其他

 osg::Group* group =  new osg::Group; osg::Node* node = osgDB::readNodeFile("D:\\cow.osg"); osg::Camera* camera = new osg::Camera; camera->setViewport(0, 0, 256, 256); osg::Image* img = new osg::Image; img->allocateImage(256, 256, 1, GL_RGBA,

 The first version preseted in here computes an intensity per vertex. Then the fragment shader uses the vertex interpolated intensity to compute a tone for the fragment. The vertex shader must therefore declare a varying variable to store the

This is kind of a Hello World for GLSL. A minimal shader that performs the most basic tasks: transform the vertices and render the primitives in a single color. In here it this shaders, vertex and fragment, are presented.

void RenderBin::drawImplementation(osg::RenderInfo& renderInfo,RenderLeaf*& previous){    osg::State& state = *renderInfo.getState();    // osg::notify(osg::NOTICE)<<"begin RenderBin::drawImplementation "<<className()<<"

Intersector* LineSegmentIntersector::clone(osgUtil::IntersectionVisitor& iv){    if (_coordinateFrame==MODEL && iv.getModelMatrix()==0)    {        osg::ref_ptr<LineSegmentIntersector> lsi = new LineSegmentIntersector(_start, _end);

> I tried using a different attribute index from 0, and the colours are now showing up. I had come across the link earlier that you posted, but didn't realise that was how OpenGL worked (I tested it out in an OpenGL app and got the same problem

1、Windows下的調色盤OpenGL可以使用16色、256色、64K和16M真彩色。真彩模式下不需要調色盤，而在16色模式下根本不可能得到較為滿意的效果，因此對OpenGL而言，調色盤只有在256色模式下才有意義。我們知道，Windows把調色盤分為系統調色盤和邏輯調色盤。每個應用程式都擁有一套自己的邏輯調色盤（或使用預設調色盤），當該應用程式擁有鍵盤輸入焦點時可以最多使用從16M種色彩中選取的256種顏色（20種系統保留顏色和236種自由選取的顏色），而失去焦點的應用程式可能會有某些顏色顯

class Test : public osgGA::AnimationPathManipulator{public: Test(osg::AnimationPath* path) : AnimationPathManipulator(path) { } ~Test(){}private: osg::Quat _rotation; osg::Vec3d _center; double _distance; double _current;public:    virtual void

 class PickEvent : public osgGA::GUIEventHandler{public: PickEvent(osg::Geometry* drawable) : _drawable(drawable){} ~PickEvent(){}public: bool handle(const osgGA::GUIEventAdapter& ea, osgGA::GUIActionAdapter& aa) {  if (ea.getEventType() ==

The gl_NormalMatrix The gl_NormalMatrix is present in many vertex shaders. In here some light is shed on what is this matrix and what is it for. This section was inspired by the excellent book by Eric Lengyel "Mathematics for 3D Game Programming and

OSG通過對NodeVisitor的使用,實現了GOF的Visitor的模式.在Osg的實現中,這個模式實現了雙派發.所以在Node中有一個虛方法為apply(NodeVisitor),而在NodeVisitor中有一個方法apply(Node&).這兩個方法的調用是有區別的.我們應該總是調用Node::accept而別使用NodeVisitor::apply.因為只有調用前者才能享受到雙派發的能力.(Node的具體類型和NodeVisitor的具體類型都參與到了Visitor模式)那麼

 Color Shader GLSL has access to part of the OpenGL state. In this tutorial we'll see how to access the color as set in an OpenGL application with glColor. GLSL has an attribute variable where it keeps track of the current color. It also provides

Octree(by J. Eder 9225396)   What is an Octree?  Using an Octree  Types of Octrees     What does it represent?     How is it managed? How to structure Octree-structures Pointerless full Octree Traditional design of Pointer Octrees

/*=========================================================================  Program:   Visualization Toolkit  Module:    $RCSfile: vtkAbstractMapper.h,v $  Copyright (c) Ken Martin, Will Schroeder, Bill Lorensen  All rights reserved.  See Copyright.

     Vec3d f(center-eye);    f.normalize();    Vec3d s(f^up);    s.normalize();    Vec3d u(s^f);    u.normalize();    set(        s[0],     u[0],     -f[0],     0.0,        s[1],     u[1],     -f[1],     0.0,        s[2],     u[2],     -f[2],     0.0

 GLSL Tutorial Pipeline Overview The following figure is a (very) simplified diagram of the pipeline stages and the data that travels amongst them. Although extremely simplified it is enough to present some important concepts for shader programming.

 一直對齊次座標這個概念的理解不夠徹底，只見大部分的書中說道“齊次座標在仿射變換中非常的方便”，然後就沒有了後文，今天在一個叫做“三百年 重生”的部落格上看到一篇關於透視投影變換的探討的文章，其中有對齊次座標有非常精闢的說明，特別是針對這樣一句話進行了有力的證明：“齊次座標表示是電腦圖形學的重要手段之一，它既能夠用來明確區分向量和點，同時也更易用於進行仿射（線性）幾何變換。”—— F.S. Hill, JR。      由於作者對齊次座標真的解釋的不錯，我就原封不動的摘抄過來：    

opengl中的累積緩衝（Accumulation buffer）2010-06-28 18:36累積緩衝是為合成多幅映像而設計的，它不是簡單的用引入象素片元來代替象素值，而是將片元進行縮放，然後加到已有的象素值上。為了經過一系列的混合操作後能夠保持精度，累積緩衝每個顏色分量的位元要比一般的可視化系統要多。我們可以象其他緩衝一樣清空累積緩衝，可以用glClearAccum()來設定紅、綠和藍色分量的清空值，按位順序清空累積緩衝或以GL_ACCUM_BUFFER_BIT調用glClear()命令。

void SceneView::updateUniforms(){    if (!_localStateSet)    {        _localStateSet = new osg::StateSet;    }    if (!_localStateSet) return;        if ((_activeUniforms & FRAME_NUMBER_UNIFORM) && _frameStamp.valid())    {       

class PickEvent : public osgGA::GUIEventHandler{public: PickEvent(osg::Geometry* drawable) : _drawable(drawable){} ~PickEvent(){}public: bool handle(const osgGA::GUIEventAdapter& ea, osgGA::GUIActionAdapter& aa) {  if (ea.getEventType() ==