Started on C++ side of SSAO effect.

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);
 }

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);
     

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;
     

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);    
+}

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__) */