添加文本

DXUT框架對文本繪制進行了封裝，提供了類CDXUTHelper來簡化文本顯示，使用該接口大體分為3個步驟：初始化ID3DXSprite和ID3DXFont對象，顯示文本，釋放ID3DXSprite和ID3DXFont對象。

首先來看看CDXUTHelper的定義部分：

接著來看看CDXUTHelper的實現部分：

以及ID3DXSprite::Begin()的聲明：

Prepares a device for drawing sprites.

HRESULT Begin(
  DWORD Flags
);

Parameters

Flags

[in] Combination of zero or more flags that describe sprite rendering options. For this method, the valid flags are:

• D3DXSPRITE_ALPHABLEND
• D3DXSprite__BILLBOARD
• D3DXSPRITE_DONOTMODIFY_RENDERSTATE
• D3DXSPRITE_DONOTSAVESTATE
• D3DXSPRITE_OBJECTSPACE
• D3DXSprite__SORT_DEPTH_BACKTOFRONT
• D3DXSprite__SORT_DEPTH_FRONTTOBACK
• D3DXSprite__SORT_TEXTURE

For a description of the flags and for information on how to control device state capture and device view transforms, see D3DXSPRITE.

Return Values

If the method succeeds, the return value is S_OK. If the method fails, the return value can be one of the following: D3DERR_INVALIDCALL, D3DERR_OUTOFVIDEOMEMORY, D3DXERR_INVALIDDATA, E_OUTOFMEMORY.

Remarks

This method must be called from inside a IDirect3DDevice9::BeginScene . . . IDirect3DDevice9::EndScene sequence. ID3DXSprite::Begin cannot be used as a substitute for either IDirect3DDevice9::BeginScene or ID3DXRenderToSurface::BeginScene.

This method will set the following states on the device.

Render States:

Texture Stage States:

Sampler States:

Note    This method disables N-patches.

D3DXSPRITE

The following flags are used to specify sprite rendering options to the flags parameter in the ID3DXSprite::Begin method:

初始化ID3DXSprite和ID3DXFont對象

在回調函數OnCreateDevice()中創建ID3DXFont對象：

//--------------------------------------------------------------------------------------
// Create any D3DPOOL_MANAGED resources here 
//--------------------------------------------------------------------------------------
HRESULT CALLBACK OnCreateDevice( IDirect3DDevice9* pd3dDevice, const D3DSURFACE_DESC* pBackBufferSurfaceDesc, 
								 void* pUserContext )
{
	D3DXCreateFont(pd3dDevice, 18, 0, FW_BOLD, 1, FALSE, DEFAULT_CHARSET, OUT_DEFAULT_PRECIS, DEFAULT_QUALITY,
				   DEFAULT_PITCH | FF_DONTCARE, L"Arial", &g_font);

    return S_OK;
}

繪制文本

//--------------------------------------------------------------------------------------
// 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( D3DXCOLOR(1.0f, 0.475f, 0.0f, 1.0f) );
	text_helper.DrawTextLine( DXUTGetFrameStats(true) );
	text_helper.DrawTextLine( DXUTGetDeviceStats() );

	// show other simple information
	text_helper.SetForegroundColor( D3DXCOLOR(1.0f, 1.0f, 1.0f, 1.0f) );
	text_helper.DrawTextLine(L"Put whatever misc status here");

	// show helper information
	

	const D3DSURFACE_DESC* surface_desc = DXUTGetBackBufferSurfaceDesc();

	if(g_show_help)
	{
		text_helper.SetInsertionPos(10, surface_desc->Height - 15 * 6);
		text_helper.SetForegroundColor( D3DXCOLOR(1.0f, 0.475f, 0.0f, 1.0f) );
		text_helper.DrawTextLine(L"Controls (F1 to hide):");
		

		text_helper.SetInsertionPos(40, surface_desc->Height - 15 * 5);
		text_helper.DrawTextLine(L"Quir: 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();
}

處理鍵盤消息

程序通過鍵盤上的"F1"鍵切換來表明是否顯示簡單幫助文本，處理代碼如下：

//--------------------------------------------------------------------------------------
// 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;
		}
	}
}

運行效果圖：

主程序：

下載示例工程