[vtkusers] Problems with uniform shader variables in Cg shader

[Cory Quammen]

Rocco,

Try declaring your uniforms as ApplicationUniforms, e.g.:

<ApplicationUniform name="Ka" value="Ambient" />
<ApplicationUniform name="AmbientColor" value="AmbientColor" />
<ApplicationUniform name="Kd" value="Diffuse" />
<ApplicationUniform name="DiffuseColor" value="DiffuseColor" />
<ApplicationUniform name="Ks" value="Specular" />
<ApplicationUniform name="Ksp" value="SpecularPower" />
<ApplicationUniform name="SpecularColor" value="SpecularColor" />

Your light properties can be set in the same way.

This works in an XML-material file I am using.

Best,
Cory

On Thu, Oct 15, 2009 at 9:17 AM, Rocco Gasteiger
<post at rocco-gasteiger.de> wrote:
> Dear vtk community,
>
>
>
> For my research project I want to use the Cg shader support of VTK. I can
> load a VTK included XML-material file into a vtkProperty object, which reads
> the shader code correctly. However, if I add uniform shader variables, which
> are used within the shader code, it has no influence for the rendering.
> Below I present the xml-material file (provided by VTK), my vtk-code and the
> cg-shader code (provided by VTK).
>
>
>
> Does anybody know what I have done wrong or missed?
>
>
>
> Thanks in advanced and best regards,
>
> Rocco Gasteiger
>
>
>
> --------------------------------------------------
>
> Dipl.-Ing. Rocco Gasteiger
>
> Otto-von-Guericke University
> Faculty of Computer Science
> Department of Simulation and Graphics
> Universitätsplatz 2, 39106 Magdeburg, Germany
>
>
>
> Office:  G29-223
>
> Phone:   +49 391 67 127 59
> Fax:     +49 391 67 111 64
>
> Website: http://wwwisg.cs.uni-magdeburg.de/cvcms/
>
> --------------------------------------------------
>
>
>
>
>
> ********************
>
> XML-Material file:
>
> ********************
>
>
>
> <?xml version="1.0" encoding="UTF-8"?>
>
> <Material name="CgTestMaterial">
>
>   <Property name="Property1">
>
>     <Member name="DiffuseColor" number_of_elements="3" type="Float"
> value="1.0 1.0 1.0" />
>
>     <Member name="Ambient" number_of_elements="3" type="Float" value="1.0
> 0.0 1.0" />
>
>   </Property>
>
>
>
>   <Shader scope="Vertex" name="CGVertexLighting" location="Library"
> language="Cg"
>
>     entry="main" args="-DVERTEX_PROGRAM">
>
>     <MatrixUniform name="ModelViewProj" type="State" number_of_elements="2"
>
>       value="CG_GL_MODELVIEW_PROJECTION_MATRIX CG_GL_MATRIX_IDENTITY">
>
>     </MatrixUniform>
>
>
>
>     <PropertyUniform name="Ka" value="Ambient" />
>
>     <PropertyUniform name="AmbientColor" value="AmbientColor" />
>
>     <PropertyUniform name="Kd" value="Diffuse" />
>
>     <PropertyUniform name="DiffuseColor" value="DiffuseColor" />
>
>     <PropertyUniform name="Ks" value="Specular" />
>
>     <PropertyUniform name="Ksp" value="SpecularPower" />
>
>     <PropertyUniform name="SpecularColor" value="SpecularColor" />
>
>
>
>     <LightUniform name="lightPosition" value="Position" />
>
>     <LightUniform name="lightDiffuseColor" value="DiffuseColor" />
>
>     <LightUniform name="lightSpecularColor" value="SpecularColor" />
>
