From b294b33ac7ecc0c1d19b44f45833b27bd243792d Mon Sep 17 00:00:00 2001
From: Andrzej Kapolka <drzej.k@gmail.com>
Date: Fri, 5 Jul 2013 18:21:59 -0700
Subject: [PATCH 1/8] Started on ambient occlusion shader.

---
 .../resources/shaders/ambient_occlusion.frag  | 34 +++++++++++++++++++
 1 file changed, 34 insertions(+)
 create mode 100644 interface/resources/shaders/ambient_occlusion.frag

diff --git a/interface/resources/shaders/ambient_occlusion.frag b/interface/resources/shaders/ambient_occlusion.frag
new file mode 100644
index 0000000000..2f7a322b05
--- /dev/null
+++ b/interface/resources/shaders/ambient_occlusion.frag
@@ -0,0 +1,34 @@
+#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 depth;
+
+// 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;
+
+// given a texture coordinate, returns the 3D view space coordinate
+vec3 texCoordToViewSpace(vec2 texCoord) {
+    float z = (far * near) / (texture2D(depth, texCoord).r * (far - near) - far);
+    return vec3(((texCoord * 2.0 - vec2(1.0, 1.0)) * (rightTop - leftBottom) + rightTop + leftBottom) * z / (-2.0 * near), z);
+}
+
+void main(void) {
+    gl_FragColor = vec4(1.0, 1.0, 1.0, 1.0);
+}

From 84bb2aa26518430560b66cf2bf366e6aa82016ec Mon Sep 17 00:00:00 2001
From: Andrzej Kapolka <drzej.k@gmail.com>
Date: Sun, 14 Jul 2013 18:21:18 -0700
Subject: [PATCH 2/8] Started on C++ side of SSAO effect.

---
 .../resources/shaders/ambient_occlusion.frag  |  7 +-
 interface/src/Application.cpp                 |  2 +
 interface/src/Application.h                   |  2 +
 .../src/renderer/AmbientOcclusionEffect.cpp   | 70 +++++++++++++++++++
 .../src/renderer/AmbientOcclusionEffect.h     | 30 ++++++++
 5 files changed, 108 insertions(+), 3 deletions(-)
 create mode 100644 interface/src/renderer/AmbientOcclusionEffect.cpp
 create mode 100644 interface/src/renderer/AmbientOcclusionEffect.h

diff --git a/interface/resources/shaders/ambient_occlusion.frag b/interface/resources/shaders/ambient_occlusion.frag
index 2f7a322b05..2707415646 100644
--- a/interface/resources/shaders/ambient_occlusion.frag
+++ b/interface/resources/shaders/ambient_occlusion.frag
@@ -9,7 +9,7 @@
 //
 
 // the depth texture
-uniform sampler2D depth;
+uniform sampler2D depthTexture;
 
 // the distance to the near clip plane
 uniform float near;
@@ -25,10 +25,11 @@ uniform vec2 rightTop;
 
 // given a texture coordinate, returns the 3D view space coordinate
 vec3 texCoordToViewSpace(vec2 texCoord) {
-    float z = (far * near) / (texture2D(depth, texCoord).r * (far - near) - far);
+    float z = (far * near) / (texture2D(depthTexture, texCoord).r * (far - near) - far);
     return vec3(((texCoord * 2.0 - vec2(1.0, 1.0)) * (rightTop - leftBottom) + rightTop + leftBottom) * z / (-2.0 * near), z);
 }
 
 void main(void) {
-    gl_FragColor = vec4(1.0, 1.0, 1.0, 1.0);
+    float depth = texture2D(depthTexture, gl_TexCoord[0].st).r;
+    gl_FragColor = vec4(depth, depth, depth, 1.0);
 }
diff --git a/interface/src/Application.cpp b/interface/src/Application.cpp
index 6f70c89f3b..c67590f019 100644
--- a/interface/src/Application.cpp
+++ b/interface/src/Application.cpp
@@ -2463,6 +2463,8 @@ void Application::displaySide(Camera& whichCamera) {
     //  Render the world box
     if (!_lookingInMirror->isChecked() && _renderStatsOn->isChecked()) { render_world_box(); }
     
