shadow.cpp

《3D游戏编程》随书光盘 12章: 设计阴影的多种技巧, 有详细源代码

    D3DXMatrixRotationX( &matRotX, m_fWorldRotX );
    D3DXMatrixRotationY( &matRotY, m_fWorldRotY );

	// 物体的变换矩阵
    D3DXMatrixMultiply( &matWorld, &matRotY, &matRotX );
	D3DXMatrixTranslation( &matPos, 0, 1, 0 );
	m_matWorld = matWorld * matPos;

    return S_OK;
}




//-----------------------------------------------------------------------------
// Name: UpdateInput()
// Desc: Update the user input.  Called once per frame 
//-----------------------------------------------------------------------------
void CMyD3DApplication::UpdateInput( UserInput* pUserInput )
{
    pUserInput->bRotateUp    = ( m_bActive && (GetAsyncKeyState( VK_UP )    & 0x8000) == 0x8000 );
    pUserInput->bRotateDown  = ( m_bActive && (GetAsyncKeyState( VK_DOWN )  & 0x8000) == 0x8000 );
    pUserInput->bRotateLeft  = ( m_bActive && (GetAsyncKeyState( VK_LEFT )  & 0x8000) == 0x8000 );
    pUserInput->bRotateRight = ( m_bActive && (GetAsyncKeyState( VK_RIGHT ) & 0x8000) == 0x8000 );
}

// 绘制底.
void CMyD3DApplication::DrawFloor()
{
	D3DXMATRIXA16	matWorld;
	D3DXMatrixIdentity( &matWorld );
    D3DXMatrixRotationX( &matWorld, -(D3DX_PI)/2.0f );
	matWorld._41 = -.5f;
	matWorld._42 = -.1f;
	matWorld._43 = 6.0f;

    m_pd3dDevice->SetMaterial( &m_matFloor );
    m_pd3dDevice->SetTexture( 0, m_ptexFloor );
	m_pd3dDevice->SetTransform( D3DTS_WORLD, &matWorld );
	m_pMeshFloor->DrawSubset(0);
}

// 绘制物体.
void CMyD3DApplication::DrawOcc()
{
    m_pd3dDevice->SetMaterial( &m_matOcc );
    m_pd3dDevice->SetTexture( 0, m_ptexOcc );
    m_pd3dDevice->SetTextureStageState( 0, D3DTSS_COLOROP,   D3DTOP_SELECTARG1 );
    m_pd3dDevice->SetTextureStageState( 0, D3DTSS_COLORARG1, D3DTA_TEXTURE );
    m_pd3dDevice->SetTextureStageState( 0, D3DTSS_COLORARG2, D3DTA_DIFFUSE );
	m_pd3dDevice->SetTransform( D3DTS_WORLD, &m_matWorld );
	m_pMeshOcc->DrawSubset(0);
}

// 在stencil缓冲绘制物体阴影.
void CMyD3DApplication::DrawStencil()
{
	D3DXMATRIXA16	matShadow;
	D3DXMatrixShadow( &matShadow, &m_vLightPos, &m_planeFloor );

    m_pd3dDevice->SetRenderState( D3DRS_ZENABLE, FALSE );			// 关闭Z缓冲
    m_pd3dDevice->SetRenderState( D3DRS_ZWRITEENABLE,  FALSE );		// 禁止在Z缓冲书写
    m_pd3dDevice->SetRenderState( D3DRS_STENCILENABLE, TRUE );		// 打开stencil缓冲

    m_pd3dDevice->SetRenderState( D3DRS_SHADEMODE,     D3DSHADE_FLAT );	// 防止出现瑕疵，flat着色器 

    m_pd3dDevice->SetRenderState( D3DRS_STENCILFUNC,  D3DCMP_ALWAYS );			// 设定stencil参数
    m_pd3dDevice->SetRenderState( D3DRS_STENCILZFAIL, D3DSTENCILOP_KEEP );
    m_pd3dDevice->SetRenderState( D3DRS_STENCILFAIL,  D3DSTENCILOP_KEEP );

    m_pd3dDevice->SetRenderState( D3DRS_STENCILREF,       0x1 );		// 增加的值
    m_pd3dDevice->SetRenderState( D3DRS_STENCILMASK,      0xffffffff );
    m_pd3dDevice->SetRenderState( D3DRS_STENCILWRITEMASK, 0xffffffff );
    m_pd3dDevice->SetRenderState( D3DRS_STENCILPASS,      D3DSTENCILOP_INCR );	// 如果绘制了点，就会在stencil中一个一个增加 

    m_pd3dDevice->SetRenderState( D3DRS_ALPHABLENDENABLE, TRUE );		// 防止在画面绘制网格
    m_pd3dDevice->SetRenderState( D3DRS_SRCBLEND,  D3DBLEND_ZERO );
    m_pd3dDevice->SetRenderState( D3DRS_DESTBLEND, D3DBLEND_ONE );

	matShadow = m_matWorld * matShadow;

	m_pd3dDevice->SetTransform( D3DTS_WORLD, &matShadow );
	m_pMeshOcc->DrawSubset(0);		// 在stencil绘制网格.

