Direct-X学习笔记--天空盒

学习了三维的地形系统之后，该抬头看看天空啦。下面学习一下传说中的三维天空系统。其实三维天空的实现比地形系统简单得多，我们只需要用一点点小伎俩，就可以蒙混大多数人。

一.简介

我们在玩游戏的时候，尤其是野外的大场景中，要想更逼真离不开三维天空系统。要用程序来模拟无边无际的天空是不可能的，而聪明的前辈们自然也想到了用“天圆地方”这种古代人们对于天空的认识来作为三维天空设计思想。即用一个足够大的面罩住我们，只要这个罩足够大，在里面看天空就和真实的天空没什么区别啦。而基于这种思想的天空设计方案中，最常用的就是天空盒。所谓天空盒，就是用一个立方体，罩住玩家所在的世界空间，天空盒常常是24个点，6个面，也可以是5个面，地面用三维地形，就不需要天空盒来覆盖了。

而要做出天空的效果，我们就必须要去找到一些天空的纹理素材，找到几张无缝拼接的图片，作为纹理贴图，这样我们看起来才不会穿帮。

二.天空盒类的设计

天空盒其实比较简单，就是一个立方体，然后在立方体的内侧进行纹理贴图即可。要注意的就是纹理贴图的顺序不要搞错，不然一眼就会被发现。

和之前的地形系统一样，都需要保存设备指针，系统内部自己设定顶点，然后根据参数初始化天空盒的大小，以及设置纹理贴图。使用时，我们只需要设定这几个参数就可以创建出各式各样的天空系统啦！

.h文件

/*!
 * \file SkyBox.h
 *
 * \author puppet_master
 * \date 七月 2015
 *
 * 三维天空盒的封装
 */
#ifndef __SKYBOX_H_
#define __SKYBOX_H_

#pragma once

struct SkyBoxVertex
{
	float x, y, z;  //定点位置
	float u, v;		//纹理位置
};
#define D3DFVF_SKYBOX D3DFVF_XYZ | D3DFVF_TEX1


class CSkyBox
{
private:
	LPDIRECT3DDEVICE9 m_pDevice;			//设备指针
	LPDIRECT3DVERTEXBUFFER9 m_pVertexBuffer;//定点缓冲区指针
	LPDIRECT3DTEXTURE9 m_pTexture[5];		//纹理对象指针
	float m_fLength;						//天空盒宽度
public:
	CSkyBox(LPDIRECT3DDEVICE9 pDevice);
	virtual ~CSkyBox(void);

	//初始化天空盒
	bool InitSkyBox(float length);

	//加载纹理
	bool InitSkyBoxTexture(LPSTR szFrontTexture, LPSTR szBackTexture, LPSTR szLeftTexture, LPSTR szRightTexture, LPSTR szTopTexture);
	
	//渲染天空盒
	void RenderSkyBox(D3DXMATRIX *matWorld, bool bRenderFrame = false);
};


#endif

.cpp文件

#include "stdafx.h"
#include "SkyBox.h"


CSkyBox::CSkyBox(LPDIRECT3DDEVICE9 pDevice)
{
	m_pDevice = pDevice;
	m_pVertexBuffer = NULL;
	for (int i = 0; i < 5; i++)
		m_pTexture[i] = NULL;
	m_fLength = 0.0f;
}


CSkyBox::~CSkyBox(void)
{
	SAFE_RELEASE(m_pVertexBuffer);
	for (int i = 0; i < 5; i++)
	{
		SAFE_RELEASE(m_pTexture[i]);
	}
}

bool CSkyBox::InitSkyBox(float length)
{
	m_fLength = length;

	//创建定点缓冲区
	m_pDevice->CreateVertexBuffer(20 * sizeof(SkyBoxVertex), 0, D3DFVF_SKYBOX, D3DPOOL_MANAGED, &m_pVertexBuffer, 0);

	SkyBoxVertex vertices[] = 
	{
		//前面的顶点
		{-m_fLength / 2, 0.0f, m_fLength / 2, 0.0f, 1.0f,},
		{-m_fLength / 2, m_fLength / 2, m_fLength / 2, 0.0f, 0.0f,}, 
		{m_fLength / 2, 0.0f, m_fLength / 2, 1.0f, 1.0f,},
		{m_fLength / 2, m_fLength / 2, m_fLength / 2,  1.0f, 0.0f,},

