[vtkusers] How to pass uniform and attribute from host to shader by vtk’s python wrapping.
Ken Martin
ken.martin at kitware.com
Mon Feb 20 10:18:05 EST 2017
Ahh, I am not sure about from Python. Sounds like it isn't.
On Mon, Feb 20, 2017 at 10:14 AM, Quentan Qi <quentan at gmail.com> wrote:
> Thanks Ken.
>
> I am using vtk 7.1.0
>
> But the python wrapping of `vtkOpenGLPolyDataMapper` has no attribute
> `AddShaderReplacement`. Is there any way to do this with python wrapping?
>
> Cheers,
> Quentan
>
>
> On 20 Feb 2017, at 13:34, Ken Martin <ken.martin at kitware.com> wrote:
>
> If using the new OpenGL rendering backend end see
>
> http://www.vtk.org/Wiki/Shader_In_VTK
>
>
> On Mon, Feb 20, 2017 at 8:17 AM, Quentan Qi <quentan at gmail.com> wrote:
>
>> Hi,
>>
>> I want to ask how to pass uniform and attribute from host to shader by
>> vtk’s python wrapping.
>>
>> I follow this instruction to implement this result, but don’t know how
>> to pass uniform variables from host to fragment shader.
>>
>> Could anybody tell me how to do this?
>>
>> Cheers,
>> Quentan
>> ------------------------------
>>
>> - Shader02.py
>>
>> import vtkimport time
>> timer = [time.clock()]resolution = [600, 480]
>> file = open('Shader02.vert', 'r')vert = file.read()
>> file.close()
>> file = open('Shader02.frag', 'r')frag = file.read()
>> file.close()
>> # Plane. Is there better way to show ShaderToy's effect without use vtkPlaneSource?plane = vtk.vtkPlaneSource()
>> plane.SetNormal([0, 0, 1])
>> plane.SetResolution(100, 100)
>> plane.SetOrigin(-1, -1, 0)
>> plane.SetPoint1(1, -1, 1)
>> plane.SetPoint2(-1, 1, 0)
>> mapper = vtk.vtkPolyDataMapper()
>> mapper.SetInputConnection(plane.GetOutputPort())
>> actor = vtk.vtkActor()
>> actor.SetMapper(mapper)
>> actor.GetProperty().SetOpacity(1)
>> # Handle the rendering and interactionren = vtk.vtkRenderer()renWin = vtk.vtkRenderWindow()
>> renWin.AddRenderer(ren)iren = vtk.vtkRenderWindowInteractor()
>> iren.SetRenderWindow(renWin)
>> resolutionUniform = vtk.vtkUniformVariables()
>> resolutionUniform.SetUniformi('iResolution', 2, resolution)
>> timeUniform = vtk.vtkUniformVariables()
>> timeUniform.SetUniformf('iGlobalTime', 1, timer)
>> # Now let's get down to shader-business...# First we make a ShaderProgram2 and set it up on a date with the RenderWindowpgm = vtk.vtkShaderProgram2()
>> pgm.SetContext(renWin)
>> # For both the vertex and fragment shader, we need to make a Shader2# Also set them up with the RenderWindow, by asking the ShaderProgram2 for# an introductionshaderv = vtk.vtkShader2()
>> shaderv.SetType(vtk.VTK_SHADER_TYPE_VERTEX)
>> shaderv.SetSourceCode(vert)
>> shaderv.SetContext(pgm.GetContext())
>> shaderf = vtk.vtkShader2()
>> shaderf.SetType(vtk.VTK_SHADER_TYPE_FRAGMENT)
>> shaderf.SetSourceCode(frag)
>> shaderf.SetContext(pgm.GetContext())
>> shaderf.SetUniformVariables(resolutionUniform) # is this correct?# print shaderf.GetUniformVariables()
>> shaderf.SetUniformVariables(timeUniform)# print shaderf.GetUniformVariables()
>> # Now we add the shaders to the program
>> pgm.GetShaders().AddItem(shaderv)
>> pgm.GetShaders().AddItem(shaderf)