    // 渲染状态复原
    m_pd3dDevice->SetRenderState( D3DRS_ZENABLE, TRUE );
    m_pd3dDevice->SetRenderState( D3DRS_SHADEMODE, D3DSHADE_GOURAUD );
    m_pd3dDevice->SetRenderState( D3DRS_ZWRITEENABLE,     TRUE );
    m_pd3dDevice->SetRenderState( D3DRS_STENCILENABLE,    FALSE );
    m_pd3dDevice->SetRenderState( D3DRS_ALPHABLENDENABLE, FALSE );
}

// 在画面绘制物体阴影.
void CMyD3DApplication::DrawShadow()
{
	struct SQUARE
	{
		enum { FVF = D3DFVF_XYZRHW | D3DFVF_DIFFUSE };
		D3DXVECTOR4	p;	// pos
		DWORD		d;	// diffuse
	};

	// 覆盖整个画面的网格(四边形)
	SQUARE	v[4];
    FLOAT sx = (FLOAT)m_d3dsdBackBuffer.Width;
    FLOAT sy = (FLOAT)m_d3dsdBackBuffer.Height;
    v[0].p = D3DXVECTOR4(  0, sy, 0.0f, 1.0f );
    v[1].p = D3DXVECTOR4(  0,  0, 0.0f, 1.0f );
    v[2].p = D3DXVECTOR4( sx, sy, 0.0f, 1.0f );
    v[3].p = D3DXVECTOR4( sx,  0, 0.0f, 1.0f );
    v[0].d = 0x7f000000;
    v[1].d = 0x7f000000;
    v[2].d = 0x7f000000;
    v[3].d = 0x7f000000;

	DrawStencil();	// 在stencil缓冲绘制阴影

    m_pd3dDevice->SetRenderState( D3DRS_ZENABLE, FALSE );			// 关闭Z缓冲
	m_pd3dDevice->SetRenderState( D3DRS_STENCILENABLE,    TRUE );	// 打开stencil
    m_pd3dDevice->SetRenderState( D3DRS_ALPHABLENDENABLE, TRUE );	// 打开alpha blending
    m_pd3dDevice->SetRenderState( D3DRS_SRCBLEND,  D3DBLEND_SRCALPHA );	
    m_pd3dDevice->SetRenderState( D3DRS_DESTBLEND, D3DBLEND_INVSRCALPHA );
    m_pd3dDevice->SetTextureStageState( 0, D3DTSS_COLORARG1, D3DTA_TEXTURE );
    m_pd3dDevice->SetTextureStageState( 0, D3DTSS_COLORARG2, D3DTA_DIFFUSE );
    m_pd3dDevice->SetTextureStageState( 0, D3DTSS_COLOROP,   D3DTOP_MODULATE );
    m_pd3dDevice->SetTextureStageState( 0, D3DTSS_ALPHAARG1, D3DTA_TEXTURE );
    m_pd3dDevice->SetTextureStageState( 0, D3DTSS_ALPHAARG2, D3DTA_DIFFUSE );
    m_pd3dDevice->SetTextureStageState( 0, D3DTSS_ALPHAOP,   D3DTOP_MODULATE );

    m_pd3dDevice->SetRenderState( D3DRS_STENCILREF,  0x1 );			// 和1比较运算
    m_pd3dDevice->SetRenderState( D3DRS_STENCILFUNC, D3DCMP_LESSEQUAL );	// 如果(stencil值 >= 1) ，就绘制.
    m_pd3dDevice->SetRenderState( D3DRS_STENCILPASS, D3DSTENCILOP_KEEP );

    m_pd3dDevice->SetFVF( SQUARE::FVF );
    m_pd3dDevice->DrawPrimitiveUP( D3DPT_TRIANGLESTRIP, 2, &v[0], sizeof(SQUARE) );

    m_pd3dDevice->SetRenderState( D3DRS_ZENABLE,          TRUE );
    m_pd3dDevice->SetRenderState( D3DRS_STENCILENABLE,    FALSE );
    m_pd3dDevice->SetRenderState( D3DRS_FOGENABLE,        TRUE );
    m_pd3dDevice->SetRenderState( D3DRS_ALPHABLENDENABLE, FALSE );
}

//-----------------------------------------------------------------------------
// Name: Render()
// Desc: Called once per frame, the call is the entry point for 3d
//       rendering. This function sets up render states, clears the
//       viewport, and renders the scene.
//-----------------------------------------------------------------------------
HRESULT CMyD3DApplication::Render()
{
    // Clear the viewport
    m_pd3dDevice->Clear( 0L, NULL, D3DCLEAR_TARGET|D3DCLEAR_ZBUFFER|D3DCLEAR_STENCIL,
                         0xffc0c0c0, 1.0f, 0L );

    // Begin the scene
    if( SUCCEEDED( m_pd3dDevice->BeginScene() ) )
    {
		DrawFloor();					// 绘制底
		if( m_bShadow ) DrawShadow();	// 绘制阴影
		DrawOcc();						// 绘制网格