		//后面的顶点
		{m_fLength / 2, 0.0f, -m_fLength / 2, 0.0f, 1.0f,},
		{m_fLength / 2, m_fLength / 2, -m_fLength / 2, 0.0f, 0.0f,},
		{-m_fLength / 2, 0.0f, -m_fLength / 2, 1.0f, 1.0f,},
		{-m_fLength / 2, m_fLength / 2, -m_fLength / 2, 1.0f, 0.0f,},

		//左面的顶点
		{-m_fLength / 2, 0.0f, -m_fLength / 2 , 0.0f, 1.0f,},
		{-m_fLength / 2, m_fLength / 2, -m_fLength / 2, 0.0f, 0.0f,},
		{-m_fLength / 2, 0.0f, m_fLength / 2, 1.0f, 1.0f,},
		{-m_fLength / 2, m_fLength / 2, m_fLength / 2, 1.0f, 0.0f,},

		//右面的顶点
		{m_fLength / 2, 0.0f, m_fLength / 2, 0.0f, 1.0f,},
		{m_fLength / 2, m_fLength / 2, m_fLength / 2, 0.0f, 0.0f,},
		{m_fLength / 2, 0.0f, -m_fLength / 2, 1.0f, 1.0f,},
		{m_fLength / 2, m_fLength / 2, -m_fLength / 2, 1.0f, 0.0f,},

		//上面的顶点
		{m_fLength / 2, m_fLength / 2, -m_fLength / 2, 1.0f, 0.0f,}, 
		{m_fLength / 2, m_fLength / 2, m_fLength / 2, 1.0f, 1.0f,},
		{-m_fLength / 2, m_fLength / 2, -m_fLength / 2, 0.0f, 0.0f,},
		{-m_fLength / 2, m_fLength / 2, m_fLength / 2, 0.0f, 1.0f,},
	};
	//填充定点缓冲数据
	void* pVertices = NULL;
	//加锁
	m_pVertexBuffer->Lock(0, 0, (void**)&pVertices, 0);
	//拷贝顶点数据到缓冲区中
	memcpy(pVertices, vertices, sizeof(vertices));
	//解锁
	m_pVertexBuffer->Unlock();



	return true;
}

bool CSkyBox::InitSkyBoxTexture(LPSTR szFrontTexture, LPSTR szBackTexture, LPSTR szLeftTexture, LPSTR szRightTexture, LPSTR szTopTexture)
{
	//从文件中加载天空盒纹理
	D3DXCreateTextureFromFile(m_pDevice, szFrontTexture, &m_pTexture[0]);//前
	D3DXCreateTextureFromFile(m_pDevice, szBackTexture, &m_pTexture[1]);//后
	D3DXCreateTextureFromFile(m_pDevice, szLeftTexture, &m_pTexture[2]);//左
	D3DXCreateTextureFromFile(m_pDevice, szRightTexture, &m_pTexture[3]);//右
	D3DXCreateTextureFromFile(m_pDevice, szTopTexture, &m_pTexture[4]);//上
	
	return true;
}

void CSkyBox::RenderSkyBox(D3DXMATRIX *matWorld, bool bRenderFrame /* = false */)
{
	//纹理颜色混合的第一个参数用于输出
	m_pDevice->SetTextureStageState(0, D3DTSS_COLOROP, D3DTOP_SELECTARG1);
	//纹理颜色混合的第一个参数取纹理的颜色值
	m_pDevice->SetTextureStageState(0, D3DTSS_COLORARG1, D3DTA_TEXTURE);
	//世界变换
	m_pDevice->SetTransform(D3DTS_WORLD, matWorld);
	//设置资源流
	m_pDevice->SetStreamSource(0, m_pVertexBuffer, 0, sizeof(SkyBoxVertex));
	//设置灵活顶点格式
	m_pDevice->SetFVF(D3DFVF_SKYBOX);

	//绘制
	for(int i = 0; i < 5; i++)
	{
		m_pDevice->SetTexture(0, m_pTexture[i]);
		m_pDevice->DrawPrimitive(D3DPT_TRIANGLESTRIP, i * 4, 2);
	}
}