+    _ambientOcclusionEffect.render(_glWidget->width(), _glWidget->height());
+    
     // brad's frustum for debugging
     if (_frustumOn->isChecked()) renderViewFrustum(_viewFrustum);
     
diff --git a/interface/src/Application.h b/interface/src/Application.h
index c6bbd4eec2..6eaa9ee5ca 100644
--- a/interface/src/Application.h
+++ b/interface/src/Application.h
@@ -37,6 +37,7 @@
 #include "VoxelSystem.h"
 #include "PacketHeaders.h"
 #include "Webcam.h"
+#include "renderer/AmbientOcclusionEffect.h"
 #include "renderer/GeometryCache.h"
 #include "ui/ChatEntry.h"
 #include "ToolsPalette.h"
@@ -366,6 +367,7 @@ private:
     int _hmdWarpParamLocation;
     
     GeometryCache _geometryCache;
+    AmbientOcclusionEffect _ambientOcclusionEffect;
     
     ParticleSystem _particleSystem;
     
diff --git a/interface/src/renderer/AmbientOcclusionEffect.cpp b/interface/src/renderer/AmbientOcclusionEffect.cpp
new file mode 100644
index 0000000000..74c25235d8
--- /dev/null
+++ b/interface/src/renderer/AmbientOcclusionEffect.cpp
@@ -0,0 +1,70 @@
+//
+//  AmbientOcclusionEffect.cpp
+//  interface
+//
+//  Created by Andrzej Kapolka on 7/14/13.
+//  Copyright (c) 2013 High Fidelity, Inc. All rights reserved.
+//
+
+#include <SharedUtil.h>
+
+#include "AmbientOcclusionEffect.h"
+#include "ProgramObject.h"
+
+ProgramObject* AmbientOcclusionEffect::_program = 0;
+
+AmbientOcclusionEffect::AmbientOcclusionEffect() : _depthTextureID(0) {
+}
+
+void AmbientOcclusionEffect::render(int screenWidth, int screenHeight) {
+    // copy the z buffer into a depth texture
+    if (_depthTextureID == 0) {
+        glGenTextures(1, &_depthTextureID);
+        glBindTexture(GL_TEXTURE_2D, _depthTextureID);
+        glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
+        glCopyTexImage2D(GL_TEXTURE_2D, 0, GL_DEPTH_COMPONENT, 0, 0, screenWidth, screenHeight, 0);
+        
+    } else {
+        glBindTexture(GL_TEXTURE_2D, _depthTextureID);
+        glCopyTexSubImage2D(GL_TEXTURE_2D, 0, 0, 0, 0, 0, screenWidth, screenHeight);
+    }
+    
+    // now render a full screen quad with that texture
+    if (_program == 0) {
+        switchToResourcesParentIfRequired();
+        _program = new ProgramObject();
+        _program->addShaderFromSourceFile(QGLShader::Fragment, "resources/shaders/ambient_occlusion.frag");
+        _program->link();
+        
+        _program->bind();
+        _program->setUniformValue("depthTexture", 0);
+        
+    } else {
+        _program->bind();
+    }
+    glPushMatrix();
+    glLoadIdentity();
+    
+    glMatrixMode(GL_PROJECTION);
+    glPushMatrix();
+    glLoadIdentity();
+    
+    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();
+     
+    glPopMatrix();
+    
+    glMatrixMode(GL_MODELVIEW);
+    glPopMatrix();   
+
+    _program->release();
+    glBindTexture(GL_TEXTURE_2D, 0);    
+}
diff --git a/interface/src/renderer/AmbientOcclusionEffect.h b/interface/src/renderer/AmbientOcclusionEffect.h
new file mode 100644
index 0000000000..4c05e348e6
--- /dev/null
+++ b/interface/src/renderer/AmbientOcclusionEffect.h
@@ -0,0 +1,30 @@
+//
+//  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;
+
+class AmbientOcclusionEffect {
+public:
+    
+    AmbientOcclusionEffect();
+    
+    void render(int screenWidth, int screenHeight);
+
+private:
+    
+    GLuint _depthTextureID;
+    
+    static ProgramObject* _program;
+};
+
+#endif /* defined(__interface__AmbientOcclusionEffect__) */

