp
+++ b/interface/src/Camera.cpp
@@ -58,7 +58,9 @@ Camera::Camera() :
     _modeShift(1.0f),
     _linearModeShift(0.0f),
     _modeShiftRate(1.0f),
-    _scale(1.0f)
+    _scale(1.0f),
+    _lookingAt(0.0f, 0.0f, 0.0f),
+    _isKeepLookingAt(false)
 {
 }
 
@@ -222,6 +224,18 @@ void Camera::setFrustumWasReshaped() {
     _frustumNeedsReshape = false;
 }
 
+void Camera::lookAt(const glm::vec3& lookAt) {
+    glm::vec3 up = IDENTITY_UP;
+    glm::mat4 lookAtMatrix = glm::lookAt(_position, lookAt, up);
+    glm::quat rotation = glm::quat_cast(lookAtMatrix);
+    rotation.w = -rotation.w; // Rosedale approved
+    setTargetRotation(rotation);
+}
+
+void Camera::keepLookingAt(const glm::vec3& value) {
+    lookAt(value);
+    _isKeepLookingAt = true;
+}
 
 CameraScriptableObject::CameraScriptableObject(Camera* camera, ViewFrustum* viewFrustum) :
     _camera(camera), _viewFrustum(viewFrustum) 
diff --git a/interface/src/Camera.h b/interface/src/Camera.h
index 075f1a7ed6..5f34dbfe6c 100644
--- a/interface/src/Camera.h
+++ b/interface/src/Camera.h
@@ -10,6 +10,7 @@
 
 #include <glm/glm.hpp>
 #include <glm/gtc/quaternion.hpp>
+#include <glm/gtc/matrix_transform.hpp>
 #include <RegisteredMetaTypes.h>
 #include <ViewFrustum.h>
 
@@ -68,6 +69,17 @@ public:
 
     bool getFrustumNeedsReshape() const; // call to find out if the view frustum needs to be reshaped
     void setFrustumWasReshaped();  // call this after reshaping the view frustum.
+
+    // These only work on independent cameras
+    /// one time change to what the camera is looking at
+    void lookAt(const glm::vec3& value);
+
+    /// fix what the camera is looking at, and keep the camera looking at this even if position changes
+    void keepLookingAt(const glm::vec3& value);
+
+    /// stops the keep looking at feature, doesn't change what's being looked at, but will stop camera from
+    /// continuing to update it's orientation to keep looking at the item
+    void stopKeepLookingAt() { _isKeepLookingAt = false; }
     
 private:
 
@@ -99,6 +111,9 @@ private:
     float _linearModeShift;
     float _modeShiftRate;
     float _scale;
+
+    glm::vec3 _lookingAt;
+    bool _isKeepLookingAt;
     
     void updateFollowMode(float deltaTime);
 };
@@ -119,6 +134,17 @@ public slots:
     void setOrientation(const glm::quat& value) { _camera->setTargetRotation(value); }
     glm::quat getOrientation() const { return _camera->getRotation(); }
 
+    // These only work on independent cameras
+    /// one time change to what the camera is looking at
+    void lookAt(const glm::vec3& value) { _camera->lookAt(value);}
+
+    /// fix what the camera is looking at, and keep the camera looking at this even if position changes
+    void keepLookingAt(const glm::vec3& value) { _camera->keepLookingAt(value);}
+
+    /// stops the keep looking at feature, doesn't change what's being looked at, but will stop camera from
+    /// continuing to update it's orientation to keep looking at the item
+    void stopKeepLookingAt() { _camera->stopKeepLookingAt();}
+
     PickRay computePickRay(float x, float y);
 
 private: