IBM Rational 系统开发最佳实践工具包	WebSphere MQ 最佳实践 TOP 15

在基于单文档的OpenGL框架中，怎样用鼠标实现物体的平移，旋转，缩放功能？

楼主lcg2008（天地乾坤）2006-03-14 11:19:32 在 VC/MFC / 图形处理/算法提问

开始学习OpenGL，要实现以上功能，感觉真困难！在网上搜索了，根据一些资料，
还是实现不了，望高手给点指导，可否贴点代码出来啊？谢谢了！！问题点数：100、回复次数：15Top

1 楼syy64（太平洋）回复于 2006-03-14 11:40:21 得分 50

#include <windows.h>// Header File For Windows
#include <stdio.h>// Header File For Standard Input/Output
#include <gl\gl.h>// Header File For The OpenGL32 Library
#include <gl\glu.h>// Header File For The GLu32 Library
#include <gl\glut.h>
#include <gl\glaux.h>// Header File For The Glaux Library

static GLfloat spin = 0.0;

HGLRC hRC=NULL;
HDC hDC=NULL;
HWND hWnd=NULL;
HINSTANCE hInstance;

BOOL keys[256];
BOOL active=TRUE;
BOOL fullscreen=TRUE;

GLfloat xrot;
GLfloat yrot;
GLfloat zrot;

GLuint texture[1];

LRESULT CALLBACK WndProc(HWND, UINT, WPARAM, LPARAM);

AUX_RGBImageRec *LoadBMP(char *Filename)
{
FILE *File=NULL;
if (!Filename)
{
return NULL;
}
File=fopen(Filename,"r");
if (File)
{
fclose(File);
return auxDIBImageLoad(Filename);
}
return NULL;
}
int LoadGLTextures()
{
int Status=FALSE;
AUX_RGBImageRec *TextureImage[1];
memset(TextureImage,0,sizeof(void *)*1);
if (TextureImage[0]=LoadBMP("Data/NeHe.bmp"))
{
Status=TRUE;
glGenTextures(1, &texture[0]);
glBindTexture(GL_TEXTURE_2D, texture[0]);
glTexImage2D(GL_TEXTURE_2D, 0, 3, TextureImage[0]->sizeX, TextureImage[0]->sizeY, 0,
GL_RGB, GL_UNSIGNED_BYTE, TextureImage[0]->data);
glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_MIN_FILTER,GL_LINEAR);
glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_MAG_FILTER,GL_LINEAR);
}
if (TextureImage[0])
{
if (TextureImage[0]->data)
{
free(TextureImage[0]->data);
}

free(TextureImage[0]);
}
return Status;
}
int InitGL(GLvoid)
{
if (!LoadGLTextures())
{
return FALSE;
}

glEnable(GL_TEXTURE_2D);
glShadeModel(GL_SMOOTH);
glClearColor(0.0f, 0.0f, 0.0f, 0.5f);
glClearDepth(1.0f);
glEnable(GL_DEPTH_TEST);
glDepthFunc(GL_LEQUAL);
glHint(GL_PERSPECTIVE_CORRECTION_HINT, GL_NICEST);
return TRUE;
}

void display(void)
{
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
glPushMatrix();
glBindTexture(GL_TEXTURE_2D, texture[0]);
glRotatef(spin, 1.0, 10.0, 1.0);
glBegin(GL_QUADS);
glColor3f(0.0f,1.0f,0.0f); // 颜色改为蓝色
glTexCoord2f(0.0f, 0.0f); glVertex3f( 10.0f, 10.0f,-10.0f); // 四边形的右上顶点 (顶面)
glTexCoord2f(1.0f, 0.0f); glVertex3f(-10.0f, 10.0f,-10.0f); // 四边形的左上顶点 (顶面)
glTexCoord2f(1.0f, 1.0f); glVertex3f(-10.0f, 10.0f, 10.0f); // 四边形的左下顶点 (顶面)
glTexCoord2f(0.0f, 1.0f); glVertex3f( 10.0f, 10.0f, 10.0f); // 四边形的右下顶点 (顶面)

