248 lines
7.9 KiB
C++
248 lines
7.9 KiB
C++
/* A demonstration of Tessellation Shaders in OpenScenegraph.
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* Original code by Philip Rideout
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* Adapted to OpenScenegraph by John Kaniarz
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*/
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#include <osg/Program>
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#include <osg/ShapeDrawable>
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#include <osgViewer/Viewer>
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#include <osgViewer/ViewerEventHandlers>
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#include <osgGA/TrackballManipulator>
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static const char* vertSource = {
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"#version 400\n"
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"in vec4 osg_Vertex;\n"
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"out vec3 vPosition;\n"
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"void main(){\n"
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" vPosition = osg_Vertex.xyz;\n"
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"}\n"
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};
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static const char* tessControlSource = {
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"#version 400\n"
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"layout(vertices = 3) out;\n"
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"in vec3 vPosition[];\n"
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"out vec3 tcPosition[];\n"
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"uniform float TessLevelInner;\n"
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"uniform float TessLevelOuter;\n"
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"#define ID gl_InvocationID\n"
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"void main(){\n"
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" tcPosition[ID] = vPosition[ID];\n"
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" if (ID == 0) {\n"
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" gl_TessLevelInner[0] = TessLevelInner;\n"
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" gl_TessLevelOuter[0] = TessLevelOuter;\n"
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" gl_TessLevelOuter[1] = TessLevelOuter;\n"
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" gl_TessLevelOuter[2] = TessLevelOuter;\n"
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" }\n"
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"}\n"
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};
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static const char* tessEvalSource = {
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"#version 400\n"
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"layout(triangles, equal_spacing, cw) in;\n"
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"in vec3 tcPosition[];\n"
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"out vec3 tePosition;\n"
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"out vec3 tePatchDistance;\n"
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"uniform mat4 osg_ProjectionMatrix;\n"
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"uniform mat4 osg_ModelViewMatrix;\n"
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"void main(){\n"
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" vec3 p0 = gl_TessCoord.x * tcPosition[0];\n"
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" vec3 p1 = gl_TessCoord.y * tcPosition[1];\n"
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" vec3 p2 = gl_TessCoord.z * tcPosition[2];\n"
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" tePatchDistance = gl_TessCoord;\n"
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" tePosition = normalize(p0 + p1 + p2);\n"
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" gl_Position = osg_ProjectionMatrix * osg_ModelViewMatrix * vec4(tePosition, 1);\n"
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"}\n"
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};
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static const char* geomSource = {
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"#version 400\n"
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"uniform mat4 osg_ModelViewMatrix;\n"
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"uniform mat3 osg_NormalMatrix;\n"
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"layout(triangles) in;\n"
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"layout(triangle_strip, max_vertices = 3) out;\n"
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"in vec3 tePosition[3];\n"
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"in vec3 tePatchDistance[3];\n"
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"out vec3 gFacetNormal;\n"
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"out vec3 gPatchDistance;\n"
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"out vec3 gTriDistance;\n"
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"out vec4 gColor;\n"
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"void main(){\n"
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" vec3 A = tePosition[2] - tePosition[0];\n"
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" vec3 B = tePosition[1] - tePosition[0];\n"
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" gFacetNormal = osg_NormalMatrix * normalize(cross(A, B));\n"
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" gPatchDistance = tePatchDistance[0];\n"
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" gTriDistance = vec3(1, 0, 0);\n"
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" gColor = osg_ModelViewMatrix[0];\n"
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" gl_Position = gl_in[0].gl_Position; EmitVertex();\n"
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" gPatchDistance = tePatchDistance[1];\n"
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" gTriDistance = vec3(0, 1, 0);\n"
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" gColor = osg_ModelViewMatrix[1];\n"
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" gl_Position = gl_in[1].gl_Position; EmitVertex();\n"
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" gPatchDistance = tePatchDistance[2];\n"
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" gTriDistance = vec3(0, 0, 1);\n"
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" gColor = osg_ModelViewMatrix[2];\n"
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" gl_Position = gl_in[2].gl_Position; EmitVertex();\n"
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" EndPrimitive();\n"
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"}\n"
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};
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static const char* fragSource = {
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"#version 400\n"
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"out vec4 FragColor;\n"
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"in vec3 gFacetNormal;\n"
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"in vec3 gTriDistance;\n"
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"in vec3 gPatchDistance;\n"
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"in vec4 gColor;\n"
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"in float gPrimitive;\n"
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"uniform vec3 LightPosition;\n"
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"uniform vec3 DiffuseMaterial;\n"
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"uniform vec3 AmbientMaterial;\n"
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"float amplify(float d, float scale, float offset){\n"
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" d = scale * d + offset;\n"
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" d = clamp(d, 0, 1);\n"
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" d = 1 - exp2(-2*d*d);\n"
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" return d;\n"
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"}\n"
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"void main(){\n"
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" vec3 N = normalize(gFacetNormal);\n"
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" vec3 L = LightPosition;\n"
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" float df = abs(dot(N, L));\n"
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" vec3 color = AmbientMaterial + df * DiffuseMaterial;\n"
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" float d1 = min(min(gTriDistance.x, gTriDistance.y), gTriDistance.z);\n"
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" float d2 = min(min(gPatchDistance.x, gPatchDistance.y), gPatchDistance.z);\n"
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" color = amplify(d1, 40, -0.5) * amplify(d2, 60, -0.5) * color;\n"
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" FragColor = vec4(color, 1.0);\n"
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"}\n"
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};
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osg::ref_ptr<osg::Geode> CreateIcosahedron(osg::Program *program){
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osg::Geode *geode=new osg::Geode();
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osg::Geometry *geometry = new osg::Geometry();
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const unsigned int Faces[] = {
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2, 1, 0,
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3, 2, 0,
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4, 3, 0,
