[osg-users] Using Ortho2D projection camera under OpenSceneGraph PRE_RENDER camera
Malcolm Pigott
osg.malcolm at hydrogenrocks.me.uk
Fri Jan 20 14:12:11 PST 2017
I have a scene in OpenSceneGraph which has a "normal" 3D content overlaid with content in an Ortho2D projection. This works OK.
I am now trying to render this scene to a texture (via a Frame Buffer Object) and am working with the osgPreRender example. Below is some code derived from that example which has a 2D overlay which is shown when the scene is drawn normally, but not (seemingly) drawn when rendered to a texture using setRenderOrder(osg::Camera::PRE_RENDER).
This is using OpenSceneGraph 3.4.0 and VS2015 Update 2.
Code:
/* OpenSceneGraph example, osgprerender.
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
#include <osg/GLExtensions>
#include <osg/Node>
#include <osg/Geometry>
#include <osg/Notify>
#include <osg/MatrixTransform>
#include <osg/Texture2D>
#include <osg/TextureRectangle>
#include <osg/Stencil>
#include <osg/ColorMask>
#include <osg/Depth>
#include <osg/Billboard>
#include <osg/Material>
#include <osg/AnimationPath>
#include <osg/LineWidth>
#include <osgGA/TrackballManipulator>
#include <osgGA/FlightManipulator>
#include <osgGA/DriveManipulator>
#include <osgUtil/SmoothingVisitor>
#include <osgDB/Registry>
#include <osgDB/ReadFile>
#include <osgDB/WriteFile>
#include <osgViewer/Viewer>
#include <osgViewer/ViewerEventHandlers>
#include <iostream>
// call back which creates a deformation field to oscillate the model.
class MyGeometryCallback :
public osg::Drawable::UpdateCallback,
public osg::Drawable::AttributeFunctor
{
public:
MyGeometryCallback(const osg::Vec3& o,
const osg::Vec3& x, const osg::Vec3& y, const osg::Vec3& z,
double period, double xphase, double amplitude) :
_firstCall(true),
_startTime(0.0),
_time(0.0),
_period(period),
_xphase(xphase),
_amplitude(amplitude),
_origin(o),
_xAxis(x),
_yAxis(y),
_zAxis(z) {}
virtual void update(osg::NodeVisitor* nv, osg::Drawable* drawable)
{
// OpenThreads::Thread::microSleep( 1000 );
const osg::FrameStamp* fs = nv->getFrameStamp();
double simulationTime = fs->getSimulationTime();
if (_firstCall)
{
_firstCall = false;
_startTime = simulationTime;
}
_time = simulationTime - _startTime;
drawable->accept(*this);
drawable->dirtyBound();
osg::Geometry* geometry = dynamic_cast<osg::Geometry*>(drawable);
if (geometry)
{
osgUtil::SmoothingVisitor::smooth(*geometry);
}
}
virtual void apply(osg::Drawable::AttributeType type, unsigned int count, osg::Vec3* begin)
{
if (type == osg::Drawable::VERTICES)
{
const float TwoPI = 2.0f*osg::PI;
const float phase = -_time / _period;
osg::Vec3* end = begin + count;
for (osg::Vec3* itr = begin; itr<end; ++itr)
{
osg::Vec3 dv(*itr - _origin);
osg::Vec3 local(dv*_xAxis, dv*_yAxis, dv*_zAxis);
local.z() = local.x()*_amplitude*
sinf(TwoPI*(phase + local.x()*_xphase));
(*itr) = _origin +
_xAxis*local.x() +
_yAxis*local.y() +
_zAxis*local.z();
}
}
}
bool _firstCall;
double _startTime;
double _time;
double _period;
double _xphase;
float _amplitude;
osg::Vec3 _origin;
osg::Vec3 _xAxis;
osg::Vec3 _yAxis;
osg::Vec3 _zAxis;
};
osg::Node* createPreRenderSubGraph(osg::Node* subgraph,
unsigned tex_width, unsigned tex_height,
osg::Camera::RenderTargetImplementation renderImplementation,
bool useTextureRectangle,
unsigned int samples, unsigned int colorSamples)
{
if (!subgraph) return 0;
// create a group to contain the flag and the pre rendering camera.
osg::Group* parent = new osg::Group;
// texture to render to and to use for rendering of flag.
osg::Texture* texture = 0;
{
osg::TextureRectangle* textureRect = new osg::TextureRectangle;
textureRect->setTextureSize(tex_width, tex_height);
textureRect->setInternalFormat(GL_RGBA);
textureRect->setFilter(osg::Texture2D::MIN_FILTER, osg::Texture2D::LINEAR);
textureRect->setFilter(osg::Texture2D::MAG_FILTER, osg::Texture2D::LINEAR);
texture = textureRect;
}
// first create the geometry of the flag of which to view.
