#include "DeferredRenderer.h"
#include "FrameBufferObject.h"
#include "RenderState.h"
#include "SampleGenerator.h"
#include "Vector3.h"
#include "Camera.h"
#include "shaderenv.h"
#include "Halton.h"
#include "ShadowMapping.h"
#include "Light.h"
#include "ResourceManager.h"


#include <IL/il.h>
#include <assert.h>


#ifdef _CRT_SET
	#define _CRTDBG_MAP_ALLOC
	#include <stdlib.h>
	#include <crtdbg.h>

	// redefine new operator
	#define DEBUG_NEW new(_NORMAL_BLOCK, __FILE__, __LINE__)
	#define new DEBUG_NEW
#endif


using namespace std;


static void startil()
{
	ilInit();
	assert(ilGetError() == IL_NO_ERROR);
}


static void stopil()
{
	ilShutDown();
	assert(ilGetError() == IL_NO_ERROR);
}

namespace CHCDemoEngine
{

static ShaderProgram *sCgSsaoProgram = NULL;
static ShaderProgram *sCgGiProgram = NULL;

static ShaderProgram *sCgDeferredProgram = NULL;
static ShaderProgram *sCgAntiAliasingProgram = NULL;
static ShaderProgram *sCgDeferredShadowProgram = NULL;

static ShaderProgram *sCgCombineSsaoProgram = NULL;
static ShaderProgram *sCgCombineIllumProgram = NULL;
static ShaderProgram *sCgLogLumProgram = NULL;
static ShaderProgram *sCgToneProgram = NULL;
static ShaderProgram *sCgDownSampleProgram = NULL;

ShaderContainer DeferredRenderer::sShaders;

static GLuint noiseTex = 0;

// ssao random spherical samples
static Sample2 samples2[NUM_SAMPLES];
// number of pcf tabs
Sample2 pcfSamples[NUM_PCF_TABS];


int DeferredRenderer::colorBufferIdx = 0;



static float GaussianDistribution(float x, float y, float rho)
{
    float g = 1.0f / sqrtf(2.0f * M_PI * rho * rho);
    g *= expf( -(x*x + y*y) / (2.0f * rho * rho));

    return g;
}


static void PrintGLerror(char *msg)
{
	GLenum errCode;
	const GLubyte *errStr;
	
	if ((errCode = glGetError()) != GL_NO_ERROR) 
	{
		errStr = gluErrorString(errCode);
		fprintf(stderr,"OpenGL ERROR: %s: %s\n", errStr, msg);
	}
}

static void ComputeSampleOffsets(float *sampleOffsets, int w, int h)
{
	/*
	const float xoffs = 0.5f / w;
	const float yoffs = 0.5f / h;

	sampleOffsets[0] =  xoffs; sampleOffsets[1] =  yoffs;
	sampleOffsets[2] =  xoffs; sampleOffsets[3] = -yoffs;
	sampleOffsets[4] = -xoffs; sampleOffsets[5] = -yoffs;
	sampleOffsets[6] = -xoffs; sampleOffsets[7] =  yoffs;
	*/
	//const float xoffs = .5f / w;
	//const float yoffs = .5f / h;
	
	const float xoffs = 1.0f / w;
	const float yoffs = 1.0f / h;

	int idx  = 0;

	for (int x = -1; x <= 1; ++ x)
	{
		for (int y = -1; y <= 1; ++ y)
		{
			sampleOffsets[idx + 0] = x * xoffs;
			sampleOffsets[idx + 1] = y * yoffs;

			idx += 2;
		}
	}
}


void DeferredRenderer::DrawQuad(ShaderProgram *p)
{
	Vector3 tl, tr, bl, br;
	ComputeViewVectors(tl, tr, bl, br);

	p->Bind();

	// note: slightly larger texture could hide ambient occlusion error on border but costs resolution
	const float offs = 0.5f;
	
	glBegin(GL_QUADS);

	glTexCoord2f(0, 0); glMultiTexCoord3fARB(GL_TEXTURE1_ARB, bl.x, bl.y, bl.z); glVertex3f(-offs, -offs, -0.5f);
	glTexCoord2f(1, 0); glMultiTexCoord3fARB(GL_TEXTURE1_ARB, br.x, br.y, br.z); glVertex3f( offs, -offs, -0.5f);
	glTexCoord2f(1, 1); glMultiTexCoord3fARB(GL_TEXTURE1_ARB, tr.x, tr.y, tr.z); glVertex3f( offs,  offs, -0.5f);
	glTexCoord2f(0, 1); glMultiTexCoord3fARB(GL_TEXTURE1_ARB, tl.x, tl.y, tl.z); glVertex3f(-offs,  offs, -0.5f);