三.天空盒类的使用

CSkyBox*      g_pSkyBox      = NULL;	//天空盒类指针

void CreateSkyBox()
{
	g_pSkyBox = new CSkyBox(g_pDevice);
	g_pSkyBox->InitSkyBox(20000.0f);
	g_pSkyBox->InitSkyBoxTexture("skyfront.png", "skyback.png", "skyleft.png", "skyright.png", "skytop.png");
}

D3DXMatrixTranslation(&matWorldSky, 0.0f, -2000.0f, 0.0f);
g_pSkyBox->RenderSkyBox(&matWorldSky);

换个角度：

飞到天外：

附上主体代码：

// D3DDemo.cpp : 定义应用程序的入口点。
//

#include "stdafx.h"
#include "D3DDemo.h"
#include "DirectInput.h"
#include "Camera.h"
#include "Terrain.h"
#include "Mesh.h"
#include "SkyBox.h"
#include "Particle.h"

#define MAX_LOADSTRING 100


// 全局变量:
HINSTANCE hInst;								// 当前实例
TCHAR szTitle[MAX_LOADSTRING];					// 标题栏文本
TCHAR szWindowClass[MAX_LOADSTRING];			// 主窗口类名

// 此代码模块中包含的函数的前向声明:
HWND                g_hWnd;
ATOM				MyRegisterClass(HINSTANCE hInstance);
BOOL				InitInstance(HINSTANCE, int);
LRESULT CALLBACK	WndProc(HWND, UINT, WPARAM, LPARAM);

//---------改造3D窗口需要的内容------------
LPDIRECT3D9 g_pD3D = NULL;				//D3D接口指针
LPDIRECT3DDEVICE9 g_pDevice = NULL;		//D3D设备指针
CDirectInput* g_pDirectInput = NULL;	//控制指针
CCamera*      g_pCamera      = NULL;    //摄像机指针
CTerrain*     g_pTerrian     = NULL;	//地形类指针
CSkyBox*      g_pSkyBox      = NULL;	//天空盒类指针
CMesh*        g_pMesh1       = NULL;	//网格对象指针1
CMesh*        g_pMesh2       = NULL;	//网格对象指针2
CMesh*        g_pMesh3       = NULL;	//网格对象指针3

D3DXMATRIX g_matWorld;							//世界矩阵


void onCreatD3D()
{
	g_pD3D = Direct3DCreate9(D3D_SDK_VERSION);
	if (!g_pD3D)
		return;

	//检测硬件设备能力的方法
	/*D3DCAPS9 caps;
	ZeroMemory(&caps, sizeof(caps));
	g_pD3D->GetDeviceCaps(D3DADAPTER_DEFAULT, D3DDEVTYPE_HAL, &caps);*/

	//获得相关信息，屏幕大小，像素点属性
	D3DDISPLAYMODE d3ddm;
	ZeroMemory(&d3ddm, sizeof(d3ddm));

	g_pD3D->GetAdapterDisplayMode(D3DADAPTER_DEFAULT, &d3ddm);


	//设置全屏模式
	D3DPRESENT_PARAMETERS d3dpp;
	ZeroMemory(&d3dpp, sizeof(d3dpp));
	/*d3dpp.Windowed = false;
	d3dpp.BackBufferWidth = d3ddm.Width;
	d3dpp.BackBufferHeight = d3ddm.Height;*/

	d3dpp.Windowed = true;
	d3dpp.BackBufferFormat = d3ddm.Format;
	d3dpp.BackBufferCount = 1;

	d3dpp.SwapEffect = D3DSWAPEFFECT_DISCARD;//交换后原缓冲区数据丢弃

	//是否开启自动深度模板缓冲
	d3dpp.EnableAutoDepthStencil = true;
	//当前自动深度模板缓冲的格式
	d3dpp.AutoDepthStencilFormat = D3DFMT_D16;//每个像素点有16位的存储空间，存储离摄像机的距离
	

	g_pD3D->CreateDevice(D3DADAPTER_DEFAULT, D3DDEVTYPE_HAL, g_hWnd, D3DCREATE_SOFTWARE_VERTEXPROCESSING, &d3dpp, &g_pDevice);

	if (!g_pDevice)
		return;

	//设置渲染状态，设置启用深度值
	g_pDevice->SetRenderState(D3DRS_ZENABLE, true);