{
// create the to visualize.
osg::Geometry* polyGeom = new osg::Geometry();
polyGeom->setName("PolyGeom");
polyGeom->setDataVariance(osg::Object::DYNAMIC);
polyGeom->setSupportsDisplayList(false);
osg::Vec3 origin(0.0f, 0.0f, 0.0f);
osg::Vec3 xAxis(1.0f, 0.0f, 0.0f);
osg::Vec3 yAxis(0.0f, 0.0f, 1.0f);
osg::Vec3 zAxis(0.0f, -1.0f, 0.0f);
float height = 100.0f;
float width = 200.0f;
int noSteps = 20;
osg::Vec3Array* vertices = new osg::Vec3Array;
osg::Vec3 bottom = origin;
osg::Vec3 top = origin; top.z() += height;
osg::Vec3 dv = xAxis*(width / ((float)(noSteps - 1)));
osg::Vec2Array* texcoords = new osg::Vec2Array;
// note, when we use TextureRectangle we have to scale the tex coords up to compensate.
osg::Vec2 bottom_texcoord(0.0f, 0.0f);
osg::Vec2 top_texcoord(0.0f, useTextureRectangle ? tex_height : 1.0f);
osg::Vec2 dv_texcoord((useTextureRectangle ? tex_width : 1.0f) / (float)(noSteps - 1), 0.0f);
for (int i = 0; i<noSteps; ++i)
{
vertices->push_back(top);
vertices->push_back(bottom);
top += dv;
bottom += dv;
texcoords->push_back(top_texcoord);
texcoords->push_back(bottom_texcoord);
top_texcoord += dv_texcoord;
bottom_texcoord += dv_texcoord;
}
// pass the created vertex array to the points geometry object.
polyGeom->setVertexArray(vertices);
polyGeom->setTexCoordArray(0, texcoords);
osg::Vec4Array* colors = new osg::Vec4Array;
colors->push_back(osg::Vec4(1.0f, 1.0f, 1.0f, 1.0f));
polyGeom->setColorArray(colors, osg::Array::BIND_OVERALL);
polyGeom->addPrimitiveSet(new osg::DrawArrays(osg::PrimitiveSet::QUAD_STRIP, 0, vertices->size()));
// new we need to add the texture to the Drawable, we do so by creating a
// StateSet to contain the Texture StateAttribute.
osg::StateSet* stateset = new osg::StateSet;
stateset->setTextureAttributeAndModes(0, texture, osg::StateAttribute::ON);
polyGeom->setStateSet(stateset);
polyGeom->setUpdateCallback(new MyGeometryCallback(origin, xAxis, yAxis, zAxis, 1.0, 1.0 / width, 0.2f));
osg::Geode* geode = new osg::Geode();
geode->addDrawable(polyGeom);
parent->addChild(geode);
}
// then create the camera node to do the render to texture
{
osg::Camera* camera = new osg::Camera;
// set up the background color and clear mask.
camera->setClearColor(osg::Vec4(0.1f, 0.1f, 0.3f, 1.0f));
camera->setClearMask(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
const osg::BoundingSphere& bs = subgraph->getBound();
if (!bs.valid())
{
return subgraph;
}
float znear = 1.0f*bs.radius();
float zfar = 3.0f*bs.radius();
// 2:1 aspect ratio as per flag geometry below.
float proj_top = 0.25f*znear;
float proj_right = 0.5f*znear;
znear *= 0.9f;
zfar *= 1.1f;
// set up projection.
camera->setProjectionMatrixAsFrustum(-proj_right, proj_right, -proj_top, proj_top, znear, zfar);
// set view
camera->setReferenceFrame(osg::Transform::ABSOLUTE_RF);
camera->setViewMatrixAsLookAt(bs.center() - osg::Vec3(0.0f, 2.0f, 0.0f)*bs.radius(), bs.center(), osg::Vec3(0.0f, 0.0f, 1.0f));
// set viewport
camera->setViewport(0, 0, tex_width, tex_height);
// set the camera to render before the main camera.
