daniel
f39fb1b145
New pure curve_tessellate joins the overlay's node vertices through curveMap, one sample per pixel column; the knot no longer floats off its own trace.
66 lines
2.2 KiB
C++
66 lines
2.2 KiB
C++
// curve_tessellate.cpp — see curve_tessellate.h. Pure geometry; no host types.
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#include "core/instrument/ui/curve_tessellate.h"
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#include <algorithm>
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#include <cstdlib>
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#include "core/util/curve_law.h"
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namespace reasampler::instrument::ui {
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using StrokePoint = reasampler::ui::StrokePoint;
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namespace {
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StrokePoint pt(double x, double y) {
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return StrokePoint{static_cast<float>(x), static_cast<float>(y)};
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}
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// The samples strictly BETWEEN two nodes. The endpoints are the caller's, so a shared node is
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// emitted once and the polyline carries no zero-length joint.
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void appendInterior(int x0, int y0, int x1, int y1, double exponent,
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std::vector<StrokePoint>& out) {
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const int span = std::abs(x1 - x0);
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if (span < 2 || y1 == y0 || exponent == util::kCurveNeutral) return;
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const double dx = static_cast<double>(x1 - x0);
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const double dy = static_cast<double>(y1 - y0);
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for (int i = 1; i < span; ++i) {
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// phi is exact at every column, so x lands on the integer column and the last interior
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// sample is one column short of the end node.
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const double phi = static_cast<double>(i) / static_cast<double>(span);
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out.push_back(pt(static_cast<double>(x0) + dx * phi,
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static_cast<double>(y0) + dy * util::curveMap(phi, exponent)));
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}
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}
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} // namespace
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double segmentCurve(const StageEnvelope& env, EnvNode endNode) {
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switch (endNode) {
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case EnvNode::AttackEnd: return env.attackCurve;
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case EnvNode::DecayEnd: return env.decayCurve;
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case EnvNode::ReleaseEnd: return env.releaseCurve;
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default: return util::kCurveNeutral;
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}
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}
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void buildEnvelopeTrace(const std::vector<EnvVertex>& poly, const StageEnvelope& env, int xLo,
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int xHi, std::vector<StrokePoint>& out) {
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out.clear();
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bool started = false;
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int px = 0;
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int py = 0;
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for (const EnvVertex& v : poly) {
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if (v.knot) continue;
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const int x = std::max(xLo, std::min(xHi, v.x));
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if (started) appendInterior(px, py, x, v.y, segmentCurve(env, v.node), out);
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out.push_back(pt(x, v.y));
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started = true;
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px = x;
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py = v.y;
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}
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}
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} // namespace reasampler::instrument::ui
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