reasampler/tests/test_envelope_overlay.cpp

// Standalone tests for reasampler::instrument::ui::envelope_overlay — no VST3, no REAPER, no framework.
// Same fast assert loop as the sibling pure tests. Assert the S-VIEW-3/FA2 amp-envelope ->
// polyline FORWARD map: the Gate BOUNDED-SCHEMATIC AHDSR shape (attack ramp / hold plateau /
// decay-to-sustain / fixed-width sustain plateau / in-bounds release) and the Trigger
// fade/%-length shape at the waveform time base.
//
// Covers: timeToX / levelToY (linear maps, edge clamps, past-end CLAMPED to right-1 — the FA2
// bounds invariant, no 32-bit overflow on huge times, degenerate area/duration); gateTimedWidth
// + gatePxPerSecond; buildEnvelopePolyline Gate (node order, levels, PARAM-DOMAIN timed-region
// placement independent of sample duration, per-segment kGateNodeSepPx separation — every node
// distinct even at the tier-0 zero-hold/zero-decay defaults, fixed sustain-plateau reserve,
// release visible in-bounds, overrun compressed from the right preserving the minimum gaps,
// every vertex in-bounds); buildEnvelopePolyline Trigger (fade-in/unity/fade-out at fractions of
// the played span, overlap clamp, full-length/zero-fade-out nodes in-bounds at right-1);
// degenerate flat baseline.

#include "../src/core/instrument/ui/envelope_overlay.h"

#include <cstdio>
#include <vector>

using namespace reasampler;
using namespace reasampler::instrument::ui;

static int g_fail = 0;
#define CHECK(cond) do { if(!(cond)) { \
    std::printf("FAIL line %d: %s\n", __LINE__, #cond); ++g_fail; } } while(0)

// buildEnvelopePolyline takes the overlay type, not a bare Rect (the distinct-type
// enforcement in editor_geometry.h) — this wraps a plain test Rect for it.
static OverlayArea overlayOf(const Rect& r) { return OverlayArea{r}; }

// A comfortable overlay area: 1000px wide, 100px tall, offset so left/top != 0 (catches origin
// bugs). Under levelToY the level span is height-1 = 99 rows.
static Rect wideArea() { return Rect::ltrb(20, 10, 1020, 110); }  // width 1000, height 100

// Find the first vertex with a given node in a polyline; asserts presence via the returned bool.
static bool findNode(const std::vector<EnvVertex>& poly, EnvNode node, EnvVertex& out) {
    for (const EnvVertex& v : poly) {
        if (v.node == node) { out = v; return true; }
    }
    return false;
}

// --- timeToX / levelToY -------------------------------------------------------

static void testTimeToXEndpoints() {
    const Rect a = wideArea();
    CHECK(timeToX(a, 2.0, 0.0) == a.x);           // t=0 -> left
    CHECK(timeToX(a, 2.0, 2.0) == a.right() - 1);      // t=total -> last in-bounds column
    CHECK(timeToX(a, 2.0, 1.0) == a.x + 500);     // midpoint
}

static void testTimeToXNegativePinsLeft() {
    const Rect a = wideArea();
    CHECK(timeToX(a, 2.0, -0.5) == a.x);          // t<0 pins left
}

static void testTimeToXPastEndClamps() {
    // FA2 bounds invariant: t past total pins to the last in-bounds column, never past right.
    const Rect a = wideArea();
    CHECK(timeToX(a, 2.0, 3.0) == a.right() - 1);
    CHECK(timeToX(a, 2.0, 1000.0) == a.right() - 1);
    // A HUGE t must clamp in double space, not overflow the integer cast (32-bit long on
    // Windows would wrap to LONG_MIN and pin to the WRONG edge).
    CHECK(timeToX(a, 2.0, 1e15) == a.right() - 1);
}

static void testGateTimedWidth() {
    // 15% of the 1000px canvas is reserved for the sustain plateau -> 850px timed region.
    CHECK(gateTimedWidth(wideArea()) == 850);
    // Zero-width area -> 0; a tiny area still yields >= 1 so the px<->s scale never degenerates.
    CHECK(gateTimedWidth(Rect::ltrb(5, 5, 5, 45)) == 0);
    CHECK(gateTimedWidth(Rect::ltrb(0, 0, 1, 10)) == 1);
}

