Restructure Animation to make matrix interpolation code more reusable

[libs/gl.git] / source / animation.cpp

diff --git a/source/animation.cpp b/source/animation.cpp
index eb22ab29f0462fa5c686b2542b9b21ba155f5a6e..53543d1b89b8426f576305604c046651cea156a7 100644 (file)
--- a/source/animation.cpp
+++ b/source/animation.cpp
@@ -20,7 +20,7 @@ void Animation::add_keyframe(const Time::TimeDelta &t, const KeyFrame &kf)
        if(!keyframes.empty() && t<keyframes.back().time)
                throw invalid_argument("Animation::add_keyframe");
 
-       TimedKeyFrame tkf;
+       TimedKeyFrame tkf(*this);
        tkf.time = t;
        tkf.keyframe = &kf;
        tkf.keyframe.keep();
@@ -34,53 +34,62 @@ void Animation::prepare_keyframe(TimedKeyFrame &tkf)
        if(!tkf.prev)
                return;
 
-       tkf.delta_t = tkf.time-tkf.prev->time;
+       tkf.prepare();
 
-       const double *m1_data = tkf.prev->keyframe->get_matrix().data();
-       const double *m2_data = tkf.keyframe->get_matrix().data();
+}
+
+
+Animation::AxisInterpolation::AxisInterpolation():
+       slope(0),
+       scale(0)
+{ }
+
+Animation::AxisInterpolation::AxisInterpolation(const double *axis1, const double *axis2)
+{
+       // Compute a normalized vector halfway between the two endpoints
+       double half[3];
+       double len = 0;
        for(unsigned i=0; i<3; ++i)
        {
-               const double *m1_col = m1_data+i*4;
-               const double *m2_col = m2_data+i*4;
-
-               // Compute a normalized vector halfway between the two endpoints
-               double half[3];
-               double len = 0;
-               for(unsigned j=0; j<3; ++j)
-               {
-                       half[j] = (m1_col[j]+m2_col[j])/2;
-                       len += half[j]*half[j];
-               }
-               len = sqrt(len);
-               for(unsigned j=0; j<3; ++j)
-                       half[j] /= len;
-
-               // Compute correction factors for smooth interpolation
-               double cos_half = m1_col[0]*half[0]+m1_col[1]*half[1]+m1_col[2]*half[2];
-               double angle = acos(cos_half);
-               tkf.axes[i].slope = (angle ? angle/tan(angle) : 1);
-               tkf.axes[i].scale = cos_half;
+               half[i] = (axis1[i]+axis2[i])/2;
+               len += half[i]*half[i];
        }
+       len = sqrt(len);
+       for(unsigned i=0; i<3; ++i)
+               half[i] /= len;
+
+       // Compute correction factors for smooth interpolation
+       double cos_half = axis1[0]*half[0]+axis1[1]*half[1]+axis1[2]*half[2];
+       double angle = acos(cos_half);
+       slope = (angle ? angle/tan(angle) : 1);
+       scale = cos_half;
 }
 
-Matrix Animation::compute_matrix(const TimedKeyFrame &tkf, const Time::TimeDelta &dt) const
+
+Animation::MatrixInterpolation::MatrixInterpolation():
+       matrix1(0),
+       matrix2(0)
+{ }
+
+Animation::MatrixInterpolation::MatrixInterpolation(const Matrix &m1, const Matrix &m2):
+       matrix1(&m1),
+       matrix2(&m2)
 {
-       if(!dt)
-               return tkf.keyframe->get_matrix();
-       if(!tkf.prev)
-               throw invalid_argument("Animation::compute_matrix");
-       const TimedKeyFrame &prev = *tkf.prev;
+       const double *m1_data = matrix1->data();
+       const double *m2_data = matrix2->data();
+       for(unsigned i=0; i<3; ++i)
+               axes[i] = AxisInterpolation(m1_data+i*4, m2_data+i*4);
+}
 
-       float t = dt/tkf.delta_t;
+Matrix Animation::MatrixInterpolation::get(float t) const
+{
        float u = t*2.0f-1.0f;
 
        double matrix[16];
-       const double *m1_data = prev.keyframe->get_matrix().data();
-       const double *m2_data = tkf.keyframe->get_matrix().data();
        for(unsigned i=0; i<4; ++i)
        {
-               const double *m1_col = m1_data+i*4;
-               const double *m2_col = m2_data+i*4;
+               const double *m1_col = matrix1->data()+i*4;
+               const double *m2_col = matrix2->data()+i*4;
                double *out_col = matrix+i*4;
 
                if(i<3)
@@ -91,13 +100,13 @@ Matrix Animation::compute_matrix(const TimedKeyFrame &tkf, const Time::TimeDelta
                        around the halfway point and computing its tangent.  This is
                        approximated by a third degree polynomial, scaled so that the result
                        will be in the range [-1, 1]. */
-                       float w = (tkf.axes[i].slope+(1-tkf.axes[i].slope)*u*u)*u*0.5f+0.5f;
+                       float w = (axes[i].slope+(1-axes[i].slope)*u*u)*u*0.5f+0.5f;
 
                        /* The interpolate vectors will also be shorter than unit length.  At
                        the halfway point the length will be equal to the cosine of half the
                        angle, which was computed earlier.  Use a second degree polynomial to
                        approximate. */
-                       float n = (tkf.axes[i].scale+(1-tkf.axes[i].scale)*u*u);
+                       float n = (axes[i].scale+(1-axes[i].scale)*u*u);
 
                        for(unsigned j=0; j<3; ++j)
                                out_col[j] = ((1-w)*m1_col[j]+w*m2_col[j])/n;
@@ -118,11 +127,17 @@ Matrix Animation::compute_matrix(const TimedKeyFrame &tkf, const Time::TimeDelta
 }
 
 
-Animation::AxisInterpolation::AxisInterpolation():
-       slope(0),
-       scale(0)
+Animation::TimedKeyFrame::TimedKeyFrame(const Animation &a):
+       animation(a),
+       prev(0)
 { }
 
+void Animation::TimedKeyFrame::prepare()
+{
+       delta_t = time-prev->time;
+       matrix = MatrixInterpolation(prev->keyframe->get_matrix(), keyframe->get_matrix());
+}
+
 
 Animation::Iterator::Iterator(const Animation &a):
        animation(a),
@@ -158,7 +173,10 @@ Animation::Iterator &Animation::Iterator::operator+=(const Time::TimeDelta &t)
 
 Matrix Animation::Iterator::get_matrix() const
 {
-       return animation.compute_matrix(*iter, time_since_keyframe);
+       if(!iter->prev)
+               return iter->keyframe->get_matrix();
+
+       return iter->matrix.get(time_since_keyframe/iter->delta_t);
 }
 
 
@@ -192,7 +210,7 @@ void Animation::Loader::keyframe_inline()
        RefPtr<KeyFrame> kf = new KeyFrame;
        load_sub(*kf);
 
-       TimedKeyFrame tkf;
+       TimedKeyFrame tkf(obj);
        tkf.time = current_time;
        tkf.keyframe = kf;
        obj.prepare_keyframe(tkf);