Shader 学习笔记 （1）

Assembly-Language shader:硬件汇编着色程序. 

推荐读物：Microsoft® DirectX® 9 Programmable Graphics Pipeline

“好记性不如烂笔头，留给自己~方便他人！！”                                     -- Baesky

使用汇编着色器的步骤为:

1.声明一个字符串形式的着色代码;

2.汇编该着色代码；

3.获得shader对象；

4.声明物体顶点；

5.填充顶点缓冲；

6.创建顶点结构声明对象；

7.设置渲染状态；

8.设置其他相关变量与变换矩阵。

----------------------------------------------------------------------------------------

★声明字符串形式的着色代码

const char* strVertexShader =

"vs_1_1                 \n"

"dcl_position v0       \n"

"m4x4 v0, c0           \n"

";\n"

"";

>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>

★汇编该着色代码

LPD3DXBUFFER pShader = NULL;

hr = D3DXAssembleShader(

      strVertexShader,

      (UINT)strlen(strVertexShader),

      NULL,

      NULL,

      D3DXSHADER_DEBUG,

      &pShader,

      NULL

);

if (FAILED(hr))

{

   SAFE_RELEASE(pShader);

   return hr;

}

>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>

★获得shader对象

d3dDevice->CreateVertexShader(

                (DWORD*)pShader->GetBufferPoint(), &vsObj);

>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>

★声明物体顶点 & 填充顶点缓冲

struct CUSTOMVETEX

{

    float x,y,z;

}

CUSTOMVETEX vertices[] =

{

   {0,1,1},

   {1,0,1},

   {-1,0,1},

}

d3dDevice->CreateVertexBuffer(

                3*sizeof(CUSTOMVETEX), 0, 0, D3DPOOL_DEFAULT,

                &p_vb, NULL);

VOID* pVertex;

p_vb->Lock(0, sizeof(vertices), (VOID**)&pVertex, 0);

memcpy(pVertex, vertices, sizeof(vertices));

p_vb->Unlock();

>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>

★创建顶点结构声明对象

D3DVERTEXELEMENT9 decl[] =

{

    {0, 0, D3DDECLTYPE_FLOAT3, D3DDECLMETHOD_DEFAULT,

     D3DDECLUSAGE_POSITION, 0},

    D3DDECL_END()

}

>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>

设置渲染状态与相关参数略。

>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>

下面是源代码：

#include <d3d9.h>
#include <D3Dx9Shader.h>

#define SAFE_RELEASE(p) { if ( (p) ) { (p)->Release(); (p) = 0; } }

LPDIRECT3D9 g_pD3D = NULL;
LPDIRECT3DDEVICE9 g_pD3dDevice = NULL;
LPDIRECT3DVERTEXSHADER9 m_pAsm_VS;
LPDIRECT3DVERTEXDECLARATION9 m_pVetexDel;
D3DXMATRIX m_matWorld, m_matProj, m_matView;
LPDIRECT3DVERTEXBUFFER9 vb;
D3DXVECTOR3* eye;
D3DXVECTOR3* at = new D3DXVECTOR3(0,0,0);
D3DXVECTOR3* up = new D3DXVECTOR3(0,1,0);
struct CUSTOMVERTEX
{
	float x,y,z;
};

HRESULT InitShader()
{
	const char* strAssemblyShader = 
		"vs_1_1        //version \n"
		"dcl_position v0 //define  \n"
		"m4x4 oPos, v0, c0 //transform \n"
		";\n"
		"";
	
	LPD3DXBUFFER pShader = NULL;
	HRESULT hr = D3DXAssembleShader(strAssemblyShader, (UINT)strlen(strAssemblyShader),
				NULL,NULL,D3DXSHADER_DEBUG, &pShader, NULL);
	if(FAILED(hr))
	{
		SAFE_RELEASE(pShader);
		return hr;
	}
	hr = g_pD3dDevice->CreateVertexShader((DWORD*)pShader->GetBufferPointer(), &m_pAsm_VS);
	if (FAILED(hr))
	{
		SAFE_RELEASE(pShader);
		SAFE_RELEASE(m_pAsm_VS);
		return hr;
	}
	SAFE_RELEASE(pShader);

	
	CUSTOMVERTEX vertices[] = 
	{
		{1,0,1},
		{0,1,1},
		{-1, 0,1},	
	};
	
	if (FAILED(hr = g_pD3dDevice->CreateVertexBuffer(3*sizeof(CUSTOMVERTEX), 0, 0, D3DPOOL_DEFAULT, &vb, NULL)))
	{
		SAFE_RELEASE(vb);
		return hr;
	}
	
	VOID* pVertex;
	if (FAILED(hr = vb->Lock(0, sizeof(vertices), (VOID**)&pVertex, 0)))
	{
		return hr;
	}
	memcpy(pVertex, vertices, sizeof(vertices));
	vb->Unlock();
	D3DVERTEXELEMENT9 decl[] = 
	{
		{0, 0, D3DDECLTYPE_FLOAT3, D3DDECLMETHOD_DEFAULT, D3DDECLUSAGE_POSITION, 0},
		D3DDECL_END()
	};

	if (FAILED(hr = g_pD3dDevice->CreateVertexDeclaration(decl, &m_pVetexDel)))
	{
		SAFE_RELEASE(m_pVetexDel);
		return hr;
	}

	g_pD3dDevice->SetRenderState(D3DRS_CULLMODE, D3DCULL_NONE);
	