camera->setRenderOrder(osg::Camera::PRE_RENDER);
// tell the camera to use OpenGL frame buffer object where supported.
camera->setRenderTargetImplementation(renderImplementation);
// attach the texture and use it as the color buffer.
camera->attach(osg::Camera::COLOR_BUFFER, texture, 0, 0, false, samples, colorSamples);
// add subgraph to render
camera->addChild(subgraph);
parent->addChild(camera);
}
return parent;
}
osg::Node *createNormalScene(osgViewer::Viewer &Viewer)
{
auto topNodeOfNormalScene = new osg::Group();
{
auto normal3DScene = new osg::Group();
{
normal3DScene->addChild(osgDB::readNodeFile("cessna.osgt")); // 3D example
topNodeOfNormalScene->addChild(normal3DScene);
}
auto overlayLikeA2DHUD = new osg::Group();
{
auto overlayCamera = new osg::Camera();
overlayCamera->getOrCreateStateSet()->setGlobalDefaults();
double _orthoLeft = 0.0;
double _orthoRight = 1280.0;
double _orthoBottom = 0.0;
double _orthoTop = 1024.0;
{
// Create the symbology camera
overlayCamera->setName("OverlayViewCamera");
overlayCamera->setProjectionMatrixAsOrtho2D(_orthoLeft, _orthoRight, _orthoBottom, _orthoTop);
overlayCamera->setDataVariance(osg::Object::DYNAMIC); // gets updated when the screen size changes.
//_symbologyCamera->setRenderOrder(osg::Camera::POST_RENDER);
overlayCamera->setReferenceFrame(osg::Camera::ABSOLUTE_RF);
overlayCamera->setClearMask(GL_DEPTH_BUFFER_BIT);
overlayCamera->setViewport(new osg::Viewport(0.0, 0.0, (_orthoRight - _orthoLeft), (_orthoTop - _orthoBottom)));
}
{
auto Geometry = new osg::Geometry();
{
Geometry->setName("2DTie");
double Left = 100.0;
double Bottom = 100.0;
double Right = 924.0;
double Top = 1180.0;
// tie
osg::Vec3Array *vertexArray = new osg::Vec3Array();
vertexArray->push_back(osg::Vec3d(Left, Bottom, 0.0));
vertexArray->push_back(osg::Vec3d(Right, Bottom, 0.0));
vertexArray->push_back(osg::Vec3d(Left, Top, 0.0));
vertexArray->push_back(osg::Vec3d(Right, Top, 0.0));
Geometry->setVertexArray(vertexArray);
osg::Vec3 colors[] = { { 1.0f, 1.0f, 1.0f } };
osg::Vec3Array *colorArray = new osg::Vec3Array(1, colors);
Geometry->setColorArray(colorArray, osg::Array::BIND_OVERALL);
Geometry->addPrimitiveSet(new osg::DrawArrays(osg::PrimitiveSet::LINE_LOOP, 0, vertexArray->size()));
Geometry->getOrCreateStateSet()->setAttributeAndModes(new osg::LineWidth(2.0f), osg::StateAttribute::ON);
}
auto Geode = new osg::Geode();
Geode->addDrawable(Geometry);
auto Group = new osg::Group();
Group->addChild(Geode);
overlayCamera->addChild(Group);
}
overlayLikeA2DHUD->addChild(overlayCamera);
//Viewer.addSlave(_symbologyCamera, false);
topNodeOfNormalScene->addChild(overlayLikeA2DHUD);
}
}
return topNodeOfNormalScene;
}
int main(int argc, char **argv)
{
// use an ArgumentParser object to manage the program arguments.
osg::ArgumentParser arguments(&argc, argv);
// set up the usage document, in case we need to print out how to use this program.