	glEnd();
}


/** Generate poisson disc distributed sample points on the unit disc
*/
static void GenerateSamples(int sampling)
{
	switch (sampling)
	{
	case DeferredRenderer::SAMPLING_POISSON:
		{
			PoissonDiscSampleGenerator2 poisson(NUM_SAMPLES, 1.0f);
			poisson.Generate((float *)samples2);
		}
		break;
	case DeferredRenderer::SAMPLING_QUADRATIC:
		{
			QuadraticDiscSampleGenerator2 g(NUM_SAMPLES, 1.0f);
			g.Generate((float *)samples2);
		}
		break;
	default: // SAMPLING_DEFAULT
		{
			RandomSampleGenerator2 g(NUM_SAMPLES, 1.0f);
			g.Generate((float *)samples2);
		}
	}
}


static void CreateNoiseTex2D(int w, int h)
{
	//GLubyte *randomNormals = new GLubyte[mWidth * mHeight * 3];
	float *randomNormals = new float[w * h * 3];

	static HaltonSequence halton;
	float r[2];

	for (int i = 0; i < w * h * 3; i += 3)
	{
		// create random samples on a circle
		r[0] = RandomValue(0, 1);
		//halton.GetNext(1, r);

		const float theta = 2.0f * acos(sqrt(1.0f - r[0]));
		
		randomNormals[i + 0] = cos(theta);
		randomNormals[i + 1] = sin(theta);
		randomNormals[i + 2] = 0;
	}

	glEnable(GL_TEXTURE_2D);
	glGenTextures(1, &noiseTex);
	glBindTexture(GL_TEXTURE_2D, noiseTex);
		
	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);
	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);

	glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA16F_ARB, w, h, 0, GL_RGB, GL_FLOAT, randomNormals);

	glBindTexture(GL_TEXTURE_2D, 0);
	glDisable(GL_TEXTURE_2D);

	delete [] randomNormals;

	cout << "created noise texture" << endl;

	PrintGLerror("noisetexture");
}


static void InitBuffer(FrameBufferObject *fbo, int index)
{
	// read the second buffer, write to the first buffer
	fbo->Bind();
	glDrawBuffers(1, mrt + index);

	//glClearColor(0.0f, 0.0f, 0.0f, 1.0f);
	glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);

	glEnd();

	FrameBufferObject::Release();
}


DeferredRenderer::DeferredRenderer(int w, int h, Camera *cam, float scaleFactor):
mWidth(w), mHeight(h), 
mCamera(cam),
mUseTemporalCoherence(true),
mRegenerateSamples(true),
mSamplingMethod(SAMPLING_POISSON),
mShadingMethod(DEFAULT),
mIllumFboIndex(0)
{
	// create noise texture for ssao
	CreateNoiseTex2D(w, h);


	///////////
	//-- the flip-flop fbos

	mIllumFbo = new FrameBufferObject(w / 2, h / 2, FrameBufferObject::DEPTH_NONE);
	mFBOs.push_back(mIllumFbo);

	for (int i = 0; i < 4; ++ i)
	{
		mIllumFbo->AddColorBuffer(ColorBufferObject::RGB_FLOAT_32, ColorBufferObject::WRAP_CLAMP_TO_EDGE, ColorBufferObject::FILTER_LINEAR);
		InitBuffer(mIllumFbo, i);
	}

	mDownSampleFbo = new FrameBufferObject(w / 2, h / 2, FrameBufferObject::DEPTH_NONE);
	mDownSampleFbo->AddColorBuffer(ColorBufferObject::RGBA_FLOAT_32, ColorBufferObject::WRAP_CLAMP_TO_EDGE, ColorBufferObject::FILTER_LINEAR);
	mDownSampleFbo->AddColorBuffer(ColorBufferObject::RGB_FLOAT_16, ColorBufferObject::WRAP_CLAMP_TO_EDGE, ColorBufferObject::FILTER_LINEAR);

	mFBOs.push_back(mDownSampleFbo);

