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高级纹理映射技术(5)

Alpha混合操作

设置alpha操作的语句大致如下:

// i为纹理层序号
pd3dDevice->SetTextureStageState(i, D3DTSS_ALPHAARG1, arg1);
pd3dDevice->SetTextureStageState(i, D3DTSS_ALPHAARG2, arg2);
pd3dDevice->SetTextureStageState(i, D3DTSS_ALPHAOP, op);

参数op是属于枚举类型D3DTEXTUREOP的常量。和纹理颜色混合操作相同,纹理Alpha操作最多可接受三个颜色参数:D3DTSS_ALPHAARG0、D3DTSS_ALPHAARG1、D3DTSS_ALPHAARG2。

Direct3D在渲染一个场景时,它可以结合几种来源的颜色信息:顶点、当前材质、纹理贴图、先前写入渲染目标的颜色信息,然后将其中的一些颜色混合起来。同时也可以使用Alpha来指定Direct3D该以怎样的权重混合这些颜色,Alpha信息可以存储在顶点中、材质中、纹理贴图中。Alpha值为0表示完全透明,Alpha值为1表示不透明,其余0~1之间的值表示不同程度的透明。

如果要从一张纹理中获取Alpha值,应将D3DTA_TEXTURE作为Alpha参数。

如果要使用来自顶点中的Alpha值,应将D3DTA_DIFFUSE作为Alpha参数,并确保渲染状态D3DRS_DIFFUSEMATERIALSOURCE被设置为D3DMCS_COLOR1(这也是默认状态)。

如果要使用来自材质中的Alpha值,应将D3DTA_DIFFUSE作为Alpha参数,并确保渲染状态D3DRS_DIFFUSEMATERIALSOURCE被设置为D3DMCS_MATERIAL。

如果未用SetRenderState()设置D3DRS_DIFFUSEMATERIALSOURCE参数,则从默认来源(即顶点)获取漫反射颜色。

示例程序中将纹理颜色和Alpha混合的代码如下所示:

// set texture color and alpha blend method

pd3dDevice->SetTexture(0, g_texture);
pd3dDevice->SetTextureStageState(0, D3DTSS_TEXCOORDINDEX, 0);
pd3dDevice->SetTextureStageState(0, D3DTSS_COLORARG1, D3DTA_TEXTURE);
pd3dDevice->SetTextureStageState(0, D3DTSS_COLORARG2, D3DTA_DIFFUSE);
pd3dDevice->SetTextureStageState(0, D3DTSS_COLOROP, D3DTOP_MODULATE);

pd3dDevice->SetTextureStageState(0, D3DTSS_ALPHAARG1, D3DTA_TEXTURE);
pd3dDevice->SetTextureStageState(0, D3DTSS_ALPHAOP, D3DTOP_SELECTARG1);

pd3dDevice->SetRenderState(D3DRS_ALPHABLENDENABLE, TRUE);
pd3dDevice->SetRenderState(D3DRS_SRCBLEND, D3DBLEND_SRCALPHA);
pd3dDevice->SetRenderState(D3DRS_DESTBLEND, D3DBLEND_INVSRCALPHA);

Alpha操作从纹理中获取Alpha值,因为用到了Alpha混合,所以在上面的代码中还需要启用Alpha混合并设置Alpha混合系数。

 

运行效果:

 

主程序:

#include "dxstdafx.h"
#include 
"resource.h"

#pragma warning(disable : 
4127 4995 4996)

#define release_com(p)    do { if(p) { (p)->Release(); (p) = NULL; } } while(0)

#define IDC_TOGGLE_FULLSCREEN        1
#define IDC_TOGGLE_REF                2
#define IDC_CHANGE_DEVICE            3

struct sCustomVertex
{
    
float x, y, z;
    
float u, v;
};

#define D3DFVF_CUSTOM_VERTEX    (D3DFVF_XYZ | D3DFVF_TEX1)

const D3DXCOLOR FONT_COLOR(0.85f0.85f0.85f1.0f);

CDXUTDialogResourceManager    g_dlg_resource_manager;
CD3DSettingsDlg                g_settings_dlg;
CDXUTDialog                    g_button_dlg;

IDirect3DVertexBuffer9
*        g_vertex_buffer;
IDirect3DTexture9
*            g_texture;

