root/OpenSceneGraph/trunk/examples/osgreflect/osgreflect.cpp @ 13863

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1/* OpenSceneGraph example, osgreflect.
2*
3*  Permission is hereby granted, free of charge, to any person obtaining a copy
4*  of this software and associated documentation files (the "Software"), to deal
5*  in the Software without restriction, including without limitation the rights
6*  to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
7*  copies of the Software, and to permit persons to whom the Software is
8*  furnished to do so, subject to the following conditions:
9*
10*  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
11*  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
12*  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
13*  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
14*  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
15*  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
16*  THE SOFTWARE.
17*/
18
19#include <osg/Node>
20#include <osg/Geometry>
21#include <osg/Geode>
22#include <osg/Notify>
23#include <osg/MatrixTransform>
24#include <osg/Texture2D>
25#include <osg/BlendFunc>
26#include <osg/Stencil>
27#include <osg/ColorMask>
28#include <osg/Depth>
29#include <osg/ClipNode>
30#include <osg/AnimationPath>
31
32#include <osgDB/ReadFile>
33#include <osgDB/WriteFile>
34
35#include <osgUtil/Optimizer>
36#include <osgViewer/Viewer>
37
38#include <iostream>
39
40//
41// A simple demo demonstrating planar reflections using multiple renderings
42// of a subgraph, overriding of state attribures and use of the stencil buffer.
43//
44// The multipass system implemented here is a variation if Mark Kilgard's
45// paper "Improving Shadows and Reflections via the Stencil Buffer" which
46// can be found on the developer parts of the NVidia web site.
47//
48// The variations comes from the fact that the mirrors stencil values
49// are done on the first pass, rather than the second as in Mark's paper.
50// The second pass is now Mark's first pass - drawing the unreflected scene,
51// but also unsets the stencil buffer.  This variation stops the unreflected
52// world poking through the mirror to be seen in the final rendering and
53// also obscures the world correctly when on the reverse side of the mirror.
54// Although there is still some unresolved issue with the clip plane needing
55// to be flipped when looking at the reverse side of the mirror.  Niether
56// of these issues are mentioned in the Mark's paper, but trip us up when
57// we apply them.
58
59
60osg::StateSet* createMirrorTexturedState(const std::string& filename)
61{
62    osg::StateSet* dstate = new osg::StateSet;
63    dstate->setMode(GL_CULL_FACE,osg::StateAttribute::OFF|osg::StateAttribute::PROTECTED);
64
65    // set up the texture.
66    osg::Image* image = osgDB::readImageFile(filename.c_str());
67    if (image)
68    {
69        osg::Texture2D* texture = new osg::Texture2D;
70        texture->setImage(image);
71        dstate->setTextureAttributeAndModes(0,texture,osg::StateAttribute::ON|osg::StateAttribute::PROTECTED);
72    }
73
74    return dstate;
75}
76
77
78osg::Drawable* createMirrorSurface(float xMin,float xMax,float yMin,float yMax,float z)
79{
80
81    // set up the drawstate.
82
83    // set up the Geometry.
84    osg::Geometry* geom = new osg::Geometry;
85
86    osg::Vec3Array* coords = new osg::Vec3Array(4);
87    (*coords)[0].set(xMin,yMax,z);
88    (*coords)[1].set(xMin,yMin,z);
89    (*coords)[2].set(xMax,yMin,z);
90    (*coords)[3].set(xMax,yMax,z);
91    geom->setVertexArray(coords);
92
93    osg::Vec3Array* norms = new osg::Vec3Array(1);
94    (*norms)[0].set(0.0f,0.0f,1.0f);
95    geom->setNormalArray(norms, osg::Array::BIND_OVERALL);
96
97    osg::Vec2Array* tcoords = new osg::Vec2Array(4);
98    (*tcoords)[0].set(0.0f,1.0f);
99    (*tcoords)[1].set(0.0f,0.0f);
100    (*tcoords)[2].set(1.0f,0.0f);
101    (*tcoords)[3].set(1.0f,1.0f);
102    geom->setTexCoordArray(0,tcoords);
103
104    osg::Vec4Array* colours = new osg::Vec4Array(1);
105    (*colours)[0].set(1.0f,1.0f,1.0,1.0f);
106    geom->setColorArray(colours, osg::Array::BIND_OVERALL);
107
108    geom->addPrimitiveSet(new osg::DrawArrays(osg::PrimitiveSet::QUADS,0,4));
109
110    return geom;
111}
112
113osg::Node* createMirroredScene(osg::Node* model)
114{
115
116    // calculate where to place the mirror according to the
117    // loaded models bounding sphere.
