diff --git a/interface/resources/shaders/ambient_occlusion.frag b/interface/resources/shaders/ambient_occlusion.frag
new file mode 100644
index 0000000000..b59c87d797
--- /dev/null
+++ b/interface/resources/shaders/ambient_occlusion.frag
@@ -0,0 +1,66 @@
+#version 120
+
+//
+//  ambient_occlusion.frag
+//  fragment shader
+//
+//  Created by Andrzej Kapolka on 7/5/13.
+//  Copyright (c) 2013 High Fidelity, Inc. All rights reserved.
+//
+
+// the depth texture
+uniform sampler2D depthTexture;
+
+// the random rotation texture
+uniform sampler2D rotationTexture;
+
+// the sample kernel containing the unit offset vectors
+const int SAMPLE_KERNEL_SIZE = 16;
+uniform vec3 sampleKernel[SAMPLE_KERNEL_SIZE];
+
+// the distance to the near clip plane
+uniform float near;
+
+// the distance to the far clip plane
+uniform float far;
+
+// the left and bottom edges of the view window
+uniform vec2 leftBottom;
+
+// the right and top edges of the view window
+uniform vec2 rightTop;
+
+// the radius of the effect
+uniform float radius;
+
+// the scale for the noise texture
+uniform vec2 noiseScale;
+
+// given a texture coordinate, returns the 3D view space z coordinate
+float texCoordToViewSpaceZ(vec2 texCoord) {
+    return (far * near) / (texture2D(depthTexture, texCoord).r * (far - near) - far);
+}
+
+// given a texture coordinate, returns the 3D view space coordinate
+vec3 texCoordToViewSpace(vec2 texCoord) {
+    float z = texCoordToViewSpaceZ(texCoord);
+    return vec3(((texCoord * 2.0 - vec2(1.0, 1.0)) * (rightTop - leftBottom) + rightTop + leftBottom) * z / (-2.0 * near), z);
+}
+
+void main(void) {
+    vec3 rotationX = texture2D(rotationTexture, gl_TexCoord[0].st * noiseScale).rgb;
+    vec3 rotationY = normalize(cross(rotationX, vec3(0.0, 0.0, 1.0)));
+    mat3 rotation = mat3(rotationX, rotationY, cross(rotationX, rotationY));
+    
+    vec3 center = texCoordToViewSpace(gl_TexCoord[0].st);
+    
+    float occlusion = 4.0;
+    for (int i = 0; i < SAMPLE_KERNEL_SIZE; i++) {
+        vec3 offset = center + rotation * (radius * sampleKernel[i]);
+        vec4 projected = gl_ProjectionMatrix * vec4(offset, 1.0);
+        float depth = texCoordToViewSpaceZ(projected.xy * 0.5 / projected.w + vec2(0.5, 0.5));
+        occlusion += 1.0 - step(offset.z, depth); //  * step(abs(center.z - depth), radius);
+    }
+    
+    gl_FragColor = vec4(occlusion, occlusion, occlusion, 0.0) / 16.0;
+}
diff --git a/interface/resources/shaders/ambient_occlusion.vert b/interface/resources/shaders/ambient_occlusion.vert
new file mode 100644
index 0000000000..ca6af718bd
--- /dev/null
+++ b/interface/resources/shaders/ambient_occlusion.vert
@@ -0,0 +1,14 @@
+#version 120
+
+//
+//  ambient_occlusion.vert
+//  vertex shader
+//
+//  Created by Andrzej Kapolka on 8/16/13.
+//  Copyright (c) 2013 High Fidelity, Inc. All rights reserved.
+//
+
+void main(void) {
+    gl_TexCoord[0] = gl_MultiTexCoord0;
+    gl_Position = gl_Vertex;
+}
diff --git a/interface/resources/shaders/occlusion_blur.frag b/interface/resources/shaders/occlusion_blur.frag
new file mode 100644
index 0000000000..2ee5eaf2cb
--- /dev/null
+++ b/interface/resources/shaders/occlusion_blur.frag
@@ -0,0 +1,25 @@
+#version 120
+
+//
+//  occlusion_blur.frag
+//  fragment shader
+//
+//  Created by Andrzej Kapolka on 8/16/13.
+//  Copyright (c) 2013 High Fidelity, Inc. All rights reserved.
+//
+
+// the original texture
+uniform sampler2D originalTexture;
+
+void main(void) {
+    float ds = dFdx(gl_TexCoord[0].s);
+    float dt = dFdy(gl_TexCoord[0].t);
+    vec4 sum = vec4(0.0, 0.0, 0.0, 0.0);
+    for (int i = 0; i < 4; i++) {
+        for (int j = 0; j < 4; j++) {
+            sum += texture2D(originalTexture, gl_TexCoord[0].st +
+                vec2(ds, dt) * vec2(-2.0 + float(i), -2.0 + float(j)));
+        }
+    }
+    gl_FragColor = sum / 16.0;
+}
diff --git a/interface/src/Application.cpp b/interface/src/Application.cpp
index 1785bf4d0c..adc5bb1b71 100644
--- a/interface/src/Application.cpp
+++ b/interface/src/Application.cpp
@@ -1449,6 +1449,7 @@ void Application::init() {
     _environment.init();
 
