InitRenderStruct Manual

Table of Contents

• About
• Functionality
• Properties
• Further Reading

About

A InitRenderStruct element is used to initialize materials and shaders for rendering. It is typically created by Cinema 4D but it can be created on demand to sample materials or shaders. See Sampling a Shader.

Functionality

A InitRenderStruct element can be initiated and used with these functions:

• InitRenderStruct::InitRenderStruct(): Constructor, accepts a BaseDocument argument.
• InitRenderStruct::Init(): Initiates the render structure with the given argument.
• InitRenderStruct::GetThreadCount(): Returns the thread count by accessing the stored VolumeData pointer.
• InitRenderStruct::TransformColor(): Transforms a color based on the internally stored color profile and linear workflow settings.

  // This example samples the given shader in UV space.
 
  // init the shader
 
  InitRenderStruct irs { doc };
 
  COLORSPACETRANSFORMATION transform = COLORSPACETRANSFORMATION::NONE;
  // check if linear workflow is enabled
  if (irs.linear_workflow)
    transform = COLORSPACETRANSFORMATION::LINEAR_TO_SRGB;
 
  const INITRENDERRESULT res = shader->InitRender(irs);
  if (res != INITRENDERRESULT::OK)
    return maxon::UnexpectedError(MAXON_SOURCE_LOCATION);
 
  // sample the shader in UV space
 
  ChannelData channelData;
  channelData.off = 0;
  channelData.scale = 0;
  channelData.t = doc->GetTime().Get();
  channelData.texflag = CALC_TEXINFO(0, CHANNEL_COLOR);
 
  channelData.d  = Vector { 1, 1, 1 };
  channelData.n  = Vector { 0, 1, 0 };
  channelData.vd = nullptr; // VolumeData is nullptr
 
  for (Int32 y = 0; y < height; ++y)
  {
    for (Int32 x = 0; x < width; ++x)
    {
      // generate UV coordinates
      const Float64 xFloat = (Float64)x;
      const Float64 yFloat = (Float64)y;
      const Float64 u = xFloat / widthFloat;
      const Float64 v = yFloat / heightFloat;
 
      channelData.p.x = u;
      channelData.p.y = v;
      channelData.p.z = 0.0f;
 
      const Vector color = shader->Sample(&channelData);
      const Vector transformedColor = TransformColor(color, transform).Clamp01();
 
      // write into the given BaseBitmap
      const Int32 r = SAFEINT32(transformedColor.x * COLORTOINT_MULTIPLIER);
      const Int32 g = SAFEINT32(transformedColor.y * COLORTOINT_MULTIPLIER);
      const Int32 b = SAFEINT32(transformedColor.z * COLORTOINT_MULTIPLIER);
 
      bitmap->SetPixel(x, y, r, g, b);
    }
  }
 
  // free shader resources
  shader->FreeRender();

Properties

The settings of InitRenderStruct are:

• InitRenderStruct::version: The Cinema 4D version.
• InitRenderStruct::time: The current time.
• InitRenderStruct::fps: The framerate.
• InitRenderStruct::docpath: The path for the document.
• InitRenderStruct::matname: The material name.
• InitRenderStruct::errorlist: A private error list.
• InitRenderStruct::vd: The volume data. Can be nullptr, always check.
• InitRenderStruct::doc: The document to render.
• InitRenderStruct::thread: The current thread or nullptr for the main Cinema 4D thread.
• InitRenderStruct::flags: The flags, see INITRENDERFLAG.
• InitRenderStruct::linear_workflow: True if Linear workflow is enabled.
• InitRenderStruct::document_colorprofile: The document color profile.

Further Reading

• Materials and Shaders Overview
• BaseMaterial Manual
• BaseShader Manual