118    const osg::BoundingSphere& bs = model->getBound();
119
120    float width_factor = 1.5;
121    float height_factor = 0.3;
122
123    float xMin = bs.center().x()-bs.radius()*width_factor;
124    float xMax = bs.center().x()+bs.radius()*width_factor;
125    float yMin = bs.center().y()-bs.radius()*width_factor;
126    float yMax = bs.center().y()+bs.radius()*width_factor;
127
128    float z = bs.center().z()-bs.radius()*height_factor;
129
130
131    // create a textured, transparent node at the appropriate place.
132    osg::Drawable* mirror = createMirrorSurface(xMin,xMax,yMin,yMax,z);
133
134
135    osg::MatrixTransform* rootNode = new osg::MatrixTransform;
136    rootNode->setMatrix(osg::Matrix::rotate(osg::inDegrees(45.0f),1.0f,0.0f,0.0f));
137
138    // make sure that the global color mask exists.
139    osg::ColorMask* rootColorMask = new osg::ColorMask;
140    rootColorMask->setMask(true,true,true,true);
141
142    // set up depth to be inherited by the rest of the scene unless
143    // overrideen. this is overridden in bin 3.
144    osg::Depth* rootDepth = new osg::Depth;
145    rootDepth->setFunction(osg::Depth::LESS);
146    rootDepth->setRange(0.0,1.0);
147
148    osg::StateSet* rootStateSet = new osg::StateSet();
149    rootStateSet->setAttribute(rootColorMask);
150    rootStateSet->setAttribute(rootDepth);
151
152    rootNode->setStateSet(rootStateSet);
153
154
155    // bin1  - set up the stencil values and depth for mirror.
156    {
157
158        // set up the stencil ops so that the stencil buffer get set at
159        // the mirror plane
160        osg::Stencil* stencil = new osg::Stencil;
161        stencil->setFunction(osg::Stencil::ALWAYS,1,~0u);
162        stencil->setOperation(osg::Stencil::KEEP, osg::Stencil::KEEP, osg::Stencil::REPLACE);
163
164        // switch off the writing to the color bit planes.
165        osg::ColorMask* colorMask = new osg::ColorMask;
166        colorMask->setMask(false,false,false,false);
167
168        osg::StateSet* statesetBin1 = new osg::StateSet();
169        statesetBin1->setRenderBinDetails(1,"RenderBin");
170        statesetBin1->setMode(GL_CULL_FACE,osg::StateAttribute::OFF);
171        statesetBin1->setAttributeAndModes(stencil,osg::StateAttribute::ON);
172        statesetBin1->setAttribute(colorMask);
173
174        // set up the mirror geode.
175        osg::Geode* geode = new osg::Geode;
176        geode->addDrawable(mirror);
177        geode->setStateSet(statesetBin1);
178
179        rootNode->addChild(geode);
180
181    }
182
183    // bin one - draw scene without mirror or reflection, unset
184    // stencil values where scene is infront of mirror and hence
185    // occludes the mirror.