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5, 4, 0,
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1, 5, 0,
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11, 6, 7,
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11, 7, 8,
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11, 8, 9,
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11, 9, 10,
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11, 10, 6,
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1, 2, 6,
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2, 3, 7,
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3, 4, 8,
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4, 5, 9,
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5, 1, 10,
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2, 7, 6,
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3, 8, 7,
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4, 9, 8,
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5, 10, 9,
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1, 6, 10 };
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int IndexCount = sizeof(Faces) / sizeof(Faces[0]);
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const float Verts[] = {
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0.000f, 0.000f, 1.000f,
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0.894f, 0.000f, 0.447f,
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0.276f, 0.851f, 0.447f,
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-0.724f, 0.526f, 0.447f,
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-0.724f, -0.526f, 0.447f,
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0.276f, -0.851f, 0.447f,
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0.724f, 0.526f, -0.447f,
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-0.276f, 0.851f, -0.447f,
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-0.894f, 0.000f, -0.447f,
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-0.276f, -0.851f, -0.447f,
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0.724f, -0.526f, -0.447f,
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0.000f, 0.000f, -1.000f };
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int VertexCount = sizeof(Verts)/sizeof(float);
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osg::Vec3Array* vertices = new osg::Vec3Array();
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for(int i=0;i<VertexCount;i+=3){
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vertices->push_back(osg::Vec3(Verts[i],Verts[i+1],Verts[i+2]));
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}
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geometry->setVertexArray(vertices);
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geometry->addPrimitiveSet(new osg::DrawElementsUInt(osg::PrimitiveSet::PATCHES,IndexCount,Faces));
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geode->addDrawable(geometry);
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return geode;
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}
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osg::ref_ptr<osg::Program> createProgram(){
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osg::Program *program = new osg::Program();
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program->addShader(new osg::Shader(osg::Shader::VERTEX,vertSource));
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program->addShader(new osg::Shader(osg::Shader::TESSCONTROL,tessControlSource));
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program->addShader(new osg::Shader(osg::Shader::TESSEVALUATION,tessEvalSource));
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program->addShader(new osg::Shader(osg::Shader::GEOMETRY,geomSource));
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program->addShader(new osg::Shader(osg::Shader::FRAGMENT,fragSource));
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program->setParameter(GL_GEOMETRY_VERTICES_OUT_EXT, 3);
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program->setParameter(GL_GEOMETRY_INPUT_TYPE_EXT, GL_TRIANGLES);
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program->setParameter(GL_GEOMETRY_OUTPUT_TYPE_EXT, GL_TRIANGLE_STRIP);
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program->setParameter(GL_PATCH_VERTICES,3);
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return program;
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}
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float tessInner=1.0f;
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float tessOuter=1.0f;
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osg::ref_ptr<osg::Uniform> tessInnerU = new osg::Uniform("TessLevelInner",tessInner);
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osg::ref_ptr<osg::Uniform> tessOuterU = new osg::Uniform("TessLevelOuter",tessOuter);
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class KeyboardEventHandler : public osgGA::GUIEventHandler {
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public:
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KeyboardEventHandler():osgGA::GUIEventHandler(){}
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virtual bool handle(const osgGA::GUIEventAdapter& ea,osgGA::GUIActionAdapter& gaa){
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if(ea.getEventType()==osgGA::GUIEventAdapter::KEYDOWN){
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switch (ea.getKey()){
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case osgGA::GUIEventAdapter::KEY_Up:
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tessOuter++;
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tessOuterU->set(tessOuter);
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return true;
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case osgGA::GUIEventAdapter::KEY_Down:
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tessOuter--;
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tessOuter=std::max(1.0f,tessOuter);
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tessOuterU->set(tessOuter);
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return true;
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case osgGA::GUIEventAdapter::KEY_Left:
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tessInner--;
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tessInner=std::max(1.0f,tessInner);
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tessInnerU->set(tessInner);
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return true;
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case osgGA::GUIEventAdapter::KEY_Right:
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tessInner++;
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tessInnerU->set(tessInner);
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return true;
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}
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}
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return osgGA::GUIEventHandler::handle(ea,gaa);
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}
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};
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int main(int argc, char* argv[])
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{
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osgViewer::Viewer viewer;
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viewer.setUpViewInWindow(100,100,800,600);
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osg::ref_ptr<osg::Program> program = createProgram();
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osg::ref_ptr<osg::Geode> geode = CreateIcosahedron(program.get());
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osg::StateSet *state;
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state = geode->getOrCreateStateSet();
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state->addUniform(new osg::Uniform("AmbientMaterial",osg::Vec3(0.04f, 0.04f, 0.04f)));
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state->addUniform(new osg::Uniform("DiffuseMaterial",osg::Vec3(0.0f, 0.75f, 0.75f)));
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state->addUniform(new osg::Uniform("LightPosition",osg::Vec3(0.25f, 0.25f, 1.0f)));
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state->addUniform(tessInnerU.get());
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state->addUniform(tessOuterU.get());
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state->setAttribute(program.get());
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// switch on the uniforms that track the modelview and projection matrices
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osgViewer::Viewer::Windows windows;
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viewer.getWindows(windows);
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for(osgViewer::Viewer::Windows::iterator itr = windows.begin();
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itr != windows.end();
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++itr)
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{
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osg::State *s=(*itr)->getState();
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s->setUseModelViewAndProjectionUniforms(true);
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s->setUseVertexAttributeAliasing(true);
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}
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viewer.addEventHandler(new KeyboardEventHandler());
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viewer.setSceneData(geode.get());
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return viewer.run();
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}
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