     _glowEffect.init();
+    _ambientOcclusionEffect.init();
     
     _handControl.setScreenDimensions(_glWidget->width(), _glWidget->height());
 
@@ -2375,6 +2376,11 @@ void Application::displaySide(Camera& whichCamera) {
         renderWorldBox();
     }
     
+    // render the ambient occlusion effect if enabled
+    if (Menu::getInstance()->isOptionChecked(MenuOption::AmbientOcclusion)) {
+        _ambientOcclusionEffect.render();
+    }
+    
     // brad's frustum for debugging
     if (Menu::getInstance()->isOptionChecked(MenuOption::DisplayFrustum)) {
         renderViewFrustum(_viewFrustum);
diff --git a/interface/src/Application.h b/interface/src/Application.h
index 32fa39eb83..51606ce75a 100644
--- a/interface/src/Application.h
+++ b/interface/src/Application.h
@@ -32,6 +32,7 @@
 #include "Environment.h"
 #include "GLCanvas.h"
 #include "PacketHeaders.h"
+#include "PieMenu.h"
 #include "SerialInterface.h"
 #include "Stars.h"
 #include "Swatch.h"
@@ -42,9 +43,9 @@
 #include "VoxelPacketProcessor.h"
 #include "VoxelSystem.h"
 #include "Webcam.h"
-#include "PieMenu.h"
 #include "avatar/Avatar.h"
 #include "avatar/HandControl.h"
+#include "renderer/AmbientOcclusionEffect.h"
 #include "renderer/GeometryCache.h"
 #include "renderer/GlowEffect.h"
 #include "renderer/TextureCache.h"
@@ -314,6 +315,7 @@ private:
     TextureCache _textureCache;
     
     GlowEffect _glowEffect;
+    AmbientOcclusionEffect _ambientOcclusionEffect;
     
     #ifndef _WIN32
     Audio _audio;
diff --git a/interface/src/Menu.cpp b/interface/src/Menu.cpp
index 67bb1d3f8e..1e55c8f911 100644
--- a/interface/src/Menu.cpp
+++ b/interface/src/Menu.cpp
@@ -163,6 +163,7 @@ Menu::Menu() :
                                   appInstance->getGlowEffect(),
                                   SLOT(cycleRenderMode()));
     
