Use bezier splines in Animation
authorMikko Rasa <tdb@tdb.fi>
Fri, 7 Jun 2019 23:17:43 +0000 (02:17 +0300)
committerMikko Rasa <tdb@tdb.fi>
Fri, 7 Jun 2019 23:29:09 +0000 (02:29 +0300)
Control keyframes can now be added to affect the shape of curves.  Zero,
one or two control keyframes can be present between any two regular
keyframes, resulting in a linear, quadratic or cubic segment.

source/animation.cpp
source/animation.h

index 4be00d73b3299012df11280df62e677f52039852..c58a33d818f5d588a4ced081d35c1ec56ba2f23c 100644 (file)
@@ -1,7 +1,7 @@
 #include <cmath>
 #include <msp/core/maputils.h>
 #include <msp/datafile/collection.h>
-#include <msp/interpolate/linearspline.h>
+#include <msp/interpolate/bezierspline.h>
 #include "animation.h"
 #include "animationeventobserver.h"
 #include "armature.h"
@@ -46,7 +46,10 @@ const string &Animation::get_uniform_name(unsigned i) const
 
 void Animation::add_keyframe(const Time::TimeDelta &t, const KeyFrame &kf)
 {
-       add_keyframe(t, kf, 1.0f, 1.0f);
+       RefPtr<const KeyFrame> kfr(&kf);
+       kfr.keep();
+       add_keyframe(t, kfr, false);
+       create_curves();
 }
 
 void Animation::add_keyframe(const Time::TimeDelta &t, const KeyFrame &kf, float slope)
@@ -54,16 +57,25 @@ void Animation::add_keyframe(const Time::TimeDelta &t, const KeyFrame &kf, float
        add_keyframe(t, kf, slope, slope);
 }
 
-void Animation::add_keyframe(const Time::TimeDelta &t, const KeyFrame &kf, float ss, float es)
+void Animation::add_keyframe(const Time::TimeDelta &t, const KeyFrame &kf, float, float)
+{
+       add_keyframe(t, kf);
+}
+
+void Animation::add_control_keyframe(const KeyFrame &kf)
 {
+       if(keyframes.empty())
+               throw invalid_operation("Animation::add_control_keyframe");
+
        RefPtr<const KeyFrame> kfr(&kf);
        kfr.keep();
-       add_keyframe(t, kfr, ss, es);
-       create_curves();
+       add_keyframe(keyframes.back().time, kfr, true);
 }
 
-void Animation::add_keyframe(const Time::TimeDelta &t, const RefPtr<const KeyFrame> &kf, float ss, float es)
+void Animation::add_keyframe(const Time::TimeDelta &t, const RefPtr<const KeyFrame> &kf, bool c)
 {
+       if(c && keyframes.empty())
+               throw invalid_argument("Animation::add_keyframe");
        if(keyframes.empty() && t!=Time::zero)
                throw invalid_argument("Animation::add_keyframe");
        if(!keyframes.empty() && t<keyframes.back().time)
@@ -84,9 +96,8 @@ void Animation::add_keyframe(const Time::TimeDelta &t, const RefPtr<const KeyFra
 
        TimedKeyFrame tkf;
        tkf.time = t;
-       tkf.start_slope = ss;
-       tkf.end_slope = es;
        tkf.keyframe = kf;
+       tkf.control = c;
 
        keyframes.push_back(tkf);
 
@@ -131,12 +142,44 @@ void Animation::create_curve(CurveTarget target, const T &extract)
        typedef typename ValueCurve<N>::Knot Knot;
 
        vector<Knot> knots;
+       unsigned n_control = 0;
        for(vector<TimedKeyFrame>::const_iterator i=keyframes.begin(); i!=keyframes.end(); ++i)
        {
+               if(i->control && knots.empty())
+                       continue;
+
                typename Interpolate::SplineValue<float, N>::Type value;
                if(extract(*i->keyframe, value))
-                       knots.push_back(Knot(i->time/Time::sec, value));
+               {
+                       float x = i->time/Time::sec;
+                       if(i->control)
+                       {
+                               ++n_control;
+                               if(n_control>2)
+                                       throw logic_error("too many control keyframes");
+                       }
+                       else
+                       {
+                               if(n_control==1)
+                               {
+                                       typename Knot::Value cv = knots.back().y;
+                                       knots.back().y = (knots[knots.size()-2].y+cv*2.0f)/3.0f;
+                                       knots.push_back(Knot(x, (value+cv*2.0f)/3.0f));
+                               }
+                               else if(n_control==0 && !knots.empty())
+                               {
+                                       typename Knot::Value prev = knots.back().y;
+                                       knots.push_back(Knot(knots.back().x, (prev*2.0f+value)/3.0f));
+                                       knots.push_back(Knot(x, (prev+value*2.0f)/3.0f));
+                               }
+                               n_control = 0;
+                       }
+                       knots.push_back(Knot(x, value));
+               }
        }
+       
+       while(n_control--)
+               knots.pop_back();
 