glColor3f(1.0f,0.5f,0.0f); // 颜色改成橙色
glTexCoord2f(1.0f, 0.0f); glVertex3f( 10.0f,-10.0f, 10.0f); // 四边形的右上顶点(底面)
glTexCoord2f(1.0f, 1.0f); glVertex3f(-10.0f,-10.0f, 10.0f); // 四边形的左上顶点(底面)
glTexCoord2f(0.0f, 1.0f); glVertex3f(-10.0f,-10.0f,-10.0f); // 四边形的左下顶点(底面)
glTexCoord2f(0.0f, 0.0f); glVertex3f( 10.0f,-10.0f,-10.0f); // 四边形的右下顶点(底面)

glColor3f(1.0f,0.0f,0.0f); // 颜色改成红色
glTexCoord2f(0.0f, 1.0f); glVertex3f( 10.0f, 10.0f, 10.0f); // 四边形的右上顶点(前面)
glTexCoord2f(0.0f, 0.0f); glVertex3f(-10.0f, 10.0f, 10.0f); // 四边形的左上顶点(前面)
glTexCoord2f(1.0f, 0.0f); glVertex3f(-10.0f,-10.0f, 10.0f); // 四边形的左下顶点(前面)
glTexCoord2f(1.0f, 1.0f); glVertex3f( 10.0f,-10.0f, 10.0f); // 四边形的右下顶点(前面)

glColor3f(1.0f,1.0f,0.0f); // 颜色改成黄色
glTexCoord2f(1.0f, 1.0f); glVertex3f( 10.0f,-10.0f,-10.0f); // 四边形的右上顶点(后面)
glTexCoord2f(0.0f, 1.0f); glVertex3f(-10.0f,-10.0f,-10.0f); // 四边形的左上顶点(后面)
glTexCoord2f(0.0f, 0.0f); glVertex3f(-10.0f, 10.0f,-10.0f); // 四边形的左下顶点(后面)
glTexCoord2f(1.0f, 0.0f); glVertex3f( 10.0f, 10.0f,-10.0f); // 四边形的右下顶点(后面)

glColor3f(0.0f,1.0f,1.0f); // 颜色改成蓝色
glTexCoord2f(1.0f, 0.0f); glVertex3f(-10.0f, 10.0f, 10.0f); // 四边形的右上顶点(左面)
glTexCoord2f(1.0f, 1.0f); glVertex3f(-10.0f, 10.0f,-10.0f); // 四边形的左上顶点(左面)
glTexCoord2f(0.0f, 1.0f); glVertex3f(-10.0f,-10.0f,-10.0f); // 四边形的左下顶点(左面)
glTexCoord2f(0.0f, 0.0f); glVertex3f(-10.0f,-10.0f, 10.0f); // 四边形的右下顶点(左面)

glColor3f(1.0f,0.0f,1.0f); // 颜色改成紫罗兰色
glTexCoord2f(0.0f, 0.0f); glVertex3f( 10.0f, 10.0f,-10.0f); // 四边形的右上顶点(右面)
glTexCoord2f(1.0f, 0.0f); glVertex3f( 10.0f, 10.0f, 10.0f); // 四边形的左上顶点(右面)
glTexCoord2f(1.0f, 1.0f); glVertex3f( 10.0f,-10.0f, 10.0f); // 四边形的左下顶点(右面)
glTexCoord2f(0.0f, 1.0f); glVertex3f( 10.0f,-10.0f,-10.0f); // 四边形的右下顶点(右面)
glEnd();

glPopMatrix();

glutSwapBuffers();
}

void spinDisplay(void)
{
spin = spin + 1.0;
if (spin > 360.0)
spin = spin - 360.0;
glutPostRedisplay();
}

void init(void)
{
glClearColor (1.1, 1.0, 1.0, 1.0);
glShadeModel (GL_SMOOTH);
}
void keyboard(unsigned char key, int x, int y)
{
switch (key) {
case 27:
glutIdleFunc(spinDisplay);
//exit(0);
break;
case ' ':
glutIdleFunc(NULL);
break;
default:
break;