+    addCheckableActionToQMenuAndActionHash(renderMenu, MenuOption::AmbientOcclusion);
     addCheckableActionToQMenuAndActionHash(renderMenu, MenuOption::FrameTimer);
     addCheckableActionToQMenuAndActionHash(renderMenu, MenuOption::LookAtVectors);
     addCheckableActionToQMenuAndActionHash(renderMenu, MenuOption::LookAtIndicator, 0, true);
diff --git a/interface/src/Menu.h b/interface/src/Menu.h
index e399101702..252c9a8707 100644
--- a/interface/src/Menu.h
+++ b/interface/src/Menu.h
@@ -108,6 +108,7 @@ private:
 
 namespace MenuOption {
     
+    const QString AmbientOcclusion = "Ambient Occlusion";
     const QString Avatars = "Avatars";
     const QString AvatarAsBalls = "Avatar as Balls";
     const QString Atmosphere = "Atmosphere";
diff --git a/interface/src/renderer/AmbientOcclusionEffect.cpp b/interface/src/renderer/AmbientOcclusionEffect.cpp
new file mode 100644
index 0000000000..ff86615b26
--- /dev/null
+++ b/interface/src/renderer/AmbientOcclusionEffect.cpp
@@ -0,0 +1,145 @@
+//
+//  AmbientOcclusionEffect.cpp
+//  interface
+//
+//  Created by Andrzej Kapolka on 7/14/13.
+//  Copyright (c) 2013 High Fidelity, Inc. All rights reserved.
+//
+
+// include this before QOpenGLFramebufferObject, which includes an earlier version of OpenGL
+#include "InterfaceConfig.h"
+
+#include <QOpenGLFramebufferObject>
+
+#include <glm/gtc/random.hpp>
+
+#include <SharedUtil.h>
+
+#include "AmbientOcclusionEffect.h"
+#include "Application.h"
+#include "InterfaceConfig.h"
+#include "ProgramObject.h"
+#include "RenderUtil.h"
+
+const int ROTATION_WIDTH = 4;
+const int ROTATION_HEIGHT = 4;
+    
+void AmbientOcclusionEffect::init() {
+    switchToResourcesParentIfRequired();
+    
+    _occlusionProgram = new ProgramObject();
+    _occlusionProgram->addShaderFromSourceFile(QGLShader::Vertex, "resources/shaders/ambient_occlusion.vert");
+    _occlusionProgram->addShaderFromSourceFile(QGLShader::Fragment, "resources/shaders/ambient_occlusion.frag");
+    _occlusionProgram->link();
+    
+    _blurProgram = new ProgramObject();
+    _blurProgram->addShaderFromSourceFile(QGLShader::Vertex, "resources/shaders/ambient_occlusion.vert");
+    _blurProgram->addShaderFromSourceFile(QGLShader::Fragment, "resources/shaders/occlusion_blur.frag");
+    _blurProgram->link();
+    
+    _blurProgram->bind();
+    _blurProgram->setUniformValue("originalTexture", 0);
+    _blurProgram->release();
+    
+    // create the sample kernel: an array of spherically distributed offset vectors
+    const int SAMPLE_KERNEL_SIZE = 16;
+    QVector3D sampleKernel[SAMPLE_KERNEL_SIZE];
+    for (int i = 0; i < SAMPLE_KERNEL_SIZE; i++) {
+        // square the length in order to increase density towards the center
+        glm::vec3 vector = glm::sphericalRand(1.0f);
+        float scale = randFloat();
+        const float MIN_VECTOR_LENGTH = 0.01f;
+        const float MAX_VECTOR_LENGTH = 1.0f;
+        vector *= glm::mix(MIN_VECTOR_LENGTH, MAX_VECTOR_LENGTH, scale * scale);
+        sampleKernel[i] = QVector3D(vector.x, vector.y, vector.z);
+    }
+    
+    _occlusionProgram->bind();
+    _occlusionProgram->setUniformValue("depthTexture", 0);
+    _occlusionProgram->setUniformValue("rotationTexture", 1);
+    _occlusionProgram->setUniformValueArray("sampleKernel", sampleKernel, SAMPLE_KERNEL_SIZE);
+    _occlusionProgram->setUniformValue("radius", 0.1f);
+    _occlusionProgram->release();
+    
+    _nearLocation = _occlusionProgram->uniformLocation("near");
+    _farLocation = _occlusionProgram->uniformLocation("far");
+    _leftBottomLocation = _occlusionProgram->uniformLocation("leftBottom");
+    _rightTopLocation = _occlusionProgram->uniformLocation("rightTop");
+    _noiseScaleLocation = _occlusionProgram->uniformLocation("noiseScale");
+    
+    // generate the random rotation texture
+    glGenTextures(1, &_rotationTextureID);
+    glBindTexture(GL_TEXTURE_2D, _rotationTextureID);
+    const int ELEMENTS_PER_PIXEL = 3;
+    unsigned char rotationData[ROTATION_WIDTH * ROTATION_HEIGHT * ELEMENTS_PER_PIXEL];
+    unsigned char* rotation = rotationData;
+    for (int i = 0; i < ROTATION_WIDTH * ROTATION_HEIGHT; i++) {
+        glm::vec3 randvec = glm::sphericalRand(1.0f);