ID3DXFont
*        g_font;
ID3DXSprite
*    g_text_sprite;
bool            g_show_help = true;

//--------------------------------------------------------------------------------------
// Rejects any devices that aren't acceptable by returning false
//--------------------------------------------------------------------------------------
bool CALLBACK IsDeviceAcceptable( D3DCAPS9* pCaps, D3DFORMAT AdapterFormat, 
                                  D3DFORMAT BackBufferFormat, 
bool bWindowed, void* pUserContext )
{
    
// Typically want to skip backbuffer formats that don't support alpha blending

    IDirect3D9
* pD3D = DXUTGetD3DObject(); 

    
if( FAILED( pD3D->CheckDeviceFormat( pCaps->AdapterOrdinal, pCaps->DeviceType, AdapterFormat, 
                    D3DUSAGE_QUERY_POSTPIXELSHADER_BLENDING, D3DRTYPE_TEXTURE, BackBufferFormat ) ) )
        
return false;

    
return true;
}


//--------------------------------------------------------------------------------------
// Before a device is created, modify the device settings as needed.
//--------------------------------------------------------------------------------------
bool CALLBACK ModifyDeviceSettings( DXUTDeviceSettings* pDeviceSettings, const D3DCAPS9* pCaps, void* pUserContext )
{
    
// If video card does not support hardware vertex processing, then uses sofaware vertex processing.
    if((pCaps->DevCaps & D3DDEVCAPS_HWTRANSFORMANDLIGHT) == 0)
        pDeviceSettings
->BehaviorFlags = D3DCREATE_SOFTWARE_VERTEXPROCESSING;

    
static bool is_first_time = true;

    
if(is_first_time)
    {
        is_first_time 
= false;

        
// if using reference device, then pop a warning message box.
        if(pDeviceSettings->DeviceType == D3DDEVTYPE_REF)
            DXUTDisplaySwitchingToREFWarning();
    }

    
return true;
}


//--------------------------------------------------------------------------------------
// Create any D3DPOOL_MANAGED resources here 
//--------------------------------------------------------------------------------------
HRESULT CALLBACK OnCreateDevice( IDirect3DDevice9* pd3dDevice, 
                                 
const D3DSURFACE_DESC* pBackBufferSurfaceDesc, 
                                 
void* pUserContext )
{
    HRESULT    hr;

    V_RETURN(g_dlg_resource_manager.OnCreateDevice(pd3dDevice));
    V_RETURN(g_settings_dlg.OnCreateDevice(pd3dDevice));

    D3DXCreateFont(pd3dDevice, 
180, FW_BOLD, 1, FALSE, DEFAULT_CHARSET, OUT_DEFAULT_PRECIS, DEFAULT_QUALITY,
                   DEFAULT_PITCH 
| FF_DONTCARE, L"Arial"&g_font);

    V_RETURN(D3DXCreateTextureFromFile(pd3dDevice, L
"tree.tga",    &g_texture));
    
    
// create vertex buffer and fill data

    sCustomVertex vertices[] 
=     
    {
        { 
-3.0f-3.0f,  0.0f,  0.0f1.0f},
        { 
-3.0f,  3.0f,  0.0f,  0.0f0.0f},
        {  
3.0f-3.0f,  0.0f,  1.0f1.0f},
        {  
3.0f,  3.0f,  0.0f,  1.0f0.0f}
    };

    pd3dDevice
->CreateVertexBuffer(sizeof(vertices), 0, D3DFVF_CUSTOM_VERTEX, D3DPOOL_MANAGED, &g_vertex_buffer, NULL);

    
void* ptr;
    g_vertex_buffer
->Lock(0sizeof(vertices), (void**)&ptr, 0);
    memcpy(ptr, vertices, 
sizeof(vertices));
    g_vertex_buffer
->Unlock();

    
return S_OK;
}


//--------------------------------------------------------------------------------------
// Create any D3DPOOL_DEFAULT resources here 
//--------------------------------------------------------------------------------------
HRESULT CALLBACK OnResetDevice( IDirect3DDevice9* pd3dDevice, 
                                
const D3DSURFACE_DESC* pBackBufferSurfaceDesc, 
                                
void* pUserContext )
{
    HRESULT hr;