>> # And tell the actor property that it should totally use this cool programopenGLproperty = actor.GetProperty()
>> openGLproperty.SetPropProgram(pgm)
>> openGLproperty.ShadingOn()
>> # openGLproperty.AddShaderVariable('iGlobalTime', 1, timer) # is this correct?# openGLproperty.AddShaderVariable('iResolution', 2, resolution)
>> # Add the actor and set a nice bg color
>> ren.AddActor(actor)
>> ren.SetBackground(0.3, 0, 0.4)
>> ren.SetBackground2(0.1, 0, 0.2)
>> ren.SetGradientBackground(1)
>> renWin.SetSize(resolution)
>>
>> iren.Initialize()
>> ren.GetActiveCamera().SetPosition(0, -1, 0)
>> ren.GetActiveCamera().SetViewUp(0, 0, 1)
>> ren.ResetCamera()
>> renWin.Render()
>> iren.Start()
>>
>>
>> - Shader02.vert
>>
>> void propFuncVS(void) {
>> gl_Position = vec4((gl_Vertex.xy), 0.0, 1.0);
>> }
>>
>>
>> - Shader02.frag
>>
>> // ShaderToy: The Blob// https://www.shadertoy.com/view/XsXGRS
>> uniform float iGlobalTime; // not work. uniform or varying?uniform vec2 iResolution;// float iGlobalTime = 1.0;// vec2 iResolution = vec2(600, 480); // This works, but not from host
>> #ifdef GL_ESprecision highp float;#endif
>> #define AA 4.
>> #define CI vec3(.3,.5,.6)#define CO vec3(.2)#define CM vec3(.0)#define CE vec3(.8,.7,.5)
>> float metaball(vec2 p, float r)
>> {
>> return r / dot(p, p);
>> }
>> vec3 samplef(in vec2 uv)
>> {#if 1
>> float t0 = sin(iGlobalTime * 1.9) * .46;
>> float t1 = sin(iGlobalTime * 2.4) * .49;
>> float t2 = cos(iGlobalTime * 1.4) * .57;
>>
>> float r = metaball(uv + vec2(t0, t2), .33) *
>> metaball(uv - vec2(t0, t1), .27) *
>> metaball(uv + vec2(t1, t2), .59);
>> #else
>> float r = length(uv); // test for time-independent
>> #endif
>> vec3 c = (r > .4 && r < .7)
>> ? (vec3(step(.1, r*r*r)) * CE)
>> : (r < .9 ? (r < .7 ? CO: CM) : CI);
>>
>> return c;
>> }
>> void propFuncFS(void)
>> {
>> vec2 uv = (gl_FragCoord.xy / iResolution.xy * 2. - 1.)
>> * vec2(iResolution.x / iResolution.y, 1) * 1.25;
>>
>> vec3 col = vec3(0);
>> #ifdef AA
>> // Antialiasing via supersampling
>> float e = 1. / min(iResolution.y , iResolution.x);
>> for (float i = -AA; i < AA; ++i) {
>> for (float j = -AA; j < AA; ++j) {
>> col += samplef(uv + vec2(i, j) * (e/AA)) / (4.*AA*AA);
>> }
>> }#else
>> col += sample(uv);#endif /* AA */
>>
>> gl_FragColor = vec4(clamp(col, 0., 1.), 1);
>> }
>>
>>
>>
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>
>
> --
> Ken Martin PhD
> Chairman & CFO
> Kitware Inc.
> 28 Corporate Drive
> Clifton Park NY 12065
> 518 371 3971 <(518)%20371-3971>
>
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--
Ken Martin PhD
Chairman & CFO
Kitware Inc.
28 Corporate Drive
Clifton Park NY 12065
518 371 3971
This communication, including all attachments, contains confidential and
legally privileged information, and it is intended only for the use of the
addressee. Access to this email by anyone else is unauthorized. If you are
not the intended recipient, any disclosure, copying, distribution or any
action taken in reliance on it is prohibited and may be unlawful. If you
received this communication in error please notify us immediately and
destroy the original message. Thank you.
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