Examples/Simple/geometryshader.cpp

   1 // OpenSG GLSL shader example: Geometry Shader
   2 //
   3 // Demonstrates the use of the SHLChunk
   4 // Implements a geometry shader which creates for each triangle an
   5 // extra triangle showing the face normal.
   6
   7 #ifdef OSG_BUILD_ACTIVE
   8 // Headers
   9 #include <OSGConfig.h>
  10 #include <OSGSimpleGeometry.h>
  11 #include <OSGGLUT.h>
  12 #include <OSGGLEXT.h>
  13 #include <OSGGLUTWindow.h>
  14 #include <OSGSimpleSceneManager.h>
  15 #include <OSGAction.h>
  16 #include <OSGSceneFileHandler.h>
  17 #include <OSGBaseFunctions.h>
  18
  19 #include <OSGNode.h>
  20 #include <OSGGroup.h>
  21 #include <OSGTransform.h>
  22 #include <OSGPointLight.h>
  23
  24 #include <OSGImage.h>
  25 #include <OSGChunkMaterial.h>
  26 #include <OSGMaterialChunk.h>
  27 #include <OSGTextureChunk.h>
  28 #include <OSGSHLChunk.h>
  29 #else
  30 // Headers
  31 #include <OpenSG/OSGConfig.h>
  32 #include <OpenSG/OSGSimpleGeometry.h>
  33 #include <OpenSG/OSGGLUT.h>
  34 #include <OpenSG/OSGGLEXT.h>
  35 #include <OpenSG/OSGGLUTWindow.h>
  36 #include <OpenSG/OSGSimpleSceneManager.h>
  37 #include <OpenSG/OSGAction.h>
  38 #include <OpenSG/OSGSceneFileHandler.h>
  39 #include <OpenSG/OSGBaseFunctions.h>
  40
  41 #include <OpenSG/OSGNode.h>
  42 #include <OpenSG/OSGGroup.h>
  43 #include <OpenSG/OSGTransform.h>
  44 #include <OpenSG/OSGPointLight.h>
  45
  46 #include <OpenSG/OSGImage.h>
  47 #include <OpenSG/OSGChunkMaterial.h>
  48 #include <OpenSG/OSGMaterialChunk.h>
  49 #include <OpenSG/OSGTextureChunk.h>
  50 #include <OpenSG/OSGSHLChunk.h>
  51 #endif
  52
  53
  54
  55 // ------------------- global vars ----------------------
  56 //
  57 // The SimpleSceneManager to manage simple applications
  58 SimpleSceneManagerRefPtr _mgr;
  59 // The scene
  60 NodeRefPtr               _scene;
  61
  62 // forward declaration so we can have the interesting stuff upfront
  63 int setupGLUT( int *argc, char *argv[] );
  64
  65 static std::string _vertex_shader =
  66 "void main(void)\n"
  67 "{\n"
  68 "    gl_Position = gl_Vertex;\n"
  69 "    gl_TexCoord[0] = vec4(abs(gl_Normal), 0.0);\n"
  70 "}\n"
  71 "\n";
  72
  73 static std::string _fragment_shader =
  74 "void main (void)\n"
  75 "{\n"
  76 "    gl_FragColor = gl_Color;\n"
  77 "\n"
  78 "}\n";
  79
  80 // ok we create some triangles to draw the face normals.
  81 static std::string _geometry_shader =
  82 "#version 120\n"
  83 "#extension GL_EXT_geometry_shader4 : enable\n"
  84 "\n"
  85 "void main(void)\n"
  86 "{\n"
  87 "    vec4 v1 = gl_PositionIn[0];\n"
  88 "    vec4 v2 = gl_PositionIn[1];\n"
  89 "    vec4 v3 = gl_PositionIn[2];\n"
  90 "\n"
  91 "    vec4 l1 = v2 - v1;\n"
  92 "    vec4 l2 = v3 - v1;\n"
  93 "\n"
  94 "    // create the original triangle.\n"
  95 "    gl_Position = gl_ModelViewProjectionMatrix * v1;\n"
  96 "    gl_FrontColor = vec4(0.0, 1.0, 0.0, 0.0);\n"
  97 "    EmitVertex();\n"
  98 "    gl_Position = gl_ModelViewProjectionMatrix * v2;\n"
  99 "    gl_FrontColor = vec4(0.0, 1.0, 0.0, 0.0);\n"
 100 "    EmitVertex();\n"
 101 "    gl_Position = gl_ModelViewProjectionMatrix * v3;\n"
 102 "    gl_FrontColor = vec4(0.0, 1.0, 0.0, 0.0);\n"
 103 "    EmitVertex();\n"
 104 "    EndPrimitive();\n"
 105 "\n"
 106 "    vec3 l1n = l1.xyz;\n"
 107 "    vec3 l2n = l2.xyz;\n"
 108 "\n"
 109 "    vec3 N = cross(l1n.xyz, l2n.xyz);\n"
 110 "    N = normalize(N);\n"
 111 "    vec4 middle = v1 + 0.333 * l1 + 0.333 * l2;\n"
 112 "    // create the face normal triangle.\n"
 113 "    gl_Position = gl_ModelViewProjectionMatrix * middle;\n"
 114 "    gl_FrontColor = gl_TexCoordIn[0][0];\n"
 115 "    EmitVertex();\n"
 116 "    gl_FrontColor = gl_TexCoordIn[0][0];\n"
 117 "    gl_Position = gl_ModelViewProjectionMatrix * (middle + 0.1 * vec4(N, 0.0));\n"
 118 "    EmitVertex();\n"
 119 "    gl_FrontColor = gl_TexCoordIn[0][0];\n"
 120 "    gl_Position = gl_ModelViewProjectionMatrix * (middle + vec4(0.01,0.01,0.01,0.0));\n"
 121 "    EmitVertex();\n"
 122 "    EndPrimitive();\n"
 123 "\n"
 124 "}\n";
 125
 126 // Initialize GLUT & OpenSG and set up the scene
 127 int main(int argc, char **argv)
 128 {
 129     // OSG init
 130     osgInit(argc,argv);
 131
 132     // GLUT init
 133     int winid = setupGLUT(&argc, argv);
 134
 135     // open a new scope, because the pointers below should go out of scope
 136     // before entering glutMainLoop.