	//设置渲染状态，关闭灯光
	//g_pDevice->SetRenderState(D3DRS_LIGHTING, false);

	//设置渲染状态，裁剪模式
	g_pDevice->SetRenderState(D3DRS_CULLMODE, D3DCULL_NONE);

	//g_pDevice->SetRenderState(D3DRS_CULLMODE, D3DCULL_NONE) ;

}

void CreateMesh()
{
	g_pMesh1 = new CMesh(g_pDevice);
	g_pMesh1->CreateMesh("Demon.X");

	g_pMesh2 = new CMesh(g_pDevice);
	g_pMesh2->CreateMesh("dragon.X");

	g_pMesh3 = new CMesh(g_pDevice);
	g_pMesh3->CreateMesh("miki.X");
}

void CreateCamera()
{
	g_pCamera = new CCamera(g_pDevice);
	g_pCamera->SetCameraPosition(&D3DXVECTOR3(0.0f, 800.0f, -500.0f));
	g_pCamera->SetTargetPosition(&D3DXVECTOR3(0.0f, 800.0f, 0.0f));
	g_pCamera->SetViewMatrix();
	g_pCamera->SetProjectionMartix();
}

void CreateTerrain()
{
	g_pTerrian = new CTerrain(g_pDevice);
	g_pTerrian->LoadTerrainFromFile(TEXT("heighmap.raw"), TEXT("TerrainTexture.jpg"));
	g_pTerrian->InitTerrain(200, 200, 100.0f, 5.0f);
}

void CreateSkyBox()
{
	g_pSkyBox = new CSkyBox(g_pDevice);
	g_pSkyBox->InitSkyBox(20000.0f);
	g_pSkyBox->InitSkyBoxTexture("skyfront.png", "skyback.png", "skyleft.png", "skyright.png", "skytop.png");
}

void SetLight()
{
	D3DLIGHT9 light;  
	::ZeroMemory(&light, sizeof(light));  
	light.Type          = D3DLIGHT_DIRECTIONAL;  
	light.Ambient       = D3DXCOLOR(0.7f, 0.7f, 0.7f, 1.0f);  
	light.Diffuse       = D3DXCOLOR(1.0f, 1.0f, 1.0f, 1.0f);  
	light.Specular      = D3DXCOLOR(0.9f, 0.9f, 0.9f, 1.0f);  
	light.Direction     = D3DXVECTOR3(1.0f, 1.0f, 1.0f);  
	g_pDevice->SetLight(0, &light);  
	g_pDevice->LightEnable(0, true);  
	g_pDevice->SetRenderState(D3DRS_NORMALIZENORMALS, true);  
	g_pDevice->SetRenderState(D3DRS_SPECULARENABLE, true);
}



void onInit()
{
	//初始化D3D
	onCreatD3D();

	//创建Mesh模型
	CreateMesh();

	//创建摄像机
	CreateCamera();

	//创建地形
	CreateTerrain();

	//创建天空盒
	CreateSkyBox();
	
	//设置光照
	SetLight();
}



void onDestroy()
{
	SAFE_DELETE(g_pDirectInput);
	SAFE_DELETE(g_pCamera);
	SAFE_DELETE(g_pTerrian);
	SAFE_DELETE(g_pSkyBox);
	SAFE_RELEASE(g_pDevice);
	SAFE_DELETE(g_pMesh1);
	SAFE_DELETE(g_pMesh2);
	SAFE_DELETE(g_pMesh3);
}

void onLogic(float fElapsedTime)
{
	//使用DirectInput类读取数据
	g_pDirectInput->GetInput();

	// 沿摄像机各分量移动视角
	if (g_pDirectInput->IsKeyDown(DIK_A))  g_pCamera->MoveAlongRightVec(-10.0f);
	if (g_pDirectInput->IsKeyDown(DIK_D))  g_pCamera->MoveAlongRightVec( 10.0f);
	if (g_pDirectInput->IsKeyDown(DIK_W)) g_pCamera->MoveAlongLookVec( 10.0f);
	if (g_pDirectInput->IsKeyDown(DIK_S))  g_pCamera->MoveAlongLookVec(-10.0f);
	if (g_pDirectInput->IsKeyDown(DIK_I))  g_pCamera->MoveAlongUpVec( 10.0f);
	if (g_pDirectInput->IsKeyDown(DIK_K))  g_pCamera->MoveAlongUpVec(-10.0f);