	InitCg();
}


DeferredRenderer::~DeferredRenderer() 
{
	CLEAR_CONTAINER(mFBOs);
	glDeleteTextures(1, &noiseTex);
}


void DeferredRenderer::SetUseTemporalCoherence(bool temporal)
{
	mUseTemporalCoherence = temporal;
}



void DeferredRenderer::InitCg()
{	
	ResourceManager *rm = ResourceManager::GetSingleton();

	sCgDeferredProgram = rm->CreateFragmentProgram("deferred", "main");
	sCgDeferredShadowProgram = rm->CreateFragmentProgram("deferred", "main_shadow");
	sCgSsaoProgram = rm->CreateFragmentProgram("ssao", "main");
	sCgGiProgram = rm->CreateFragmentProgram("globillum", "main");
	sCgCombineIllumProgram = rm->CreateFragmentProgram("globillum", "combine");
	sCgCombineSsaoProgram = rm->CreateFragmentProgram("ssao", "combine");
	sCgAntiAliasingProgram = rm->CreateFragmentProgram("antialiasing", "main");
	sCgToneProgram = rm->CreateFragmentProgram("tonemap", "ToneMap");
	sCgDownSampleProgram = rm->CreateFragmentProgram("tonemap", "DownSample");
	sCgToneProgram = rm->CreateFragmentProgram("tonemap", "ToneMap");
	sCgLogLumProgram = rm->CreateFragmentProgram("tonemap", "CalcAvgLogLum");

	int i;

	i = 0;

	sCgSsaoProgram->AddParameter("colors", i ++);
	sCgSsaoProgram->AddParameter("normals", i ++);
	sCgSsaoProgram->AddParameter("oldTex", i ++);
	sCgSsaoProgram->AddParameter("noise", i ++);
	sCgSsaoProgram->AddParameter("eyePos", i ++);
	sCgSsaoProgram->AddParameter("temporalCoherence", i ++);
	sCgSsaoProgram->AddParameter("samples", i ++);
	sCgSsaoProgram->AddParameter("bl", i ++);
	sCgSsaoProgram->AddParameter("br", i ++);
	sCgSsaoProgram->AddParameter("tl", i ++);
	sCgSsaoProgram->AddParameter("tr", i ++);
	sCgSsaoProgram->AddParameter("modelViewProj", i ++);
	sCgSsaoProgram->AddParameter("oldModelViewProj", i ++);

	i = 0;

	sCgGiProgram->AddParameter("colors", i ++);
	sCgGiProgram->AddParameter("normals", i ++);
	sCgGiProgram->AddParameter("noise", i ++);
	sCgGiProgram->AddParameter("oldSsaoTex", i ++);
	sCgGiProgram->AddParameter("oldIllumTex", i ++);
	sCgGiProgram->AddParameter("eyePos", i ++);
	sCgGiProgram->AddParameter("temporalCoherence", i ++);
	sCgGiProgram->AddParameter("samples", i ++);
	sCgGiProgram->AddParameter("bl", i ++);
	sCgGiProgram->AddParameter("br", i ++);
	sCgGiProgram->AddParameter("tl", i ++);
	sCgGiProgram->AddParameter("tr", i ++);
	sCgGiProgram->AddParameter("oldModelViewProj", i ++);
	sCgGiProgram->AddParameter("modelViewProj", i ++);

	sCgAntiAliasingProgram->AddParameter("colors", 0);
	sCgAntiAliasingProgram->AddParameter("normals", 1);

	sCgDeferredProgram->AddParameter("colors", 0);
	sCgDeferredProgram->AddParameter("normals", 1);
	sCgDeferredProgram->AddParameter("lightDir", 2);

	sCgLogLumProgram->AddParameter("colors", 0);
	
	sCgToneProgram->AddParameter("colors", 0);
	sCgToneProgram->AddParameter("imageKey", 1);
	sCgToneProgram->AddParameter("whiteLum", 2);
	sCgToneProgram->AddParameter("middleGrey", 3);

	sCgDownSampleProgram->AddParameter("colors", 0);
	sCgDownSampleProgram->AddParameter("downSampleOffs", 1);

	sCgDeferredShadowProgram->AddParameter("colors", 0);
	sCgDeferredShadowProgram->AddParameter("normals", 1);
  	sCgDeferredShadowProgram->AddParameter("shadowMap", 2);
  	sCgDeferredShadowProgram->AddParameter("noise", 3);
 	sCgDeferredShadowProgram->AddParameter("shadowMatrix", 4);
  	sCgDeferredShadowProgram->AddParameter("sampleWidth", 5);
	sCgDeferredShadowProgram->AddParameter("lightDir", 6);
 	sCgDeferredShadowProgram->AddParameter("eyePos", 7);
	sCgDeferredShadowProgram->AddParameter("samples", 8);
	sCgDeferredShadowProgram->AddParameter("weights", 9);

