MarbleShaderDemo
VTKExamples/Cxx/Shaders/MarbleShaderDemo
Description¶
Makes solid marble texture with strong veins. The "veincolor" parameter controls the color of the veins. The background color is given by the surface's DiffuseColor.
Explore the parameter space with the vtkSliderWidget.
Parameters:¶
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veinfreq - controls the lowest frequency of the color veins
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veinlevels - how many "levels" of vein tendrills it has
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warpfreq - lowest frequency of the turbulent warping in the marble
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_ warping_ - controls how much turbulent warping there will be
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veincolor - the color of the veins
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sharpness - controls how sharp or fuzzy the veins are (higher = sharper)
Cite
This shader is inspired by Larry Gritz's veined marble shader.
Code¶
MarbleShaderDemo.cxx
#include <vtkSmartPointer.h> #include <vtkNamedColors.h> #include <vtkCamera.h> #include <vtkRenderer.h> #include <vtkRenderWindow.h> #include <vtkShaderProgram.h> #include <vtkActor.h> #include <vtkOpenGLPolyDataMapper.h> #include <vtkProperty.h> #include <vtkTransform.h> #include <vtkTransformPolyDataFilter.h> #include <vtkTriangleMeshPointNormals.h> #include <vtkTriangleFilter.h> #include <vtkRenderWindowInteractor.h> #include <vtksys/SystemTools.hxx> #include <vtkBYUReader.h> #include <vtkOBJReader.h> #include <vtkPLYReader.h> #include <vtkPolyDataReader.h> #include <vtkSTLReader.h> #include <vtkXMLPolyDataReader.h> #include <vtkSphereSource.h> #include <vtkSliderRepresentation2D.h> #include <vtkSliderWidget.h> #include <fstream> #include <sstream> namespace { // ----------------------------------------------------------------------- // Update uniform variables in the shader for each render. We do this with a // callback for the UpdateShaderEvent class ShaderCallback : public vtkCommand { public: static ShaderCallback *New() { return new ShaderCallback; } vtkRenderer *Renderer; float veincolor[3]; float veinfreq; float veinlevels; float warpfreq; float warping; float sharpness; void Execute(vtkObject *, unsigned long, void* calldata) override { vtkShaderProgram *program = reinterpret_cast<vtkShaderProgram*>(calldata); if (program) { program->SetUniform3f("veincolor", veincolor); program->SetUniformf("veinfreq", veinfreq); program->SetUniformi("veinlevels", veinlevels); program->SetUniformf("warpfreq", warpfreq); program->SetUniformf("warping", warping); program->SetUniformf("sharpness", sharpness); std::cout << "------------" << std::endl; Print(std::cout); } } void Print(std::ostream &os) { os << "veincolor: " << veincolor[0] << ", " << veincolor[1] << ", " << veincolor[2] << std::endl; os << "veinfreq: " << veinfreq << std::endl; os << "veinlevels: " << veinlevels << std::endl; os << "warpfreq: " << warpfreq << std::endl; os << "warping: " << warping << std::endl; os << "sharpness: " << sharpness << std::endl; } ShaderCallback() { this->Renderer = nullptr; this->veincolor[0] = this->veincolor[1] = this->veincolor[2] = 1.0; this->veinfreq = 10.0; this->veinlevels = 2; this->warpfreq = 1.0; this->warping = .5; this->sharpness = 8.0; } }; // These callbacks do the actual work. // Callbacks for the interactions class SliderCallbackVeinFreq : public vtkCommand { public: static SliderCallbackVeinFreq *New() { return new SliderCallbackVeinFreq; } virtual void Execute(vtkObject *caller, unsigned long, void*) { vtkSliderWidget *sliderWidget = reinterpret_cast<vtkSliderWidget*>(caller); float value = static_cast<vtkSliderRepresentation2D *>(sliderWidget->GetRepresentation())->GetValue(); this->Shader->veinfreq = value; } SliderCallbackVeinFreq():Shader(0) {} ShaderCallback *Shader; }; // These callbacks do the actual work. // Callbacks for the interactions class SliderCallbackVeinLevels : public vtkCommand { public: static SliderCallbackVeinLevels *New() { return new SliderCallbackVeinLevels; } virtual void Execute(vtkObject *caller, unsigned long, void*) { vtkSliderWidget *sliderWidget = reinterpret_cast<vtkSliderWidget*>(caller); int value = static_cast<vtkSliderRepresentation2D *>(sliderWidget->GetRepresentation())->GetValue(); static_cast<vtkSliderRepresentation2D *>(sliderWidget->GetRepresentation())->SetValue(value); this->Shader->veinlevels = value; } SliderCallbackVeinLevels():Shader(0) {} ShaderCallback *Shader; }; class SliderCallbackWarpFreq : public vtkCommand { public: static SliderCallbackWarpFreq *New() { return new SliderCallbackWarpFreq; } virtual void Execute(vtkObject *caller, unsigned long, void*) { vtkSliderWidget *sliderWidget = reinterpret_cast<vtkSliderWidget*>(caller); float value = static_cast<vtkSliderRepresentation2D *>(sliderWidget->GetRepresentation())->GetValue(); this->Shader->warpfreq = value; } SliderCallbackWarpFreq():Shader(0) {} ShaderCallback *Shader; }; class SliderCallbackWarping : public vtkCommand { public: static SliderCallbackWarping *New() { return new SliderCallbackWarping; } virtual void Execute(vtkObject *caller, unsigned long, void*) { vtkSliderWidget *sliderWidget = reinterpret_cast<vtkSliderWidget*>(caller); float value = static_cast<vtkSliderRepresentation2D *>(sliderWidget->GetRepresentation())->GetValue(); this->Shader->warping = value; } SliderCallbackWarping():Shader(0) {} ShaderCallback *Shader; }; } namespace { vtkSmartPointer<vtkPolyData> ReadPolyData(const char *fileName); } //---------------------------------------------------------------------------- int main(int argc, char *argv[]) { if (argc < 2) { std::cout << "Usage: " << argv[0] << " PerlnNoise.glsl " << "[polydataFile] " << "[veincolor(1,1,1)] " << "[veinfreq(10)] " << "[veinlevels(2)] " << "[warpfreq(1)] " << "[warping(.5)] " << "[sharpness(8)]" << std::endl; return EXIT_FAILURE; } vtkSmartPointer<vtkPolyData> polyData = ReadPolyData(argc > 2 ? argv[2] : ""); std::ifstream shaderFile(argv[1]); std::ostringstream shaderCode; shaderCode << shaderFile.rdbuf(); // Create a transform to rescale model double center[3]; polyData->GetCenter(center); double bounds[6]; polyData->GetBounds(bounds); double maxBound = std::max(std::max(bounds[1] - bounds[0], bounds[3] - bounds[2]), bounds[5] - bounds[4]); vtkSmartPointer<vtkNamedColors> colors = vtkSmartPointer<vtkNamedColors>::New(); vtkSmartPointer<vtkActor> actor = vtkSmartPointer<vtkActor>::New(); vtkSmartPointer<vtkRenderer> renderer = vtkSmartPointer<vtkRenderer>::New(); vtkSmartPointer<vtkOpenGLPolyDataMapper> mapper = vtkSmartPointer<vtkOpenGLPolyDataMapper>::New(); renderer->SetBackground(colors->GetColor3d("SlateGray").GetData()); vtkSmartPointer<vtkRenderWindow> renderWindow = vtkSmartPointer<vtkRenderWindow>::New(); renderWindow->SetSize(640, 480); renderWindow->AddRenderer(renderer); renderer->AddActor(actor); vtkSmartPointer<vtkRenderWindowInteractor> interactor = vtkSmartPointer<vtkRenderWindowInteractor>::New(); interactor->SetRenderWindow(renderWindow); // Rescale polydata to [-1,1] vtkSmartPointer<vtkTransform> userTransform = vtkSmartPointer<vtkTransform>::New(); userTransform->Translate(-center[0], -center[1], -center[2]); userTransform->Scale(1.0/maxBound, 1.0/maxBound, 1.0/maxBound); vtkSmartPointer<vtkTransformPolyDataFilter> transform = vtkSmartPointer<vtkTransformPolyDataFilter>::New(); transform->SetTransform(userTransform); transform->SetInputData(polyData); vtkSmartPointer<vtkTriangleFilter> triangles = vtkSmartPointer<vtkTriangleFilter>::New(); triangles->SetInputConnection(transform->GetOutputPort()); vtkSmartPointer<vtkTriangleMeshPointNormals> norms = vtkSmartPointer<vtkTriangleMeshPointNormals>::New(); norms->SetInputConnection(triangles->GetOutputPort()); mapper->SetInputConnection(norms->GetOutputPort()); mapper->ScalarVisibilityOff(); actor->SetMapper(mapper); actor->GetProperty()->SetDiffuse(1.0); actor->GetProperty()->SetDiffuseColor(colors->GetColor3d("wheat").GetData()); actor->GetProperty()->SetSpecular(.5); actor->GetProperty()->SetSpecularPower(50); // Modify the vertex shader to pass the position of the vertex mapper->AddShaderReplacement( vtkShader::Vertex, "//VTK::Normal::Dec", // replace the normal block true, // before the standard replacements "//VTK::Normal::Dec\n" // we still want the default " out vec4 myVertexMC;\n" , false // only do it once ); mapper->AddShaderReplacement( vtkShader::Vertex, "//VTK::Normal::Impl", // replace the normal block true, // before the standard replacements "//VTK::Normal::Impl\n" // we still want the default " myVertexMC = vertexMC;\n" , false // only do it once ); // Add the code to generate noise // These functions need to be defined outside of main. Use the System::Dec // to declare and implement mapper->AddShaderReplacement( vtkShader::Fragment, "//VTK::System::Dec", false, // before the standard replacements shaderCode.str(), false // only do it once ); // Define varying and uniforms for the fragment shader here mapper->AddShaderReplacement( vtkShader::Fragment, // in the fragment shader "//VTK::Normal::Dec", // replace the normal block true, // before the standard replacements "//VTK::Normal::Dec\n" // we still want the default " varying vec4 myVertexMC;\n" " uniform vec3 veincolor = vec3(1.0, 1.0, 1.0);\n" " uniform float veinfreq = 10.0;\n" " uniform int veinlevels = 2;\n" " uniform float warpfreq = 1;\n" " uniform float warping = .5;\n" " uniform float sharpness = 8.0;\n" , false // only do it once ); mapper->AddShaderReplacement( vtkShader::Fragment, // in the fragment shader "//VTK::Light::Impl", // replace the light block false, // after the standard replacements "//VTK::Light::Impl\n" // we still want the default calc "\n" "#define pnoise(x) ((noise(x) + 