+        *rotation++ = ((randvec.x + 1.0f) / 2.0f) * 255.0f;
+        *rotation++ = ((randvec.y + 1.0f) / 2.0f) * 255.0f;
+        *rotation++ = ((randvec.z + 1.0f) / 2.0f) * 255.0f;
+    }
+    glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, ROTATION_WIDTH, ROTATION_HEIGHT, 0, GL_RGB, GL_UNSIGNED_BYTE, rotationData);
+    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
+    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
+    glBindTexture(GL_TEXTURE_2D, 0);
+}
+
+void AmbientOcclusionEffect::render() {
+    glDisable(GL_BLEND);
+    glDisable(GL_DEPTH_TEST);
+    glDepthMask(GL_FALSE);
+    
+    glBindTexture(GL_TEXTURE_2D, Application::getInstance()->getTextureCache()->getPrimaryDepthTextureID());
+    
+    glActiveTexture(GL_TEXTURE1);
+    glBindTexture(GL_TEXTURE_2D, _rotationTextureID);
+    
+    // render with the occlusion shader to the secondary buffer
+    QOpenGLFramebufferObject* secondaryFBO = Application::getInstance()->getTextureCache()->getSecondaryFramebufferObject();
+    secondaryFBO->bind();
+    
+    float left, right, bottom, top, nearVal, farVal;
+    glm::vec4 nearClipPlane, farClipPlane;
+    Application::getInstance()->getViewFrustum()->computeOffAxisFrustum(
+        left, right, bottom, top, nearVal, farVal, nearClipPlane, farClipPlane);
+    
+    _occlusionProgram->bind();
+    _occlusionProgram->setUniformValue(_nearLocation, nearVal);
+    _occlusionProgram->setUniformValue(_farLocation, farVal);
+    _occlusionProgram->setUniformValue(_leftBottomLocation, left, bottom);
+    _occlusionProgram->setUniformValue(_rightTopLocation, right, top);
+    QSize size = Application::getInstance()->getGLWidget()->size();
+    _occlusionProgram->setUniformValue(_noiseScaleLocation, size.width() / (float)ROTATION_WIDTH,
+        size.height() / (float)ROTATION_HEIGHT);
+    
+    renderFullscreenQuad();
+    
+    _occlusionProgram->release();
+    
+    secondaryFBO->release();
+    
+    glBindTexture(GL_TEXTURE_2D, 0);
+    glActiveTexture(GL_TEXTURE0);
+    
+    // now render secondary to primary with 4x4 blur
+    Application::getInstance()->getTextureCache()->getPrimaryFramebufferObject()->bind();
+    
+    glEnable(GL_BLEND);
+    glBlendFuncSeparate(GL_ZERO, GL_SRC_COLOR, GL_ZERO, GL_ONE);
+    
+    glBindTexture(GL_TEXTURE_2D, secondaryFBO->texture());
+    
+    _blurProgram->bind();
+    
+    renderFullscreenQuad();
+    
+    _blurProgram->release();
+    
+    glBindTexture(GL_TEXTURE_2D, 0);
+    
+    //glEnable(GL_BLEND);
+    glBlendFuncSeparate(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA, GL_CONSTANT_ALPHA, GL_ONE);
+    glEnable(GL_DEPTH_TEST);
+    glDepthMask(GL_TRUE);
+}
diff --git a/interface/src/renderer/AmbientOcclusionEffect.h b/interface/src/renderer/AmbientOcclusionEffect.h
new file mode 100644
index 0000000000..d41bb65381
--- /dev/null
+++ b/interface/src/renderer/AmbientOcclusionEffect.h
@@ -0,0 +1,39 @@
+//
+//  AmbientOcclusionEffect.h
+//  interface
+//
+//  Created by Andrzej Kapolka on 7/14/13.
+//  Copyright (c) 2013 High Fidelity, Inc. All rights reserved.
+//
+
+#ifndef __interface__AmbientOcclusionEffect__
+#define __interface__AmbientOcclusionEffect__
+
+#include "InterfaceConfig.h"
+
+class ProgramObject;
+
+/// A screen space ambient occlusion effect.  See John Chapman's tutorial at
+/// http://john-chapman-graphics.blogspot.co.uk/2013/01/ssao-tutorial.html for reference.
+class AmbientOcclusionEffect {
+public:
+    
+    void init();
+    
+    void render();
+    
+private:
+
+    ProgramObject* _occlusionProgram;
+    int _nearLocation;
+    int _farLocation;
+    int _leftBottomLocation;
+    int _rightTopLocation;
+    int _noiseScaleLocation;
+    
+    ProgramObject* _blurProgram;
+    
+    GLuint _rotationTextureID;
+};
+
+#endif /* defined(__interface__AmbientOcclusionEffect__) */
diff --git a/interface/src/renderer/GlowEffect.cpp b/interface/src/renderer/GlowEffect.cpp
index ce069bc20b..85c4eb27b2 100644
--- a/interface/src/renderer/GlowEffect.cpp
+++ b/interface/src/renderer/GlowEffect.cpp
@@ -5,7 +5,7 @@
 //  Created by Andrzej Kapolka on 8/7/13.
 //  Copyright (c) 2013 High Fidelity, Inc. All rights reserved.
 
