//=============================================================================
// TerrainDemo.cpp by Frank Luna (C) 2005 All Rights Reserved.
//
// Demonstrates how to render a terrain with multi-texturing.
//
// Controls: Use mouse to orbit and zoom; use the 'W' and 'S' keys to 
//           alter the height of the camera.
//=============================================================================

#include "d3dApp.h"
#include "DirectInput.h"
#include <crtdbg.h>
#include "GfxStats.h"
#include <list>
#include "Terrain.h"
 

class TerrainDemo : public D3DApp
{
public:
	TerrainDemo(HINSTANCE hInstance, std::string winCaption, D3DDEVTYPE devType, DWORD requestedVP);
	~TerrainDemo();

	bool checkDeviceCaps();
	void onLostDevice();
	void onResetDevice();
	void updateScene(float dt);
	void drawScene();

	// Helper methods
	void buildViewMtx();
	void buildProjMtx();

private:
	GfxStats* mGfxStats;
	Terrain*  mTerrain;

	float mCameraRotationY;
	float mCameraRadius;
	float mCameraHeight;

	D3DXMATRIX mWorld; // Not used
	D3DXMATRIX mView;
	D3DXMATRIX mProj;
};


int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE prevInstance,
				   PSTR cmdLine, int showCmd)
{
	// Enable run-time memory check for debug builds.
	#if defined(DEBUG) | defined(_DEBUG)
		_CrtSetDbgFlag( _CRTDBG_ALLOC_MEM_DF | _CRTDBG_LEAK_CHECK_DF );
	#endif

	TerrainDemo app(hInstance, "Terrain Demo", D3DDEVTYPE_HAL, D3DCREATE_HARDWARE_VERTEXPROCESSING);
	gd3dApp = &app;

	DirectInput di(DISCL_NONEXCLUSIVE|DISCL_FOREGROUND, DISCL_NONEXCLUSIVE|DISCL_FOREGROUND);
	gDInput = &di;

    return gd3dApp->run();
}

TerrainDemo::TerrainDemo(HINSTANCE hInstance, std::string winCaption, D3DDEVTYPE devType, DWORD requestedVP)
: D3DApp(hInstance, winCaption, devType, requestedVP)
{
	if(!checkDeviceCaps())
	{
		MessageBox(0, "checkDeviceCaps() Failed", 0, 0);
		PostQuitMessage(0);
	}

	InitAllVertexDeclarations();

	mGfxStats = new GfxStats();
	
	mCameraRadius    = 75.0f;
	mCameraRotationY = 1.3f * D3DX_PI;
	mCameraHeight    = 35.0f;

	mTerrain = new Terrain(257, 257, 0.5f, 0.5f, 
		"heightmap17_257.raw",  
		"grass.dds",
		"dirt.dds",
		"stone.dds",
		"blend_hm17.dds",
		0.2f, 0.0f);

	mTerrain->setDirToSunW(D3DXVECTOR3(0.0f, 1.0f, 0.0f));


	// Scale the mesh down.
	D3DXMatrixIdentity(&mWorld);
	
	mGfxStats->addVertices(mTerrain->getNumVertices());
	mGfxStats->addTriangles(mTerrain->getNumTriangles());

	onResetDevice();
}

TerrainDemo::~TerrainDemo()
{
	delete mGfxStats;
	delete mTerrain;

	DestroyAllVertexDeclarations();
}

bool TerrainDemo::checkDeviceCaps()
{
	D3DCAPS9 caps;
	HR(gd3dDevice->GetDeviceCaps(&caps));

	// Check for vertex shader version 2.0 support.
	if( caps.VertexShaderVersion < D3DVS_VERSION(2, 0) )
		return false;

	// Check for pixel shader version 2.0 support.
	if( caps.PixelShaderVersion < D3DPS_VERSION(2, 0) )
		return false;

	return true;
}

void TerrainDemo::onLostDevice()
{
	mGfxStats->onLostDevice();
	mTerrain->onLostDevice();
}

void TerrainDemo::onResetDevice()
{
	mGfxStats->onResetDevice();
	mTerrain->onResetDevice();


	// The aspect ratio depends on the backbuffer dimensions, which can 
	// possibly change after a reset.  So rebuild the projection matrix.
	buildProjMtx();
}

void TerrainDemo::updateScene(float dt)
{
	mGfxStats->update(dt);

	// Get snapshot of input devices.
	gDInput->poll();

	// Check input.
	if( gDInput->keyDown(DIK_W) )	 
		mCameraHeight   += 25.0f * dt;
	if( gDInput->keyDown(DIK_S) )	 
		mCameraHeight   -= 25.0f * dt;

	// Divide by 50 to make mouse less sensitive. 
	mCameraRotationY += gDInput->mouseDX() / 100.0f;
	mCameraRadius    += gDInput->mouseDY() / 25.0f;

	// If we rotate over 360 degrees, just roll back to 0
	if( fabsf(mCameraRotationY) >= 2.0f * D3DX_PI ) 
		mCameraRotationY = 0.0f;

	// Don't let radius get too small.
	if( mCameraRadius < 2.0f )
		mCameraRadius = 2.0f;

	// The camera position/orientation relative to world space can 
	// change every frame based on input, so we need to rebuild the
	// view matrix every frame with the latest changes.
	buildViewMtx();
}

void TerrainDemo::drawScene()
{
	// Clear the backbuffer and depth buffer.
	HR(gd3dDevice->Clear(0, 0, D3DCLEAR_TARGET | D3DCLEAR_ZBUFFER, 0xffeeeeee, 1.0f, 0));

	HR(gd3dDevice->BeginScene());

	mTerrain->draw(mView, mProj);
	
	mGfxStats->display();

	HR(gd3dDevice->EndScene());

	// Present the backbuffer.
	HR(gd3dDevice->Present(0, 0, 0, 0));
}

void TerrainDemo::buildViewMtx()
{
	float x = mCameraRadius * cosf(mCameraRotationY);
	float z = mCameraRadius * sinf(mCameraRotationY);
	D3DXVECTOR3 pos(x, mCameraHeight, z);
	D3DXVECTOR3 target(0.0f, 0.0f, 0.0f);
	D3DXVECTOR3 up(0.0f, 1.0f, 0.0f);
	D3DXMatrixLookAtLH(&mView, &pos, &target, &up);
}

void TerrainDemo::buildProjMtx()
{
	float w = (float)md3dPP.BackBufferWidth;
	float h = (float)md3dPP.BackBufferHeight;
	D3DXMatrixPerspectiveFovLH(&mProj, D3DX_PI * 0.25f, w/h, 1.0f, 5000.0f);
}