From 94e5c8d4a1192b245a65f2482a4452887e184dbc Mon Sep 17 00:00:00 2001
From: Andrzej Kapolka <drzej.k@gmail.com>
Date: Thu, 15 Aug 2013 10:10:14 -0700
Subject: [PATCH 3/8] Missed a spot in the merge.

---
 interface/src/Application.h | 7 ++-----
 1 file changed, 2 insertions(+), 5 deletions(-)

diff --git a/interface/src/Application.h b/interface/src/Application.h
index a2db40123f..fbdbbc9ae5 100644
--- a/interface/src/Application.h
+++ b/interface/src/Application.h
@@ -32,6 +32,7 @@
 #include "Environment.h"
 #include "PacketHeaders.h"
 #include "ParticleSystem.h"
+#include "PieMenu.h"
 #include "SerialInterface.h"
 #include "Stars.h"
 #include "Swatch.h"
@@ -40,13 +41,9 @@
 #include "VoxelFade.h"
 #include "VoxelSystem.h"
 #include "Webcam.h"
-<<<<<<< HEAD
-#include "renderer/AmbientOcclusionEffect.h"
-=======
-#include "PieMenu.h"
 #include "avatar/Avatar.h"
 #include "avatar/HandControl.h"
->>>>>>> 8238d0d380944c07a14c5fd42efa1a5d3eb468ed
+#include "renderer/AmbientOcclusionEffect.h"
 #include "renderer/GeometryCache.h"
 #include "renderer/GlowEffect.h"
 #include "renderer/TextureCache.h"

From 28d306a228d956ceb5373fd981ec7819b9f97570 Mon Sep 17 00:00:00 2001
From: Andrzej Kapolka <drzej.k@gmail.com>
Date: Thu, 15 Aug 2013 13:10:48 -0700
Subject: [PATCH 4/8] Remove the code here; will be replacing it based on glow
 effect work.

---
 interface/src/Application.cpp                 |  2 +-
 .../src/renderer/AmbientOcclusionEffect.cpp   | 58 +------------------
 .../src/renderer/AmbientOcclusionEffect.h     | 10 +---
 3 files changed, 4 insertions(+), 66 deletions(-)

diff --git a/interface/src/Application.cpp b/interface/src/Application.cpp
index 0beb7fedd0..4461443287 100644
--- a/interface/src/Application.cpp
+++ b/interface/src/Application.cpp
@@ -3193,7 +3193,7 @@ void Application::displaySide(Camera& whichCamera) {
     //  Render the world box
     if (!_lookingInMirror->isChecked() && _renderStatsOn->isChecked()) { renderWorldBox(); }
     
-    _ambientOcclusionEffect.render(_glWidget->width(), _glWidget->height());
+    _ambientOcclusionEffect.render();
     
     // brad's frustum for debugging
     if (_frustumOn->isChecked()) renderViewFrustum(_viewFrustum);
diff --git a/interface/src/renderer/AmbientOcclusionEffect.cpp b/interface/src/renderer/AmbientOcclusionEffect.cpp
index 74c25235d8..5aac065647 100644
--- a/interface/src/renderer/AmbientOcclusionEffect.cpp
+++ b/interface/src/renderer/AmbientOcclusionEffect.cpp
@@ -11,60 +11,6 @@
 #include "AmbientOcclusionEffect.h"
 #include "ProgramObject.h"
 