}
}

void reshape(int w, int h)
{
glViewport (0, 0, (GLsizei) w, (GLsizei) h);
glMatrixMode(GL_PROJECTION);
glLoadIdentity();
glOrtho(-50.0, 50.0, -50.0, 50.0, -100.0, 100.0);
glMatrixMode(GL_MODELVIEW);
glLoadIdentity();
}

void mouse(int button, int state, int x, int y)
{
switch (button) {
case GLUT_LEFT_BUTTON:
if (state == GLUT_DOWN)
glutIdleFunc(spinDisplay);
break;
case GLUT_MIDDLE_BUTTON:
case GLUT_RIGHT_BUTTON:
if (state == GLUT_DOWN)
glutIdleFunc(NULL);
break;
default:
break;
}
}

/*
* Request double buffer display mode.
* Register mouse input callback functions
*/
int main(int argc, char** argv)
{
glutInit(&argc, argv);
glutInitDisplayMode (GLUT_DOUBLE | GLUT_RGB);
glutInitWindowSize (800, 800);
glutInitWindowPosition (100, 100);
glutCreateWindow (argv[0]);
InitGL();
init ();
glutDisplayFunc(display);
glutKeyboardFunc(keyboard);
glutReshapeFunc(reshape);
glutMouseFunc(mouse);
glutMainLoop();
return 0; /* ANSI C requires main to return int. */
}
Top

2 楼happy__888（[顾问团]寻开心 www.e-jjj.com）回复于 2006-03-14 12:14:33 得分 30

opengl里面这些操作都是通过变换矩阵来实现的

你可以用参数来控制的生成，这些参数就是，位置，比例和姿态（也就是你要做的移动，缩放和旋转）
鼠标如何控制的参数是你的界面UI的问题
根据这些参数的具体数值在显示前实时的生成world矩阵，就达到目的了

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3 楼besomethingbig（一个人的夏天）回复于 2006-03-14 20:02:50 得分 20

你应该已经定义了物体的平移，旋转，和缩放等需要的参数，把它们在类中声明成员变量，使它们在类中所有模块都有效。这样在鼠标位置发生改变的时候，通过位置变化改变物体的几何参数，然后调用绘制函数，就可以实现物体的变换了
小例子
定义了物体位置参数

在View类声明成员函数 CPoint MouseDownPoint;//记录鼠标的位置信息
GLfloat m_fCorX;
GLfloat m_fCorY;

初始化 m_fCorX;
m_fCorY;

在下面三个函数中填写代码
void CDialog_3D::OnLButtonDown(UINT nFlags, CPoint point)
{
// TODO: Add your message handler code here and/or call default
// remember where we clicked
MouseDownPoint=point;//记录当前点
// capture mouse movements even outside window borders
SetCapture();//捕获

CDialog::OnLButtonDown(nFlags, point);
}

void CDialog_3D::OnLButtonUp(UINT nFlags, CPoint point)
{
// TODO: Add your message handler code here and/or call default
// forget where we clicked
MouseDownPoint=CPoint(0,0);//清空位置信息
// release mouse capture
ReleaseCapture();//释放捕获

CDialog::OnLButtonUp(nFlags, point);
}

void CDialog_3D::OnMouseMove(UINT nFlags, CPoint point)
{
// TODO: Add your message handler code here and/or call default
// check if we have captured the mouse

if (GetCapture()==this)
{
if(nFlags&MK_CONTROL)//如果Ctrl按下了
{
m_fCorX+=double(point.x-MouseDownPoint.x);
m_fCorY+=double(MouseDownPoint.y-point.y);
OnPaint();//重绘
// remember the mouse point
MouseDownPoint=point;//保留当前点
}
}
CDialog::OnMouseMove(nFlags, point);
}

在OnDraw函数中，在绘制图形时，用m_fCorX和m_fCorY来控制物体的位置，这样当鼠标拖动时就会发出绘制命令，实现物体的变换

//我也是个出学者，请高手把更好的方法贡献出来，谢谢Top

4 楼lcg2008（天地乾坤）回复于 2006-03-16 09:10:55 得分 0

谢谢这么多好人的回答！！！
但是在多个物体时，我想应该先是选中某个物体吧？再在此基础上实行移动，旋转，放缩吧？
那选中物体是怎样判断和实现啊？
再次谢谢！！Top