186    {
187        osg::Stencil* stencil = new osg::Stencil;
188        stencil->setFunction(osg::Stencil::ALWAYS,0,~0u);
189        stencil->setOperation(osg::Stencil::KEEP, osg::Stencil::KEEP, osg::Stencil::REPLACE);
190
191        osg::StateSet* statesetBin2 = new osg::StateSet();
192        statesetBin2->setRenderBinDetails(2,"RenderBin");
193        statesetBin2->setAttributeAndModes(stencil,osg::StateAttribute::ON);
194
195
196        osg::Group* groupBin2 = new osg::Group();
197        groupBin2->setStateSet(statesetBin2);
198        groupBin2->addChild(model);
199
200        rootNode->addChild(groupBin2);
201    }
202
203    // bin3  - set up the depth to the furthest depth value
204    {
205
206        // set up the stencil ops so that only operator on this mirrors stencil value.
207        osg::Stencil* stencil = new osg::Stencil;
208        stencil->setFunction(osg::Stencil::EQUAL,1,~0u);
209        stencil->setOperation(osg::Stencil::KEEP, osg::Stencil::KEEP, osg::Stencil::KEEP);
210
211        // switch off the writing to the color bit planes.
212        osg::ColorMask* colorMask = new osg::ColorMask;
213        colorMask->setMask(false,false,false,false);
214
215        // set up depth so all writing to depth goes to maximum depth.
216        osg::Depth* depth = new osg::Depth;
217        depth->setFunction(osg::Depth::ALWAYS);
218        depth->setRange(1.0,1.0);
219
220        osg::StateSet* statesetBin3 = new osg::StateSet();
221        statesetBin3->setRenderBinDetails(3,"RenderBin");
222        statesetBin3->setMode(GL_CULL_FACE,osg::StateAttribute::OFF);
223        statesetBin3->setAttributeAndModes(stencil,osg::StateAttribute::ON);
224        statesetBin3->setAttribute(colorMask);
225        statesetBin3->setAttribute(depth);
226
227        // set up the mirror geode.
228        osg::Geode* geode = new osg::Geode;
229        geode->addDrawable(mirror);
230        geode->setStateSet(statesetBin3);
231
232        rootNode->addChild(geode);
233
234    }
235
236    // bin4  - draw the reflection.
237    {
238
239        // now create the 'reflection' of the loaded model by applying
240        // create a Transform which flips the loaded model about the z axis
241        // relative to the mirror node, the loadedModel is added to the
242        // Transform so now appears twice in the scene, but is shared so there
243        // is negligable memory overhead.  Also use an osg::StateSet
244        // attached to the Transform to override the face culling on the subgraph
245        // to prevert an 'inside' out view of the reflected model.
246        // set up the stencil ops so that only operator on this mirrors stencil value.
247
248
249
250        // this clip plane removes any of the scene which when mirror would
251        // poke through the mirror.  However, this clip plane should really
252        // flip sides once the eye point goes to the back of the mirror...
253        osg::ClipPlane* clipplane = new osg::ClipPlane;
254        clipplane->setClipPlane(0.0,0.0,-1.0,z);
255        clipplane->setClipPlaneNum(0);
256
257        osg::ClipNode* clipNode = new osg::ClipNode;
258        clipNode->addClipPlane(clipplane);
259
260
261        osg::StateSet* dstate = clipNode->getOrCreateStateSet();
262        dstate->setRenderBinDetails(4,"RenderBin");
263        dstate->setMode(GL_CULL_FACE,osg::StateAttribute::OVERRIDE|osg::StateAttribute::OFF);
264
265        osg::Stencil* stencil = new osg::Stencil;
266        stencil->setFunction(osg::Stencil::EQUAL,1,~0u);
267        stencil->setOperation(osg::Stencil::KEEP, osg::Stencil::KEEP, osg::Stencil::KEEP);
268        dstate->setAttributeAndModes(stencil,osg::StateAttribute::ON);
269
270        osg::MatrixTransform* reverseMatrix = new osg::MatrixTransform;
271        reverseMatrix->setStateSet(dstate);
272        reverseMatrix->preMult(osg::Matrix::translate(0.0f,0.0f,-z)*
273                     osg::Matrix::scale(1.0f,1.0f,-1.0f)*
274                     osg::Matrix::translate(0.0f,0.0f,z));
275
276        reverseMatrix->addChild(model);
277
278        clipNode->addChild(reverseMatrix);
279
280        rootNode->addChild(clipNode);
281
282    }
283
284
285    // bin5  - draw the textured mirror and blend it with the reflection.