-ProgramObject* AmbientOcclusionEffect::_program = 0;
-
-AmbientOcclusionEffect::AmbientOcclusionEffect() : _depthTextureID(0) {
-}
-
-void AmbientOcclusionEffect::render(int screenWidth, int screenHeight) {
-    // copy the z buffer into a depth texture
-    if (_depthTextureID == 0) {
-        glGenTextures(1, &_depthTextureID);
-        glBindTexture(GL_TEXTURE_2D, _depthTextureID);
-        glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
-        glCopyTexImage2D(GL_TEXTURE_2D, 0, GL_DEPTH_COMPONENT, 0, 0, screenWidth, screenHeight, 0);
-        
-    } else {
-        glBindTexture(GL_TEXTURE_2D, _depthTextureID);
-        glCopyTexSubImage2D(GL_TEXTURE_2D, 0, 0, 0, 0, 0, screenWidth, screenHeight);
-    }
-    
-    // now render a full screen quad with that texture
-    if (_program == 0) {
-        switchToResourcesParentIfRequired();
-        _program = new ProgramObject();
-        _program->addShaderFromSourceFile(QGLShader::Fragment, "resources/shaders/ambient_occlusion.frag");
-        _program->link();
-        
-        _program->bind();
-        _program->setUniformValue("depthTexture", 0);
-        
-    } else {
-        _program->bind();
-    }
-    glPushMatrix();
-    glLoadIdentity();
-    
-    glMatrixMode(GL_PROJECTION);
-    glPushMatrix();
-    glLoadIdentity();
-    
-    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();
-     
-    glPopMatrix();
-    
-    glMatrixMode(GL_MODELVIEW);
-    glPopMatrix();   
-
-    _program->release();
-    glBindTexture(GL_TEXTURE_2D, 0);    
+void AmbientOcclusionEffect::render() {
+    
 }
diff --git a/interface/src/renderer/AmbientOcclusionEffect.h b/interface/src/renderer/AmbientOcclusionEffect.h
index 4c05e348e6..f8e4be4edc 100644
--- a/interface/src/renderer/AmbientOcclusionEffect.h
+++ b/interface/src/renderer/AmbientOcclusionEffect.h
@@ -16,15 +16,7 @@ class ProgramObject;
 class AmbientOcclusionEffect {
 public:
     
-    AmbientOcclusionEffect();
-    
-    void render(int screenWidth, int screenHeight);
-
-private:
-    
-    GLuint _depthTextureID;
-    
-    static ProgramObject* _program;
+    void render();
 };
 
 #endif /* defined(__interface__AmbientOcclusionEffect__) */

From 3ddab484e0903aa5528ca2fc65d4b5116c571bb0 Mon Sep 17 00:00:00 2001
From: Andrzej Kapolka <drzej.k@gmail.com>
Date: Thu, 15 Aug 2013 17:52:31 -0700
Subject: [PATCH 5/8] Beginnings of ambient occlusion.  Looks like an
 architectural drawing.

---
 .../resources/shaders/ambient_occlusion.frag  | 11 +++-
 interface/src/Application.cpp                 |  1 +
 .../src/renderer/AmbientOcclusionEffect.cpp   | 58 +++++++++++++++++++
 .../src/renderer/AmbientOcclusionEffect.h     | 13 ++++-
 interface/src/renderer/GlowEffect.cpp         | 16 +----
 interface/src/renderer/RenderUtil.cpp         | 22 +++++++
 interface/src/renderer/RenderUtil.h           | 15 +++++
 interface/src/renderer/TextureCache.cpp       | 27 ++++++++-
 interface/src/renderer/TextureCache.h         | 16 +++++
 9 files changed, 160 insertions(+), 19 deletions(-)
 create mode 100644 interface/src/renderer/RenderUtil.cpp
 create mode 100644 interface/src/renderer/RenderUtil.h

diff --git a/interface/resources/shaders/ambient_occlusion.frag b/interface/resources/shaders/ambient_occlusion.frag
index 2707415646..b01f7f2db7 100644
--- a/interface/resources/shaders/ambient_occlusion.frag
+++ b/interface/resources/shaders/ambient_occlusion.frag
@@ -30,6 +30,13 @@ vec3 texCoordToViewSpace(vec2 texCoord) {
 }
 
