#pragma once

#include <d3d9.h>
#include <d3dx9.h>

struct InstanceData
{
	float pos[3];
	float size;
	float intensity;
};

struct FluidSettings
{
	float Softness;
	float LightTransferAmmount;
	float SpecularFactor;
	float SpecularPower;
	float TextureScale;
	float TranslucencyAmmount;
	float SurfaceTension;
	float RefractAmmount;
	int BlurSteps;
	float RenderTextureSizeScale;

	IDirect3DTexture9* DiffuseTexture;
};

struct Fluid
{
	FluidSettings Settings;

	IDirect3DTexture9* renderTexture[4];
	IDirect3DSurface9* renderSurface[4];

	IDirect3DTexture9* renderTexturePingPong[8];
	IDirect3DSurface9* renderSurfacePingPong[8];
	IDirect3DSurface9* pongPongDepthBuffer;

	D3DXVECTOR4 renderTargetPingPongDDX;
};

struct FluidParticleSystem
{
	unsigned int InstanceCount;
	IDirect3DVertexBuffer9* InstanceDataBuffer;
};

class FluidContext
{
public:
	void BuildUp(IDirect3DDevice9* device, int screenX, int screenY);

	void RenderParticles(const FluidParticleSystem& particleInfo);
	
	void Begin(const D3DXMATRIX& viewProj, const D3DXMATRIX& view, const D3DXMATRIX& inverseView, const D3DXVECTOR4& eye, const D3DXVECTOR4& eyeDir, const Fluid& fluid);
	void End();
	void Display(const Fluid& fluid, IDirect3DTexture9* backgroundTexture);

	FluidParticleSystem GenerateFluidParticleSystem(unsigned int instanceCount, InstanceData* initialData = NULL);
	Fluid GenerateFluid(FluidSettings settings);
	ID3DXEffect* effect;

private:
	IDirect3DDevice9* d3dDevice;
	IDirect3DVertexDeclaration9* quadVertexDecl;
	IDirect3DVertexDeclaration9* vertexDecl;
	IDirect3DIndexBuffer9* quadIndexBuffer;
	IDirect3DVertexBuffer9* quadVertexBuffer;

	static const int renderTextureCount = 4; // pos, normal, density, ballpos

	IDirect3DSurface9* backBufferDepthBuffer;
	IDirect3DSurface9* backBuffer;

	int renderTargetWidth;
	int renderTargetHeight;
	D3DXVECTOR4 renderTargetDDX;

	const Fluid* currentFluid;
};

static const float particleQuadVerts[20] =
{
	-1.0f,-1.0f, 0.0f, 
	0.0f, 1.0f,

	-1.0f, 1.0f, 0.0f, 
	0.0f, 0.0f,

	1.0f,  1.0f, 0.0f, 
	1.0f, 0.0f,

	1.0f, -1.0f, 0.0f, 
	1.0f, 1.0f
};

static const float screenQuadVerts[30] =
{
	-1.0f,-1.0f, 1.0f, 
	0.0f, 1.0f,

	-1.0f, 1.0f, 1.0f, 
	0.0f, 0.0f,

	1.0f,  1.0f, 1.0f, 
	1.0f, 0.0f,

	1.0f,  1.0f, 1.0f, 
	1.0f, 0.0f,

	-1.0f,-1.0f, 1.0f, 
	0.0f, 1.0f,

	1.0f, -1.0f, 1.0f, 
	1.0f, 1.0f
};