OpenGl 中glViewport(x,y,cx,cy)的x和y与窗口坐标有啥区别？

问远 2010-04-04 01:50:58

OpenGl 中glViewport(x,y,cx,cy)的x和y与窗口坐标有啥区别？

...全文

920 3 打赏收藏转发到动态举报

写回复

3 条回复

切换为时间正序

请发表友善的回复…

发表回复

VR_Lab 2010-04-07

打赏
举报

回复

glViewport(x,y,cx,cy)，其中的x,y表示你要画的窗口的左上角的坐标位置，cx,cy表示你要画的窗口的长和宽。利用这个函数可以实现多视口显示，即一个窗口中“同时”显示不同的图像，我写过一个OpenGL的窗口类继承于CWnd，比如说你要把你的窗口分为4份，实现四网格显示，那在左上角的那个窗口的设置就是glViewport(0,0,width/2,heitht/2);还有不懂的可以加我QQ726436079

degree_37 2010-04-04

打赏
举报

回复

楼上正解~

Swkjd 2010-04-04

打赏
举报

回复

OpenGL：屏幕上水平向右为x，竖直向上为y，z垂直屏幕向外，与x、y构成右手坐标系。
窗口坐标：屏幕上水平向右为x，竖直向下为y。

用MFC VC++实现的时钟源代码 // MFCFrame1View.cpp : implementation of the CMFCFrame1View class // #include "stdafx.h" #include "MFCFrame1.h" #include "MFCFrame1Doc.h" #include "MFCFrame1View.h" #include "PointDialog.h" #include "math.h" GLUquadricObj *objCylinder = gluNewQuadric(); #ifdef _DEBUG #define new DEBUG_NEW #undef THIS_FILE static char THIS_FILE[] = __FILE__; #endif ///////////////////////////////////////////////////////////////////////////// // CMFCFrame1View IMPLEMENT_DYNCREATE(CMFCFrame1View, CView) BEGIN_MESSAGE_MAP(CMFCFrame1View, CView) //{{AFX_MSG_MAP(CMFCFrame1View) ON_WM_CREATE() ON_WM_DESTROY() ON_WM_SIZE() ON_COMMAND(IDM_ZIXUAN, OnZixuan) ON_WM_TIMER() ON_COMMAND(IDM_ChangDirect, OnChangDirect) //}}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() ///////////////////////////////////////////////////////////////////////////// // CMFCFrame1View construction/destruction CMFCFrame1View::CMFCFrame1View() { // TODO: add construction code here this->m_GLPixelIndex = 0; this->m_hGLContext = NULL; Angle1=0.0; Angle2=30.0; Timer=0; x=0.0; z=0.0; juli=40.0; } CMFCFrame1View::~CMFCFrame1View() { } BOOL CMFCFrame1View::PreCreateWindow(CREATESTRUCT& cs) { // TODO: Modify the Window class or styles here by modifying // the CREATESTRUCT cs cs.style |= (WS_CLIPCHILDREN | WS_CLIPSIBLINGS); return CView::PreCreateWindow(cs); } ///////////////////////////////////////////////////////////////////////////// // CMFCFrame1View drawing ///////////////////////////////////////////////////////////////////////////// // CMFCFrame1View printing BOOL CMFCFrame1View::OnPreparePrinting(CPrintInfo* pInfo) { // default preparation return DoPreparePrinting(pInfo); } void CMFCFrame1View::OnBeginPrinting(CDC* /*pDC*/, CPrintInfo* /*pInfo*/) { // TODO: add extra initialization before printing } void CMFCFrame1View::OnEndPrinting(CDC* /*pDC*/, CPrintInfo* /*pInfo*/) { // TODO: add cleanup after printing } ///////////////////////////////////////////////////////////////////////////// // CMFCFrame1View diagnostics #ifdef _DEBUG void CMFCFrame1View::AssertValid() const { CView::AssertValid(); } void CMFCFrame1View::Dump(CDumpContext& dc) const { CView::Dump(dc); } CMFCFrame1Doc* CMFCFrame1View::GetDocument() // non-debug version is inline { ASSERT(m_pDocument->IsKindOf(RUNTIME_CLASS(CMFCFrame1Doc))); return (CMFCFrame1Doc*)m_pDocument; } #endif //_DEBUG ///////////////////////////////////////////////////////////////////////////// // CMFCFrame1View message handlers BOOL CMFCFrame1View::SetWindowPixelFormat(HDC hDC) { PIXELFORMATDESCRIPTOR pixelDesc= { sizeof(PIXELFORMATDESCRIPTOR), 1, PFD_DRAW_TO_WINDOW|PFD_SUPPORT_OPENGL| PFD_DOUBLEBUFFER|PFD_SUPPORT_GDI, PFD_TYPE_RGBA, 24, 0,0,0,0,0,0, 0, 0, 0, 0,0,0,0, 32, 0, 0, PFD_MAIN_PLANE, 0, 0,0,0 }; this->m_GLPixelIndex = ChoosePixelFormat(hDC,&pixelDesc); if(this->m_GLPixelIndex==0) { this->m_GLPixelIndex = 1; if(DescribePixelFormat(hDC,this->m_GLPixelIndex,sizeof(PIXELFORMATDESCRIPTOR),&pixelDesc)==0) { return FALSE; } } if(SetPixelFormat(hDC,this->m_GLPixelIndex,&pixelDesc)==FALSE) { return FALSE; } return TRUE; } int CMFCFrame1View::OnCreate(LPCREATESTRUCT lpCreateStruct) { if (CView::OnCreate(lpCreateStruct) == -1) return -1; // TODO: Add your specialized creation code here HWND hWnd = this->GetSafeHwnd(); HDC hDC = ::GetDC(hWnd); if(this->SetWindowPixelFormat(hDC)==FALSE) { return 0; } if(this->CreateViewGLContext(hDC)==FALSE) { return 0; } return 0; } BOOL CMFCFrame1View::CreateViewGLContext(HDC hDC) { this->m_hGLContext = wglCreateContext(hDC); if(this->m_hGLContext==NULL) {//创建失败 return FALSE; } if(wglMakeCurrent(hDC,this->m_hGLContext)==FALSE) {//选为当前RC失败 return FALSE; } return TRUE; } void CMFCFrame1View::OnDestroy() { CView::OnDestroy(); // TODO: Add your message handler code here if(wglGetCurrentContext()!=NULL) { wglMakeCurrent(NULL,NULL); } if(this->m_hGLContext!=NULL) { wglDeleteContext(this->m_hGLContext); this->m_hGLContext = NULL; } } void CMFCFrame1View::OnSize(UINT nType, int cx, int cy) { CView::OnSize(nType, cx, cy); // TODO: Add your message handler code here GLsizei width,height; GLdouble aspect; width = cx; height = cy; if(cy==0) { aspect = (GLdouble)width; } else { aspect = (GLdouble)width/(GLdouble)height; } glViewport(0,0,width,height); glMatrixMode(GL_PROJECTION); glLoadIdentity(); gluPerspective(40.0,aspect,5.0,1000.0); } void CMFCFrame1View::OnDraw(CDC* pDC) { CMFCFrame1Doc* pDoc = GetDocument(); ASSERT_VALID(pDoc); // TODO: add draw code for native data here CPaintDC dc(this); glClearColor(1.0,1.0,1.0,1.0); glClear(GL_COLOR_BUFFER_BIT); glMatrixMode(GL_MODELVIEW); glLoadIdentity(); gluLookAt(0.0,0.0,10.0,0.0,0.0,0.0,0.0,1.0,0.0); glRotatef(-90.0,1.0,0.0,0.0);/*返回原坐标*/ glTranslatef(-3.0,0.0,0.0); SwapBuffers(dc.m_ps.hdc); glDrawBuffer (GL_BACK); glFlush(); } void CMFCFrame1View::OnZixuan() { // TODO: Add your command handler code here Timer=1; SetTimer(1,100,NULL); } void CMFCFrame1View::OnTimer(UINT nIDEvent) { // TODO: Add your message handler code here and/or call default CPaintDC dc(this); if (Timer==1) { Angle1=Angle1-1; Angle2=Angle2-1; glClearColor(1.0,1.0,1.0,1.0); glClear(GL_COLOR_BUFFER_BIT); glMatrixMode(GL_MODELVIEW);/**/ glLoadIdentity(); gluLookAt(0.0,20.0,0.000000001,0.0,0.0,0.0,0.0,1.0,0.0); glPushMatrix(); glColor3f(0.7,0.7,0.7); glTranslatef(0.0,0.0,1.1); glRotatef(-90.0,1.0,0.0,0.0); glutSolidCone(5.0,0.0,60.0,60.0); /*底盘*/ glPopMatrix(); glPushMatrix(); glColor3f(0.0,0.0,0.0); glTranslatef(3.9,0.99,1.0); /*刻度*/ glRotatef(90.0,0.0,1.0,0.0); gluCylinder(objCylinder, 0.05, 0.05, 0.8, 9999, 9); glPopMatrix(); glPushMatrix(); glColor3f(0.0,0.0,0.0); glTranslatef(-4.7,0.99,1.0); /*刻度*/ glRotatef(90.0,0.0,1.0,0.0); gluCylinder(objCylinder,0.05, 0.05, 0.8, 9999, 9); glPopMatrix(); glPushMatrix(); glColor3f(0.0,0.0,0.0); glTranslatef(0.0,0.99,-2.9); /*刻度*/ glRotatef(180.0,0.0,1.0,0.0); gluCylinder(objCylinder,0.05, 0.05, 0.8, 9999, 9); glPopMatrix(); glPushMatrix(); glColor3f(0.0,0.0,0.0); glTranslatef(0.0,0.99,5.8); /*刻度*/ glRotatef(180.0,0.0,1.0,0.0); gluCylinder(objCylinder,0.05, 0.05,0.8, 9999, 9); glPopMatrix(); glPushMatrix(); glColor3f(0.0,1.0,0.0); glRotatef(45.0,0.0,1.0,0.0); glTranslatef(-0.67,0.99,0.7); /*时针*/ glRotatef(Angle1/129600,0.0,1.0,0.0); gluCylinder(objCylinder, 0.07, 0.02, 2.5, 9999, 9); glPopMatrix(); glPushMatrix(); glColor3f(1.0,0.0,0.0); glTranslatef(0.0,0.99,1.0); /*分针*/ glRotatef(Angle2/360,0.0,1.0,0.0); gluCylinder(objCylinder, 0.05, 0.02, 3.5, 9999, 9); glPopMatrix(); glPushMatrix(); glColor3f(0.0,0.0,0.5); glTranslatef(0.0,0.99,1.0); /*秒针*/ glRotatef(Angle1,0.0,1.0,0.0); gluCylinder(objCylinder, 0.07, 0.02, 4.5, 9999, 9); glPopMatrix(); SwapBuffers(dc.m_ps.hdc); glDrawBuffer (GL_BACK); glFlush(); } else if(Timer==2) { glClearColor(1.0,1.0,1.0,1.0); glClear(GL_COLOR_BUFFER_BIT); if (juli>12.0) { glMatrixMode(GL_MODELVIEW);/*建立了从世界坐标系到观察坐标系的转换矩阵*/ glLoadIdentity(); gluLookAt(0.0,8.0,juli,0.0,0.0,0.0,0.0,1.0,0.0); juli=juli-0.1; glPushMatrix(); glColor3f(0.0,0.0,0.0); glRotatef(-90.0,1.0,0.0,0.0); glutWireCone(40.0,0.0,30.0,30.0); /*画高度为0的圆锥*/ glPopMatrix(); glPushMatrix(); glColor3f(1.0,0.0,1.0); glLineWidth(4.0); glTranslatef(4.0,1.0,0.0); glutWireOctahedron(); /*画八面体*/ glLineWidth(1.0); glPopMatrix(); glPushMatrix(); glColor3f(1.0,0.0,1.0); glTranslatef(0.0,1.1,0.0); glRotatef(Angle2,0.0,1.0,0.0); gluCylinder(objCylinder, 1.0, 1.0, 10.0, 9999, 9); /*画壶*/ glPopMatrix(); } else if(juli<=12.0) { Angle2=Angle2+0.01; if (Angle2==360.0) Angle2=0.0; glMatrixMode(GL_MODELVIEW);/*建立了从世界坐标系到观察坐标系的转换矩阵*/ glLoadIdentity(); x=12.0*sin(Angle2); z=12.0*cos(Angle2); gluLookAt(x,5.0,z,0.0,0.0,0.0,0.0,1.0,0.0); glPushMatrix(); glColor3f(0.0,0.0,0.0); glRotatef(-90.0,1.0,0.0,0.0); glutWireCone(40.0,0.0,30.0,30.0); /*画高度为0的圆锥*/ glPopMatrix(); glPushMatrix(); glColor3f(1.0,0.0,1.0); glLineWidth(4.0); glTranslatef(4.0,1.0,0.0); glutWireOctahedron(); /*画八面体*/ glLineWidth(1.0); glPopMatrix(); glPushMatrix(); glColor3f(1.0,0.0,1.0); glTranslatef(0.0,1.1,0.0); gluCylinder(objCylinder, 1.0, 1.0, 10.0, 9999, 9); /*画壶*/ glPopMatrix(); } SwapBuffers(dc.m_ps.hdc); glDrawBuffer (GL_BACK); glFlush(); } CView::OnTimer(nIDEvent); } void CMFCFrame1View::OnChangDirect() { // TODO: Add your command handler code here Timer=2; SetTimer(1,100 ,NULL); }