static void testGatePxPerSecond() {
    // PARAM-DOMAIN scale: (timedW - 1 - 4*sep) px spread over 4 x kGateStageMaxSeconds. For the
    // 1000px canvas: (850 - 1 - 32) / 8.0s = 817/8 px/s. Independent of any sample duration.
    const double expected = 817.0 / (4.0 * kGateStageMaxSeconds);
    CHECK(gatePxPerSecond(wideArea()) == expected);
    CHECK(gatePxPerSecond(Rect::ltrb(5, 5, 5, 45)) == 0.0);   // zero-width area -> 0
    CHECK(gatePxPerSecond(Rect::ltrb(0, 0, 10, 10)) > 0.0);   // tiny area: usable floors at 1px, > 0
}

static void testTimeToXDegenerate() {
    const Rect a = wideArea();
    CHECK(timeToX(a, 0.0, 1.0) == a.x);           // no duration -> left
    const Rect z = Rect::ltrb(5, 5, 5, 45);                // zero width
    CHECK(timeToX(z, 2.0, 1.0) == z.x);
}

static void testLevelToYEndpoints() {
    const Rect a = wideArea();
    CHECK(levelToY(a, 1.0) == a.y);                // level 1 -> top row
    CHECK(levelToY(a, 0.0) == a.bottom() - 1);         // level 0 -> bottom row
    CHECK(levelToY(a, 0.5) == a.y + 50);           // mid: round((1-0.5)*99)=round(49.5)=50
}

static void testLevelToYClamps() {
    const Rect a = wideArea();
    CHECK(levelToY(a, 2.0) == a.y);                // >1 clamps to top
    CHECK(levelToY(a, -1.0) == a.bottom() - 1);        // <0 clamps to bottom
    const Rect z = Rect::ltrb(5, 5, 45, 5);                // zero height
    CHECK(levelToY(z, 0.5) == z.y);
}

// --- Gate polyline ------------------------------------------------------------

static void testGateNodeOrderAndLevels() {
    AmpEnvelope env;
    env.mode = EnvMode::Gate;
    env.attackSeconds  = 0.2;
    env.holdSeconds    = 0.1;
    env.decaySeconds   = 0.3;
    env.sustainLevel   = 0.5;
    env.releaseSeconds = 0.4;
    const Rect a = wideArea();
    const std::vector<EnvVertex> poly = buildEnvelopePolyline(env, overlayOf(a), 2.0);

    // Six vertices, in draw order.
    CHECK(poly.size() == 6);
    CHECK(poly[0].node == EnvNode::Origin);
    CHECK(poly[1].node == EnvNode::AttackEnd);
    CHECK(poly[2].node == EnvNode::HoldEnd);
    CHECK(poly[3].node == EnvNode::DecayEnd);
    CHECK(poly[4].node == EnvNode::ReleaseStart);
    CHECK(poly[5].node == EnvNode::ReleaseEnd);

    // Levels: origin 0, attack/hold peak 1, decay settles to sustain, plateau holds sustain,
    // release ends at 0.
    CHECK(poly[0].level == 0.0);
    CHECK(poly[1].level == 1.0);
    CHECK(poly[2].level == 1.0);
    CHECK(poly[3].level == 0.5);   // sustain
    CHECK(poly[4].level == 0.5);   // plateau end holds sustain
    CHECK(poly[5].level == 0.0);
}

static void testGateSchematicPlacement() {
    // FA2 bounded schematic at the PARAM-DOMAIN scale: timed region = 850px (150px reserved
    // plateau), pps = (850-1-32)/8s = 102.125 px/s, each segment prefixed by the 8px separation
    // base. attack .2 -> x@round(8+20.425)=28; hold .1 -> x@round(28.425+8+10.2125)=47; decay
    // .3 -> x@round(46.6375+8+30.6375)=85; plateau is the FIXED 150px reserve -> ReleaseStart
    // x@235; release .4 -> x@round(235.275+8+40.85)=284, well inside the canvas.
    AmpEnvelope env;
    env.mode = EnvMode::Gate;
    env.attackSeconds  = 0.2;
    env.holdSeconds    = 0.1;
    env.decaySeconds   = 0.3;
    env.sustainLevel   = 0.5;
    env.releaseSeconds = 0.4;
    const Rect a = wideArea();
    const std::vector<EnvVertex> poly = buildEnvelopePolyline(env, overlayOf(a), 2.0);