 void main(void) {
-    float depth = texture2D(depthTexture, gl_TexCoord[0].st).r;
-    gl_FragColor = vec4(depth, depth, depth, 1.0);
+    float ds = dFdx(gl_TexCoord[0].s);
+    float dt = dFdy(gl_TexCoord[0].t);
+    vec3 center = texCoordToViewSpace(gl_TexCoord[0].st);
+    vec3 left = texCoordToViewSpace(gl_TexCoord[0].st - vec2(-ds, 0.0)) - center;
+    vec3 right = texCoordToViewSpace(gl_TexCoord[0].st - vec2(ds, 0.0)) - center;
+    vec3 up = texCoordToViewSpace(gl_TexCoord[0].st - vec2(0.0, dt)) - center;
+    vec3 down = texCoordToViewSpace(gl_TexCoord[0].st - vec2(0.0, -dt)) - center;
+    float occlusion = 0.5 - (left.z / length(left) + right.z / length(right) + up.z / length(up) + down.z / length(down)) / 8.0;
+    gl_FragColor = vec4(occlusion, occlusion, occlusion, 0.0);
 }
diff --git a/interface/src/Application.cpp b/interface/src/Application.cpp
index 4bf760139d..a701fde1f2 100644
--- a/interface/src/Application.cpp
+++ b/interface/src/Application.cpp
@@ -2121,6 +2121,7 @@ void Application::init() {
     _environment.init();
 
     _glowEffect.init();
+    _ambientOcclusionEffect.init();
     
     _handControl.setScreenDimensions(_glWidget->width(), _glWidget->height());
 
diff --git a/interface/src/renderer/AmbientOcclusionEffect.cpp b/interface/src/renderer/AmbientOcclusionEffect.cpp
index 5aac065647..8719350ec8 100644
--- a/interface/src/renderer/AmbientOcclusionEffect.cpp
+++ b/interface/src/renderer/AmbientOcclusionEffect.cpp
@@ -9,8 +9,66 @@
 #include <SharedUtil.h>
 
 #include "AmbientOcclusionEffect.h"
+#include "Application.h"
+#include "InterfaceConfig.h"
 #include "ProgramObject.h"
+#include "RenderUtil.h"
+
+void AmbientOcclusionEffect::init() {
+    switchToResourcesParentIfRequired();
+    
+    _program = new ProgramObject();
+    _program->addShaderFromSourceFile(QGLShader::Fragment, "resources/shaders/ambient_occlusion.frag");
+    _program->link();
+    
+    _nearLocation = _program->uniformLocation("near");
+    _farLocation = _program->uniformLocation("far");
+    _leftBottomLocation = _program->uniformLocation("leftBottom");
+    _rightTopLocation = _program->uniformLocation("rightTop");
+    
+    _program->bind();
+    _program->setUniformValue("depthTexture", 0);
+    _program->release();
+}
 
 void AmbientOcclusionEffect::render() {
+    glPushMatrix();
+    glLoadIdentity();
     
+    glMatrixMode(GL_PROJECTION);
+    glPushMatrix();
+    glLoadIdentity();
+    
+    glDisable(GL_BLEND);
+    //glBlendFuncSeparate(GL_ZERO, GL_SRC_COLOR, GL_ZERO, GL_ONE);
+    glDisable(GL_DEPTH_TEST);
+    glDepthMask(GL_FALSE);
+    
+    glBindTexture(GL_TEXTURE_2D, Application::getInstance()->getTextureCache()->getPrimaryDepthTextureID());
+    
+    float left, right, bottom, top, nearVal, farVal;
+    glm::vec4 nearClipPlane, farClipPlane;
+    Application::getInstance()->getViewFrustum()->computeOffAxisFrustum(
+        left, right, bottom, top, nearVal, farVal, nearClipPlane, farClipPlane);
+    
+    _program->bind();
+    _program->setUniformValue(_nearLocation, nearVal);
+    _program->setUniformValue(_farLocation, farVal);
+    _program->setUniformValue(_leftBottomLocation, left, bottom);
+    _program->setUniformValue(_rightTopLocation, right, top);
+    
+    renderFullscreenQuad();
+    
+    _program->release();
+    
+    glPopMatrix();
+    
+    glMatrixMode(GL_MODELVIEW);
+    glPopMatrix();
+       
+    glEnable(GL_BLEND);
+    //glBlendFuncSeparate(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA, GL_CONSTANT_ALPHA, GL_ONE);
+    glEnable(GL_DEPTH_TEST);
+    glDepthMask(GL_TRUE);
+    glBindTexture(GL_TEXTURE_2D, 0);
 }
diff --git a/interface/src/renderer/AmbientOcclusionEffect.h b/interface/src/renderer/AmbientOcclusionEffect.h
index f8e4be4edc..8fba351827 100644
--- a/interface/src/renderer/AmbientOcclusionEffect.h
+++ b/interface/src/renderer/AmbientOcclusionEffect.h
@@ -9,14 +9,23 @@
 #ifndef __interface__AmbientOcclusionEffect__
 #define __interface__AmbientOcclusionEffect__
 