	sCgCombineIllumProgram->AddParameter("colors", 0);
	sCgCombineIllumProgram->AddParameter("ssaoTex", 1);
	sCgCombineIllumProgram->AddParameter("illumTex", 2);

	sCgCombineSsaoProgram->AddParameter("colors", 0);
	sCgCombineSsaoProgram->AddParameter("ssaoTex", 1);
	sCgCombineSsaoProgram->AddParameter("filterOffs", 2);
	sCgCombineSsaoProgram->AddParameter("filterWeights", 3);


	float filterWeights[NUM_PCF_TABS];
	PoissonDiscSampleGenerator2 poisson(NUM_PCF_TABS, 1.0f);
	poisson.Generate((float *)pcfSamples);

	for (int i = 0; i < NUM_PCF_TABS; ++ i)
	{
		filterWeights[i] = GaussianDistribution(pcfSamples[i].x, pcfSamples[i].y, 1.0f);
	}

	sCgDeferredShadowProgram->SetArray2f(8, (float *)pcfSamples, NUM_PCF_TABS);
	sCgDeferredShadowProgram->SetArray1f(9, (float *)filterWeights, NUM_PCF_TABS);

	PrintGLerror("init");
}


void DeferredRenderer::Render(FrameBufferObject *fbo, 
							  const Matrix4x4 &oldProjViewMatrix,
							  const Matrix4x4 &projViewMatrix,
							  float tempCohFactor,
							  DirectionalLight *light,
							  bool useToneMapping,
							  ShadowMap *shadowMap
							  )
{
	// switch roles of old and new fbo
	// the algorihm uses two input fbos, where the one
	// contais the color buffer from the last frame, 
	// the other one will be written

	mIllumFboIndex = 2 - mIllumFboIndex;
	

	ResourceManager::GetSingleton()->EnableFragmentProfile();

	glDisable(GL_ALPHA_TEST);
	glDisable(GL_TEXTURE_2D);
	glDisable(GL_LIGHTING);
	glDisable(GL_BLEND);
	glDisable(GL_DEPTH_TEST);

	glPushAttrib(GL_VIEWPORT_BIT);
	glViewport(0, 0, mWidth, mHeight);

	glMatrixMode(GL_PROJECTION);
	glPushMatrix();
	glLoadIdentity();

	const float offs = 0.5f;
	glOrtho(-offs, offs, -offs, offs, 0, 1);

	glMatrixMode(GL_MODELVIEW);
	glPushMatrix();
	glLoadIdentity();

	if (shadowMap)
		FirstPassShadow(fbo, light, shadowMap);
	else
		FirstPass(fbo, light);

	switch (mShadingMethod)
	{
	case SSAO:
		// downsample fbo buffers for colors, normals
		DownSample(fbo, colorBufferIdx, mDownSampleFbo, 0);
		DownSample(fbo, 1, mDownSampleFbo, 1);

		ComputeSsao(fbo, tempCohFactor, projViewMatrix, oldProjViewMatrix);
		CombineSsao(fbo);
		break;
	case GI:
		// downsample fbo buffers for colors, normals
		DownSample(fbo, colorBufferIdx, mDownSampleFbo, 0);
		DownSample(fbo, 1, mDownSampleFbo, 1);

		ComputeGlobIllum(fbo, tempCohFactor, projViewMatrix, oldProjViewMatrix);
		CombineIllum(fbo);
		break;
	default: // DEFAULT
		// do nothing: standard deferred shading
		break;
	}

	if (useToneMapping)
	{
		float imageKey, whiteLum, middleGrey;

		ComputeToneParameters(fbo, light, imageKey, whiteLum, middleGrey);
		ToneMap(fbo, imageKey, whiteLum, middleGrey);
	}

	AntiAliasing(fbo, light);

	glEnable(GL_LIGHTING);
	glDisable(GL_TEXTURE_2D);

	glMatrixMode(GL_PROJECTION);
	glPopMatrix();

	glMatrixMode(GL_MODELVIEW);
	glPopMatrix();

	glPopAttrib();

	FrameBufferObject::Release();
	ResourceManager::GetSingleton()->DisableFragmentProfile();
}


void DeferredRenderer::ComputeSsao(FrameBufferObject *fbo, 
								   float tempCohFactor,
								   const Matrix4x4 &projViewMatrix,
								   const Matrix4x4 &oldProjViewMatrix
								   )
{
#if 0
	GLuint colorsTex = fbo->GetColorBuffer(colorBufferIdx)->GetTexture();
	GLuint normalsTex = fbo->GetColorBuffer(1)->GetTexture();
#else
	GLuint colorsTex = mDownSampleFbo->GetColorBuffer(0)->GetTexture();
	GLuint normalsTex = mDownSampleFbo->GetColorBuffer(1)->GetTexture();
#endif