286    {
287
288        // set up depth so all writing to depth goes to maximum depth.
289        osg::Depth* depth = new osg::Depth;
290        depth->setFunction(osg::Depth::ALWAYS);
291
292        osg::Stencil* stencil = new osg::Stencil;
293        stencil->setFunction(osg::Stencil::EQUAL,1,~0u);
294        stencil->setOperation(osg::Stencil::KEEP, osg::Stencil::KEEP, osg::Stencil::ZERO);
295
296        // set up additive blending.
297        osg::BlendFunc* trans = new osg::BlendFunc;
298        trans->setFunction(osg::BlendFunc::ONE,osg::BlendFunc::ONE);
299
300        osg::StateSet* statesetBin5 = createMirrorTexturedState("Images/tank.rgb");
301
302        statesetBin5->setRenderBinDetails(5,"RenderBin");
303        statesetBin5->setMode(GL_CULL_FACE,osg::StateAttribute::OFF);
304        statesetBin5->setAttributeAndModes(stencil,osg::StateAttribute::ON);
305        statesetBin5->setAttributeAndModes(trans,osg::StateAttribute::ON);
306        statesetBin5->setAttribute(depth);
307
308        // set up the mirror geode.
309        osg::Geode* geode = new osg::Geode;
310        geode->addDrawable(mirror);
311        geode->setStateSet(statesetBin5);
312
313        rootNode->addChild(geode);
314
315    }
316
317    return rootNode;
318}
319
320
321/////////////////////////////////////////////////////////////////////////////////////////////////////////
322//
323// create the viewer
324// load a model
325// decoate the model so it renders using a multipass stencil buffer technique for planar reflections.
326// release the viewer
327// run main loop.
328//
329int main( int argc, char **argv )
330{
331    // use an ArgumentParser object to manage the program arguments.
332    osg::ArgumentParser arguments(&argc,argv);
333
334    // construct the viewer.
335    osgViewer::Viewer viewer;
336
337    // read the scene from the list of file specified commandline args.
338    osg::ref_ptr<osg::Node> loadedModel = osgDB::readNodeFiles(arguments);
339
340    // if not loaded assume no arguments passed in, try use default mode instead.
341    if (!loadedModel) loadedModel = osgDB::readNodeFile("cessna.osgt");
342
343    // if no model has been successfully loaded report failure.
344    if (!loadedModel)
345    {
346        std::cout << arguments.getApplicationName() <<": No data loaded" << std::endl;
347        return 1;
348    }
349
350
351    // optimize the scene graph, remove redundant nodes and state etc.
352    osgUtil::Optimizer optimizer;
353    optimizer.optimize(loadedModel.get());
354
355    // add a transform with a callback to animate the loaded model.
356    osg::ref_ptr<osg::MatrixTransform> loadedModelTransform = new osg::MatrixTransform;
357    loadedModelTransform->addChild(loadedModel.get());
358
359    osg::ref_ptr<osg::NodeCallback> nc = new osg::AnimationPathCallback(loadedModelTransform->getBound().center(),osg::Vec3(0.0f,0.0f,1.0f),osg::inDegrees(45.0f));
360    loadedModelTransform->setUpdateCallback(nc.get());
361
362
363    // finally decorate the loaded model so that it has the required multipass/bin scene graph to do the reflection effect.
364    osg::ref_ptr<osg::Node> rootNode = createMirroredScene(loadedModelTransform.get());
365
366    // set the scene to render
367    viewer.setSceneData(rootNode.get());
368
369    // hint to tell viewer to request stencil buffer when setting up windows
370    osg::DisplaySettings::instance()->setMinimumNumStencilBits(8);
371
372    //osgDB::writeNodeFile(*rootNode, "test.osgt");
373
374    return viewer.run();
375
376}
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