-#include "InterfaceConfig.h"
-
 class ProgramObject;
 
+/// A screen space ambient occlusion effect.
 class AmbientOcclusionEffect {
 public:
     
+    void init();
+    
     void render();
+    
+private:
+
+    ProgramObject* _program;
+    int _nearLocation;
+    int _farLocation;
+    int _leftBottomLocation;
+    int _rightTopLocation;
 };
 
 #endif /* defined(__interface__AmbientOcclusionEffect__) */
diff --git a/interface/src/renderer/GlowEffect.cpp b/interface/src/renderer/GlowEffect.cpp
index ce069bc20b..35d1777be3 100644
--- a/interface/src/renderer/GlowEffect.cpp
+++ b/interface/src/renderer/GlowEffect.cpp
@@ -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;
 };

From b41fa1e03ce5045fa13b98f329d6b0b2e0112457 Mon Sep 17 00:00:00 2001
From: Andrzej Kapolka <drzej.k@gmail.com>
Date: Fri, 16 Aug 2013 17:26:47 -0700
Subject: [PATCH 6/8] Basic ambient occlusion effect up and running; needs
 tweaking and optimization.

---
 .../resources/shaders/ambient_occlusion.frag  |  42 ++++--
 .../resources/shaders/ambient_occlusion.vert  |  14 ++
 .../resources/shaders/occlusion_blur.frag     |  25 ++++
 .../src/renderer/AmbientOcclusionEffect.cpp   | 126 +++++++++++++-----
 .../src/renderer/AmbientOcclusionEffect.h     |   9 +-
 interface/src/renderer/GlowEffect.cpp         |   2 +-
 6 files changed, 177 insertions(+), 41 deletions(-)
 create mode 100644 interface/resources/shaders/ambient_occlusion.vert
 create mode 100644 interface/resources/shaders/occlusion_blur.frag

diff --git a/interface/resources/shaders/ambient_occlusion.frag b/interface/resources/shaders/ambient_occlusion.frag
index b01f7f2db7..b59c87d797 100644
--- a/interface/resources/shaders/ambient_occlusion.frag
+++ b/interface/resources/shaders/ambient_occlusion.frag
@@ -11,6 +11,13 @@
 // 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;
 