-// include this before QGLWidget, which includes an earlier version of OpenGL
+// include this before QOpenGLFramebufferObject, which includes an earlier version of OpenGL
 #include "InterfaceConfig.h"
 
 #include <QOpenGLFramebufferObject>
@@ -13,6 +13,7 @@
 #include "Application.h"
 #include "GlowEffect.h"
 #include "ProgramObject.h"
+#include "RenderUtil.h"
 
 GlowEffect::GlowEffect() : _renderMode(BLUR_ADD_MODE) {
 }
@@ -68,19 +69,6 @@ void GlowEffect::end() {
     glBlendColor(0.0f, 0.0f, 0.0f, 0.0f);
 }
 
-static void renderFullscreenQuad() {
-    glBegin(GL_QUADS);
-        glTexCoord2f(0.0f, 0.0f);
-        glVertex2f(-1.0f, -1.0f);
-        glTexCoord2f(1.0f, 0.0f);
-        glVertex2f(1.0f, -1.0f);
-        glTexCoord2f(1.0f, 1.0f);
-        glVertex2f(1.0f, 1.0f);
-        glTexCoord2f(0.0f, 1.0f);
-        glVertex2f(-1.0f, 1.0f);
-    glEnd();
-}
-
 void GlowEffect::render() {
     QOpenGLFramebufferObject* primaryFBO = Application::getInstance()->getTextureCache()->getPrimaryFramebufferObject();
     primaryFBO->release();
@@ -95,6 +83,7 @@ void GlowEffect::render() {
     
     glDisable(GL_BLEND);
     glDisable(GL_DEPTH_TEST);
+    glDepthMask(GL_FALSE);
     
