Add camera pixel perfect.

src/dawn/scene/item/SceneItemTransform.cpp

@@ -194,6 +194,25 @@ void SceneItemTransform::lookAt(
   this->setWorldTransform(glm::lookAt(position, target, up));
 }
 
+float_t SceneItemTransform::lookAtPixelPerfect(
+  const glm::vec3 &position,
+  const glm::vec3 &look,
+  const float_t viewportHeight,
+  const float_t fov,
+  const float_t scale
+) {
+  float_t z = (
+    tanf((glm::radians(180.0f) - fov) / 2.0f) *
+    (viewportHeight/2.0f)
+  ) / scale;
+  this->lookAt(
+    glm::vec3(position.x, position.y, position.z + z),
+    look,
+    glm::vec3(0, 1, 0)
+  );
+  return z;
+}
+
 SceneItemTransform::~SceneItemTransform() {
   std::for_each(
     this->children.begin(),

src/dawn/scene/item/SceneItemTransform.hpp

@@ -171,6 +171,24 @@ namespace Dawn {
         const glm::vec3 up
       );
 
+      /**
+       * Shorthand combined for lookAt and perspectivePixelPerfectDistance
+       * to allow you to create pixel perfect lookAt camera view matricies.
+       * 
+       * @param position Position of the camera. Z is for an offset.
+       * @param look Position in world space this transform looks at.
+       * @param viewportHeight Height of the viewport.
+       * @param fov Field of view (in radians).
+       * @return The Z distance that was calculated.
+       */
+      float_t lookAtPixelPerfect(
+        const glm::vec3 &position,
+        const glm::vec3 &look,
+        const float_t viewportHeight,
+        const float_t fov,
+        const float_t scale = 1.0f
+      );
+
       virtual ~SceneItemTransform();
   };
 }