    EnvVertex v;
    CHECK(findNode(poly, EnvNode::AttackEnd, v)    && v.x == a.x + 28);
    CHECK(findNode(poly, EnvNode::HoldEnd, v)      && v.x == a.x + 47);
    CHECK(findNode(poly, EnvNode::DecayEnd, v)     && v.x == a.x + 85);
    CHECK(findNode(poly, EnvNode::ReleaseStart, v) && v.x == a.x + 235);
    CHECK(findNode(poly, EnvNode::ReleaseEnd, v)   && v.x == a.x + 284);
}

static void testGateLayoutIndependentOfSampleDuration() {
    // The Gate schematic is scaled by the PARAM domain, NOT the capture length: the same params
    // produce the SAME polyline over a 0.3s and a 10s sample (pre-fix, a 60ms release on a 10s
    // capture collapsed to ~5px while 2s stages on a 0.3s capture pinned to the right edge).
    AmpEnvelope env;
    env.mode = EnvMode::Gate;
    env.attackSeconds  = 0.2;
    env.holdSeconds    = 0.1;
    env.decaySeconds   = 0.3;
    env.sustainLevel   = 0.5;
    env.releaseSeconds = 0.06;
    const Rect a = wideArea();
    CHECK(buildEnvelopePolyline(env, overlayOf(a), 0.3) == buildEnvelopePolyline(env, overlayOf(a), 10.0));
}

static void testGateMinSeparationAtDefaults() {
    // THE FA2 headline: at the tier-0 Gate defaults (attack 3ms, hold 0, decay 0, sustain 1.0,
    // release 60ms) every consecutive node pair is at least kGateNodeSepPx apart — no node ever
    // renders on top of its neighbour, so each is individually grabbable.
    const AmpEnvelope env;   // struct defaults ARE the tier-0 Gate defaults
    const Rect a = wideArea();
    const std::vector<EnvVertex> poly = buildEnvelopePolyline(env, overlayOf(a), 2.0);
    CHECK(poly.size() == 6);
    for (size_t i = 1; i < poly.size(); ++i) {
        CHECK(poly[i].x - poly[i - 1].x >= kGateNodeSepPx);
    }
}

static void testGateSustainPlateauFixedWidth() {
    // The sustain plateau is ALWAYS the reserved width (canvas - timed region), independent of
    // the AHDSR times — the bounded region that replaces the old plateau-to-sample-end.
    AmpEnvelope env;
    env.mode = EnvMode::Gate;
    env.attackSeconds  = 0.1;
    env.holdSeconds    = 0.0;
    env.decaySeconds   = 0.2;
    env.sustainLevel   = 0.6;
    env.releaseSeconds = 0.3;
    const Rect a = wideArea();
    const int plateauPx = a.width - gateTimedWidth(a);   // 150
    const std::vector<EnvVertex> poly = buildEnvelopePolyline(env, overlayOf(a), 2.0);

    EnvVertex decay, plateauEnd;
    CHECK(findNode(poly, EnvNode::DecayEnd, decay));
    CHECK(findNode(poly, EnvNode::ReleaseStart, plateauEnd));
    CHECK(plateauEnd.x - decay.x == plateauPx);
    CHECK(plateauEnd.level == 0.6);               // plateau holds the sustain level
}

static void testGateReleaseVisibleInBounds() {
    // The FA2 fix: Release is a VISIBLE, in-bounds segment — ReleaseEnd sits strictly right of
    // the plateau end and strictly inside the canvas (pre-FA2 it mapped past area.right() and the
    // shell clipped its handle away).
    AmpEnvelope env;
    env.mode = EnvMode::Gate;
    env.attackSeconds  = 0.2;
    env.holdSeconds    = 0.1;
    env.decaySeconds   = 0.3;
    env.sustainLevel   = 0.5;
    env.releaseSeconds = 0.4;
    const Rect a = wideArea();
    const std::vector<EnvVertex> poly = buildEnvelopePolyline(env, overlayOf(a), 2.0);