	GLuint oldTex = mIllumFbo->GetColorBuffer(2 - mIllumFboIndex)->GetTexture();

	glPushAttrib(GL_VIEWPORT_BIT);
	glViewport(0, 0, mIllumFbo->GetWidth(), mIllumFbo->GetHeight());

	// read the second buffer, write to the first buffer
	mIllumFbo->Bind();
	glDrawBuffers(1, mrt + mIllumFboIndex);

	sCgSsaoProgram->SetTexture(0, colorsTex);
	sCgSsaoProgram->SetTexture(1, normalsTex);
	sCgSsaoProgram->SetTexture(2, oldTex);
	sCgSsaoProgram->SetTexture(3, noiseTex);

	const Vector3 pos = mCamera->GetPosition();
	sCgSsaoProgram->SetValue3f(4, pos.x, pos.y, pos.z);

	sCgSsaoProgram->SetValue1f(5, (mUseTemporalCoherence && !mRegenerateSamples) ? tempCohFactor : 0);
	
	if (mUseTemporalCoherence || mRegenerateSamples)
	{
		mRegenerateSamples = false;

		// q: should we generate new samples or only rotate the old ones?
		// in the first case, the sample patterns look nicer, but the kernel
		// needs longer to converge
		GenerateSamples(mSamplingMethod); 
		sCgSsaoProgram->SetArray2f(6, (float *)samples2, NUM_SAMPLES);
	}

	Vector3 tl, tr, bl, br;
	ComputeViewVectors(tl, tr, bl, br);

	sCgSsaoProgram->SetValue3f(7, bl.x, bl.y, bl.z);
	sCgSsaoProgram->SetValue3f(8, br.x, br.y, br.z);
	sCgSsaoProgram->SetValue3f(9, tl.x, tl.y, tl.z);
	sCgSsaoProgram->SetValue3f(10, tr.x, tr.y, tr.z);

	sCgSsaoProgram->SetMatrix(11, projViewMatrix);
	sCgSsaoProgram->SetMatrix(12, oldProjViewMatrix);


	DrawQuad(sCgSsaoProgram);

	glPopAttrib();

	PrintGLerror("ssao first pass");
}


void DeferredRenderer::ComputeViewVectors(Vector3 &tl, Vector3 &tr, Vector3 &bl, Vector3 &br)
{
	Vector3 ftl, ftr, fbl, fbr, ntl, ntr, nbl, nbr;

	mCamera->ComputePoints(ftl, ftr, fbl, fbr, ntl, ntr, nbl, nbr);

	bl = Normalize(nbl - fbl);
	br = Normalize(nbr - fbr);
	tl = Normalize(ntl - ftl);
	tr = Normalize(ntr - ftr);
}


static void SetVertex(float x, float y, float x_offs, float y_offs)
{
	glMultiTexCoord2fARB(GL_TEXTURE0_ARB, x, y); // center
	glMultiTexCoord2fARB(GL_TEXTURE1_ARB, x - x_offs, y + y_offs); // left top
	glMultiTexCoord2fARB(GL_TEXTURE2_ARB, x + x_offs, y - y_offs); // right bottom
	glMultiTexCoord2fARB(GL_TEXTURE3_ARB, x + x_offs, y + y_offs); // right top
	glMultiTexCoord2fARB(GL_TEXTURE4_ARB, x - x_offs, y - y_offs); // left bottom

	glMultiTexCoord4fARB(GL_TEXTURE5_ARB, x - x_offs, y, x + x_offs, y); // left right
	glMultiTexCoord4fARB(GL_TEXTURE6_ARB, x, y + y_offs, x, y - y_offs); // top bottom

	glVertex3f(x - 0.5f, y - 0.5f, -0.5f);
}


void DeferredRenderer::AntiAliasing(FrameBufferObject *fbo, DirectionalLight *light)
{
	FrameBufferObject::Release();

	ColorBufferObject *colorBuffer = fbo->GetColorBuffer(colorBufferIdx);

	GLuint colorsTex = colorBuffer->GetTexture();
	GLuint normalsTex = fbo->GetColorBuffer(2)->GetTexture();

	sCgAntiAliasingProgram->SetTexture(0, colorsTex);
	sCgAntiAliasingProgram->SetTexture(1, normalsTex);

	sCgAntiAliasingProgram->Bind();

	glColor3f(1.0f, 1.0f, 1.0f);

	glBegin(GL_QUADS);

