CurveEdInterface.h

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// Copyright Epic Games, Inc. All Rights Reserved.
 
#pragma once
 
#include "CoreTypes.h"
#include "Math/Color.h"
#include "Math/InterpCurvePoint.h"
 
/** Interface that allows the CurveEditor to edit this type of object. */
class FCurveEdInterface
{
public:
    /** Get number of keyframes in curve. */
    virtual int32   GetNumKeys() const { return 0; }
 
    /** Get number of 'sub curves' in this Curve. For example, a vector curve will have 3 sub-curves, for X, Y and Z. */
    virtual int32       GetNumSubCurves() const { return 0; }
 
    /**
     * Provides the color for the sub-curve button that is present on the curve tab.
     *
     * @param   SubCurveIndex       The index of the sub-curve. Cannot be negative nor greater or equal to the number of sub-curves.
     * @param   bIsSubCurveHidden   Is the curve hidden?
     * @return                      The color associated to the given sub-curve index.
     */
    virtual FColor  GetSubCurveButtonColor(int32 SubCurveIndex, bool bIsSubCurveHidden) const { return  bIsSubCurveHidden ? FColor( 32,  0,  0) : FColor(255,  0,  0); }
 
    /** Get the input value for the Key with the specified index. KeyIndex must be within range ie >=0 and < NumKeys. */
    virtual float   GetKeyIn(int32 KeyIndex) { return 0.f; }
 
    /** 
     *  Get the output value for the key with the specified index on the specified sub-curve. 
     *  SubIndex must be within range ie >=0 and < NumSubCurves.
     *  KeyIndex must be within range ie >=0 and < NumKeys.
     */
    virtual float   GetKeyOut(int32 SubIndex, int32 KeyIndex) { return 0.f; }
 
    /**
     * Provides the color for the given key at the given sub-curve.
     *
     * @param       SubIndex    The index of the sub-curve
     * @param       KeyIndex    The index of the key in the sub-curve
     * @param[in]   CurveColor  The color of the curve
     * @return                  The color that is associated the given key at the given sub-curve
     */
    virtual FColor  GetKeyColor(int32 SubIndex, int32 KeyIndex, const FColor& CurveColor) { return CurveColor; }
 
    /** Evaluate a subcurve at an arbitary point. Outside the keyframe range, curves are assumed to continue their end values. */
    virtual float   EvalSub(int32 SubIndex, float InVal) { return 0.f; }
 
    /** 
     *  Get the interpolation mode of the specified keyframe. This can be CIM_Constant, CIM_Linear or CIM_Curve. 
     *  KeyIndex must be within range ie >=0 and < NumKeys.
     */
    virtual EInterpCurveMode    GetKeyInterpMode(int32 KeyIndex) const { return CIM_Linear; }
 
    /** 
     *  Get the incoming and outgoing tangent for the given subcurve and key.
     *  SubIndex must be within range ie >=0 and < NumSubCurves.
     *  KeyIndex must be within range ie >=0 and < NumKeys.
     */
    virtual void    GetTangents(int32 SubIndex, int32 KeyIndex, float& ArriveTangent, float& LeaveTangent) const { ArriveTangent=0.f; LeaveTangent=0.f; }
 
    /** Get input range of keys. Outside this region curve continues constantly the start/end values. */
    virtual void    GetInRange(float& MinIn, float& MaxIn) const { MinIn=0.f; MaxIn=0.f; }
 
    /** Get overall range of output values. */
    virtual void    GetOutRange(float& MinOut, float& MaxOut) const { MinOut=0.f; MaxOut=0.f; }
 
    /** 
     *  Add a new key to the curve with the specified input. Its initial value is set using EvalSub at that location. 
     *  Returns the index of the new key.
     */
    virtual int32       CreateNewKey(float KeyIn) { return INDEX_NONE; }
 
    /** 
     *  Remove the specified key from the curve.
     *  KeyIndex must be within range ie >=0 and < NumKeys.
     */
    virtual void    DeleteKey(int32 KeyIndex) {}
 
    /** 
     *  Set the input value of the specified Key. This may change the index of the key, so the new index of the key is retured. 
     *  KeyIndex must be within range ie >=0 and < NumKeys.
     */
    virtual int32       SetKeyIn(int32 KeyIndex, float NewInVal) { return KeyIndex; }
 
    /** 
     *  Set the output values of the specified key.
     *  SubIndex must be within range ie >=0 and < NumSubCurves.
     *  KeyIndex must be within range ie >=0 and < NumKeys.
     */
    virtual void    SetKeyOut(int32 SubIndex, int32 KeyIndex, float NewOutVal) {}
 
    /** 
     *  Set the method to use for interpolating between the give keyframe and the next one.
     *  KeyIndex must be within range ie >=0 and < NumKeys.
     */
    virtual void    SetKeyInterpMode(int32 KeyIndex, EInterpCurveMode NewMode) {}
 
 
    /** 
     *  Set the incoming and outgoing tangent for the given subcurve and key.
     *  SubIndex must be within range ie >=0 and < NumSubCurves.
     *  KeyIndex must be within range ie >=0 and < NumKeys.
     */
    virtual void    SetTangents(int32 SubIndex, int32 KeyIndex, float ArriveTangent, float LeaveTangent) {}
};