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++实例程序

时间:2023-02-01 理论教育 版权反馈
【摘要】:以Microsoft Visual Studio为开发工具,基于Open GL图形库开发三维可视化的地学信息系统是比较快捷的方式。以下通过Microsoft Visual C++2010建立基于Open GL图形库的单文档应用程序框架为例,实现了一个简单的三维可视化系统。2.通过Class Wizard给视图类添加成员变量及成员函数,并增加WM_CREA-TE、WM_SIZE、WM_ERAZEBKGND、WM_KEYDOWN、WM_DESTROY等消息响应函数Ex Open GLView.h的主要程序代码内容如下:class CEx Open GLView:public CView{……
++实例程序_地学三维可视化与

以Microsoft Visual Studio为开发工具,基于Open GL图形库开发三维可视化的地学信息系统是比较快捷的方式。以下通过Microsoft Visual C++2010建立基于Open GL图形库的单文档应用程序框架为例,实现了一个简单的三维可视化系统。

1.使用MFCApp Wizard建立单文档的应用程序框架,并加入Open GL图形库

用MFC App Wizard创建一个单文档的MFC EXE项目,工程名称假设为“Ex Open GL”, Application Type选择“Single Document”,Project Style选择“MFC Standard”。如图7-4所示,在工程属性设置中的“Additional Dependencies”中添加“opengl32.lib;glaux.lib;glu32. lib”等Open GL图形库。

并在视图类的Ex Open GLView.h中增加Open GL图形库的文件包含:

#pragma once

#include<GL\GL.h>

#include<GL\GLU.h>

#include<GL\GLaux.h>

class CEx Open GLView:public CView

……

};

给工程添加一个位图资源IDB_BITMAP_SHOW对应某个图片,用于本例中的纹理贴图。

2.通过Class Wizard给视图类添加成员变量及成员函数,并增加WM_CREA-TE、WM_SIZE、WM_ERAZEBKGND、WM_KEYDOWN、WM_DESTROY等消息响应函数

Ex Open GLView.h的主要程序代码内容如下:

class CEx Open GLView:public CView

……

图7-4 应用程序框架设置中添加Open GL图形库

public:

void initialize RC();//初始化Open GL Render Context

void destroy RC();//删除Open GL Render Context

void display Scene();//渲染场景

//读资源位图

BYTE*glt Resource BMPBits(UINT n Resource,int*n Width,int*n Height);

void load Texture Image();//导入纹理图片

public:

CClient DC*m_p DC;//DC

HGLRC m_RC;//Open GL RC

//相机参数:眼睛位置,视点,向上方向

double m_eye Position[3],m_eye Center[3],m_eye Updirection[3];

int m_viewport[4];//视口参数(xloc,yloc,width,height)

};

Ex Open GLView.cpp中的成员函数代码主要如下:

#include"Resource.h"

#include<math.h>

#define PI 3.1415926

//读资源位图

BYTE*CEx Open GLView::glt Resource BMPBits(UINT n Resource,int*n Width,int*n Height)

HINSTANCE h Instance;//Instance Handle

HANDLE h Bitmap;//Handle to bitmap resource

BITMAPINFO bm Info;

BYTE*p Data;

//Find the bitmap resource

h Instance=Get Module Handle(NULL);

h Bitmap=Load Bitmap(h Instance,MAKEINTRESOURCE(n Resource));

if(h Bitmap==NULL)

return NULL;

Get Object(h Bitmap,sizeof(BITMAPINFO),&bm Info);

Delete Object(h Bitmap);

h Bitmap=Load Resource(h Instance,

Find Resource(h Instance,MAKEINTRESOURCE(n Resource),RT_BITMAP));

if(h Bitmap==NULL)

return NULL;

p Data=(BYTE*)Lock Resource(h Bitmap);

p Data+=sizeof(BITMAPINFO)1;

*n Width=bm Info.bmi Header.bi Width;//bm.bm Width;

*n Height=bm Info.bmi Header.bi Height;//bm.bm Height;

return p Data;

//导入纹理图片

void CEx Open GLView::load Texture Image()

BYTE*p Bytes;

int n Width,n Height;

p Bytes=glt Resource BMPBits(IDB_BITMAP_SHOW,&n Width,&n Height);

gl Tex Envi(GL_TEXTURE_ENV,GL_TEXTURE_ENV_MODE,GL_DECAL);

gl Tex Parameteri(GL_TEXTURE_2D,GL_TEXTURE_MIN_FILTER,GL_LINEAR);

gl Tex Parameteri(GL_TEXTURE_2D,GL_TEXTURE_MAG_FILTER,GL_LINEAR);

gl Tex Parameteri(GL_TEXTURE_2D,GL_TEXTURE_WRAP_S,GL_REPEAT);

gl Tex Parameteri(GL_TEXTURE_2D,GL_TEXTURE_WRAP_T,GL_REPEAT);

gl Tex Image2D(GL_TEXTURE_2D,0,GL_RGB8,n Width,n Height,0,

GL_BGR_EXT,GL_UNSIGNED_BYTE,p Bytes);