>     <LightUniform name="lightAmbientColor" value="AmbientColor" />
>
>
>
>     <CameraUniform name="eyePosition" value="Position" />
>
>   </Shader>
>
> </Material>
>
>
>
>
>
> ********************
>
> My vtk-Code:
>
> ********************
>
>
>
> vtkSphereSource* sphere = vtkSphereSource::New();
>
>
>
>   vtkPolyDataMapper *sphereMapper = vtkPolyDataMapper::New();
>
>   sphereMapper->SetInput(sphere->GetOutput());
>
>
>
>   vtkActor *sphereActor = vtkActor::New();
>
>   sphereActor->SetMapper(sphereMapper);
>
>
> sphereActor->GetProperty()->LoadMaterial("D:\\Bibliotheken\\VTK\\VTKSource\\Utilities\\MaterialLibrary\\Materials\\CgLighting.xml");
>
>   sphereActor->GetProperty()->ShadingOn();
>
>   // I also tried the different version of “AddShaderVariable()” but it
> didn’t help.
>
>   float color = (0.0, 0.0, 0.0);
>
>   sphereActor->GetProperty()->AddShaderVariable("DiffuseColor", 3, &color);
>
>
>
>   vtkRenderer *renderer = vtkRenderer::New();
>
>   vtkRenderWindow *renWin = vtkRenderWindow::New();
>
>   renWin->AddRenderer(renderer);
>
>
>
>   vtkRenderWindowInteractor *iren = vtkRenderWindowInteractor::New();
>
>   iren->SetRenderWindow(renWin);
>
>
>
>   renderer->AddActor(sphereActor);
>
>   renderer->ResetCamera();
>
>
>
>   renWin->Render();
>
>   iren->Start();
>
>
>
>
>
> ********************
>
> The Cg-Shader code:
>
> ********************
>
>
>
> struct vertin
>
> {
>
>   float4 Position: POSITION;
>
>   float3 Normal: NORMAL;
>
> };
>
>
>
> struct vertout
>
> {
>
>   float4 Position : POSITION;
>
>   float4 Color    : COLOR;
>
> };
>
>
>
> vertout main(vertin IN,
>
>   uniform float4x4 ModelViewProj,
>
>   uniform float Ka,
>
>   uniform float3 AmbientColor,
>
>   uniform float Kd,
>
>   uniform float3 DiffuseColor,
>
>   uniform float Ks,
>
>   uniform float Ksp,
>
>   uniform float3 SpecularColor,
>
>
>
>   uniform float3 lightPosition,
>
>   uniform float3 eyePosition,
>
>   uniform float3 lightDiffuseColor,
>
>   uniform float3 lightAmbientColor,
>
>   uniform float3 lightSpecularColor
>
> )
>
> {
>
>   float3 N = IN.Normal; //invert(IN.Normal);
>
>   vertout OUT;
>
>   OUT.Position = mul(ModelViewProj, IN.Position);
>
>
>
>   // Computer Ambient intensity.
>
>   float3 ambient = Ka * AmbientColor * lightAmbientColor;
>
>
>
>   // Comput Diffuse intensity.
>
>   float3 L = normalize(lightPosition - IN.Position);
>
>   float diffuseLight = max(dot(N, L), 0);
>
>   float3 diffuse = Kd * DiffuseColor * lightDiffuseColor * diffuseLight;
>
>
>
>   // Compute Specular intensity.
>
>   float3 V = normalize(eyePosition - IN.Position);
>
>   float3 H = normalize(L + V);
>
>   float specularLight = pow(max(dot(N, H), 0), Ksp);
>
>   if (diffuseLight <= 0) specularLight = 0;
>
>   float3 specular = Ks * SpecularColor * lightSpecularColor * specularLight;
>
>
>
>   OUT.Color.xyz = ambient + diffuse + specular;
>
>   OUT.Color.w = 1;
>
>
>
>   return OUT;
>
> }
>
>
>
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-- 
Cory Quammen
Center for Computer Integrated Systems for Microscopy and Manipulation (CISMM)
Department of Computer Science
University of North Carolina at Chapel Hill
http://www.cs.unc.edu/~cquammen