From 6f69ed2561009d3c099d90b680773781f453d245 Mon Sep 17 00:00:00 2001
From: Ryan Huffman <ryanhuffman@gmail.com>
Date: Wed, 20 May 2015 09:11:48 -0700
Subject: [PATCH] Fix calculated dimensions of spotlight

The spotlights region of effect is the intersection of the spotlight
with radius r, and the sphere of radius r
---
 examples/libraries/entitySelectionTool.js  | 2 +-
 libraries/entities/src/LightEntityItem.cpp | 6 +++---
 2 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/examples/libraries/entitySelectionTool.js b/examples/libraries/entitySelectionTool.js
index f3ea18aef3..1790767bec 100644
--- a/examples/libraries/entitySelectionTool.js
+++ b/examples/libraries/entitySelectionTool.js
@@ -1213,7 +1213,7 @@ SelectionDisplay = (function () {
                     rotation: rotation,
                     visible: true,
                 });
-                var distance = (properties.dimensions.z / 2) * Math.tan(properties.cutoff * (Math.PI / 180));
+                var distance = (properties.dimensions.z / 2) * Math.sin(properties.cutoff * (Math.PI / 180));
 
                 Overlays.editOverlay(grabberSpotLightL, {
                     position: EdgeNL,
diff --git a/libraries/entities/src/LightEntityItem.cpp b/libraries/entities/src/LightEntityItem.cpp
index a66cb56bd2..fa09c9bd60 100644
--- a/libraries/entities/src/LightEntityItem.cpp
+++ b/libraries/entities/src/LightEntityItem.cpp
@@ -46,7 +46,7 @@ void LightEntityItem::setDimensions(const glm::vec3& value) {
         // If we are a spotlight, treat the z value as our radius or length, and
         // recalculate the x/y dimensions to properly encapsulate the spotlight.
         const float length = value.z;
-        const float width = length * glm::tan(glm::radians(_cutoff));
+        const float width = length * glm::sin(glm::radians(_cutoff));
         _dimensions = glm::vec3(width, width, length);
     } else {
         float maxDimension = glm::max(value.x, value.y, value.z);
@@ -73,7 +73,7 @@ void LightEntityItem::setIsSpotlight(bool value) {
 
         if (_isSpotlight) {
             const float length = _dimensions.z;
-            const float width = length * glm::tan(glm::radians(_cutoff));
+            const float width = length * glm::sin(glm::radians(_cutoff));
             _dimensions = glm::vec3(width, width, length);
         } else {
             float maxDimension = glm::max(_dimensions.x, _dimensions.y, _dimensions.z);
@@ -89,7 +89,7 @@ void LightEntityItem::setCutoff(float value) {
         // If we are a spotlight, adjusting the cutoff will affect the area we encapsulate,
         // so update the dimensions to reflect this.
         const float length = _dimensions.z;
-        const float width = length * glm::tan(glm::radians(_cutoff));
+        const float width = length * glm::sin(glm::radians(_cutoff));
         _dimensions = glm::vec3(width, width, length);
     }
 }