        // Render stats and help text  
        RenderText();

        // End the scene.
        m_pd3dDevice->EndScene();
    }

    return S_OK;
}




//-----------------------------------------------------------------------------
// Name: RenderText()
// Desc: Renders stats and help text to the scene.
//-----------------------------------------------------------------------------
HRESULT CMyD3DApplication::RenderText()
{
    D3DCOLOR fontColor        = D3DCOLOR_ARGB(255,255,255,0);
    TCHAR szMsg[MAX_PATH] = TEXT("");

    // Output display stats
    FLOAT fNextLine = 40.0f; 

    lstrcpy( szMsg, m_strDeviceStats );
    fNextLine -= 20.0f;
    m_pFont->DrawText( 2, fNextLine, fontColor, szMsg );

    lstrcpy( szMsg, m_strFrameStats );
    fNextLine -= 20.0f;
    m_pFont->DrawText( 2, fNextLine, fontColor, szMsg );

    // Output statistics & help
    fNextLine = (FLOAT) m_d3dsdBackBuffer.Height; 

    wsprintf( szMsg, TEXT("Arrow keys: Up=%d Down=%d Left=%d Right=%d"), 
              m_UserInput.bRotateUp, m_UserInput.bRotateDown, m_UserInput.bRotateLeft, m_UserInput.bRotateRight );
    fNextLine -= 20.0f; m_pFont->DrawText( 2, fNextLine, fontColor, szMsg );

    lstrcpy( szMsg, TEXT("Use arrow keys to rotate object") );
    fNextLine -= 20.0f; m_pFont->DrawText( 2, fNextLine, fontColor, szMsg );

    lstrcpy( szMsg, TEXT("Press 'F2' to configure display") );
    fNextLine -= 20.0f; m_pFont->DrawText( 2, fNextLine, fontColor, szMsg );

    return S_OK;
}




//-----------------------------------------------------------------------------
// Name: MsgProc()
// Desc: Overrrides the main WndProc, so the sample can do custom message
//       handling (e.g. processing mouse, keyboard, or menu commands).
//-----------------------------------------------------------------------------
LRESULT CMyD3DApplication::MsgProc( HWND hWnd, UINT msg, WPARAM wParam,
                                    LPARAM lParam )
{
    switch( msg )
    {
		case WM_KEYDOWN :
		{
			switch( wParam )
			{
				case VK_ESCAPE :
					PostMessage( hWnd, WM_DESTROY, 0, 0L );
					break;
				case '1' :
					m_bWireframe = !m_bWireframe;
					m_pd3dDevice->SetRenderState( D3DRS_FILLMODE, m_bWireframe ? D3DFILL_WIREFRAME : D3DFILL_SOLID );
					break;
				case '2' :
					m_bShadow = !m_bShadow;
					break;
			}
		}
        case WM_PAINT:
        {
            if( m_bLoadingApp )
            {
                // Draw on the window tell the user that the app is loading
                // TODO: change as needed
                HDC hDC = GetDC( hWnd );
                TCHAR strMsg[MAX_PATH];
                wsprintf( strMsg, TEXT("Loading... Please wait") );
                RECT rct;
                GetClientRect( hWnd, &rct );
                DrawText( hDC, strMsg, -1, &rct, DT_CENTER|DT_VCENTER|DT_SINGLELINE );
                ReleaseDC( hWnd, hDC );
            }
            break;
        }

    }

    return CD3DApplication::MsgProc( hWnd, msg, wParam, lParam );
}




//-----------------------------------------------------------------------------
// Name: InvalidateDeviceObjects()
// Desc: Invalidates device objects.  Paired with RestoreDeviceObjects()
//-----------------------------------------------------------------------------
HRESULT CMyD3DApplication::InvalidateDeviceObjects()
{
    // TODO: Cleanup any objects created in RestoreDeviceObjects()
    m_pFont->InvalidateDeviceObjects();

    return S_OK;
}




//-----------------------------------------------------------------------------
// Name: DeleteDeviceObjects()
// Desc: Paired with InitDeviceObjects()
//       Called when the app is exiting, or the device is being changed,
//       this function deletes any device dependent objects.  
//-----------------------------------------------------------------------------
HRESULT CMyD3DApplication::DeleteDeviceObjects()
{
    // TODO: Cleanup any objects created in InitDeviceObjects()
    m_pFont->DeleteDeviceObjects();
    SAFE_RELEASE( m_pMeshFloor );
    SAFE_RELEASE( m_pMeshOcc );
    SAFE_RELEASE( m_ptexFloor );
    SAFE_RELEASE( m_ptexOcc );

    return S_OK;
}




//-----------------------------------------------------------------------------
// Name: FinalCleanup()
// Desc: Paired with OneTimeSceneInit()
//       Called before the app exits, this function gives the app the chance
//       to cleanup after itself.
//-----------------------------------------------------------------------------
HRESULT CMyD3DApplication::FinalCleanup()
{
    // TODO: Perform any final cleanup needed
    // Cleanup D3D font
    SAFE_DELETE( m_pFont );

    return S_OK;
}