1.0) / 2.0)\n" "#define snoise(x) (2.0 * pnoise(x) - 1.0)\n" " vec3 Ct;\n" " int i;\n" " float turb, freq;\n" " float turbsum;\n" " /* perturb the lookup */\n" " freq = 1.0;\n" " vec4 offset = vec4(0.0,0.0,0.0,0.0);\n" " vec4 noisyPoint;\n" " vec4 myLocalVertexMC = myVertexMC;\n" "\n" " for (i = 0; i < 6; i += 1) {\n" " noisyPoint[0] = snoise(warpfreq * freq * myLocalVertexMC);\n" " noisyPoint[1] = snoise(warpfreq * freq * myLocalVertexMC);\n" " noisyPoint[2] = snoise(warpfreq * freq * myLocalVertexMC);\n" " noisyPoint[3] = 1.0;\n" " offset += 2.0 * warping * (noisyPoint - 0.5) / freq;\n" " freq *= 2.0;\n" " }\n" " myLocalVertexMC.x += offset.x;\n" " myLocalVertexMC.y += offset.y;\n" " myLocalVertexMC.z += offset.z;\n" "\n" " /* Now calculate the veining function for the lookup area */\n" " turbsum = 0.0; freq = 1.0;\n" " myLocalVertexMC *= veinfreq;\n" " for (i = 0; i < veinlevels; i += 1) {\n" " turb = abs (snoise (myLocalVertexMC));\n" " turb = pow (smoothstep (0.8, 1.0, 1.0 - turb), sharpness) / freq;\n" " turbsum += (1.0-turbsum) * turb;\n" " freq *= 1.5;\n" " myLocalVertexMC *= 1.5;\n" " }\n" "\n" " Ct = mix (diffuseColor, veincolor, turbsum);\n" "\n" " fragOutput0.rgb = opacity * (ambientColor + Ct + specular);\n" " fragOutput0.a = opacity;\n" , false // only do it once ); vtkSmartPointer<ShaderCallback> myCallback = vtkSmartPointer<ShaderCallback>::New(); myCallback->Renderer = renderer; std::cout << "Input: " << (argc > 2 ? argv[2] : "Generated Sphere") << std::endl; myCallback->Print(std::cout); mapper->AddObserver(vtkCommand::UpdateShaderEvent, myCallback); // Setup a slider widget for each varying parameter double tubeWidth(.015); double sliderLength(.008); double titleHeight(.02); double labelHeight(.02); vtkSmartPointer<vtkSliderRepresentation2D> sliderRepVeinFreq = vtkSmartPointer<vtkSliderRepresentation2D>::New(); sliderRepVeinFreq->SetMinimumValue(1.0); sliderRepVeinFreq->SetMaximumValue(15.0); sliderRepVeinFreq->SetValue(7.5); sliderRepVeinFreq->SetTitleText("Vein Frequency"); sliderRepVeinFreq->GetPoint1Coordinate()->SetCoordinateSystemToNormalizedDisplay(); sliderRepVeinFreq->GetPoint1Coordinate()->SetValue(.1, .1); sliderRepVeinFreq->GetPoint2Coordinate()->SetCoordinateSystemToNormalizedDisplay(); sliderRepVeinFreq->GetPoint2Coordinate()->SetValue(.9, .1); sliderRepVeinFreq->SetTubeWidth(tubeWidth); sliderRepVeinFreq->SetSliderLength(sliderLength); sliderRepVeinFreq->SetTitleHeight(titleHeight); sliderRepVeinFreq->SetLabelHeight(labelHeight); vtkSmartPointer<vtkSliderWidget> sliderWidgetVeinFreq = vtkSmartPointer<vtkSliderWidget>::New(); sliderWidgetVeinFreq->SetInteractor(interactor); sliderWidgetVeinFreq->SetRepresentation(sliderRepVeinFreq); sliderWidgetVeinFreq->SetAnimationModeToJump(); sliderWidgetVeinFreq->EnabledOn(); vtkSmartPointer<SliderCallbackVeinFreq> callbackVeinFreq = vtkSmartPointer<SliderCallbackVeinFreq>::New(); callbackVeinFreq->Shader = myCallback; sliderWidgetVeinFreq->AddObserver(vtkCommand::InteractionEvent,callbackVeinFreq); vtkSmartPointer<vtkSliderRepresentation2D> sliderRepVeinLevels = vtkSmartPointer<vtkSliderRepresentation2D>::New(); sliderRepVeinLevels->SetMinimumValue(1); sliderRepVeinLevels->SetMaximumValue(5); sliderRepVeinLevels->SetValue(3); sliderRepVeinLevels->SetTitleText("Vein