 137     // Otherwise OpenSG will complain about objects being alive after shutdown.
 138     {
 139         // the connection between GLUT and OpenSG
 140         GLUTWindowRefPtr gwin = GLUTWindow::create();
 141         gwin->setGlutId(winid);
 142         gwin->setSize( 800, 800 );
 143         gwin->init();
 144
 145         // Create the shader material
 146         ChunkMaterialRefPtr cmat = ChunkMaterial::create();
 147
 148         SHLChunkRefPtr shl = SHLChunk::create();
 149         shl->setProgramParameter(GL_GEOMETRY_INPUT_TYPE_EXT, GL_TRIANGLES_ADJACENCY_EXT);
 150         shl->setProgramParameter(GL_GEOMETRY_OUTPUT_TYPE_EXT, GL_TRIANGLES);
 151         // ok we create a maximum of 6 vertices.
 152         shl->setProgramParameter(GL_GEOMETRY_VERTICES_OUT_EXT, 6);
 153
 154         shl->setVertexProgram(_vertex_shader);
 155         shl->setFragmentProgram(_fragment_shader);
 156         shl->setGeometryProgram(_geometry_shader);
 157
 158         cmat->addChunk(shl);
 159
 160         // create root node
 161         _scene = Node::create();
 162
 163         // create torus
 164         GeometryRefPtr geo = makeTorusGeo(.8, 1.8, 32, 32);
 165         geo->setMaterial(cmat);
 166
 167         NodeRefPtr torus = Node::create();
 168         torus->setCore(geo);
 169
 170         // add torus to scene
 171         GroupRefPtr group = Group::create();
 172         _scene->setCore(group);
 173         _scene->addChild(torus);
 174
 175         // create the SimpleSceneManager helper
 176         _mgr = SimpleSceneManager::create();
 177
 178         // tell the manager what to manage
 179         _mgr->setWindow(gwin );
 180         _mgr->setRoot(_scene);
 181
 182         // show the whole scene
 183         _mgr->showAll();
 184     }
 185
 186     // GLUT main loop
 187     glutMainLoop();
 188
 189     return 0;
 190 }
 191
 192 //
 193 // GLUT callback functions
 194 //
 195
 196 // redraw the window
 197 void display(void)
 198 {
 199   // render scene
 200   _mgr->redraw();
 201 }
 202
 203 // react to size changes
 204 void reshape(int w, int h)
 205 {
 206     _mgr->resize(w, h);
 207     glutPostRedisplay();
 208 }
 209
 210 // react to mouse button presses
 211 void mouse(int button, int state, int x, int y)
 212 {
 213     if (state)
 214         _mgr->mouseButtonRelease(button, x, y);
 215     else
 216         _mgr->mouseButtonPress(button, x, y);
 217
 218     glutPostRedisplay();
 219 }
 220
 221 // react to mouse motions with pressed buttons
 222 void motion(int x, int y)
 223 {
 224     _mgr->mouseMove(x, y);
 225     glutPostRedisplay();
 226 }
 227
 228 // react to keys
 229 void keyboard(unsigned char k, int x, int y)
 230 {
 231     switch(k)
 232     {
 233         case 27:
 234         case 'q':
 235             // clean up global variables
 236             _mgr   = NULL;
 237             _scene = NULL;
 238
 239             osgExit();
 240             exit(1);
 241         break;
 242         case 'w':
 243             SceneFileHandler::the()->write(_scene, "scene.osb.gz", true);
 244             printf("wrote scene.osb.gz\n");
 245         break;
 246     }
 247
 248     glutPostRedisplay();
 249 }
 250
 251 // setup the GLUT library which handles the windows for us
 252 int setupGLUT(int *argc, char *argv[])
 253 {
 254     glutInit(argc, argv);
 255     glutInitDisplayMode(GLUT_RGB | GLUT_DEPTH | GLUT_DOUBLE);
 256
 257     int winid = glutCreateWindow("OpenSG GLSL Geometry Shader");
 258
 259     glutReshapeFunc(reshape);
 260     glutDisplayFunc(display);
 261     glutMouseFunc(mouse);
 262     glutMotionFunc(motion);
 263     glutKeyboardFunc(keyboard);
 264
 265     return winid;
 266 }
 267
 268