5 楼syy64（太平洋）回复于 2006-03-16 09:13:14 得分 0

用OpenGL选择模式。Top

6 楼besomethingbig（一个人的夏天）回复于 2006-03-16 09:44:18 得分 0

syy64(太平洋),我对楼主的第二个问题也很感兴趣，能否描述的详细一点，谢谢Top

7 楼lcg2008（天地乾坤）回复于 2006-03-16 12:09:45 得分 0

到处寻找资料，组合成了一个东东，能够勉强实现选中一个物体实现移动（代码中的蓝色的earth），但还是有点问题：（1）拖动过程中，圆形的earth变形了，成为了椭圆形之类。
（2）earth跟鼠标不是完全贴在一起移动。
（3）如何让鼠标选中earth后，鼠标由箭头形变成手指形。
请syy64(太平洋),happy_888([顾问团]寻开心)等大侠帮帮忙啊？谢谢！！Top

8 楼lcg2008（天地乾坤）回复于 2006-03-16 12:11:16 得分 0

// Test_1View.cpp : implementation of the CTest_1View class
//

#include "stdafx.h"
#include "Test_1.h"

#include "Test_1Doc.h"
#include "Test_1View.h"

#ifdef _DEBUG
#define new DEBUG_NEW
#undef THIS_FILE
static char THIS_FILE[] = __FILE__;
#endif
///////////////////////////////
// Define object names
#define EARTH 1
#define MARS 2
#define MOON1 3
#define MOON2 4
////////////////////////////////
//define the global variable

GLfloat m_fCorX=-100.0f;
GLfloat m_fCorY=0.0f;
bool istrue;

/////////////////////////////////////////////////////////////////////////////
// CTest_1View

IMPLEMENT_DYNCREATE(CTest_1View, CView)

BEGIN_MESSAGE_MAP(CTest_1View, CView)
//{{AFX_MSG_MAP(CTest_1View)
ON_WM_CREATE()
ON_WM_DESTROY()
ON_WM_ERASEBKGND()
ON_WM_SIZE()
ON_WM_LBUTTONDOWN()
ON_WM_MOUSEMOVE()
ON_WM_LBUTTONUP()
//}}AFX_MSG_MAP
// Standard printing commands
ON_COMMAND(ID_FILE_PRINT, CView::OnFilePrint)
ON_COMMAND(ID_FILE_PRINT_DIRECT, CView::OnFilePrint)
ON_COMMAND(ID_FILE_PRINT_PREVIEW, CView::OnFilePrintPreview)
END_MESSAGE_MAP()

/////////////////////////////////////////////////////////////////////////////
// CTest_1View construction/destruction

CTest_1View::CTest_1View()
{
// TODO: add construction code here

}

CTest_1View::~CTest_1View()
{
}

BOOL CTest_1View::PreCreateWindow(CREATESTRUCT& cs)
{
// TODO: Modify the Window class or styles here by modifying
// the CREATESTRUCT cs
cs.style |= WS_CLIPSIBLINGS | WS_CLIPCHILDREN | CS_OWNDC;
return CView::PreCreateWindow(cs);
}

/////////////////////////////////////////////////////////////////////////////
// CTest_1View drawing

void CTest_1View::OnDraw(CDC* pDC)
{
CTest_1Doc* pDoc = GetDocument();
ASSERT_VALID(pDoc);
// TODO: add draw code for native data here
///////////////////////////////////////////////////////////////////////
myDrawScene( ); //具体的绘图函数，在 RC 中绘制
///////////////////////////////////////////////////////////////////////
}

/////////////////////////////////////////////////////////////////////////////
// CTest_1View printing

BOOL CTest_1View::OnPreparePrinting(CPrintInfo* pInfo)
{
// default preparation
return DoPreparePrinting(pInfo);
}

void CTest_1View::OnBeginPrinting(CDC* /*pDC*/, CPrintInfo* /*pInfo*/)
{
// TODO: add extra initialization before printing
}

void CTest_1View::OnEndPrinting(CDC* /*pDC*/, CPrintInfo* /*pInfo*/)
{
// TODO: add cleanup after printing
}

/////////////////////////////////////////////////////////////////////////////
// CTest_1View diagnostics

#ifdef _DEBUG
void CTest_1View::AssertValid() const
{
CView::AssertValid();
}

void CTest_1View::Dump(CDumpContext& dc) const
{
CView::Dump(dc);
}

CTest_1Doc* CTest_1View::GetDocument() // non-debug version is inline
{
ASSERT(m_pDocument->IsKindOf(RUNTIME_CLASS(CTest_1Doc)));
return (CTest_1Doc*)m_pDocument;
}
#endif //_DEBUG

