Channel Mod Simple Kinematics
Channel_Mod_Simple_Kinematics is a basic example plugin. This wiki page is intended as a walkthrough of the code in order to help you better understand the SDK.
When installed this plugin adds the Simple Kinematics channel modifier, allowing you to take in channels as starting position, time, speed, and acceleration and output them.
The simple kinematics channel modifier display.
Contents
Code Walkthrough
Class Declarations
We want to have this class write out to the log, so we inherit from CLxLuxologyLogMessage.
class CSimpleKinematicsLog : public CLxLuxologyLogMessage { public: CSimpleKinematicsLog () : CLxLuxologyLogMessage ("cmSimpleKinematics") { } const char * GetFormat () { return "Linear Blend Object"; } };
To create an instance of the SimpleKinematics object we need to implement the Simple Kinematics Package object so we inherit from CLxPackageInstance. We also need to modify channels as part of our instance, so we inherit from CLxImpl_ChannelModItem.
class CSimpleKinematicsInstance : public CLxImpl_PackageInstance, public CLxImpl_ChannelModItem { CSimpleKinematicsLog log; public: CSimpleKinematicsPackage *src_pkg; CLxUser_Item m_item; ILxUnknownID inst_ifc; LxResult pins_Initialize (ILxUnknownID item, ILxUnknownID super); void pins_Cleanup (void); LxResult pins_SynthName (char *buf, unsigned len); unsigned int cmod_Flags (ILxUnknownID item, unsigned int index); LxResult cmod_Allocate ( ILxUnknownID cmod, ILxUnknownID eval, ILxUnknownID item, void **ppvData); void cmod_Cleanup (void *data); LxResult cmod_Evaluate (ILxUnknownID cmod, ILxUnknownID attr, void *data); };
To set up our object we need a package, so we have this class inherit from CLxImpl_Package.
class CSimpleKinematicsPackage : public CLxImpl_Package { public: static LXtTagInfoDesc descInfo[]; CLxPolymorph<CSimpleKinematicsInstance> chanmod_factory; CSimpleKinematicsPackage (); LxResult pkg_SetupChannels (ILxUnknownID addChan); LxResult pkg_TestInterface (const LXtGUID *guid); LxResult pkg_Attach (void **ppvObj); };
Server Tags
The tags here indicate that the CSimpleKinematicsPackage class is dependent on the chanmodify SuperType with the internal name of cmSimpleKinematics.
LXtTagInfoDesc CSimpleKinematicsPackage::descInfo[] = { { LXsPKG_SUPERTYPE, "chanModify" }, { LXsSRV_LOGSUBSYSTEM, "cmSimpleKinematics" }, { 0 } };
Initialize
Our initialize function indicates that we will be exporting one server dependent on the CSimpleKinematicsPackage class that uses the Package and StaticDesc interfaces as well as being names cmSimpleKinematics.
initialize () { CLxGenericPolymorph *srv; srv = new CLxPolymorph<CSimpleKinematicsPackage>; srv->AddInterface (new CLxIfc_Package <CSimpleKinematicsPackage>); srv->AddInterface (new CLxIfc_StaticDesc <CSimpleKinematicsPackage>); thisModule.AddServer ("cmSimpleKinematics", srv); }
Implementations
This function evaluates the modifiers we have used on the given channels.
LxResult CSimpleKinematicsInstance::cmod_Evaluate ( ILxUnknownID cmod, // ILxChannelModifierID ILxUnknownID attr, // ILxAttributesID void *data) { CLxLoc_ChannelModifier chanMod (cmod); double t0, v0, x0, a, t=1; // log.Info ("cmod_Evaluate Method"); chanMod.ReadInputFloat (attr, 0, &x0); chanMod.ReadInputFloat (attr, 1, &t0); chanMod.ReadInputFloat (attr, 2, &v0); chanMod.ReadInputFloat (attr, 3, &a); chanMod.ReadInputFloat (attr, 4, &t); if(t>=t0) { t -= t0; x0 += v0*t + 0.5*a*t*t; } chanMod.WriteOutputFloat (attr, 0, x0); return LXe_OK; }
We create factories here to export CMathMultiInstance.
CSimpleKinematicsPackage::CSimpleKinematicsPackage () { chanmod_factory.AddInterface (new CLxIfc_PackageInstance<CSimpleKinematicsInstance>); chanmod_factory.AddInterface (new CLxIfc_ChannelModItem<CSimpleKinematicsInstance>); }