    V_RETURN(g_dlg_resource_manager.OnResetDevice());
    V_RETURN(g_settings_dlg.OnResetDevice());
    V_RETURN(g_font
->OnResetDevice());
    V_RETURN(D3DXCreateSprite(pd3dDevice, 
&g_text_sprite));

    
// set dialog position and size

    g_button_dlg.SetLocation(pBackBufferSurfaceDesc
->Width - 1700);
    g_button_dlg.SetSize(
170170);

    
// setup world matrix
    D3DXMATRIX mat_world;
    D3DXMatrixIdentity(
&mat_world);
    pd3dDevice
->SetTransform(D3DTS_WORLD, &mat_world);

    
// setup view matrix

    D3DXMATRIX mat_view;
    D3DXVECTOR3 eye(
0.0f0.0f-10.0f);
    D3DXVECTOR3  at(
0.0f0.0f,  0.0f);
    D3DXVECTOR3  up(
0.0f1.0f,  0.0f);

    D3DXMatrixLookAtLH(
&mat_view, &eye, &at, &up);
    pd3dDevice
->SetTransform(D3DTS_VIEW, &mat_view);

    
// set projection matrix
    D3DXMATRIX mat_proj;
    
float aspect = (float)pBackBufferSurfaceDesc->Width / pBackBufferSurfaceDesc->Height;
    D3DXMatrixPerspectiveFovLH(
&mat_proj, D3DX_PI/4, aspect, 1.0f100.0f);
    pd3dDevice
->SetTransform(D3DTS_PROJECTION, &mat_proj);

    
// setup material

    D3DMATERIAL9 material;
    ZeroMemory(
&material, sizeof(D3DMATERIAL9));

    material.Ambient.r 
= 1.0f;
    material.Ambient.g 
= 1.0f;
    material.Ambient.b 
= 1.0f;
    material.Ambient.a 
= 1.0f;

    pd3dDevice
->SetMaterial(&material);

    pd3dDevice
->SetRenderState(D3DRS_AMBIENT, 0xFF00FF00);

    
// set texture color and alpha blend method

    pd3dDevice
->SetTexture(0, g_texture);
    pd3dDevice
->SetTextureStageState(0, D3DTSS_TEXCOORDINDEX,    0);
    pd3dDevice
->SetTextureStageState(0, D3DTSS_COLORARG1,        D3DTA_TEXTURE);
    pd3dDevice
->SetTextureStageState(0, D3DTSS_COLORARG2,        D3DTA_DIFFUSE);
    pd3dDevice
->SetTextureStageState(0, D3DTSS_COLOROP,            D3DTOP_MODULATE);

    pd3dDevice
->SetTextureStageState(0, D3DTSS_ALPHAARG1,        D3DTA_TEXTURE);
    pd3dDevice
->SetTextureStageState(0, D3DTSS_ALPHAOP,            D3DTOP_SELECTARG1);

    pd3dDevice
->SetRenderState(D3DRS_ALPHABLENDENABLE,    TRUE);
    pd3dDevice
->SetRenderState(D3DRS_SRCBLEND,            D3DBLEND_SRCALPHA);
    pd3dDevice
->SetRenderState(D3DRS_DESTBLEND,            D3DBLEND_INVSRCALPHA);

    
return S_OK;
}

//--------------------------------------------------------------------------------------
// Release resources created in the OnResetDevice callback here 
//--------------------------------------------------------------------------------------
void CALLBACK OnLostDevice( void* pUserContext )
{
    g_dlg_resource_manager.OnLostDevice();
    g_settings_dlg.OnLostDevice();
    g_font
->OnLostDevice();

    release_com(g_text_sprite);
}


//--------------------------------------------------------------------------------------
// Release resources created in the OnCreateDevice callback here
//--------------------------------------------------------------------------------------
void CALLBACK OnDestroyDevice( void* pUserContext )
{
    g_dlg_resource_manager.OnDestroyDevice();
    g_settings_dlg.OnDestroyDevice();    

    release_com(g_font);
    release_com(g_vertex_buffer);
    release_com(g_texture);
}

//--------------------------------------------------------------------------------------
// Handle updates to the scene
//--------------------------------------------------------------------------------------
void CALLBACK OnFrameMove( IDirect3DDevice9* pd3dDevice, double fTime, float fElapsedTime, void* pUserContext )
{
}