/////////////////////////////////////////////////////////////////////////////
// CTest_1View message handlers

int CTest_1View::OnCreate(LPCREATESTRUCT lpCreateStruct)
{
if (CView::OnCreate(lpCreateStruct) == -1)
return -1;

// TODO: Add your specialized creation code here
myInitOpenGL();
return 0;
}

void CTest_1View::myInitOpenGL()
{
m_pDC = new CClientDC(this); //创建 DC
ASSERT(m_pDC != NULL);
if (!mySetupPixelFormat()) //设定绘图的位图格式，函数下面列出
return;
m_hRC = wglCreateContext(m_pDC->m_hDC);//创建 RC
wglMakeCurrent(m_pDC->m_hDC, m_hRC); //RC 与当前 DC 相关联
// Lighting values
GLfloat dimLight[] = { 0.1f, 0.1f, 0.1f, 1.0f };
GLfloat sourceLight[] = { 0.65f, 0.65f, 0.65f, 1.0f };
GLfloat lightPos[] = { 0.0f, 0.0f, 0.0f, 1.0f };

// Light values and coordinates
glEnable(GL_DEPTH_TEST); // Hidden surface removal
glFrontFace(GL_CCW); // Counter clock-wise polygons face out
glEnable(GL_CULL_FACE); // Do not calculate insides

// Enable lighting
glEnable(GL_LIGHTING);

// Setup and enable light 0
glLightfv(GL_LIGHT0, GL_AMBIENT, dimLight);
glLightfv(GL_LIGHT0,GL_DIFFUSE,sourceLight);
glLightfv(GL_LIGHT0,GL_POSITION,lightPos);
glEnable(GL_LIGHT0);

// Enable color tracking
glEnable(GL_COLOR_MATERIAL);

// Set Material properties to follow glColor values
glColorMaterial(GL_FRONT, GL_AMBIENT_AND_DIFFUSE);

// Gray background
glClearColor(1.0f, 0.20f, 0.80f, 1.0f );
}

BOOL CTest_1View::mySetupPixelFormat()
{
static PIXELFORMATDESCRIPTOR pfd ={
sizeof(PIXELFORMATDESCRIPTOR), // size of this pfd
1, // version number
PFD_DRAW_TO_WINDOW | // support window
PFD_SUPPORT_OPENGL | // support OpenGL
PFD_DOUBLEBUFFER, // double buffered
PFD_TYPE_RGBA, // RGBA type
24, // 24-bit color depth
0, 0, 0, 0, 0, 0, // color bits ignored
0, // no alpha buffer
0, // shift bit ignored
0, // no accumulation buffer
0, 0, 0, 0, // accum bits ignored
32, // 32-bit z-buffer
0, // no stencil buffer
0, // no auxiliary buffer
PFD_MAIN_PLANE, // main layer
0, // reserved
0, 0, 0 // layer masks ignored
};
int pixelformat;
if ( (pixelformat = ChoosePixelFormat(m_pDC->m_hDC, &pfd)) == 0 )
{
MessageBox("ChoosePixelFormat failed");
return FALSE;
}
if (SetPixelFormat(m_pDC->m_hDC, pixelformat, &pfd) == FALSE)
{
MessageBox("SetPixelFormat failed");
return FALSE;
}
return TRUE;
}

void CTest_1View::OnDestroy()
{
CView::OnDestroy();

// TODO: Add your message handler code here
wglMakeCurrent(m_pDC->m_hDC,NULL); //释放与m_hDC 对应的 RC
wglDeleteContext(m_hRC); //删除 RC
if (m_pDC)
delete m_pDC; //删除当前 View 拥有的 DC
}

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9 楼lcg2008（天地乾坤）回复于 2006-03-16 12:11:47 得分 0

接着上面的
BOOL CTest_1View::OnEraseBkgnd(CDC* pDC)
{
// TODO: Add your message handler code here and/or call default
return TRUE;//只要空返回即可
//return CView::OnEraseBkgnd(pDC);
}

void CTest_1View::myDrawScene()
{
// Clear the window with current clearing color
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);