    EnvVertex plateauEnd, rel;
    CHECK(findNode(poly, EnvNode::ReleaseStart, plateauEnd));
    CHECK(findNode(poly, EnvNode::ReleaseEnd, rel));
    CHECK(rel.x > plateauEnd.x);                 // a visible ramp, not a collapsed point
    CHECK(rel.x < a.right());                       // strictly in-bounds
    CHECK(rel.level == 0.0);
}

static void testGateOverrunCompressesFromRight() {
    // Stages BEYOND the schematic domain (4.0s each > kGateStageMaxSeconds): the layout
    // compresses from the right preserving the minimum gaps — ReleaseEnd pins to the last
    // in-bounds column, but the trailing nodes stay strictly increasing and individually
    // separated (>= kGateNodeSepPx), NOT piled on one pixel. NOTHING maps past area.right().
    AmpEnvelope env;
    env.mode = EnvMode::Gate;
    env.attackSeconds  = 4.0;
    env.holdSeconds    = 4.0;
    env.decaySeconds   = 4.0;
    env.sustainLevel   = 0.7;
    env.releaseSeconds = 4.0;
    const Rect a = wideArea();
    const std::vector<EnvVertex> poly = buildEnvelopePolyline(env, overlayOf(a), 2.0);
    CHECK(poly.size() == 6);

    EnvVertex plateauEnd, rel;
    CHECK(findNode(poly, EnvNode::ReleaseStart, plateauEnd));
    CHECK(findNode(poly, EnvNode::ReleaseEnd, rel));
    CHECK(rel.x == a.right() - 1);                  // pinned to the last in-bounds column
    CHECK(plateauEnd.level == 0.7);               // still at sustain
    for (size_t i = 1; i < poly.size(); ++i) {
        CHECK(poly[i].x > poly[i - 1].x);                       // strictly monotonic
        CHECK(poly[i].x - poly[i - 1].x >= kGateNodeSepPx - 1); // min gaps survive compression
        CHECK(poly[i].x >= a.x && poly[i].x < a.right());      // in-bounds
    }
}

static void testGateAllVerticesInBounds() {
    // The FA2 bounds invariant, swept over representative param sets (including extremes): every
    // vertex of every polyline stays inside the canvas rect.
    const Rect a = wideArea();
    const AmpEnvelope base;   // defaults
    AmpEnvelope big = base;
    big.mode = EnvMode::Gate;
    big.attackSeconds = 4.0; big.holdSeconds = 4.0; big.decaySeconds = 4.0;
    big.sustainLevel = 1.0;  big.releaseSeconds = 4.0;
    AmpEnvelope zero = base;
    zero.mode = EnvMode::Gate;
    zero.attackSeconds = 0.0; zero.holdSeconds = 0.0; zero.decaySeconds = 0.0;
    zero.sustainLevel = 0.0;  zero.releaseSeconds = 0.0;
    AmpEnvelope trig = base;
    trig.mode = EnvMode::Trigger;
    trig.lengthFraction = 1.0; trig.fadeInFraction = 0.0; trig.fadeOutFraction = 0.0;
    // ABSURD stage values must clamp in double space, not overflow the integer cast (32-bit
    // long on Windows would wrap negative and land on the WRONG edge).
    AmpEnvelope huge = base;
    huge.mode = EnvMode::Gate;
    huge.releaseSeconds = 1e12;

    for (const AmpEnvelope& env : {base, big, zero, trig, huge}) {
        for (const EnvVertex& v : buildEnvelopePolyline(env, overlayOf(a), 2.0)) {
            CHECK(v.x >= a.x && v.x < a.right());
            CHECK(v.y >= a.y && v.y < a.bottom());
        }
    }
}

// --- Trigger polyline ---------------------------------------------------------

static void testTriggerShape() {
    // played span = length * total = 0.5 * 2.0 = 1.0s -> 500px wide. fadeIn .2 of play -> 0.2s
    // (x@100), fade-out .3 of play -> begins at 0.7s (x@350), playEnd at 1.0s (x@500).
    AmpEnvelope env;
    env.mode = EnvMode::Trigger;
    env.lengthFraction  = 0.5;
    env.fadeInFraction  = 0.2;
    env.fadeOutFraction = 0.3;
    const Rect a = wideArea();
    const std::vector<EnvVertex> poly = buildEnvelopePolyline(env, overlayOf(a), 2.0);

    CHECK(poly.size() == 4);
    CHECK(poly[0].node == EnvNode::Origin);
    CHECK(poly[1].node == EnvNode::FadeInEnd);
    CHECK(poly[2].node == EnvNode::FadeOutStart);
    CHECK(poly[3].node == EnvNode::LengthEnd);