//--------------------------------------------------------------------------------------
// Render the helper information
//--------------------------------------------------------------------------------------
void RenderText()
{
    CDXUTTextHelper text_helper(g_font, g_text_sprite, 
20);
    
    text_helper.Begin();

    
// show frame and device states
    text_helper.SetInsertionPos(55);
    text_helper.SetForegroundColor(FONT_COLOR);
    text_helper.DrawTextLine( DXUTGetFrameStats(
true) );
    text_helper.DrawTextLine( DXUTGetDeviceStats() );

    
// show other simple information
    text_helper.SetForegroundColor( D3DXCOLOR(1.0f1.0f1.0f1.0f) );
    text_helper.DrawTextLine(L
"Texture Alpha Blend");

    
// show helper information
    
    
const D3DSURFACE_DESC* surface_desc = DXUTGetBackBufferSurfaceDesc();

    
if(g_show_help)
    {
        text_helper.SetInsertionPos(
10, surface_desc->Height - 18 * 5);
        text_helper.SetForegroundColor(FONT_COLOR);
        text_helper.DrawTextLine(L
"Controls (F1 to hide):");
        
        text_helper.SetInsertionPos(
40, surface_desc->Height - 18 * 4);
        text_helper.DrawTextLine(L
"Quit: ESC");
    }
    
else
    {
        text_helper.SetInsertionPos(
10, surface_desc->Height - 15 * 4);
        text_helper.SetForegroundColor( D3DXCOLOR(
1.0f1.0f1.0f1.0f) );
        text_helper.DrawTextLine(L
"Press F1 for help");
    }

    text_helper.End();
}

//--------------------------------------------------------------------------------------
// Render the scene 
//--------------------------------------------------------------------------------------
void CALLBACK OnFrameRender( IDirect3DDevice9* pd3dDevice, double fTime, float fElapsedTime, void* pUserContext )
{
    HRESULT hr;

    
if(g_settings_dlg.IsActive())
    {
        g_settings_dlg.OnRender(fElapsedTime);
        
return;
    }

    
// Clear the render target and the zbuffer 
    V( pd3dDevice->Clear(0, NULL, D3DCLEAR_TARGET | D3DCLEAR_ZBUFFER, D3DCOLOR_ARGB(0326480), 1.0f0) );

    
// Render the scene
    if( SUCCEEDED( pd3dDevice->BeginScene() ) )
    {
        pd3dDevice
->SetStreamSource(0, g_vertex_buffer, 0sizeof(sCustomVertex));
        pd3dDevice
->SetFVF(D3DFVF_CUSTOM_VERTEX);
        pd3dDevice
->DrawPrimitive(D3DPT_TRIANGLESTRIP, 02);

        RenderText();

        V(g_button_dlg.OnRender(fElapsedTime));

        V( pd3dDevice
->EndScene() );
    }
}


//--------------------------------------------------------------------------------------
// Handle messages to the application 
//--------------------------------------------------------------------------------------
LRESULT CALLBACK MsgProc( HWND hWnd, UINT uMsg, WPARAM wParam, LPARAM lParam, 
                          
bool* pbNoFurtherProcessing, void* pUserContext )
{
    
*pbNoFurtherProcessing = g_dlg_resource_manager.MsgProc(hWnd, uMsg, wParam, lParam);
    
if(*pbNoFurtherProcessing)
        
return 0;

    
if(g_settings_dlg.IsActive())
    {
        g_settings_dlg.MsgProc(hWnd, uMsg, wParam, lParam);
        
return 0;
    }

    
*pbNoFurtherProcessing = g_button_dlg.MsgProc(hWnd, uMsg, wParam, lParam);
    
if(*pbNoFurtherProcessing)
        
return 0;

    
return 0;
}


//--------------------------------------------------------------------------------------
// Handle keybaord event
//--------------------------------------------------------------------------------------
void CALLBACK OnKeyboardProc(UINT charater, bool is_key_down, bool is_alt_down, void* user_context)
{
    
if(is_key_down)
    {
        
switch(charater)
        {
        
case VK_F1:
            g_show_help 
= !g_show_help;
            