// Save the matrix state and do the rotations
glMatrixMode(GL_MODELVIEW);
glPushMatrix();

// Translate the whole scene out and into view
glTranslatef(0.0f, 0.0f, -300.0f);

// Initialize the names stack
glInitNames();
glPushName(0);

// Draw the Earth
glPushMatrix();
glColor3f(0.0f, 0.0f, 1.0f);
//glTranslatef(-100.0f,0.0f,0.0f);
glTranslatef(m_fCorX,m_fCorY,0.0f);
glLoadName(EARTH);
DrawSphere(30.0f);
glPopMatrix();

// Draw the Moon
glPushMatrix();
glTranslatef(45.0f, 0.0f, 0.0f);
glColor3f(0.85f, 0.85f, 0.85f);
glLoadName(MOON1);
DrawSphere(5.0f);
glPopName();
glPopMatrix();

// Draw Mars
glColor3f(1.0f, 0.0f, 0.0f);
glPushMatrix();
glTranslatef(100.0f, 0.0f, 0.0f);
glLoadName(MARS);
DrawSphere(20.0f);

// Draw Moon1
glTranslatef(-40.0f, 40.0f, 0.0f);
glColor3f(0.85f, 0.85f, 0.85f);
glPushName(MOON1);
DrawSphere(5.0f);
glPopName();

// Draw Moon2
glTranslatef(0.0f, -80.0f, 0.0f);
glPushName(MOON2);
DrawSphere(5.0f);
glPopName();
glPopMatrix();

// Restore the matrix state
glPopMatrix(); // Modelview matrix
::SwapBuffers(m_pDC->GetSafeHdc());
}

void CTest_1View::OnSize(UINT nType, int cx, int cy)
{
CView::OnSize(nType, cx, cy);
w=cx;
h=cy;
GLfloat fAspect; // Screen aspect ratio

// Prevent a divide by zero
if(h == 0)
h = 1;

// Set Viewport to window dimensions
glViewport(0, 0, w, h);

// Calculate aspect ratio of the window
fAspect = (GLfloat)w/(GLfloat)h;

// Set the perspective coordinate system
glMatrixMode(GL_PROJECTION);
glLoadIdentity();

// Field of view of 45 degrees, near and far planes 1.0 and 425
gluPerspective(45.0f, fAspect, 1.0, 425.0);

// Modelview matrix reset
glMatrixMode(GL_MODELVIEW);
glLoadIdentity();
}
void CTest_1View::OnLButtonDown(UINT nFlags, CPoint point)
{
// TODO: Add your message handler code here and/or call default
CView::OnLButtonDown(nFlags, point);
ProcessSelection(point.x, point.y);
// remember where we clicked
MouseDownPoint=point;//记录当前点
// capture mouse movements even outside window borders
SetCapture();//捕获

}

void CTest_1View::DrawSphere(float radius)
{
GLUquadricObj *pObj;
pObj = gluNewQuadric();
gluQuadricNormals(pObj, GLU_SMOOTH);
gluSphere(pObj, radius, 26, 13);
gluDeleteQuadric(pObj);
}
#define BUFFER_LENGTH 64
void CTest_1View::ProcessSelection(int xPos, int yPos)
{
GLfloat fAspect; // Screen aspect ratio

// Space for selection buffer
GLuint selectBuff[BUFFER_LENGTH];

// Hit counter and viewport storeage
GLint hits, viewport[4];

// Setup selection buffer
glSelectBuffer(BUFFER_LENGTH, selectBuff);

// Get the viewport
glGetIntegerv(GL_VIEWPORT, viewport);

// Switch to projection and save the matrix
glMatrixMode(GL_PROJECTION);
glPushMatrix();

// Change render mode
glRenderMode(GL_SELECT);

glLoadIdentity();
gluPickMatrix(xPos, viewport[3] - yPos, 2,2, viewport);

// Apply perspective matrix
fAspect = (float)viewport[2] / (float)viewport[3];
gluPerspective(45.0f, fAspect, 1.0, 425.0);

// Draw the scene
myDrawScene();

// Collect the hits
hits = glRenderMode(GL_RENDER);

// If a single hit occured, display the info.
if(hits == 1)
ProcessPlanet(selectBuff);
//else
//MessageBox("You clicked empty space!");