//初始化RC

void CEx Open GLView::initialize RC()

HDC hdc=m_p DC >Get Safe Hdc();

//初始化像素格式

PIXELFORMATDESCRIPTOR pfd={

sizeof(PIXELFORMATDESCRIPTOR), //pfd结构的大小

1, //版本号

PFD_DRAW_TO_WINDOW| //支持在窗口中绘图

PFD_SUPPORT_OPENGL| //支持Open GL

PFD_DOUBLEBUFFER, //双缓存模式

PFD_TYPE_RGBA, //RGBA颜色模式

24, //24位颜色深度

0,0,0,0,0,0, //忽略颜色位

0, //没有非透明度缓存

0, //忽略Alpha偏移位

0, //无累加缓存

0,0,0,0, //忽略累加位

32, //32位深度缓存

0, //无模板缓存

0, //无辅助缓存

PFD_MAIN_PLANE, //主层

0, //保留

0,0,0 //忽略层,可见性和损毁掩模

};

int pixelformat=::Choose Pixel Format(hdc,&pfd);//选择像素格式

BOOL rt=Set Pixel Format(hdc,pixelformat,&pfd);

m_RC=wgl Create Context(hdc);//创建RC

wgl Make Current(hdc,m_RC);//关联DC与RC

//删除RC

void CEx Open GLView::destroy RC()

wgl Make Current(NULL,NULL);

if(m_RC)

wgl Delete Context(m_RC);

m_RC=NULL;

//绘制场景

void CEx Open GLView::display Scene()

gl Clear Color(1.0f,1.0f,1.0f,1.0f);//背景为白色

gl Clear(GL_COLOR_BUFFER_BIT|GL_DEPTH_BUFFER_BIT|GL_STENCIL_BUFFER_BIT);

gl Draw Buffer(GL_BACK);

gl Enable(GL_COLOR_MATERIAL);

gl Enable(GL_DITHER);

gl Shade Model(GL_SMOOTH);

gl Enable(GL_DEPTH_TEST);//深度测试

gl Front Face(GL_CW);

gl Polygon Mode(GL_FRONT_AND_BACK,GL_FILL);

gl Viewport(m_viewport[0],m_viewport[1],m_viewport[2],m_viewport[3]);

gl Matrix Mode(GL_PROJECTION);

gl Load Identity();

int w=m_viewport[2],h=m_viewport[3];

if(w==0) w=1;

if(h==0) h=1;

glu Perspective(45.0,(double)w/(double)h,0.01,1000.0);

gl Matrix Mode(GL_MODELVIEW);

gl Load Identity();

wgl Use Font Bitmaps(wgl Get Current DC(),0,256,1000);

gl List Base(1000);

gl Color3ub(255,0,0);

gl Raster Pos3f(20.0f,35.0f,100.0f);//文字的三维位置

char info[]="Three dimensional visualization by Open GL.";

gl Call Lists(strlen(info),GL_UNSIGNED_BYTE,info);

glu Look At(m_eye Position[0],m_eye Position[1],m_eye Position[2],

m_eye Center[0],m_eye Center[1],m_eye Center[2],

m_eye Updirection[0],m_eye Updirection[1],m_eye Updirection[2]);

//绘制一个红色的平面

gl Push Matrix();//压入堆栈

gl Begin(GL_POLYGON);

gl Color3ub(255,0,0);

gl Vertex3d(1.0,1.0,1.0);

gl Vertex3d(1.0, 1.0,1.0);

gl Vertex3d(1.0, 1.0, 1.0);

gl Vertex3d(1.0,1.0,1.0);

gl End();

gl Pop Matrix();//弹出堆栈

//绘制一个绿色的半透明平面

gl Blend Func(GL_SRC_ALPHA,GL_ONE_MINUS_SRC_ALPHA);

gl Enable(GL_BLEND);

gl Push Matrix();//压入堆栈

gl Color4ub(0,255,0,125);//最后一个分量alpha表示透明度

gl Begin(GL_POLYGON);

gl Vertex3d(1.0, 1.0,1.0);

gl Vertex3d(1.0,1.0,1.0);

gl Vertex3d(1.0,1.0, 1.0);

gl Vertex3d(1.0, 1.0, 1.0);

gl End();

gl Pop Matrix();//弹出堆栈

gl Disable(GL_BLEND);