arguments.getApplicationUsage()->setDescription(arguments.getApplicationName() + " is the example which demonstrates pre rendering of scene to a texture, and then apply this texture to geometry.");
arguments.getApplicationUsage()->setCommandLineUsage(arguments.getApplicationName() + " [options] filename ...");
arguments.getApplicationUsage()->addCommandLineOption("-h or --help", "Display this information");
arguments.getApplicationUsage()->addCommandLineOption("--fbo", "Use Frame Buffer Object for render to texture, where supported.");
arguments.getApplicationUsage()->addCommandLineOption("--fb", "Use FrameBuffer for render to texture.");
arguments.getApplicationUsage()->addCommandLineOption("--pbuffer", "Use Pixel Buffer for render to texture, where supported.");
arguments.getApplicationUsage()->addCommandLineOption("--window", "Use a separate Window for render to texture.");
arguments.getApplicationUsage()->addCommandLineOption("--width", "Set the width of the render to texture.");
arguments.getApplicationUsage()->addCommandLineOption("--height", "Set the height of the render to texture.");
arguments.getApplicationUsage()->addCommandLineOption("--image", "Render to an image, then apply a post draw callback to it, and use this image to update a texture.");
arguments.getApplicationUsage()->addCommandLineOption("--texture-rectangle", "Use osg::TextureRectangle for doing the render to texture to.");
// construct the viewer.
osgViewer::Viewer viewer(arguments);
// add stats
viewer.addEventHandler(new osgViewer::StatsHandler());
// add the record camera path handler
viewer.addEventHandler(new osgViewer::RecordCameraPathHandler);
// add the threading handler
viewer.addEventHandler(new osgViewer::ThreadingHandler());
// if user request help write it out to cout.
if (arguments.read("-h") || arguments.read("--help"))
{
arguments.getApplicationUsage()->write(std::cout);
return 1;
}
unsigned int tex_width = 1280;
unsigned int tex_height = 1024;
unsigned int samples = 0;
unsigned int colorSamples = 0;
while (arguments.read("--width", tex_width)) {}
while (arguments.read("--height", tex_height)) {}
osg::Camera::RenderTargetImplementation renderImplementation = osg::Camera::FRAME_BUFFER_OBJECT;
while (arguments.read("--fbo")) { renderImplementation = osg::Camera::FRAME_BUFFER_OBJECT; }
while (arguments.read("--pbuffer")) { renderImplementation = osg::Camera::PIXEL_BUFFER; }
while (arguments.read("--pbuffer-rtt")) { renderImplementation = osg::Camera::PIXEL_BUFFER_RTT; }
while (arguments.read("--fb")) { renderImplementation = osg::Camera::FRAME_BUFFER; }
while (arguments.read("--window")) { renderImplementation = osg::Camera::SEPARATE_WINDOW; }
while (arguments.read("--fbo-samples", samples)) {}
while (arguments.read("--color-samples", colorSamples)) {}
bool useTextureRectangle = true;
while (arguments.read("--texture-rectangle")) { useTextureRectangle = true; }
// load the nodes from the commandline arguments.
osg::Node* loadedModel = osgDB::readNodeFiles(arguments);
// if not loaded assume no arguments passed in, try use default mode instead.
if (!loadedModel) loadedModel = createNormalScene(viewer); // osgDB::readNodeFile("cessna.osgt");
if (!loadedModel)
{
return 1;
}
bool PreRender = true; // alter via debugger
if (PreRender)
{
// create a transform to spin the model.
osg::MatrixTransform* loadedModelTransform = new osg::MatrixTransform;
loadedModelTransform->addChild(loadedModel);
osg::NodeCallback* nc = new osg::AnimationPathCallback(loadedModelTransform->getBound().center(), osg::Vec3(0.0f, 0.0f, 1.0f), osg::inDegrees(45.0f));
loadedModelTransform->setUpdateCallback(nc);
osg::Group* rootNode = new osg::Group();
rootNode->addChild(createPreRenderSubGraph(loadedModelTransform, tex_width, tex_height, renderImplementation, useTextureRectangle, samples, colorSamples));
bool WriteOutNodeFile = false; // alter via debugger
if (WriteOutNodeFile)
{
osgDB::writeNodeFile(*rootNode, "PreRenderExample.osgt"); // view using Notepad++ and LUA language mode (for example).
}
// add model to the viewer.
viewer.setSceneData(rootNode);
}
else
{
auto camera = viewer.getCamera();
// set up the background color and clear mask.
camera->setClearColor(osg::Vec4(0.1f, 0.1f, 0.3f, 1.0f));
camera->setClearMask(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
viewer.setSceneData(loadedModel);
}
return viewer.run();
}
Many thanks for any guidance.
------------------
Read this topic online here:
http://forum.openscenegraph.org/viewtopic.php?p=70025#70025
Attachments:
http://forum.openscenegraph.org//files/ortho2dinprerender_895.cpp
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