break;
        }
    }
}

//--------------------------------------------------------------------------------------
// Handle events for controls
//--------------------------------------------------------------------------------------
void CALLBACK OnGUIEvent(UINT eventint control_id, CDXUTControl* control, void* user_context)
{
    
switch(control_id)
    {
    
case IDC_TOGGLE_FULLSCREEN:
        DXUTToggleFullScreen();
        
break;

    
case IDC_TOGGLE_REF:
        DXUTToggleREF();
        
break;

    
case IDC_CHANGE_DEVICE:
        g_settings_dlg.SetActive(
true);
        
break;
    }
}

//--------------------------------------------------------------------------------------
// Initialize dialogs
//--------------------------------------------------------------------------------------
void InitDialogs()
{
    g_settings_dlg.Init(
&g_dlg_resource_manager);
    g_button_dlg.Init(
&g_dlg_resource_manager);

    g_button_dlg.SetCallback(OnGUIEvent);

    
int x = 35, y = 10, width = 125, height = 22;

    g_button_dlg.AddButton(IDC_TOGGLE_FULLSCREEN, L
"Toggle full screen", x, y,         width, height);
    g_button_dlg.AddButton(IDC_TOGGLE_REF,          L
"Toggle REF (F3)",     x, y += 24, width, height);
    g_button_dlg.AddButton(IDC_CHANGE_DEVICE,      L
"Change device (F2)", x, y += 24, width, height, VK_F2);    
}

//--------------------------------------------------------------------------------------
// Initialize everything and go into a render loop
//--------------------------------------------------------------------------------------
INT WINAPI WinMain( HINSTANCE, HINSTANCE, LPSTR, int )
{
    
// Enable run-time memory check for debug builds.
#if defined(DEBUG) | defined(_DEBUG)
    _CrtSetDbgFlag( _CRTDBG_ALLOC_MEM_DF 
| _CRTDBG_LEAK_CHECK_DF );
#endif

    
// Set the callback functions
    DXUTSetCallbackDeviceCreated( OnCreateDevice );
    DXUTSetCallbackDeviceReset( OnResetDevice );
    DXUTSetCallbackDeviceLost( OnLostDevice );
    DXUTSetCallbackDeviceDestroyed( OnDestroyDevice );
    DXUTSetCallbackMsgProc( MsgProc );
    DXUTSetCallbackFrameRender( OnFrameRender );
    DXUTSetCallbackFrameMove( OnFrameMove );
    DXUTSetCallbackKeyboard(OnKeyboardProc);
   
    
// TODO: Perform any application-level initialization here
    InitDialogs();

    
// Initialize DXUT and create the desired Win32 window and Direct3D device for the application
    DXUTInit( truetruetrue ); // Parse the command line, handle the default hotkeys, and show msgboxes
    DXUTSetCursorSettings( truetrue ); // Show the cursor and clip it when in full screen
    DXUTCreateWindow( L"Texture Color And Alpha Blend" );
    DXUTCreateDevice( D3DADAPTER_DEFAULT, 
true640480, IsDeviceAcceptable, ModifyDeviceSettings );

    
// Start the render loop
    DXUTMainLoop();

    
// TODO: Perform any application-level cleanup here

    
return DXUTGetExitCode();
}


下载示例工程


posted on 2008-05-20 16:17 lovedday 阅读(1757) 评论(4)  编辑 收藏 引用

评论

# re: 高级纹理映射技术(5) 2008-05-20 18:27 w2001

楼主,你的文章写得很好哇~ 我有个问题想请教你一下,不知你看高级纹理映射看的是哪本书?我一直找不到一本好教材,郁闷~~~  回复  更多评论   

# re: 高级纹理映射技术(5) 2008-05-20 18:51 lovedday

马马虎虎啦,呵呵。我看的是《精通 DirectX 3D 图形与动画程序设计》,写出来的主要目的是方便查阅,也为了加深印象。  回复  更多评论   

# re: 高级纹理映射技术(5) 2008-05-20 20:43 w2001

哦。你总结得很好啊,看得出楼主是很勤奋的人,向你学习!呵呵  回复  更多评论   

# re: 高级纹理映射技术(5) 2008-05-20 21:00 lovedday

不勤奋不行啊,这世道。  回复  更多评论   


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