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// check for successful allocation const Bool materialFailure = material == nullptr ; const Bool shaderFailure = bitmapShader == nullptr ; const Bool tagFailure = textureTag == nullptr ; if (materialFailure || shaderFailure || tagFailure) { BaseShader::Free (bitmapShader); Material::Free (material); TextureTag::Free (textureTag); return maxon::OutOfMemoryError( MAXON_SOURCE_LOCATION ); }

// start undo for the complete task doc-> StartUndo ();

// configure the texture tag const DescID projectionParam { TEXTURETAG_PROJECTION }; const Int32 projectionUVW = TEXTURETAG_PROJECTION_UVW ; textureTag-> SetParameter (projectionParam, projectionUVW, DESCFLAGS_SET::NONE ); textureTag-> SetMaterial (material); object ->InsertTag(textureTag); doc-> AddUndo ( UNDOTYPE::NEWOBJ , textureTag);

// configure the bitmap shader and the material bitmapShader-> SetParameter ( DescID ( BITMAPSHADER_FILENAME ), imageFile, DESCFLAGS_SET::NONE ); material-> SetParameter ( DescID ( MATERIAL_COLOR_SHADER ), bitmapShader, DESCFLAGS_SET::NONE ); material-> InsertShader (bitmapShader);

// insert the material doc-> InsertMaterial (material); doc-> AddUndo ( UNDOTYPE::NEWOBJ , material);

// finalize doc-> EndUndo ();

Access

Shaders are owned by the object that uses them. The shaders owned by a given object are organized in a list:

• BaseList2D::GetFirstShader() : Returns the first shader of the shader list.

Shaders are typically organized in a list but can also be organized in a tree:

• BaseShader::GetNext() : Returns the next shader in the list.
• BaseShader::GetPred() : Returns the previous shader in the list.
• BaseShader::GetUp() : Returns the parent shader.
• BaseShader::GetDown() : Returns the child shader.
• BaseShader::GetDownLast() : Returns the last child shader.

Allocation/Deallocation

Shaders are created with the usual tools.

• BaseShader::Alloc() : Creates a new shader.
• BaseShader::Free() : Deletes the given shader.

Newly created shaders are typically handed over to the object that uses them:

• BaseList2D::InsertShader() : Inserts the given shader into the shader list.

For a list of shader IDs see Shader Types .

Read-Only Properties

• BaseShader::GetRenderInfo() : Returns information about what the plugin requires from the raytracer and what it will return.
• BaseShader::IsColorManagementOff() : Returns true if color management is disabled for shaders within reflectance, bump, alpha, displacement or normal channels when linear workflow is enabled.
• BaseShader::GetSubsurfaceShader() : Returns the best SSS shader.
• BaseShader::HasGPURendererSupport() : Returns true if the shader is supported natively by the Cinema 4D GPU Renderer. If the shader is not supported, it will be baked into a texture.

注意

Also supported shaders may be baked into a texture, depending on the used material channel and shader context.

Sampling a Shader

A shader returns a color value for a given point. This point can be a point in world or object space or a set of UV-coordinates. A shader is sampled this way typically in the rendering pipeline.

A shader has to be initiated:

• BaseShader::InitRender() : Initiates the shader and its resources.

After the shader has been initiated these functions can be used:

• BaseShader::GetBitmap() : Utility function that returns the BaseBitmap of a bitmap shader ( Xbitmap ).
• BaseShader::Sample() : Samples the shader.
• BaseShader::SampleBump() : Samples the shader to modify a normal vector.

In the end the resources of the shader must be released:

• BaseShader::FreeRender() : Frees all resources used by this shader that were allocated by calling BaseShader::InitRender() .

警告

Without properly initiated InitRenderStruct::vd argument it is not safe to sample a shader multi-threaded.

A shader can sipmply be baked into a BaseBitmap using:

• BaseShader::BakeShaderIntoBaseBitmap() : Creates a 2D representation of the shader.

// bake shader const Bool bakeResult = shader-> BakeShaderIntoBaseBitmap (bitmap, *doc, parentThread, alpha, colorProfile, linearWorkflow, hdr, xmin, xmax, ymin, ymax); if (bakeResult == false ) return maxon::UnknownError( MAXON_SOURCE_LOCATION );

// show result ShowBitmap (bitmap);

// 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 = 向量 { 1, 1, 1 }; channelData. n = 向量 { 0, 1, 0 }; channelData. vd = nullptr ; // VolumeData is nullptr

// 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 ();

比较

Two BaseShader elements can be compared with:

• BaseShader::Compare() : Returns true if the given shader is identical.

注意

The comparison is mostly based on the shader's BaseContainer . Other internal data may not be compared.

延伸阅读

• Materials and Shaders Overview
• BaseMaterial Manual
• InitRenderStruct Manual