@@ -23,20 +30,37 @@ 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 = (far * near) / (texture2D(depthTexture, texCoord).r * (far - near) - far);
+    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) {
-    float ds = dFdx(gl_TexCoord[0].s);
-    float dt = dFdy(gl_TexCoord[0].t);
+    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);
-    vec3 left = texCoordToViewSpace(gl_TexCoord[0].st - vec2(-ds, 0.0)) - center;
-    vec3 right = texCoordToViewSpace(gl_TexCoord[0].st - vec2(ds, 0.0)) - center;
-    vec3 up = texCoordToViewSpace(gl_TexCoord[0].st - vec2(0.0, dt)) - center;
-    vec3 down = texCoordToViewSpace(gl_TexCoord[0].st - vec2(0.0, -dt)) - center;
-    float occlusion = 0.5 - (left.z / length(left) + right.z / length(right) + up.z / length(up) + down.z / length(down)) / 8.0;
-    gl_FragColor = vec4(occlusion, occlusion, occlusion, 0.0);
+    
+    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/renderer/AmbientOcclusionEffect.cpp b/interface/src/renderer/AmbientOcclusionEffect.cpp
index 8719350ec8..83ed2fdbec 100644
--- a/interface/src/renderer/AmbientOcclusionEffect.cpp
+++ b/interface/src/renderer/AmbientOcclusionEffect.cpp
@@ -6,6 +6,13 @@
 //  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"
@@ -14,61 +21,120 @@
 #include "ProgramObject.h"
 #include "RenderUtil.h"
 
+const int ROTATION_WIDTH = 4;
+const int ROTATION_HEIGHT = 4;
+    
 void AmbientOcclusionEffect::init() {
     switchToResourcesParentIfRequired();
     
-    _program = new ProgramObject();
-    _program->addShaderFromSourceFile(QGLShader::Fragment, "resources/shaders/ambient_occlusion.frag");
-    _program->link();
+    _occlusionProgram = new ProgramObject();
+    _occlusionProgram->addShaderFromSourceFile(QGLShader::Vertex, "resources/shaders/ambient_occlusion.vert");
+    _occlusionProgram->addShaderFromSourceFile(QGLShader::Fragment, "resources/shaders/ambient_occlusion.frag");
+    _occlusionProgram->link();
     
-    _nearLocation = _program->uniformLocation("near");
-    _farLocation = _program->uniformLocation("far");
-    _leftBottomLocation = _program->uniformLocation("leftBottom");
-    _rightTopLocation = _program->uniformLocation("rightTop");
+    _blurProgram = new ProgramObject();
+    _blurProgram->addShaderFromSourceFile(QGLShader::Vertex, "resources/shaders/ambient_occlusion.vert");
+    _blurProgram->addShaderFromSourceFile(QGLShader::Fragment, "resources/shaders/occlusion_blur.frag");
+    _blurProgram->link();
     
-    _program->bind();
-    _program->setUniformValue("depthTexture", 0);
-    _program->release();
+    _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++) {
+        glm::vec3 vector = glm::ballRand(1.0f);
+        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() {
-    glPushMatrix();
-    glLoadIdentity();
-    
-    glMatrixMode(GL_PROJECTION);
-    glPushMatrix();
-    glLoadIdentity();
-    
     glDisable(GL_BLEND);
-    //glBlendFuncSeparate(GL_ZERO, GL_SRC_COLOR, GL_ZERO, GL_ONE);
     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);
     
-    _program->bind();
-    _program->setUniformValue(_nearLocation, nearVal);
-    _program->setUniformValue(_farLocation, farVal);
-    _program->setUniformValue(_leftBottomLocation, left, bottom);
-    _program->setUniformValue(_rightTopLocation, right, top);
+    _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();
     
-    _program->release();
+    _occlusionProgram->release();
     
-    glPopMatrix();
+    secondaryFBO->release();
+    
+    glBindTexture(GL_TEXTURE_2D, 0);
+    glActiveTexture(GL_TEXTURE0);
+    
+    // now render secondary to primary with 4x4 blur
+    Application::getInstance()->getTextureCache()->getPrimaryFramebufferObject()->bind();
     
-    glMatrixMode(GL_MODELVIEW);
-    glPopMatrix();
-       
     glEnable(GL_BLEND);
-    //glBlendFuncSeparate(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA, GL_CONSTANT_ALPHA, GL_ONE);
+    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);
-    glBindTexture(GL_TEXTURE_2D, 0);
 }
diff --git a/interface/src/renderer/AmbientOcclusionEffect.h b/interface/src/renderer/AmbientOcclusionEffect.h
index 8fba351827..4891a6eb2c 100644
--- a/interface/src/renderer/AmbientOcclusionEffect.h
+++ b/interface/src/renderer/AmbientOcclusionEffect.h
@@ -9,6 +9,8 @@
 #ifndef __interface__AmbientOcclusionEffect__
 #define __interface__AmbientOcclusionEffect__
 
