Text3D是什么

Text3D就是一个网格模型，在3D空间中，文字对象对待方式就是一个模型，只不过代表的信息很不一般罢了。Text3D看起来有一定的立体感觉，因为有Z轴控制。这篇文章主要研究Text3D如何显示到3D场景中的。

Text3D显示原理

Text3D将文字看成一般的网格模型，设置属性的时候按照字体来设置，最后显示的时候按照3D空间中的网格模型来显示。

Text3D程序实现

说明

程序中有关Text3D的重要部分，我用中文注释了，如果想研究程序的框架，请参考DXUT。

程序源码

#pragma once

//win32
#pragma comment(lib,"comctl32.lib")
#pragma comment(lib,"winmm.lib")

//d3d
#pragma comment(lib,"dxerr.lib")
#pragma comment(lib,"d3dx9.lib")

//dxut
#pragma comment(lib,"dxut.lib")

//dxut
#include"DXUT.h"

HRESULT CALLBACK OnDeviceCreate( 
	IDirect3DDevice9* pd3dDevice,
	const D3DSURFACE_DESC* pBackBufferSurfaceDesc, 
	void* pUserContext );

void    CALLBACK OnDeviceDestroyed(void* pUserContext );

void    CALLBACK OnFrameRender(
	IDirect3DDevice9* pd3dDevice,
	double fTime,
	float fElapsedTime, 
	void* pUserContext );

void SetUpMatrix(IDirect3DDevice9* pd3dDevice);

void SetupLight(IDirect3DDevice9* pd3dDevice);

//TODO: global variables.
//声明文字模型
ID3DXMesh* g_pd3dxTextMesh=NULL;

INT WINAPI wWinMain(
	HINSTANCE,
	HINSTANCE,
	LPWSTR,
	INT)
{
	DXUTSetCallbackD3D9DeviceCreated(
		OnDeviceCreate,
		NULL);

	DXUTSetCallbackD3D9DeviceDestroyed(
		OnDeviceDestroyed,
		NULL);

	DXUTSetCallbackD3D9FrameRender(
		OnFrameRender,
		NULL);

	//0.dxut init.
	DXUTInit(true,true,NULL,true);

	//1.create window
	DXUTCreateWindow(
		L"dxut window",
		GetModuleHandle(NULL),
		NULL,
		NULL,
		CW_USEDEFAULT,
		CW_USEDEFAULT);

	//2.create device.
	DXUTCreateDevice(true,640,480);

	//3.main loop
	DXUTMainLoop();

	//exit.
	return DXUTGetExitCode();
}

HRESULT CALLBACK OnDeviceCreate( 
	IDirect3DDevice9* pd3dDevice,
	const D3DSURFACE_DESC* pBackBufferSurfaceDesc, 
	void* pUserContext )
{
	//TODO: create d3d device.
	//创建文字模型。
	HDC hdc=CreateCompatibleDC(NULL);
	HFONT hNewFont=NULL;
	HFONT hOldFont=NULL;

	hNewFont=CreateFont(
		24,
		0,
		0,
		0,
		FW_BOLD,
		FALSE,
		FALSE,
		FALSE,
		DEFAULT_CHARSET,
		OUT_DEFAULT_PRECIS,
		CLIP_DEFAULT_PRECIS,
		DEFAULT_QUALITY,
		DEFAULT_PITCH|FF_DONTCARE,
		L"Arial");

	hOldFont=(HFONT)SelectObject(hdc,hNewFont);

	if(FAILED(D3DXCreateText(
		pd3dDevice,
		hdc,
		L"你好，世界！",
		0.001f,
		0.4f,
		&g_pd3dxTextMesh,
		NULL,
		NULL)))
	{
		return E_FAIL;
	}

	SelectObject(hdc,hOldFont);

