142 lines
4.4 KiB
C++
142 lines
4.4 KiB
C++
#include <osg/GL>
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#include <osg/Group>
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#include <osg/Geometry>
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#include <osg/Geode>
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#include <osg/Viewport>
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#include <osg/Texture2D>
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#include <osg/MatrixTransform>
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#include <osgProducer/Viewer>
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#include <osgDB/ReadFile>
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#include <osg/FrameBufferObject>
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// This function builds a textured quad
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osg::Node *build_quad(osg::Texture2D *tex)
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{
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osg::Geometry *geo = new osg::Geometry;
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osg::Vec3Array *vx = new osg::Vec3Array;
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vx->push_back(osg::Vec3(-10, 0, -10));
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vx->push_back(osg::Vec3(10, 0, -10));
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vx->push_back(osg::Vec3(10, 0, 10));
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vx->push_back(osg::Vec3(-10, 0, 10));
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geo->setVertexArray(vx);
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osg::Vec3Array *nx = new osg::Vec3Array;
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nx->push_back(osg::Vec3(0, -1, 0));
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geo->setNormalArray(nx);
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geo->setNormalBinding(osg::Geometry::BIND_OVERALL);
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osg::Vec2Array *tx = new osg::Vec2Array;
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tx->push_back(osg::Vec2(0, 0));
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tx->push_back(osg::Vec2(1, 0));
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tx->push_back(osg::Vec2(1, 1));
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tx->push_back(osg::Vec2(0, 1));
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geo->setTexCoordArray(0, tx);
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geo->addPrimitiveSet(new osg::DrawArrays(GL_QUADS, 0, 4));
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geo->getOrCreateStateSet()->setTextureAttributeAndModes(0, tex);
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osg::Geode *geode = new osg::Geode;
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geode->addDrawable(geo);
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return geode;
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}
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void build_world(osg::Group *root)
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{
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int width = 2048;
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int height = 2048;
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// create and configure the texture that we're going
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// to use as target for render-to-texture
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osg::ref_ptr<osg::Texture2D> tex = new osg::Texture2D;
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tex->setTextureSize(width, height);
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tex->setInternalFormat(GL_RGBA);
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tex->setFilter(osg::Texture::MIN_FILTER, osg::Texture::LINEAR);
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tex->setFilter(osg::Texture::MAG_FILTER, osg::Texture::LINEAR);
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tex->setWrap(osg::Texture::WRAP_S, osg::Texture::CLAMP_TO_EDGE);
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tex->setWrap(osg::Texture::WRAP_T, osg::Texture::CLAMP_TO_EDGE);
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// create and configure a framebuffer object.
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// We attach the texture to the first color buffer,
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// and we attach a simple offscreen image (RenderBuffer)
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// to the depth buffer in order to allow depth operations
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osg::ref_ptr<osg::FrameBufferObject> fbo = new osg::FrameBufferObject();
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fbo->setAttachment(GL_COLOR_ATTACHMENT0_EXT, osg::FrameBufferAttachment(tex.get()));
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fbo->setAttachment(GL_DEPTH_ATTACHMENT_EXT, osg::FrameBufferAttachment(new osg::RenderBuffer(width, height, GL_DEPTH_COMPONENT24)));
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osg::ref_ptr<osg::Node> subgraph = osgDB::readNodeFile("cow.osg");
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if (!subgraph) return;
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const osg::BoundingSphere& bs = subgraph->getBound();
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if (!bs.valid())
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{
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return;
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}
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osg::ref_ptr<osg::CameraNode> camera = new osg::CameraNode;
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camera->setClearColor(osg::Vec4(0.1f,0.1f,0.3f,1.0f));
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camera->setClearMask(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
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camera->setViewport(0, 0, width, height);
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// set the camera to render before the main camera.
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camera->setRenderOrder(osg::CameraNode::PRE_RENDER);
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float znear = 1.0f*bs.radius();
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float zfar = 3.0f*bs.radius();
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// 2:1 aspect ratio as per flag geomtry below.
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float proj_top = 0.5f*znear;
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float proj_right = 0.5f*znear;
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znear *= 0.9f;
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zfar *= 1.1f;
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// set up projection.
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camera->setProjectionMatrixAsFrustum(-proj_right,proj_right,-proj_top,proj_top,znear,zfar);
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// set view
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camera->setReferenceFrame(osg::Transform::ABSOLUTE_RF);
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camera->setViewMatrixAsLookAt(bs.center()+osg::Vec3(0.0f,2.0f,0.0f)*bs.radius(),bs.center(),osg::Vec3(0.0f,0.0f,1.0f));
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// tell the camera to use OpenGL frame buffer object where supported.
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camera->setRenderTargetImplementation(osg::CameraNode::FRAME_BUFFER_OBJECT);
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// attach the texture and use it as the color buffer.
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camera->attach(osg::CameraNode::COLOR_BUFFER,tex.get());
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// attach the subgraph
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camera->addChild(subgraph.get());
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// attach the camera to the main scene graph.
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root->addChild(camera.get());
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// now create a simple quad that will be rendered
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// in the main framebuffers. The quad's texture
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// will be the content of the FBO's color buffer
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root->addChild(build_quad(tex.get()));
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}
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int main()
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{
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osg::ref_ptr<osg::Group> root = new osg::Group;
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build_world(root.get());
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osgProducer::Viewer viewer;
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viewer.setUpViewer();
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viewer.setSceneData(root.get());
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viewer.realize();
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while (!viewer.done())
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{
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viewer.sync();
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viewer.update();
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viewer.frame();
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}
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viewer.sync();
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viewer.cleanup_frame();
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viewer.sync();
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return 0;
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}
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