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Keyframe interpolation: In own function; only for Y coordinate

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This commit is contained in:
Daniel Jour
2019-12-06 01:03:56 +01:00
parent ed0b081803
commit f00edbad7e
1 changed files with 23 additions and 25 deletions
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48
src/KeyFrame.cpp
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@@ -40,7 +40,14 @@ namespace {
return p.co.X < x;
}
double InterpolateBezierCurve(Point const & left, Point const & right, bool const needY, double const target, double const allowed_error) {
double InterpolateLinearCurve(Point const & left, Point const & right, double const target) {
double const diff_Y = right.co.Y - left.co.Y;
double const diff_X = right.co.X - left.co.X;
double const slope = diff_Y / diff_X;
return left.co.Y + slope * (target - left.co.X);
}
double InterpolateBezierCurve(Point const & left, Point const & right, double const target, double const allowed_error) {
double const X_diff = right.co.X - left.co.X;
double const Y_diff = right.co.Y - left.co.Y;
Coordinate const p0 = left.co;
@@ -63,12 +70,10 @@ namespace {
}
double const x = p0.X * B[0] + p1.X * B[1] + p2.X * B[2] + p3.X * B[3];
double const y = p0.Y * B[0] + p1.Y * B[1] + p2.Y * B[2] + p3.Y * B[3];
bool const stop = abs(target - (needY ? x : y)) < allowed_error;
bool const move_left = (needY ? x : y) > target;
if (stop) {
return needY ? y : x;
if (abs(target - x) < allowed_error) {
return y;
}
if (move_left) {
if (x > target) {
t -= t_step;
}
else {
@@ -77,6 +82,17 @@ namespace {
t_step /= 2;
} while (true);
}
double InterpolateBetween(Point const & left, Point const & right, double target, double allowed_error) {
assert(left.co.X < target);
assert(target <= right.co.X);
switch (right.interpolation) {
case CONSTANT: return left.co.Y;
case LINEAR: return InterpolateLinearCurve(left, right, target);
case BEZIER: return InterpolateBezierCurve(left, right, target, allowed_error);
}
}
}
@@ -245,25 +261,7 @@ double Keyframe::GetValue(int64_t index) const {
return candidate->co.Y;
}
std::vector<Point>::const_iterator predecessor = candidate - 1;
assert(predecessor->co.X < index);
assert(index < candidate->co.X);
// CONSTANT and LINEAR interpolations are fast to compute!
switch (candidate->interpolation) {
case CONSTANT: return predecessor->co.Y;
case LINEAR: {
double const diff_Y = candidate->co.Y - predecessor->co.Y;
double const diff_X = candidate->co.X - predecessor->co.X;
double const slope = diff_Y / diff_X;
return predecessor->co.Y + slope * (index - predecessor->co.X);
}
case BEZIER: break;
}
// BEZIER curve!
assert(candidate->interpolation == BEZIER);
return InterpolateBezierCurve(*predecessor, *candidate, true, index, 0.01);
return InterpolateBetween(*predecessor, *candidate, index, 0.01);
}
// Get the rounded INT value at a specific index