	// the neighbouring texels
	float x_offs = 1.0f / mWidth;
	float y_offs = 1.0f / mHeight;

	SetVertex(0, 0, x_offs, y_offs);
	SetVertex(1, 0, x_offs, y_offs);
	SetVertex(1, 1, x_offs, y_offs);
	SetVertex(0, 1, x_offs, y_offs);

	glEnd();

	PrintGLerror("antialiasing");
}


void DeferredRenderer::FirstPass(FrameBufferObject *fbo, DirectionalLight *light)
{
	GLuint colorsTex = fbo->GetColorBuffer(colorBufferIdx)->GetTexture();
	GLuint normalsTex = fbo->GetColorBuffer(1)->GetTexture();
	GLuint positionsTex = fbo->GetColorBuffer(2)->GetTexture();

	fbo->Bind();

	colorBufferIdx = 3 - colorBufferIdx;
	glDrawBuffers(1, mrt + colorBufferIdx);

	const Vector3 lightDir = -light->GetDirection();

	sCgDeferredProgram->SetTexture(0, colorsTex);
	sCgDeferredProgram->SetTexture(1, normalsTex);
	sCgDeferredProgram->SetValue3f(2, lightDir.x, lightDir.y, lightDir.z);
	
	DrawQuad(sCgDeferredProgram);

	PrintGLerror("deferred shading");
}


void DeferredRenderer::ComputeGlobIllum(FrameBufferObject *fbo, 
										float tempCohFactor,
										const Matrix4x4 &projViewMatrix,
										const Matrix4x4 &oldProjViewMatrix)
{
#if 0
	GLuint colorsTex = fbo->GetColorBuffer(colorBufferIdx)->GetTexture();
	GLuint normalsTex = fbo->GetColorBuffer(1)->GetTexture();
#else
	GLuint colorsTex = mDownSampleFbo->GetColorBuffer(0)->GetTexture();
	GLuint normalsTex = mDownSampleFbo->GetColorBuffer(1)->GetTexture();
#endif

	glPushAttrib(GL_VIEWPORT_BIT);
	glViewport(0, 0, mIllumFbo->GetWidth(), mIllumFbo->GetHeight());

	// read the second buffer, write to the first buffer
	mIllumFbo->Bind();

	glDrawBuffers(2, mrt + mIllumFboIndex);

	GLuint oldSsaoTex = mIllumFbo->GetColorBuffer(2 - mIllumFboIndex)->GetTexture();
	GLuint oldIllumTex = mIllumFbo->GetColorBuffer(2 - mIllumFboIndex + 1)->GetTexture();
	

	sCgGiProgram->SetTexture(0, colorsTex);
	sCgGiProgram->SetTexture(1, normalsTex);
	sCgGiProgram->SetTexture(2, noiseTex);
	sCgGiProgram->SetTexture(3, oldSsaoTex);
	sCgGiProgram->SetTexture(4, oldIllumTex);

	const Vector3 pos = mCamera->GetPosition();
	sCgGiProgram->SetValue3f(5, pos.x, pos.y, pos.z);


	sCgGiProgram->SetValue1f(6, 
		(mUseTemporalCoherence && !mRegenerateSamples) ? tempCohFactor : 0);

	if (mUseTemporalCoherence || mRegenerateSamples)
	{
		mRegenerateSamples = false;

		// q: should we generate new samples or only rotate the old ones?
		// in the first case, the sample patterns look nicer, but the kernel
		// needs longer to converge
		GenerateSamples(mSamplingMethod); 

		sCgGiProgram->SetArray2f(7, (float *)samples2, NUM_SAMPLES);
	}


	Vector3 tl, tr, bl, br;
	ComputeViewVectors(tl, tr, bl, br);
	
	sCgGiProgram->SetValue3f(8, bl.x, bl.y, bl.z);
	sCgGiProgram->SetValue3f(9, br.x, br.y, br.z);
	sCgGiProgram->SetValue3f(10, tl.x, tl.y, tl.z);
	sCgGiProgram->SetValue3f(11, tr.x, tr.y, tr.z);

	sCgGiProgram->SetMatrix(12, oldProjViewMatrix);
	sCgGiProgram->SetMatrix(13, projViewMatrix);


	DrawQuad(sCgGiProgram);

	glPopAttrib();

