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特性

The parameters of a 材质 can be edited as usual with C4DAtom::SetParameter() and C4DAtom::GetParameter() . The parameter IDs are defined in mmaterial.h . For convenience the parameters of a group are often combined to a "channel".

Channel States

These utility functions allow to edit the state of a "channel":

• Material::GetChannelState() : Returns the state of the given channel.
• Material::SetChannelState() : Sets the state of the given channel.

Channels

Certain parameters and functionality of a parameter group are combined in a BaseChannel object:

• BaseMaterial::GetChannel() : Returns a BaseChannel 对象。

The returned BaseChannel object can be used to handle the referenced shaders:

• BaseChannel::InitTexture() : Initializes the channel texture, loading any files required.
• BaseChannel::FreeTexture() : Frees all resources used by this channel.

Between the call of InitTexture() and FreeTexture() the shader of the channel can be sampled:

• BaseChannel::GetBitmap() : Retrieves the channels bitmap texture.
• BaseChannel::Sample() : Samples the channel's shader.

Further operations are:

• BaseChannel::GetShaderID() : Returns the ID of the channel's shader.
• BaseChannel::GetShader() : Returns the channel's shader.
• BaseChannel::Compare() : Returns true if the given BaseChannel is identical.

These functions are useful to get general settings of the channel and the settings of a used bitmap shader:

• BaseChannel::GetData() : Returns a BaseContainer with the settings.
• BaseChannel::SetData() : Sets the settings with the values stored in the given BaseContainer .

// get the BaseChannel BaseChannel * const channel = material-> GetChannel ( CHANNEL_COLOR ); if (channel == nullptr ) return maxon::UnexpectedError( MAXON_SOURCE_LOCATION );

// check the shader BaseShader * const shader = channel-> GetShader (); if (shader != nullptr ) ApplicationOutput ( "Used Shader: " + shader-> GetName ());

// if the shader is a "Bitmap" shader, access some data if (shader != nullptr && shader-> IsInstanceOf ( Xbitmap )) { const BaseContainer bc = channel-> GetData (); ApplicationOutput ( "Image File: " + bc. GetString ( BASECHANNEL_TEXTURE )); }

Reflection Layers

A standard material can manage multiple reflection layers. Such reflection layers can be created and edited. The used parameter IDs are defined in c4d_reflection.h ，见 REFLECTION_LAYER .

• Material::AddReflectionLayer() : Creates and returns a new reflection layer.
• Material::GetReflectionLayerID() : Returns the reflection layer with the given ID.
• Material::GetReflectionLayerIndex() : Returns the reflection layer at the given index.
• Material::GetReflectionLayerTrans() : Returns the transparency layer.
• Material::GetReflectionLayerCount() : Returns the number of reflection layers.
• Material::RemoveReflectionLayerID() : Removes the reflection layer with the given ID.
• Material::RemoveReflectionLayerIndex() : Removes the reflection layer at the given index.
• Material::RemoveReflectionAllLayers() : Removes all reflection layers.
• Material::GetAllReflectionShaders() : Gets an array of all shaders used by reflection layers.
• Material::GetReflectionPrimaryLayers() : Gets the indices to the primary reflection and specular layers (can be -1 for empty).

The settings of a ReflectionLayer object are:

• ReflectionLayer::GetDataID() : Returns the ID of the reflection layer.
• ReflectionLayer::GetName() : Returns the name of the layer.
• ReflectionLayer::SetName() : Sets the name of the layer.
• ReflectionLayer::GetLayerID() : Returns the ID of the layer.
• ReflectionLayer::GetFlags() : Returns the flags of the layer. See REFLECTION_FLAG .
• ReflectionLayer::SetFlags() Sets the flags of the layer.

注意

若 材质 is created and configured in some import context (e.g. SceneLoaderData ) one has to set the material parameter REFLECTION_LAYER_IMPORTED to true.

// create a new layer ReflectionLayer * const layer = material-> AddReflectionLayer (); if (layer == nullptr ) return maxon::OutOfMemoryError( MAXON_SOURCE_LOCATION ); const Int32 layerID = layer-> GetDataID ();

// configure layer layer-> SetName ( "Gold Layer" _s); layer-> SetFlags ( REFLECTION_FLAG_SELECTED | REFLECTION_FLAG_TAB | REFLECTION_FLAG_ACTIVE ); const Int32 distributionID = layerID + REFLECTION_LAYER_MAIN_DISTRIBUTION ; material-> SetParameter (distributionID, REFLECTION_DISTRIBUTION_BECKMANN , DESCFLAGS_SET::NONE ); const Int32 fresnelModeID = layerID + REFLECTION_LAYER_FRESNEL_MODE ; material-> SetParameter (fresnelModeID, REFLECTION_FRESNEL_CONDUCTOR , DESCFLAGS_SET::NONE ); const Int32 fresnelMetalID = layerID + REFLECTION_LAYER_FRESNEL_METAL ; material-> SetParameter (fresnelMetalID, REFLECTION_FRESNEL_METAL_GOLD , DESCFLAGS_SET::NONE );

and

// print name ApplicationOutput ( "Layer: " + layer-> GetName ()); const Int32 layerID = layer-> GetDataID (); GeData data;

// access and print value const DescID valueID(layerID + REFLECTION_LAYER_TRANS_BRIGHTNESS ); material-> GetParameter (valueID, data, DESCFLAGS_GET::NONE ); const Float value = data. GetFloat (); ApplicationOutput ( "Value: " + String::FloatToString (value));

// print mode const DescID blendModeID(layerID + REFLECTION_LAYER_MAIN_BLEND_MODE ); material-> GetParameter (blendModeID, data, DESCFLAGS_GET::NONE );

// check if blend mode is "Normal" if (data. GetInt32 () == MATERIAL_TEXTUREMIXING_NORMAL ) ApplicationOutput ( "Mode: Normal" );

// check if blend mode is "Add" if (data. GetInt32 () == MATERIAL_TEXTUREMIXING_ADD ) ApplicationOutput ( "Mode: Add" ); }

另请参阅 Blog post: Cinema 4D R16 Reflectance channel's API

延伸阅读

• Materials and Shaders Overview
• BaseMaterial Manual
• BaseShader Manual