     if (_isEmpty) {
         // copy the primary to the screen
@@ -210,6 +199,7 @@ void GlowEffect::render() {
        
     glEnable(GL_BLEND);
     glEnable(GL_DEPTH_TEST);
+    glDepthMask(GL_TRUE);
     glBindTexture(GL_TEXTURE_2D, 0);
 }
 
diff --git a/interface/src/renderer/RenderUtil.cpp b/interface/src/renderer/RenderUtil.cpp
new file mode 100644
index 0000000000..4b53fb4d12
--- /dev/null
+++ b/interface/src/renderer/RenderUtil.cpp
@@ -0,0 +1,22 @@
+//
+//  RenderUtil.cpp
+//  interface
+//
+//  Created by Andrzej Kapolka on 8/15/13.
+//  Copyright (c) 2013 High Fidelity, Inc. All rights reserved.
+
+#include "InterfaceConfig.h"
+#include "RenderUtil.h"
+
+void renderFullscreenQuad() {
+    glBegin(GL_QUADS);
+        glTexCoord2f(0.0f, 0.0f);
+        glVertex2f(-1.0f, -1.0f);
+        glTexCoord2f(1.0f, 0.0f);
+        glVertex2f(1.0f, -1.0f);
+        glTexCoord2f(1.0f, 1.0f);
+        glVertex2f(1.0f, 1.0f);
+        glTexCoord2f(0.0f, 1.0f);
+        glVertex2f(-1.0f, 1.0f);
+    glEnd();
+}
diff --git a/interface/src/renderer/RenderUtil.h b/interface/src/renderer/RenderUtil.h
new file mode 100644
index 0000000000..51e31fe260
--- /dev/null
+++ b/interface/src/renderer/RenderUtil.h
@@ -0,0 +1,15 @@
+//
+//  RenderUtil.h
+//  interface
+//
+//  Created by Andrzej Kapolka on 8/15/13.
+//  Copyright (c) 2013 High Fidelity, Inc. All rights reserved.
+//
+
+#ifndef __interface__RenderUtil__
+#define __interface__RenderUtil__
+
+/// Renders a quad from (-1, -1, 0) to (1, 1, 0) with texture coordinates from (0, 0) to (1, 1).
+void renderFullscreenQuad();
+
+#endif /* defined(__interface__RenderUtil__) */
diff --git a/interface/src/renderer/TextureCache.cpp b/interface/src/renderer/TextureCache.cpp
index d4cc97edbf..5696475487 100644
--- a/interface/src/renderer/TextureCache.cpp
+++ b/interface/src/renderer/TextureCache.cpp
@@ -5,6 +5,9 @@
 //  Created by Andrzej Kapolka on 8/6/13.
 //  Copyright (c) 2013 High Fidelity, Inc. All rights reserved.
 
+// include this before QGLWidget, which includes an earlier version of OpenGL
+#include "InterfaceConfig.h"
+
 #include <QGLWidget>
 #include <QOpenGLFramebufferObject>
 
@@ -23,6 +26,7 @@ TextureCache::~TextureCache() {
     }
     if (_primaryFramebufferObject != NULL) {
         delete _primaryFramebufferObject;
+        glDeleteTextures(1, &_primaryDepthTextureID);
     }
     if (_secondaryFramebufferObject != NULL) {
         delete _secondaryFramebufferObject;
@@ -60,13 +64,31 @@ GLuint TextureCache::getPermutationNormalTextureID() {
 