	PrintGLerror("globillum first pass");
}


void DeferredRenderer::CombineIllum(FrameBufferObject *fbo)
{
	GLuint colorsTex = fbo->GetColorBuffer(colorBufferIdx)->GetTexture();

	GLuint ssaoTex = mIllumFbo->GetColorBuffer(mIllumFboIndex)->GetTexture();
	GLuint illumTex = mIllumFbo->GetColorBuffer(mIllumFboIndex + 1)->GetTexture();


	fbo->Bind();

	// overwrite old color texture
	colorBufferIdx = 3 - colorBufferIdx;

	glDrawBuffers(1, mrt + colorBufferIdx);

	sCgCombineIllumProgram->SetTexture(0, colorsTex);
	sCgCombineIllumProgram->SetTexture(1, ssaoTex);
	sCgCombineIllumProgram->SetTexture(2, illumTex);
	
	DrawQuad(sCgCombineIllumProgram);

	PrintGLerror("combine");
}


void DeferredRenderer::CombineSsao(FrameBufferObject *fbo)
{
	fbo->Bind();

	GLuint colorsTex = fbo->GetColorBuffer(colorBufferIdx)->GetTexture();
	GLuint positionsTex = fbo->GetColorBuffer(2)->GetTexture();
	
	GLuint ssaoTex = mIllumFbo->GetColorBuffer(mIllumFboIndex)->GetTexture();

	// overwrite old color texture
	colorBufferIdx = 3 - colorBufferIdx;
	glDrawBuffers(1, mrt + colorBufferIdx);

	float filterOffsets[NUM_DOWNSAMPLES * 2];
	float filterWeights[NUM_DOWNSAMPLES];

	PoissonDiscSampleGenerator2 poisson(NUM_DOWNSAMPLES, 1.0f);
	poisson.Generate((float *)filterOffsets);

	const float xoffs = 2.0f / fbo->GetWidth();
	const float yoffs = 2.0f / fbo->GetHeight();

	for (int i = 0; i < NUM_DOWNSAMPLES; ++ i)
	{
		float x = filterOffsets[2 * i + 0];
		float y = filterOffsets[2 * i + 1];

		filterOffsets[2 * i + 0] *= xoffs;
		filterOffsets[2 * i + 1] *= yoffs;

		filterWeights[i] = GaussianDistribution(x, y, 1.0f);
	}

	
	sCgCombineSsaoProgram->SetTexture(0, colorsTex);
	sCgCombineSsaoProgram->SetTexture(1, ssaoTex);

	sCgCombineSsaoProgram->SetArray2f(2, (float *)filterOffsets, NUM_DOWNSAMPLES);
	sCgCombineSsaoProgram->SetArray1f(3, (float *)filterWeights, NUM_DOWNSAMPLES);
	
	DrawQuad(sCgCombineSsaoProgram);
	
	PrintGLerror("combine ssao");
}


void DeferredRenderer::FirstPassShadow(FrameBufferObject *fbo, 
									   DirectionalLight *light, 
									   ShadowMap *shadowMap)
{
	fbo->Bind();

	GLuint colorsTex = fbo->GetColorBuffer(colorBufferIdx)->GetTexture();
	GLuint normalsTex = fbo->GetColorBuffer(1)->GetTexture();
	GLuint positionsTex = fbo->GetColorBuffer(2)->GetTexture();

	GLuint shadowTex = shadowMap->GetDepthTexture();

	Matrix4x4 shadowMatrix;
	shadowMap->GetTextureMatrix(shadowMatrix);

	colorBufferIdx = 3 - colorBufferIdx;
	glDrawBuffers(1, mrt + colorBufferIdx);

	sCgDeferredShadowProgram->SetTexture(0, colorsTex);
	sCgDeferredShadowProgram->SetTexture(1, normalsTex);
	sCgDeferredShadowProgram->SetTexture(2, shadowTex);
	sCgDeferredShadowProgram->SetTexture(3, noiseTex);

	sCgDeferredShadowProgram->SetMatrix(4, shadowMatrix);

	sCgDeferredShadowProgram->SetValue1f(5, 2.0f / shadowMap->GetSize());

	const Vector3 lightDir = -light->GetDirection();
	sCgDeferredShadowProgram->SetValue3f(6, lightDir.x, lightDir.y, lightDir.z);

	const Vector3 pos = mCamera->GetPosition();
	sCgDeferredShadowProgram->SetValue3f(7, pos.x, pos.y, pos.z);

	DrawQuad(sCgDeferredShadowProgram);