01.相机如何在OpenGL中工作?
02.我怎样才可以移动我的视点, 或者是相机,在我的场景中?
03.我的相机该去哪, 模型视点矩阵还是投射矩阵?
04.我该怎么执行一个缩放操作?
05.给出当前模型视点矩阵,我怎么才可以确定相机的物体空间位置?
06.我怎样才可以使照相机在我的场景中围绕一个点转?
07.如何自动计算一个观察点可以显示全部的场景?(我知道边界球体和向上分量(bounding sphere

一.OpenGLES2.0原理浅析 1. OpenGLES通过获取物体的控件顶点信息, 可以实现3维物体到2维物体的坐标转换输出到屏幕，并且可以对物体实现平移，旋转，缩放，而且利用着色器可编程渲染通道实现多种光学作用，特殊形状变换等效果。从而能实现丰富的物体再现功能。 2. 通过模拟人眼观察物体, 可能引起屏幕图像改变的几种行为和分别对应的几种OpenGL变换:

OpenGL里面的旋转缩放与平移其实就是坐标系的相关变换，不过由于初学者(像我)很容易被OpenGL里面各种坐标系搞晕而难以理解，现在将我的理解记录如下。PS: 由于学校课程要求，使用的是过时的固定管线。为了清楚地理解这三种变换，我们只关心两个坐标系：建模坐标系和世界坐标系。眼坐标之类的使用默认值。文末有一段程序代码，绘制了一个正方体，并实现了这三种变换。世界坐标系(WC)：你现在正对绘图窗口，右方

OpenGL的状态管理机制视口与视口坐标系概念测试视口设置 1 移动视口 2 多视口视口小结1 OpenGL的状态管理机制从前面的最简单例子可以看出，我们几乎没有进行任何关于颜色和坐标系的配置，OpenGL就已经能够实施渲染了。这是因为OpenGL本身管理了很多渲染时需要的状态数据，并且在初始化时自动设置了合理的默认值。例如，默认的清屏颜色就是黑色，这才是我们看到窗口客户区呈现黑色的原因。Op

图形处理/算法

19,468

社区成员

50,698

社区内容

发帖

与我相关

我的任务

社区管理员

加入社区

近7日
近30日
至今

加载中

查看更多榜单

社区公告

暂无公告

试试用AI创作助手写篇文章吧

+ 用AI写文章