 QOpenGLFramebufferObject* TextureCache::getPrimaryFramebufferObject() {
     if (_primaryFramebufferObject == NULL) {
-        _primaryFramebufferObject = new QOpenGLFramebufferObject(Application::getInstance()->getGLWidget()->size(),
-            QOpenGLFramebufferObject::Depth);
+        QSize size = Application::getInstance()->getGLWidget()->size();
+        _primaryFramebufferObject = new QOpenGLFramebufferObject(size);
         Application::getInstance()->getGLWidget()->installEventFilter(this);
+    
+        glGenTextures(1, &_primaryDepthTextureID);
+        glBindTexture(GL_TEXTURE_2D, _primaryDepthTextureID);
+        glTexImage2D(GL_TEXTURE_2D, 0, GL_DEPTH_COMPONENT, size.width(), size.height(),
+            0, GL_DEPTH_COMPONENT, GL_UNSIGNED_BYTE, 0);
+        glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
+        glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
+        glBindTexture(GL_TEXTURE_2D, 0);
+        
+        _primaryFramebufferObject->bind();
+        glFramebufferTexture2D(GL_DRAW_FRAMEBUFFER, GL_DEPTH_ATTACHMENT, GL_TEXTURE_2D, _primaryDepthTextureID, 0);
+        _primaryFramebufferObject->release();
     }
     return _primaryFramebufferObject;
 }
 
+GLuint TextureCache::getPrimaryDepthTextureID() {
+    // ensure that the primary framebuffer object is initialized before returning the depth texture id
+    getPrimaryFramebufferObject();
+    return _primaryDepthTextureID;
+}
+
 QOpenGLFramebufferObject* TextureCache::getSecondaryFramebufferObject() {
     if (_secondaryFramebufferObject == NULL) {
         _secondaryFramebufferObject = new QOpenGLFramebufferObject(Application::getInstance()->getGLWidget()->size());
@@ -89,6 +111,7 @@ bool TextureCache::eventFilter(QObject* watched, QEvent* event) {
         if (_primaryFramebufferObject != NULL && _primaryFramebufferObject->size() != size) {
             delete _primaryFramebufferObject;
             _primaryFramebufferObject = NULL;
+            glDeleteTextures(1, &_primaryDepthTextureID);
         }
         if (_secondaryFramebufferObject != NULL && _secondaryFramebufferObject->size() != size) {
             delete _secondaryFramebufferObject;
diff --git a/interface/src/renderer/TextureCache.h b/interface/src/renderer/TextureCache.h
index 716f087992..1f2fc96ac5 100644
--- a/interface/src/renderer/TextureCache.h
+++ b/interface/src/renderer/TextureCache.h
@@ -15,16 +15,31 @@
 
 class QOpenGLFramebufferObject;
 
+/// Stored cached textures, including render-to-texture targets.
 class TextureCache : public QObject {
 public:
     
     TextureCache();
     ~TextureCache();
     
+    /// Returns the ID of the permutation/normal texture used for Perlin noise shader programs.  This texture
+    /// has two lines: the first, a set of random numbers in [0, 255] to be used as permutation offsets, and
+    /// the second, a set of random unit vectors to be used as noise gradients.
     GLuint getPermutationNormalTextureID();
 
+    /// Returns a pointer to the primary framebuffer object.  This render target includes a depth component, and is
+    /// used for scene rendering.
     QOpenGLFramebufferObject* getPrimaryFramebufferObject();
+    
+    /// Returns the ID of the primary framebuffer object's depth texture.  This contains the Z buffer used in rendering.
+    GLuint getPrimaryDepthTextureID();
+    
+    /// Returns a pointer to the secondary framebuffer object, used as an additional render target when performing full
+    /// screen effects.
     QOpenGLFramebufferObject* getSecondaryFramebufferObject();
+    
+    /// Returns a pointer to the tertiary framebuffer object, used as an additional render target when performing full
+    /// screen effects.
     QOpenGLFramebufferObject* getTertiaryFramebufferObject();
     
     virtual bool eventFilter(QObject* watched, QEvent* event);
@@ -34,6 +49,7 @@ private:
     GLuint _permutationNormalTextureID;
     
     QOpenGLFramebufferObject* _primaryFramebufferObject;
+    GLuint _primaryDepthTextureID;
     QOpenGLFramebufferObject* _secondaryFramebufferObject;
     QOpenGLFramebufferObject* _tertiaryFramebufferObject;
 };