	//沿摄像机各分量旋转视角
	if (g_pDirectInput->IsKeyDown(DIK_LEFT))  g_pCamera->RotationUpVec(-0.003f);
	if (g_pDirectInput->IsKeyDown(DIK_RIGHT))  g_pCamera->RotationUpVec( 0.003f);
	if (g_pDirectInput->IsKeyDown(DIK_UP))  g_pCamera->RotationRightVec(-0.003f);
	if (g_pDirectInput->IsKeyDown(DIK_DOWN))  g_pCamera->RotationRightVec( 0.003f);
	if (g_pDirectInput->IsKeyDown(DIK_J)) g_pCamera->RotationLookVec(-0.001f);
	if (g_pDirectInput->IsKeyDown(DIK_L)) g_pCamera->RotationLookVec( 0.001f);

	//鼠标控制右向量和上向量的旋转
	//g_pCamera->RotationUpVec(g_pDirectInput->MouseDX()* 0.001f);
	//g_pCamera->RotationRightVec(g_pDirectInput->MouseDY() * 0.001f);

	//鼠标滚轮控制观察点收缩操作
	static FLOAT fPosZ=0.0f;
	fPosZ += g_pDirectInput->MouseDZ()*3.0f;

	//计算并设置取景变换矩阵
	D3DXMATRIX matView;
	g_pCamera->CalculateViewMatrix(&matView);
	g_pDevice->SetTransform(D3DTS_VIEW, &matView);

	//把正确的世界变换矩阵存到g_matWorld中
	D3DXMatrixTranslation(&g_matWorld, 0.0f, 0.0f, fPosZ);

}

void onRender(float fElasedTime)
{
	//前两个参数是0和NULL时，清空整个游戏窗口的内容（清的是后台）
	//第三个是清除的对象：前面表示清除颜色缓冲区，后面表示清除深度缓冲区,D3DCLEAR_STENCIL清空模板缓冲区
	g_pDevice->Clear(0, NULL, D3DCLEAR_TARGET|D3DCLEAR_ZBUFFER, D3DCOLOR_XRGB(0,100,100), 1.0f, 0);

	g_pDevice->BeginScene();

	D3DXMATRIX matWorld1, matWorld2, matWorld3, matWorldTerrain, matWorldSky;  
	D3DXMatrixTranslation(&matWorld1, 0.0f, 800.0f, 0.0f);  
	D3DXMatrixTranslation(&matWorld2, 0.0f, 1300.0f, 0.0f);
	D3DXMatrixTranslation(&matWorld3, -30.0f, 900.0f, -50.0f);
	D3DXMatrixTranslation(&matWorldTerrain, 0.0f, 0.0f, 0.0f);
	D3DXMatrixTranslation(&matWorldSky, 0.0f, -2000.0f, 0.0f);

	g_pMesh1->DrawMesh(matWorld1);
	g_pMesh2->DrawMesh(matWorld2);
	g_pMesh3->DrawMesh(matWorld3);
	g_pSkyBox->RenderSkyBox(&matWorldSky);
	g_pTerrian->RenderTerrain(&matWorldTerrain, false);

	g_pDevice->EndScene();


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


int APIENTRY _tWinMain(_In_ HINSTANCE hInstance,
                     _In_opt_ HINSTANCE hPrevInstance,
                     _In_ LPTSTR    lpCmdLine,
                     _In_ int       nCmdShow){
	UNREFERENCED_PARAMETER(hPrevInstance);
	UNREFERENCED_PARAMETER(lpCmdLine);

 	// TODO: 在此放置代码。
	MSG msg;
	HACCEL hAccelTable;

	// 初始化全局字符串
	LoadString(hInstance, IDS_APP_TITLE, szTitle, MAX_LOADSTRING);
	LoadString(hInstance, IDC_D3DDEMO, szWindowClass, MAX_LOADSTRING);
	MyRegisterClass(hInstance);

	// 执行应用程序初始化:
	if (!InitInstance (hInstance, nCmdShow))
	{
		return FALSE;
	}

	hAccelTable = LoadAccelerators(hInstance, MAKEINTRESOURCE(IDC_D3DDEMO));