        curves.push_back(new ValueCurve<N>(target, knots));
 }
@@ -191,7 +234,7 @@ Animation::Curve::Curve(CurveTarget t):
 template<unsigned N>
 Animation::ValueCurve<N>::ValueCurve(CurveTarget t, const vector<Knot> &k):
        Curve(t),
-       spline(Interpolate::LinearSpline<float, N>(k))
+       spline(Interpolate::BezierSpline<float, 3, N>(k))
 { }
 
 template<unsigned N>
@@ -327,6 +370,8 @@ void Animation::Loader::init()
        start_slope = 1;
        end_slope = 1;
        add("armature", &Animation::armature);
+       add("control_keyframe", &Loader::control_keyframe);
+       add("control_keyframe", &Loader::control_keyframe_inline);
        add("event", &Loader::event);
        add("event", &Loader::event1i);
        add("event", &Loader::event1f);
@@ -345,6 +390,32 @@ void Animation::Loader::finish()
        obj.create_curves();
 }
 
+void Animation::Loader::load_kf(const string &n, bool c)
+{
+       obj.add_keyframe(current_time, get_collection().get<KeyFrame>(n), c);
+}
+
+void Animation::Loader::load_kf_inline(bool c)
+{
+       RefPtr<KeyFrame> kf = new KeyFrame;
+       if(coll)
+               load_sub(*kf, get_collection());
+       else
+               load_sub(*kf);
+
+       obj.add_keyframe(current_time, kf, c);
+}
+
+void Animation::Loader::control_keyframe(const string &n)
+{
+       load_kf(n, true);
+}
+
+void Animation::Loader::control_keyframe_inline()
+{
+       load_kf_inline(true);
+}
+
 void Animation::Loader::event(const string &n)
 {
        obj.add_event(current_time, n);
@@ -382,22 +453,12 @@ void Animation::Loader::interval(float t)
 
 void Animation::Loader::keyframe(const string &n)
 {
-       obj.add_keyframe(current_time, get_collection().get<KeyFrame>(n), start_slope, end_slope);
-       start_slope = end_slope;
-       end_slope = 1;
+       load_kf(n, false);
 }
 
 void Animation::Loader::keyframe_inline()
 {
-       RefPtr<KeyFrame> kf = new KeyFrame;
-       if(coll)
-               load_sub(*kf, get_collection());
-       else
-               load_sub(*kf);
-
-       obj.add_keyframe(current_time, kf, start_slope, end_slope);
-       start_slope = end_slope;
-       end_slope = 1;
+       load_kf_inline(false);
 }
 
 void Animation::Loader::slopes(float s, float e)
index 92c177b685fead92aa15ee34c8721af1e16e4924..43cfc2894013016ec9018244e60c5bff0b2a7f26 100644 (file)
@@ -36,6 +36,11 @@ public:
                void init();
                virtual void finish();
 
+               void load_kf(const std::string &, bool);
+               void load_kf_inline(bool);
+
+               void control_keyframe(const std::string &);
+               void control_keyframe_inline();
                void event(const std::string &);
                void event1i(const std::string &, int);
                void event1f(const std::string &, float);
@@ -77,7 +82,7 @@ private:
                typedef typename Interpolate::SplineKnot<float, N> Knot;
 
        private:
-               Interpolate::Spline<float, 1, N> spline;
+               Interpolate::Spline<float, 3, N> spline;
 
        public:
                ValueCurve(CurveTarget, const std::vector<Knot> &);
@@ -99,9 +104,8 @@ private:
        struct TimedKeyFrame
        {
                Time::TimeDelta time;
-               float start_slope;
-               float end_slope;
                RefPtr<const KeyFrame> keyframe;
+               bool control;
        };
 
        struct Event
@@ -162,8 +166,9 @@ public:
        void add_keyframe(const Time::TimeDelta &, const KeyFrame &);
        void add_keyframe(const Time::TimeDelta &, const KeyFrame &, float);
        void add_keyframe(const Time::TimeDelta &, const KeyFrame &, float, float);
+       void add_control_keyframe(const KeyFrame &);
 private:
-       void add_keyframe(const Time::TimeDelta &, const RefPtr<const KeyFrame> &, float, float);
+       void add_keyframe(const Time::TimeDelta &, const RefPtr<const KeyFrame> &, bool);
        void prepare_keyframe(TimedKeyFrame &);
        void create_curves();
        template<unsigned N, typename T>