#include "SceneQuery.h"
#include "glInterface.h"
#include "Vector3.h"
#include "Camera.h"
#include "SceneQuery.h"
#include "RenderTraverser.h"
#include "FrameBufferObject.h"

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




using namespace std;

const static int texWidth = 2048;
const static int texHeight = 2048;


static GLenum mrt[] = {GL_COLOR_ATTACHMENT0_EXT, GL_COLOR_ATTACHMENT1_EXT, GL_COLOR_ATTACHMENT2_EXT};


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


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


namespace CHCDemoEngine
{


static void GrabDepthBuffer(float *data, GLuint depthTexture)
{
	glEnable(GL_TEXTURE_2D);
	glBindTexture(GL_TEXTURE_2D, depthTexture);

	glGetTexImage(GL_TEXTURE_2D, 0, GL_DEPTH_COMPONENT, GL_FLOAT, data);

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


static void ExportDepthBuffer(float *data)
{
	startil();

	ILstring filename = ILstring("depth.tga");
	ilRegisterType(IL_FLOAT);

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

	if (!ilTexImage(texWidth, texHeight, depth, bpp, IL_LUMINANCE, IL_FLOAT, data))
	{
		cerr << "IL error " << ilGetError() << endl;
		stopil();
		return;
	}

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

	stopil();

	cout << "exported depth buffer" << endl;
}


SceneQuery::SceneQuery(const AxisAlignedBox3 &sceneBox, 
					   RenderTraverser *renderer): 
mSceneBox(sceneBox), mDepth(NULL)
{
	Prepare(renderer);
}


bool SceneQuery::CalcIntersection(Vector3 &pt)
{
	const int px = (pt.x - mSceneBox.Min(0)) * (texWidth - 1) / mSceneBox.Size(0);
	const int py = (pt.y - mSceneBox.Min(1)) * (texHeight - 1) / mSceneBox.Size(1);

	float d = mDepth[px + py * texHeight];

	static float depth = d;

	if (d > 0)
	{
		// temporal smoothing of depth values
		const float x = .5f;
		depth = d * x + depth * (1.0f - x);

		const float offs = mSceneBox.Size(2) * 5e-2f;
		pt.z =  mSceneBox.Max().z - mSceneBox.Size().z * depth + offs;

		return true;
	}

	return false;
}


void SceneQuery::Prepare(RenderTraverser *renderer)
{
	cout << "Preparing scene queries" << endl;

	const float xlen = mSceneBox.Size().x * 0.5f;
	const float ylen = mSceneBox.Size().y * 0.5f;
	
	Camera *orthoCam = new Camera(xlen, ylen);
	orthoCam->SetOrtho(true);

	orthoCam->SetNear(0.0f);
	orthoCam->SetDirection(Vector3(0, 0, 1));

	cout << orthoCam->GetDirection() << endl;
	Vector3 pos = Vector3(mSceneBox.Center().x, mSceneBox.Center().y, mSceneBox.Max().z);
	orthoCam->SetPosition(pos);

	FrameBufferObject *fbo = new FrameBufferObject(texWidth, texHeight, FrameBufferObject::DEPTH_32, true);
	fbo->AddColorBuffer(ColorBufferObject::BUFFER_UBYTE, ColorBufferObject::WRAP_CLAMP_TO_EDGE, ColorBufferObject::FILTER_NEAREST, false);


	fbo->Bind();

	glDrawBuffers(1, mrt);

	glPushAttrib(GL_VIEWPORT_BIT);
	glViewport(0, 0, texWidth, texHeight);

	glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);

	glFrontFace(GL_CCW);
	glCullFace(GL_BACK);
	
	glEnable(GL_CULL_FACE);

	glShadeModel(GL_FLAT);
	glEnable(GL_DEPTH_TEST);

	glMatrixMode(GL_PROJECTION);
	glPushMatrix();


	glOrtho(+xlen, -xlen, ylen, -ylen, 0.0f, mSceneBox.Size().z); 

	glMatrixMode(GL_MODELVIEW);
	glPushMatrix();

	orthoCam->SetupCameraView();

	mDepth = new float[texHeight * texWidth];

	renderer->RenderScene();
	
	glPopMatrix();
	glMatrixMode(GL_PROJECTION);
	
	glPopMatrix();

	glPopAttrib();
	
	FrameBufferObject::Release();

	GrabDepthBuffer(mDepth, fbo->GetDepthTex());
	ExportDepthBuffer(mDepth); PrintGLerror("grab");

	DEL_PTR(fbo);
	DEL_PTR(orthoCam);
}




}