Files
reasampler/src/core/instrument/ui/envelope_overlay.h
T

109 lines
5.0 KiB
C++

// envelope_overlay.h — amp-envelope -> polyline geometry for the Sample-view envelope overlay.
// Engine-free by design (no sample_map/sampler_core dependency); mirror of waveform_view /
// param_slider. The shell packs the one parameter set's AdsrSeconds/TriggerParams into
// AmpEnvelope and draws the polyline plus a handle at each node (envelope_edit does the
// hit-test).
#pragma once
#include <cstdint>
#include <vector>
#include "core/instrument/ui/editor_geometry.h" // Rect — the shared geometry idiom
namespace reasampler::instrument::ui {
// Local mirror of sampler_core's PlayMode, kept here so this module stays engine-free.
enum class EnvMode { Gate, Trigger };
// Gate nodes: Origin -> AttackEnd -> HoldEnd -> DecayEnd(sustain) -> ReleaseStart -> ReleaseEnd.
// Trigger nodes: Origin -> FadeInEnd -> FadeOutStart -> LengthEnd(playEnd).
// Shared by envelope_overlay (forward/draw map) and envelope_edit (inverse/edit map).
enum class EnvNode {
Origin, // t=0, level 0 — not draggable
AttackEnd, // Gate: attack ramp top — sets attackSeconds
HoldEnd, // Gate: hold plateau end — sets holdSeconds
DecayEnd, // Gate: decay settles to sustain — sets decaySeconds (X) and sustainLevel (Y)
ReleaseStart, // Gate: sustain plateau end — drawing-only, not draggable
ReleaseEnd, // Gate: release tail end — sets releaseSeconds
FadeInEnd, // Trigger: fade-in top — sets fadeInFraction
FadeOutStart, // Trigger: fade-out start — sets fadeOutFraction
LengthEnd, // Trigger: playEnd terminal — sets lengthFraction
};
// Amp-envelope params the overlay draws. Trigger's fadeIn/fadeOutFraction are derived from
// TriggerParams' frame counts, not a direct field copy — see the trigger_seam gotcha in
// core/instrument/CLAUDE.md.
struct AmpEnvelope {
EnvMode mode = EnvMode::Gate;
// Gate (AHDSR): seconds, plus a dimensionless sustain level.
double attackSeconds = 0.003;
double holdSeconds = 0.0;
double decaySeconds = 0.0;
double sustainLevel = 1.0;
double releaseSeconds = 0.060;
// Trigger: fractions of the played span.
double lengthFraction = 1.0;
double fadeInFraction = 0.0;
double fadeOutFraction = 0.0;
};
// One polyline vertex: pixel point plus which node it is. level is redundant with y, carried for
// inspection.
struct EnvVertex {
EnvNode node = EnvNode::Origin;
int x = 0;
int y = 0;
double level = 0.0;
bool operator==(const EnvVertex& o) const {
return node == o.node && x == o.x && y == o.y && level == o.level;
}
};
// Fraction of canvas width reserved for the Gate sustain-plateau display; the remaining width
// carries A/H/D/R at the param-domain scale. Shared with envelope_edit.
inline constexpr double kGateSustainDisplayFraction = 0.15;
// Minimum pixel separation between consecutive Gate nodes, so zero-duration stages (tier-0
// defaults) still render as distinct, grabbable handles. Larger than envelope_edit's grab
// radius (6) so a click can never tie between neighbours.
inline constexpr int kGateNodeSepPx = 8;
// Gate schematic's per-stage time domain (seconds) — the timed region represents four stages
// end-to-end at this max each. Must match the shell's stage-slider ceiling so a maxed slider
// lands exactly at the canvas edge.
inline constexpr double kGateStageMaxSeconds = 2.0;
// Pixel width of the Gate timed region (area width minus the sustain reserve), floored at 1 for
// a non-empty area; 0 for a zero/negative-width area.
int gateTimedWidth(const Rect& area);
// Pixels per second of the Gate timed region, independent of the sample's actual duration.
// Shared by buildEnvelopePolyline and envelope_edit's drag inverse so a dragged handle tracks
// the cursor 1:1.
double gatePxPerSecond(const Rect& area);
// Maps an amp envelope to polyline vertices inside `area` over a sample of `totalSeconds`
// duration. y maps level [0,1] across [area.bottom()-1, area.y] (level 1 at the top); vertices
// are in draw order, Origin first.
//
// Gate's x-axis is a bounded schematic independent of totalSeconds (does NOT line up with the
// waveform under it); Trigger's x-axis is PCM-aligned wall-clock. Every vertex is clamped inside
// the canvas: x in [area.x, area.right()-1], y in [area.y, area.bottom()-1]. A degenerate area
// or totalSeconds <= 0 yields the flat two-point baseline [Origin, end at level 0].
std::vector<EnvVertex> buildEnvelopePolyline(const AmpEnvelope& env, const Rect& area,
double totalSeconds);
// Maps a time (seconds) to a pixel x inside `area`, linear and clamped at both ends. Shared
// with envelope_edit's node hit-test so the drawn handle and its grab region agree.
int timeToX(const Rect& area, double totalSeconds, double t);
// Maps a level [0,1] to a pixel y inside `area` (level 1 at the top, 0 at the bottom row),
// clamped. Shared with envelope_edit's node hit-test.
int levelToY(const Rect& area, double level);
} // namespace reasampler::instrument::ui