	PrintGLerror("deferred shading + shadows");
}


void DeferredRenderer::SetSamplingMethod(SAMPLING_METHOD s) 
{ 
	if (s != mSamplingMethod)
	{
		mSamplingMethod = s; 
		mRegenerateSamples = true;
	}
}


void DeferredRenderer::SetShadingMethod(SHADING_METHOD s)
{
	if (s != mShadingMethod)
	{
		mShadingMethod = s; 
		mRegenerateSamples = true;
	}
}


void DeferredRenderer::ComputeToneParameters(FrameBufferObject *fbo, 
											 DirectionalLight *light,
											 float &imageKey, 
											 float &whiteLum,
											 float &middleGrey)
{
	// hack: estimate value where sky burns out
	whiteLum = log(WHITE_LUMINANCE);
	
	////////////////////
	//-- linear interpolate brightness key depending on the current sun position

	const float minKey = 0.09f;
	const float maxKey = 0.36f;

	const float lightIntensity = DotProd(-light->GetDirection(), Vector3::UNIT_Z());
	middleGrey = lightIntensity * maxKey + (1.0f - lightIntensity) * minKey;


	//////////
	//-- compute avg loglum

	ColorBufferObject *colorBuffer = fbo->GetColorBuffer(colorBufferIdx);
	GLuint colorsTex = colorBuffer->GetTexture();

	fbo->Bind();

	colorBufferIdx = 3 - colorBufferIdx;
	glDrawBuffers(1, mrt + colorBufferIdx);
	
	sCgLogLumProgram->SetTexture(0, colorsTex);
	DrawQuad(sCgLogLumProgram);
	
	PrintGLerror("ToneMapParams");


	///////////////////
	//-- compute avg loglum in scene using mipmapping

	glBindTexture(GL_TEXTURE_2D, fbo->GetColorBuffer(colorBufferIdx)->GetTexture());
	glGenerateMipmapEXT(GL_TEXTURE_2D);
}


static void ExportData(float *data, int w, int h)
{
	startil();

	cout << "w: " << w << " h: " << h << endl;
	ILstring filename = ILstring("downsample2.jpg");
	ilRegisterType(IL_FLOAT);

	const int depth = 1;
	const int bpp = 4;

	if (!ilTexImage(w, h, depth, bpp, IL_RGBA, IL_FLOAT, data))
	{
		cerr << "IL error " << ilGetError() << endl;
		stopil();
		return;
	}

	if (!ilSaveImage(filename))
	{
		cerr << "TGA write error " << ilGetError() << endl;
	}

	stopil();
}


void DeferredRenderer::DownSample(FrameBufferObject *fbo, int bufferIdx,
								  FrameBufferObject *downSampleFbo, 
								  int downSampleBufferIdx)
{
	ColorBufferObject *colorBuffer = fbo->GetColorBuffer(bufferIdx);
	GLuint colorsTex = colorBuffer->GetTexture();

	glPushAttrib(GL_VIEWPORT_BIT);
	glViewport(0, 0, downSampleFbo->GetWidth(), downSampleFbo->GetHeight());
	
	sCgDownSampleProgram->SetTexture(0, colorsTex);

	float downSampleOffsets[NUM_DOWNSAMPLES * 2];
	ComputeSampleOffsets(downSampleOffsets, fbo->GetWidth(), fbo->GetHeight());

	sCgDownSampleProgram->SetArray2f(1, (float *)downSampleOffsets, NUM_DOWNSAMPLES);

	mDownSampleFbo->Bind();
	glDrawBuffers(1, mrt + downSampleBufferIdx);

	DrawQuad(sCgDownSampleProgram);
	
	glPopAttrib();
	
	PrintGLerror("downsample");
}


void DeferredRenderer::ToneMap(FrameBufferObject *fbo,
							   float imageKey, 
							   float whiteLum,
							   float middleGrey)
{
	ColorBufferObject *colorBuffer = fbo->GetColorBuffer(colorBufferIdx);
	GLuint colorsTex = colorBuffer->GetTexture();

	fbo->Bind();
	
	colorBufferIdx = 3 - colorBufferIdx;
	glDrawBuffers(1, mrt + colorBufferIdx);

	sCgToneProgram->SetTexture(0, colorsTex);
	sCgToneProgram->SetValue1f(1, imageKey);
	sCgToneProgram->SetValue1f(2, whiteLum);
	sCgToneProgram->SetValue1f(3, middleGrey);

	DrawQuad(sCgToneProgram);

	PrintGLerror("ToneMap");
}


} // namespace