	DeleteObject(hNewFont);
	DeleteDC(hdc);

	return S_OK;
}

void    CALLBACK OnDeviceDestroyed(
	void* pUserContext )
{
	//TODO:destroy d3d device.
	//释放文字模型
	if(g_pd3dxTextMesh != NULL)
	{
		g_pd3dxTextMesh->Release();
		g_pd3dxTextMesh=NULL;
	}
}

void    CALLBACK OnFrameRender(
	IDirect3DDevice9* pd3dDevice,
	double fTime,
	float fElapsedTime, 
	void* pUserContext )
{
	pd3dDevice->Clear(
		0,
		NULL,
		D3DCLEAR_TARGET,
		D3DCOLOR_XRGB(0,0,255),
		1.0f,
		0);

	//设置矩阵变换
	SetUpMatrix(pd3dDevice);

	SetupLight(pd3dDevice);

	if(SUCCEEDED(pd3dDevice->BeginScene()))
	{
		//TODO:render d3d scene.
		//绘制文字模型
		g_pd3dxTextMesh->DrawSubset(0);

		pd3dDevice->EndScene();
	}

	pd3dDevice->Present(NULL,NULL,NULL,NULL);
}

void SetUpMatrix(IDirect3DDevice9* pd3dDevice)
{
	D3DXMATRIXA16 worldMatrix;
	D3DXMatrixIdentity(&worldMatrix);
	D3DXMatrixTranslation(&worldMatrix,-2.0f,0.0f,0.0f);
	pd3dDevice->SetTransform(D3DTS_WORLD,&worldMatrix);

	D3DXMATRIXA16 viewMatrix;
	D3DXVECTOR3 vEye(0.0f,0.0f,-10.0f);
	D3DXVECTOR3 vLookAt(0.0f,0.0f,0.0f);
	D3DXVECTOR3 vUp(0.0f,1.0f,0.0f);
	D3DXMatrixLookAtLH(&viewMatrix,&vEye,&vLookAt,&vUp);
	pd3dDevice->SetTransform(D3DTS_VIEW,&viewMatrix);

	D3DXMATRIXA16 projectionMatrix;
	D3DXMatrixPerspectiveFovLH(&projectionMatrix,D3DX_PI/4,1.0f,1.0f,1000.0f);
	pd3dDevice->SetTransform(D3DTS_PROJECTION,&projectionMatrix);
}

void SetupLight(IDirect3DDevice9* pd3dDevice)
{
	D3DMATERIAL9 mtrl;
	ZeroMemory(&mtrl,sizeof(mtrl));
	mtrl.Ambient.r=mtrl.Diffuse.r=1.0f;
	mtrl.Ambient.g=mtrl.Diffuse.g=1.0f;
	mtrl.Ambient.b=mtrl.Diffuse.b=0.0f;
	mtrl.Ambient.a=mtrl.Diffuse.a=1.0f;
	pd3dDevice->SetMaterial(&mtrl);

	D3DLIGHT9 light;
	D3DXVECTOR3 dir(1.0f,0.0f,0.0f);
	D3DXCOLOR color(1.0f,1.0f,1.0f,0.0f);
	ZeroMemory(&light,sizeof(light));
	light.Type=D3DLIGHT_DIRECTIONAL;
	light.Ambient=color*0.6f;
	light.Diffuse=color;
	light.Specular=color*0.6f;
	light.Direction=dir;
	pd3dDevice->SetLight(0,&light);
	pd3dDevice->LightEnable(0,TRUE);

	pd3dDevice->SetRenderState(D3DRS_LIGHTING,TRUE);
	pd3dDevice->SetRenderState(D3DRS_NORMALIZENORMALS,TRUE);
}

Text3D程序结果

Text3D总结

1.程序的逻辑不是很难，声明3D文字模型，创建文字模型，渲染显示文字模型，释放文字模型。

2.需要注意的地方是 创建文字模型 需要有字体属性，这里的字体是windowsGUI里面的字体。创建字体需要获得设备句柄。在渲染的时候需要设置坐标转换，字体的位置按照第一个字的左下角定位。

3.需要注意的函数

  创建字体：CreateFont()

  创建文字模型：D3DXCreateText()

  平移矩阵函数：D3DXMatrixTranslation()

4.呵呵，我终于把文字研究了一下 ，刚开始的时候连程序都看不懂，就是抄程序抄出来的，慢慢的也就理解了，可是距离研究游戏引擎还远呢。

D3D文字 Text3D