	
	D3DXMatrixIdentity(&m_matWorld);
	D3DXMatrixPerspectiveFovLH(&m_matProj, D3DX_PI/4, 1.0f, 0.1f, 100.0f);

	return S_OK;
}

HRESULT InitD3D(HWND hWnd)
{
	if ( (g_pD3D = Direct3DCreate9(D3D_SDK_VERSION)) == NULL )
	{
		return E_FAIL;
	}

	D3DPRESENT_PARAMETERS d3dpp;
	ZeroMemory(&d3dpp, sizeof(d3dpp));
	d3dpp.Windowed = TRUE;
	d3dpp.SwapEffect = D3DSWAPEFFECT_DISCARD;
	d3dpp.BackBufferFormat = D3DFMT_UNKNOWN;

	if (FAILED(g_pD3D->CreateDevice(D3DADAPTER_DEFAULT, D3DDEVTYPE_HAL, hWnd, D3DCREATE_SOFTWARE_VERTEXPROCESSING, &d3dpp, &g_pD3dDevice)))
	{
		return E_FAIL;
	}

	if (FAILED(InitShader()))
	{
		return E_FAIL;
	}

	return S_OK;
	 
}

VOID CleanUp()
{
	if (g_pD3D)
	{
		g_pD3D->Release();
		g_pD3D = NULL;
	}
	if (g_pD3dDevice)
	{
		g_pD3dDevice->Release();
		g_pD3dDevice = NULL;
	}
}

VOID Render()
{
	if (NULL==g_pD3dDevice)
		return;
	eye = new D3DXVECTOR3(0,0,-3);
	D3DXMatrixLookAtLH(&m_matView, eye,at, up);
	g_pD3dDevice->Clear(0, NULL, D3DCLEAR_TARGET, D3DCOLOR_XRGB(128,128,180), 1.0f, 0);
	if (SUCCEEDED(g_pD3dDevice->BeginScene()))
	{
		
		
		//TODO:render scene
		if (vb)
		{
		D3DXMATRIX mat;
		D3DXMatrixMultiply(&mat, &m_matWorld, &m_matView);
		D3DXMatrixMultiply(&mat, &mat, &m_matProj);
		D3DXMatrixTranspose(&mat, &mat);

		g_pD3dDevice->SetVertexShaderConstantF(0, (float*)&mat, 4);
		g_pD3dDevice->SetVertexDeclaration(m_pVetexDel);
		g_pD3dDevice->SetVertexShader(m_pAsm_VS);
		g_pD3dDevice->SetStreamSource(0, vb, 0, sizeof(CUSTOMVERTEX));
		g_pD3dDevice->DrawPrimitive(D3DPT_TRIANGLELIST,0,1);
		g_pD3dDevice->SetVertexShader(NULL);
		}
		
		g_pD3dDevice->EndScene();
	}
	g_pD3dDevice->Present(NULL, NULL, NULL, NULL);
	
}

LRESULT WINAPI MsgProc(HWND hWnd, UINT msg, WPARAM wParam, LPARAM lParam)
{
	switch (msg)
	{
		case WM_DESTROY:
			{
				PostQuitMessage(0);	
				return 0;
			}
			
			break;
	}

	return DefWindowProc(hWnd, msg, wParam, lParam);
}

INT WINAPI wWinMain( HINSTANCE hInstance, HINSTANCE hPrevInstance, LPWSTR cmdLine, int ShowCmd)
{
	WNDCLASSEX wc =
	{
		sizeof( WNDCLASSEX ), CS_CLASSDC, MsgProc, 0L, 0L,
		GetModuleHandle( NULL ), NULL, NULL, NULL, NULL,
		L"baesky", NULL
	};
	RegisterClassEx( &wc );

	// Create the application's window
	HWND hWnd = CreateWindow( L"baesky", L"我写的很乱 >_<",
		WS_OVERLAPPEDWINDOW, 100, 100, 300, 300,
		NULL, NULL, wc.hInstance, NULL );
	if (SUCCEEDED(InitD3D(hWnd)))
	{
		ShowWindow(hWnd, SW_SHOWDEFAULT);
		UpdateWindow(hWnd);

		// Enter the message loop
		MSG msg;
		ZeroMemory( &msg, sizeof( msg ) );
		while( msg.message != WM_QUIT )
		{
			if( PeekMessage( &msg, NULL, 0U, 0U, PM_REMOVE ) )
			{
				TranslateMessage( &msg );
				DispatchMessage( &msg );
			}
			else
				Render();
		}
		
	}
	CleanUp();
	UnregisterClass(L"baesky", hInstance);
	return 0;
}