	

	ZeroMemory(&msg, sizeof(msg));
	while (msg.message != WM_QUIT)
	{
		if (PeekMessage(&msg, NULL, 0, 0, PM_REMOVE))
		{
			TranslateMessage(&msg);
			DispatchMessage(&msg);
		}
		else
		{
			static DWORD dwTime = timeGetTime();
			DWORD dwCurrentTime = timeGetTime();
			DWORD dwElapsedTime = dwCurrentTime - dwTime;
			float fElapsedTime = dwElapsedTime * 0.001f;

			//------------渲染和逻辑部分代码----------
			onLogic(fElapsedTime);
			onRender(fElapsedTime);
			//-----------------------------------------
			if (dwElapsedTime < 1000 / 60)
			{
				Sleep(1000/ 60 - dwElapsedTime);
			}
			dwTime = dwCurrentTime;
		}
	}

	onDestroy();
	return (int) msg.wParam;
}



//
//  函数: MyRegisterClass()
//
//  目的: 注册窗口类。
//
ATOM MyRegisterClass(HINSTANCE hInstance)
{
	WNDCLASSEX wcex;

	wcex.cbSize = sizeof(WNDCLASSEX);

	wcex.style			= CS_HREDRAW | CS_VREDRAW;
	wcex.lpfnWndProc	= WndProc;
	wcex.cbClsExtra		= 0;
	wcex.cbWndExtra		= 0;
	wcex.hInstance		= hInstance;
	wcex.hIcon			= LoadIcon(hInstance, MAKEINTRESOURCE(IDI_D3DDEMO));
	wcex.hCursor		= LoadCursor(NULL, IDC_ARROW);
	wcex.hbrBackground	= (HBRUSH)(COLOR_WINDOW+1);
	wcex.lpszMenuName	= MAKEINTRESOURCE(IDC_D3DDEMO);
	wcex.lpszClassName	= szWindowClass;
	wcex.hIconSm		= LoadIcon(wcex.hInstance, MAKEINTRESOURCE(IDI_SMALL));

	return RegisterClassEx(&wcex);
}

//
//   函数: InitInstance(HINSTANCE, int)
//
//   目的: 保存实例句柄并创建主窗口
//
//   注释:
//
//        在此函数中，我们在全局变量中保存实例句柄并
//        创建和显示主程序窗口。
//
BOOL InitInstance(HINSTANCE hInstance, int nCmdShow)
{

   hInst = hInstance; // 将实例句柄存储在全局变量中

   g_hWnd = CreateWindow(szWindowClass, szTitle, WS_OVERLAPPEDWINDOW,
      CW_USEDEFAULT, 0, CW_USEDEFAULT, 0, NULL, NULL, hInstance, NULL);

   if (!g_hWnd)
   {
      return FALSE;
   }

  //初始化DirectInput类
   g_pDirectInput = new CDirectInput();
   g_pDirectInput->Init(g_hWnd, hInst, DISCL_FOREGROUND|DISCL_NONEXCLUSIVE, DISCL_FOREGROUND|DISCL_NONEXCLUSIVE);

   SetMenu(g_hWnd, NULL);
   ShowWindow(g_hWnd, nCmdShow);
   UpdateWindow(g_hWnd);

   onInit();

   return TRUE;
}

//
//  函数: WndProc(HWND, UINT, WPARAM, LPARAM)
//
//  目的: 处理主窗口的消息。
//
//  WM_COMMAND	- 处理应用程序菜单
//  WM_PAINT	- 绘制主窗口
//  WM_DESTROY	- 发送退出消息并返回
//
//
LRESULT CALLBACK WndProc(HWND g_hWnd, UINT message, WPARAM wParam, LPARAM lParam)
{
	switch (message)
	{
	case WM_KEYDOWN:
		if (wParam == VK_ESCAPE)
			PostQuitMessage(0);
		break;
	case WM_CLOSE:
		DestroyWindow(g_hWnd);
		break;
	case WM_DESTROY:
		PostQuitMessage(0);
		break;
	default:
		return DefWindowProc(g_hWnd, message, wParam, lParam);
	}
	return 0;
}

Direct-X学习笔记--天空盒

原文：http://blog.csdn.net/puppet_master/article/details/47281617