+#include "InterfaceConfig.h"
+
 class ProgramObject;
 
 /// A screen space ambient occlusion effect.
@@ -21,11 +23,16 @@ public:
     
 private:
 
-    ProgramObject* _program;
+    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 35d1777be3..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>

From e7dab88d69269ac7a778543676a436eae146ba73 Mon Sep 17 00:00:00 2001
From: Andrzej Kapolka <drzej.k@gmail.com>
Date: Mon, 19 Aug 2013 10:32:56 -0700
Subject: [PATCH 7/8] Square vector lengths to bunch them up towards the
 center, add a minimum length, include the URL of the SSAO tutorial.

---
 interface/src/renderer/AmbientOcclusionEffect.cpp | 7 ++++++-
 interface/src/renderer/AmbientOcclusionEffect.h   | 3 ++-
 2 files changed, 8 insertions(+), 2 deletions(-)

diff --git a/interface/src/renderer/AmbientOcclusionEffect.cpp b/interface/src/renderer/AmbientOcclusionEffect.cpp
index 83ed2fdbec..ff86615b26 100644
--- a/interface/src/renderer/AmbientOcclusionEffect.cpp
+++ b/interface/src/renderer/AmbientOcclusionEffect.cpp
@@ -45,7 +45,12 @@ void AmbientOcclusionEffect::init() {
     const int SAMPLE_KERNEL_SIZE = 16;
     QVector3D sampleKernel[SAMPLE_KERNEL_SIZE];
     for (int i = 0; i < SAMPLE_KERNEL_SIZE; i++) {
-        glm::vec3 vector = glm::ballRand(1.0f);
+        // 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);
     }
     
diff --git a/interface/src/renderer/AmbientOcclusionEffect.h b/interface/src/renderer/AmbientOcclusionEffect.h
index 4891a6eb2c..d41bb65381 100644
--- a/interface/src/renderer/AmbientOcclusionEffect.h
+++ b/interface/src/renderer/AmbientOcclusionEffect.h
@@ -13,7 +13,8 @@
 
 class ProgramObject;
 
-/// A screen space ambient occlusion effect.
+/// 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:
     

From dec4a4c4222bc9d26ec67a60604494ab9fa1f9f9 Mon Sep 17 00:00:00 2001
From: Andrzej Kapolka <drzej.k@gmail.com>
Date: Mon, 19 Aug 2013 11:45:43 -0700
Subject: [PATCH 8/8] Added toggle for ambient occlusion (defaults to off).

---
 interface/src/Application.cpp | 5 ++++-
 interface/src/Menu.cpp        | 1 +
 interface/src/Menu.h          | 1 +
 3 files changed, 6 insertions(+), 1 deletion(-)

diff --git a/interface/src/Application.cpp b/interface/src/Application.cpp
index dc7fd14d49..47248ecaeb 100644
--- a/interface/src/Application.cpp
+++ b/interface/src/Application.cpp
@@ -2378,7 +2378,10 @@ void Application::displaySide(Camera& whichCamera) {
         renderWorldBox();
     }
     
-    _ambientOcclusionEffect.render();
+    // 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)) {
diff --git a/interface/src/Menu.cpp b/interface/src/Menu.cpp
index 56317b86a2..d49d322f34 100644
--- a/interface/src/Menu.cpp
+++ b/interface/src/Menu.cpp
@@ -157,6 +157,7 @@ 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 2d871fd890..e7ecbcaf79 100644
--- a/interface/src/Menu.h
+++ b/interface/src/Menu.h
@@ -107,6 +107,7 @@ private:
 
 namespace MenuOption {
     
+    const QString AmbientOcclusion = "Ambient Occlusion";
     const QString Avatars = "Avatars";
     const QString AvatarAsBalls = "Avatar as Balls";
     const QString Atmosphere = "Atmosphere";