Levels"); sliderRepVeinLevels->GetPoint1Coordinate()->SetCoordinateSystemToNormalizedDisplay(); sliderRepVeinLevels->GetPoint1Coordinate()->SetValue(.1, .9); sliderRepVeinLevels->GetPoint2Coordinate()->SetCoordinateSystemToNormalizedDisplay(); sliderRepVeinLevels->GetPoint2Coordinate()->SetValue(.9, .9); sliderRepVeinLevels->SetTubeWidth(tubeWidth); sliderRepVeinLevels->SetSliderLength(sliderLength); sliderRepVeinLevels->SetTitleHeight(titleHeight); sliderRepVeinLevels->SetLabelHeight(labelHeight); vtkSmartPointer<vtkSliderWidget> sliderWidgetVeinLevels = vtkSmartPointer<vtkSliderWidget>::New(); sliderWidgetVeinLevels->SetInteractor(interactor); sliderWidgetVeinLevels->SetRepresentation(sliderRepVeinLevels); sliderWidgetVeinLevels->SetAnimationModeToJump(); sliderWidgetVeinLevels->EnabledOn(); vtkSmartPointer<SliderCallbackVeinLevels> callbackVeinLevels = vtkSmartPointer<SliderCallbackVeinLevels>::New(); callbackVeinLevels->Shader = myCallback; myCallback->veincolor[0] = colors->GetColor3d("Green").GetData()[0]; myCallback->veincolor[1] = colors->GetColor3d("Green").GetData()[1]; myCallback->veincolor[2] = colors->GetColor3d("Green").GetData()[2]; sliderWidgetVeinLevels->AddObserver(vtkCommand::InteractionEvent,callbackVeinLevels); vtkSmartPointer<vtkSliderRepresentation2D> sliderRepWarpFreq = vtkSmartPointer<vtkSliderRepresentation2D>::New(); sliderRepWarpFreq->SetMinimumValue(1.0); sliderRepWarpFreq->SetMaximumValue(2.0); sliderRepWarpFreq->SetValue(1.5); sliderRepWarpFreq->SetTitleText("Warp Frequency"); sliderRepWarpFreq->GetPoint1Coordinate()->SetCoordinateSystemToNormalizedDisplay(); sliderRepWarpFreq->GetPoint1Coordinate()->SetValue(.1, .1); sliderRepWarpFreq->GetPoint2Coordinate()->SetCoordinateSystemToNormalizedDisplay(); sliderRepWarpFreq->GetPoint2Coordinate()->SetValue(.1, .9); sliderRepWarpFreq->SetTubeWidth(tubeWidth); sliderRepWarpFreq->SetSliderLength(sliderLength); sliderRepWarpFreq->SetTitleHeight(titleHeight); sliderRepWarpFreq->SetLabelHeight(labelHeight); vtkSmartPointer<vtkSliderWidget> sliderWidgetWarpFreq = vtkSmartPointer<vtkSliderWidget>::New(); sliderWidgetWarpFreq->SetInteractor(interactor); sliderWidgetWarpFreq->SetRepresentation(sliderRepWarpFreq); sliderWidgetWarpFreq->SetAnimationModeToJump(); sliderWidgetWarpFreq->EnabledOn(); vtkSmartPointer<SliderCallbackWarpFreq> callbackWarpFreq = vtkSmartPointer<SliderCallbackWarpFreq>::New(); callbackWarpFreq->Shader = myCallback; sliderWidgetWarpFreq->AddObserver(vtkCommand::InteractionEvent,callbackWarpFreq); vtkSmartPointer<vtkSliderRepresentation2D> sliderRepWarping = vtkSmartPointer<vtkSliderRepresentation2D>::New(); sliderRepWarping->SetMinimumValue(0.0); sliderRepWarping->SetMaximumValue(1.0); sliderRepWarping->SetValue(.5); sliderRepWarping->SetTitleText("Warping"); sliderRepWarping->GetPoint1Coordinate()->SetCoordinateSystemToNormalizedDisplay(); sliderRepWarping->GetPoint1Coordinate()->SetValue(.9, .1); sliderRepWarping->GetPoint2Coordinate()->SetCoordinateSystemToNormalizedDisplay(); sliderRepWarping->GetPoint2Coordinate()->SetValue(.9, .9); sliderRepWarping->SetTubeWidth(tubeWidth); sliderRepWarping->SetSliderLength(sliderLength); sliderRepWarping->SetTitleHeight(titleHeight); sliderRepWarping->SetLabelHeight(labelHeight); vtkSmartPointer<vtkSliderWidget> sliderWidgetWarping = vtkSmartPointer<vtkSliderWidget>::New(); sliderWidgetWarping->SetInteractor(interactor); sliderWidgetWarping->SetRepresentation(sliderRepWarping); sliderWidgetWarping->SetAnimationModeToJump(); sliderWidgetWarping->EnabledOn(); vtkSmartPointer<SliderCallbackWarping> callbackWarping = vtkSmartPointer<SliderCallbackWarping>::New(); callbackWarping->Shader = myCallback; sliderWidgetWarping->AddObserver(vtkCommand::InteractionEvent,callbackWarping); renderWindow->Render(); renderer->ResetCamera(); renderer->GetActiveCamera()->Zoom(1.5); renderWindow->Render(); interactor->Start(); transform->GetOutput()->GetBounds(bounds); std::cout << "Range: " << " x " << bounds[1] - bounds[0] << " y " << bounds[3] - bounds[2] << " y " << bounds[5] - bounds[4] << std::endl; return EXIT_SUCCESS; } namespace { vtkSmartPointer<vtkPolyData> ReadPolyData(const char *fileName) { vtkSmartPointer<vtkPolyData> polyData; std::string extension = vtksys::SystemTools::GetFilenameExtension(std::string(fileName)); if (extension == ".ply") { vtkSmartPointer<vtkPLYReader> reader = vtkSmartPointer<vtkPLYReader>::New(); reader->SetFileName (fileName); reader->Update(); polyData = reader->GetOutput(); } else if (extension == ".vtp") { vtkSmartPointer<vtkXMLPolyDataReader> reader = vtkSmartPointer<vtkXMLPolyDataReader>::New(); reader->SetFileName (fileName); reader->Update(); polyData = reader->GetOutput(); } else if (extension == ".obj") { vtkSmartPointer<vtkOBJReader> reader = vtkSmartPointer<vtkOBJReader>::New(); reader->SetFileName (fileName); reader->Update(); polyData = reader->GetOutput(); } else if (extension == ".stl") { vtkSmartPointer<vtkSTLReader> reader = vtkSmartPointer<vtkSTLReader>::New(); reader->SetFileName (fileName); reader->Update(); polyData = reader->GetOutput(); } else if (extension == ".vtk") { vtkSmartPointer<vtkPolyDataReader> reader = vtkSmartPointer<vtkPolyDataReader>::New(); reader->SetFileName (fileName); reader->Update(); polyData = reader->GetOutput(); } else if (extension == ".g") { vtkSmartPointer<vtkBYUReader> reader = vtkSmartPointer<vtkBYUReader>::New(); reader->SetGeometryFileName (fileName); reader->Update(); polyData = reader->GetOutput(); } else { vtkSmartPointer<vtkSphereSource> source = vtkSmartPointer<vtkSphereSource>::New(); source->SetPhiResolution(25); source->SetThetaResolution(25); source->Update(); polyData = source->GetOutput(); } return polyData; } }
CMakeLists.txt¶
cmake_minimum_required(VERSION 2.8) PROJECT(MarbleShaderDemo) find_package(VTK REQUIRED) include(${VTK_USE_FILE}) add_executable(MarbleShaderDemo MACOSX_BUNDLE MarbleShaderDemo.cxx ) target_link_libraries(MarbleShaderDemo ${VTK_LIBRARIES})
Download and Build MarbleShaderDemo¶
Click here to download MarbleShaderDemo and its CMakeLists.txt file. Once the tarball MarbleShaderDemo.tar has been downloaded and extracted,
cd MarbleShaderDemo/build
If VTK is installed:
cmake ..
If VTK is not installed but compiled on your system, you will need to specify the path to your VTK build:
cmake -DVTK_DIR:PATH=/home/me/vtk_build ..
Build the project:
make
and run it:
./MarbleShaderDemo
WINDOWS USERS
Be sure to add the VTK bin directory to your path. This will resolve the VTK dll's at run time.