    EnvVertex v;
    CHECK(findNode(poly, EnvNode::FadeInEnd, v)    && v.x == a.x + 100 && v.level == 1.0);
    CHECK(findNode(poly, EnvNode::FadeOutStart, v) && v.x == a.x + 350 && v.level == 1.0);
    CHECK(findNode(poly, EnvNode::LengthEnd, v)    && v.x == a.x + 500 && v.level == 0.0);
}

static void testTriggerFadeOverlapClamp() {
    // fadeIn + fadeOut > 1: the fade-out is trimmed so they meet exactly (no crossed nodes).
    AmpEnvelope env;
    env.mode = EnvMode::Trigger;
    env.lengthFraction  = 1.0;   // played span = full 2.0s -> 1000px
    env.fadeInFraction  = 0.8;   // fade-in end at 0.8*2.0 = 1.6s -> x@800
    env.fadeOutFraction = 0.6;   // would be 1.4s -> clamped to 1-0.8=0.2 -> begins at 0.8*2.0 too
    const Rect a = wideArea();
    const std::vector<EnvVertex> poly = buildEnvelopePolyline(env, overlayOf(a), 2.0);

    EnvVertex fin, fout;
    CHECK(findNode(poly, EnvNode::FadeInEnd, fin));
    CHECK(findNode(poly, EnvNode::FadeOutStart, fout));
    CHECK(fin.x == fout.x);   // fades meet exactly, never cross
    CHECK(fin.x == a.x + 800);
}

static void testTriggerFullLengthZeroFadeOutInBounds() {
    // The FA2 fix: at full length + zero fade-out, FadeOutStart and LengthEnd land AT the last
    // in-bounds column (right-1), NOT at the half-open right edge — so the shell draws their
    // handles and the fade-out node is grabbable even when fade-out == 0.
    AmpEnvelope env;
    env.mode = EnvMode::Trigger;
    env.lengthFraction  = 1.0;
    env.fadeInFraction  = 0.1;
    env.fadeOutFraction = 0.0;
    const Rect a = wideArea();
    const std::vector<EnvVertex> poly = buildEnvelopePolyline(env, overlayOf(a), 2.0);

    EnvVertex fout, lend;
    CHECK(findNode(poly, EnvNode::FadeOutStart, fout));
    CHECK(findNode(poly, EnvNode::LengthEnd, lend));
    CHECK(fout.x == a.right() - 1);   // present + in-bounds at zero fade-out
    CHECK(lend.x == a.right() - 1);
    CHECK(fout.level == 1.0 && lend.level == 0.0);
}

// --- Degenerate ---------------------------------------------------------------

static void testDegenerateFlatBaseline() {
    AmpEnvelope env;   // any params
    const Rect zeroW = Rect::ltrb(0, 0, 0, 100);
    const std::vector<EnvVertex> p1 = buildEnvelopePolyline(env, overlayOf(zeroW), 2.0);
    CHECK(p1.size() == 2);                       // always a drawable line
    CHECK(p1.front().level == 0.0 && p1.back().level == 0.0);

    const Rect ok = wideArea();
    const std::vector<EnvVertex> p2 = buildEnvelopePolyline(env, overlayOf(ok), 0.0);  // no duration
    CHECK(p2.size() == 2);
    CHECK(p2.front().level == 0.0 && p2.back().level == 0.0);
    CHECK(p2.front().x == ok.x && p2.back().x == ok.right() - 1);   // spans the area, in-bounds
}

int main() {
    testTimeToXEndpoints();
    testTimeToXNegativePinsLeft();
    testTimeToXPastEndClamps();
    testTimeToXDegenerate();
    testGateTimedWidth();
    testGatePxPerSecond();
    testLevelToYEndpoints();
    testLevelToYClamps();

    testGateNodeOrderAndLevels();
    testGateSchematicPlacement();
    testGateLayoutIndependentOfSampleDuration();
    testGateMinSeparationAtDefaults();
    testGateSustainPlateauFixedWidth();
    testGateReleaseVisibleInBounds();
    testGateOverrunCompressesFromRight();
    testGateAllVerticesInBounds();

    testTriggerShape();
    testTriggerFadeOverlapClamp();
    testTriggerFullLengthZeroFadeOutInBounds();

    testDegenerateFlatBaseline();

    if (g_fail == 0) std::printf("envelope_overlay: all tests passed\n");
    else std::printf("envelope_overlay: %d FAILED\n", g_fail);
    return g_fail == 0 ? 0 : 1;
}