//绘制一个带纹理的平面

gl Enable(GL_TEXTURE_2D);

gl Push Matrix();//压入堆栈

gl Begin(GL_POLYGON);

gl Tex Coord2f(0.0,0.0);

gl Vertex3d(2.0, 2.0,0.0);

gl Tex Coord2f(1.0,0.0);

gl Vertex3d(2.0,2.0,0.0);

gl Tex Coord2f(1.0,1.0);

gl Vertex3d(2.0,2.0, 0.0);

gl Tex Coord2f(0.0,1.0);

gl Vertex3d(2.0, 2.0, 0.0);

gl End();

gl Pop Matrix();//弹出堆栈

gl Disable(GL_TEXTURE_2D);

//绘制一个茶壶

gl Push Matrix();//压入堆栈

gl Translatef(0.0,0.0,2.0);

gl Rotatef(90.0,1.0,0.0,0.0);

gl Color3ub(0,0,255);

aux Solid Teapot(0.5);

gl Pop Matrix();//弹出堆栈

//绘制文字

wgl Use Font Bitmaps(wgl Get Current DC(),0,256,1000);

gl List Base(1000);

gl Raster Pos3f(1.0f,1.0f,1.0f);//文字的三维位置

gl Call Lists(34,GL_UNSIGNED_BYTE,"This is an example of Open GL text.");

gl Flush();//执行

Swap Buffers(m_p DC >Get Safe Hdc());//把后台的绘制交换到前台显示

//CEx Open GLView消息处理程序

int CEx Open GLView::On Create(LPCREATESTRUCT lp Create Struct)

if(CView::On Create(lp Create Struct)==1)

return 1;

m_p DC=new CClient DC(this);

if(!m_p DC)return 0;

initialize RC();//初始化RC

load Texture Image();//导入纹理图片,以进行纹理贴图

//初始化其他参数

m_eye Position[0]=8.0, m_eye Position[1]=0.0, m_eye Position[2]=4.0;

m_eye Center[0]=0.0, m_eye Center[1]=0.0, m_eye Center[2]=0.0;

m_eye Updirection[0]=0.0,m_eye Updirection[1]=0.0,m_eye Updirection[2]=1.0;

m_viewport[0]=0,m_viewport[1]=0,m_viewport[2]=100,m_viewport[3]=100;

return 0;

void CEx Open GLView::On Destroy()

CView::On Destroy();

destroy RC();//删除RC

if(m_p DC)delete m_p DC;

BOOL CEx Open GLView::On Erase Bkgnd(CDC*p DC)

return TRUE;

void CEx Open GLView::On Size(UINT n Type,int cx,int cy)

CView::On Size(n Type,cx,cy);

m_viewport[2]=cx,m_viewport[3]=cy;

//CEx Open GLView绘制

void CEx Open GLView::On Draw(CDC*/*p DC*/)

CEx Open GLDoc*p Doc=Get Document();

ASSERT_VALID(p Doc);

if(!p Doc)

return;

display Scene();//绘制三维场景

void CEx Open GLView::On Key Down(UINT n Char,UINT n Rep Cnt,UINT n Flags)

switch(n Char)

case VK_LEFT://按下左箭头,视图向左旋转10度

double d Sin=sin(10.0*PI/180.0),d Cos=cos(10.0*PI/180.0);

double d E[3]={(m_eye Position[0]m_eye Center[0]),

(m_eye Position[1]m_eye Center[1]),

(m_eye Position[2]m_eye Center[2])};

m_eye Position[0]=m_eye Center[0]+(d E[0]*d Cos+d E[1]*d Sin);

m_eye Position[1]=m_eye Center[1]+(d E[0]*d Sin+d E[1]*d Cos);

Invalidate(FALSE);

break;

case VK_RIGHT://按下右箭头,视图向右旋转10度

double d Sin=sin(10.0*PI/180.0),d Cos=cos(10.0*PI/180.0);

double d E[3]={(m_eye Position[0]m_eye Center[0]),

(m_eye Position[1]m_eye Center[1]),

(m_eye Position[2]m_eye Center[2])};

m_eye Position[0]=m_eye Center[0]+(d E[0]*d Cos+d E[1]*d Sin);

m_eye Position[1]=m_eye Center[1]+(d E[0]*d Sin+d E[1]*d Cos);

Invalidate(FALSE);

break;

default:;

CView::On Key Down(n Char,n Rep Cnt,n Flags);

其可视化效果如图7-5所示。该例子演示了Open GL基本的几何图形、文字等绘制以及纹理贴图、视图旋转操作等。

图7-5 基于Open GL的三维可视化图形系统示例

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