// Restore the projection matrix
glMatrixMode(GL_PROJECTION);
glPopMatrix();

// Go back to modelview for normal rendering
glMatrixMode(GL_MODELVIEW);
}

void CTest_1View::ProcessPlanet(GLuint *pSelectBuff)
{
int id,count;
char cMessage[64];
strcpy(cMessage,"Error, no selection detected");

// How many names on the name stack
count = pSelectBuff[0];

// Bottom of the name stack
id = pSelectBuff[3];

// Select on earth or mars, whichever was picked
switch(id)
{
case EARTH:
//strcpy(cMessage,"You clicked Earth.");
// Draw the scene
istrue=true;
// If there is another name on the name stack,
// then it must be the moon that was selected
// This is what was actually clicked on
if(count == 2)
strcat(cMessage," - Specifically the moon.");

break;

case MARS:
strcpy(cMessage,"You clicked Mars.");

// We know the name stack is only two deep. The precise
// moon that was selected will be here.
if(count == 2)
{
if(pSelectBuff[4] == MOON1)
strcat(cMessage," - Specifically Moon #1.");
else
strcat(cMessage," - Specifically Moon #2.");
}
break;
}

// Display the message about planet and moon selection
//MessageBox(cMessage);
}

void CTest_1View::OnMouseMove(UINT nFlags, CPoint point)
{
// TODO: Add your message handler code here and/or call default
if (GetCapture()==this)
{
if(istrue==true)//如果earth选中了
{
m_fCorX+=(point.x-MouseDownPoint.x);
m_fCorY+=(MouseDownPoint.y-point.y);
myDrawScene();//重绘
// remember the mouse point
MouseDownPoint=point;//保留当前点
}
}

CView::OnMouseMove(nFlags, point);
}

void CTest_1View::OnLButtonUp(UINT nFlags, CPoint point)
{
// TODO: Add your message handler code here and/or call default
//KillTimer(0);
//LButtonDown=false;
// forget where we clicked
MouseDownPoint=CPoint(0,0);//清空位置信息
// release mouse capture
ReleaseCapture();//释放捕获
istrue=false;
CView::OnLButtonUp(nFlags, point);
}
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10 楼LG11（一句话）回复于 2006-03-16 20:19:50 得分 0

以上代码，我运行了一下，觉得有以下问题：
（1）拖动过程中，圆形的earth变形了，成为了椭圆形之类。
（2）earth跟鼠标不是完全贴在一起移动。
请问syy64(太平洋),happy_888([顾问团]寻开心)等大侠，这该怎样解决啊？谢谢！！Top

11 楼femalelover（楼主, 请把用不着的可用分捐给我1/3 ：（）回复于 2006-03-17 01:45:54 得分 0

选择模式的使用可能不是syy64,happy_888一两句能说清楚的.俺最近也正在学选择与反馈,汗啊,有难度.Top

12 楼lcg2008（天地乾坤）回复于 2006-03-17 08:53:38 得分 0

物体如（earth）不紧跟着鼠标一起移动，在屏幕正中时没有多大位差，可移动到屏幕边缘时鼠标与物体就有一段距离了，我想做到鼠标和选中的物体一起紧贴着移动，能够实现吗？怎样实现啊？谢谢了！Top

13 楼happy__888（[顾问团]寻开心 www.e-jjj.com）回复于 2006-03-17 11:13:51 得分 0

1 变形最大的可能是你的控制矩阵搞错了，把移动的控制量作用到比例上
2 移动的时候，鼠标是在一个二维的平面内移动的，而你的物体是在三维的面内
要精确定位，就需要定位你的物体的移动面，并且计算移动平面和鼠标的交点
这个有些复杂，完整的说，还应该计算pick的时候，物体上的pick点的位置，然后把移动面太高到对应的位置去计算才能精确的
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14 楼femalelover（楼主, 请把用不着的可用分捐给我1/3 ：（）回复于 2006-03-17 14:57:46 得分 0

上面syy64给出的代码中没有这个函数glutInitWithExit ,我拿那段代码编译的时候说这个函数无法解释,怎么回事?Top

15 楼syy64（太平洋）回复于 2006-03-17 16:47:21 得分 0

需要glut32.lib库。Top