（转）纹理坐标变换

Direct3D提供了对生成的纹理坐标进行坐标变换的功能，与顶点坐标变换相类似，可以指定一个4x4的纹理坐标变换矩阵，把它与生成的纹理坐标相乘，然后将变换之后的纹理坐标输出至Direct3D渲染流水线。使用纹理坐标变换可以对纹理坐标进行诸如平移、旋转和缩放等三维变换。纹理坐标变换对于生成一些特殊效果是非常有用的，它不用直接修改顶点的纹理坐标。例如可以通过一个简单的平移矩阵对纹理坐标进行变换，从而使物体表面上的纹理不断变换位置，产生动画效果。纹理坐标自动生成在三维图形程序中最广泛的应用是环境映射。

可通过函数IDirect3DDevice9::SetTransform()来设置4x4的纹理坐标变换矩阵，它以D3DTS_TEXTURE0~ D3DTS_TEXTURE7作为第一个参数，表示设置纹理层0~7的纹理矩阵。下列代码对纹理层0设置了一个将纹理坐标u、v缩小到原来一半的纹理矩阵：

D3DXMATRIX mat;
D3DXMatrixIdentity(&mat);
mat._11 = 0.5f;
mat._22 = 0.5f;
pd3dDevice->SetTransform(D3DTS_TEXTURE0, &mat);

下面的代码将原来的纹理坐标平移（1.0, 1.0, 0）个单位。

D3DXMATRIX mat;
D3DXMatrixIdentity(&mat);
mat._41 = 1.0f;
mat._42 = 1.0f;
mat._43 = 0.0f;
pd3dDevice->SetTransform(D3DTS_TEXTURE0, &mat);

示例程序通过下列代码对自动生成的纹理坐标进行变换：

// texture coordinate transform

D3DXMATRIX mat_texture, mat_scale, mat_trans;

D3DXMatrixIdentity(&mat_texture);
D3DXMatrixScaling(&mat_scale, 0.5f, -0.5f, 1.0f);
D3DXMatrixTranslation(&mat_trans, 0.5f, 0.5f, 1.0f);

mat_texture = mat_texture * mat_scale * mat_trans;
pd3dDevice->SetTransform(D3DTS_TEXTURE0, &mat_texture);

运行效果图：

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;
    D3DCOLOR color;
};

#define D3DFVF_CUSTOM_VERTEX    (D3DFVF_XYZ | D3DFVF_DIFFUSE)

const D3DXCOLOR FONT_COLOR(1.0f, 0.5f, 0.25f, 1.0f);

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;

//--------------------------------------------------------------------------------------
// 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, 18, 0, FW_BOLD, 1, FALSE, DEFAULT_CHARSET, OUT_DEFAULT_PRECIS, DEFAULT_QUALITY,
                   DEFAULT_PITCH | FF_DONTCARE, L"Arial", &g_font);

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

    sCustomVertex vertices[] =     
    {
        { -1.0f, -1.0f,  0.0f,  0xFFFFFFFF},
        { -1.0f,  1.0f,  0.0f,  0xFFFFFFFF},
        {  1.0f, -1.0f,  0.0f,  0xFFFFFFFF},
        {  1.0f,  1.0f,  0.0f,  0xFFFFFFFF}
    };

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

    void* ptr;
    g_vertex_buffer->Lock(0, sizeof(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 - 170, 0);
    g_button_dlg.SetSize(170, 170);

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

    // setup view matrix

    D3DXMATRIX mat_view;
    D3DXVECTOR3 eye(0.0f, 0.0f, -3.0f);
    D3DXVECTOR3  at(0.0f, 0.0f,  0.0f);
    D3DXVECTOR3  up(0.0f, 1.0f,  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, 1.0f, 100.0f);
    pd3dDevice->SetTransform(D3DTS_PROJECTION, &mat_proj);

    pd3dDevice->SetRenderState(D3DRS_LIGHTING, FALSE);

    // set texture color blend method, disalbe alpha blend.

    pd3dDevice->SetTexture(0, g_texture);    
    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_ALPHAOP,            D3DTOP_DISABLE);

    // create texture coordinate using vertex position in camera space 
    pd3dDevice->SetTextureStageState(0, D3DTSS_TEXCOORDINDEX,            D3DTSS_TCI_CAMERASPACEPOSITION);    
    pd3dDevice->SetTextureStageState(0, D3DTSS_TEXTURETRANSFORMFLAGS,    D3DTTFF_COUNT2);

    // texture coordinate transform

    D3DXMATRIX mat_texture, mat_scale, mat_trans;

    D3DXMatrixIdentity(&mat_texture);
    D3DXMatrixScaling(&mat_scale, 0.5f, -0.5f, 1.0f);
    D3DXMatrixTranslation(&mat_trans, 0.5f, 0.5f, 1.0f);

    mat_texture = mat_texture * mat_scale * mat_trans;
    pd3dDevice->SetTransform(D3DTS_TEXTURE0, &mat_texture);

    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(5, 5);
    text_helper.SetForegroundColor(FONT_COLOR);
    text_helper.DrawTextLine( DXUTGetFrameStats(true) );
    text_helper.DrawTextLine( DXUTGetDeviceStats() );

    // show other simple information
    //text_helper.SetForegroundColor( D3DXCOLOR(0.2f, 0.5f, 0.8f, 1.0f) );
    //text_helper.DrawTextLine(L"Texture Coordinate Transform");

    // 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(1.0f, 1.0f, 1.0f, 1.0f) );
        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(0, 0, 0, 0), 1.0f, 0) );

    // Render the scene
    if( SUCCEEDED( pd3dDevice->BeginScene() ) )
    {
        pd3dDevice->SetStreamSource(0, g_vertex_buffer, 0, sizeof(sCustomVertex));
        pd3dDevice->SetFVF(D3DFVF_CUSTOM_VERTEX);
        pd3dDevice->DrawPrimitive(D3DPT_TRIANGLESTRIP, 0, 2);

        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 event, int 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( true, true, true ); // Parse the command line, handle the default hotkeys, and show msgboxes
    DXUTSetCursorSettings( true, true ); // Show the cursor and clip it when in full screen
    DXUTCreateWindow( L"Texture Coordinate Transform" );
    DXUTCreateDevice( D3DADAPTER_DEFAULT, true, 640, 480, IsDeviceAcceptable, ModifyDeviceSettings );

    // Start the render loop
    DXUTMainLoop();

    // TODO: Perform any application-level cleanup here

    return DXUTGetExitCode();
}