tests/ShadowTest.cpp

/*
 * Copyright 2017 Google Inc.
 *
 * Use of this source code is governed by a BSD-style license that can be
 * found in the LICENSE file.
 */

#include "include/core/SkCanvas.h"
#include "include/core/SkMatrix.h"
#include "include/core/SkPath.h"
#include "include/core/SkPathBuilder.h"
#include "include/core/SkPoint.h"
#include "include/core/SkPoint3.h"
#include "include/core/SkRRect.h"
#include "include/core/SkRect.h"
#include "include/core/SkRefCnt.h"
#include "include/core/SkScalar.h"
#include "include/core/SkTypes.h"
#include "include/core/SkVertices.h"
#include "include/private/base/SkTo.h"
#include "include/utils/SkShadowUtils.h"
#include "src/core/SkDrawShadowInfo.h"
#include "src/core/SkVerticesPriv.h"
#include "src/utils/SkShadowTessellator.h"
#include "tests/Test.h"

#if !defined(SK_ENABLE_OPTIMIZE_SIZE)

enum ExpectVerts {
    kDont_ExpectVerts,
    kDo_ExpectVerts
};

void check_result(skiatest::Reporter* reporter, sk_sp<SkVertices> verts, ExpectVerts expectVerts) {
    const bool expectSuccess = expectVerts == kDo_ExpectVerts;
    if (expectSuccess != SkToBool(verts)) {
        ERRORF(reporter, "Expected shadow tessellation to %s but it did not.",
               expectSuccess ? "succeed" : "fail");
    }
    if (SkToBool(verts)) {
        if (kDont_ExpectVerts == expectVerts && verts->priv().vertexCount()) {
            ERRORF(reporter, "Expected shadow tessellation to generate no vertices but it did.");
        } else if (kDo_ExpectVerts == expectVerts && !verts->priv().vertexCount()) {
            ERRORF(reporter, "Expected shadow tessellation to generate vertices but it didn't.");
        }
    }
}

void tessellate_shadow(skiatest::Reporter* reporter, const SkPath& path, const SkMatrix& ctm,
                       const SkPoint3& heightParams, ExpectVerts expectVerts) {

    auto verts = SkShadowTessellator::MakeAmbient(path, ctm, heightParams, true);
    check_result(reporter, verts, expectVerts);

    verts = SkShadowTessellator::MakeAmbient(path, ctm, heightParams, false);
    check_result(reporter, verts, expectVerts);

    verts = SkShadowTessellator::MakeSpot(path, ctm, heightParams, {0, 0, 128}, 128.f, true, false);
    check_result(reporter, verts, expectVerts);

    verts = SkShadowTessellator::MakeSpot(path, ctm, heightParams, {0, 0, 128}, 128.f, false,
                                          false);
    check_result(reporter, verts, expectVerts);

    verts = SkShadowTessellator::MakeSpot(path, ctm, heightParams, {0, 0, 128}, 128.f, true, true);
    check_result(reporter, verts, expectVerts);

    verts = SkShadowTessellator::MakeSpot(path, ctm, heightParams, {0, 0, 128}, 128.f, false, true);
    check_result(reporter, verts, expectVerts);
}

DEF_TEST(ShadowUtils, reporter) {
    SkCanvas canvas(100, 100);

    SkPath path = SkPathBuilder().cubicTo(100, 50, 20, 100, 0, 0).detach();
    tessellate_shadow(reporter, path, canvas.getTotalMatrix(), {0, 0, 4}, kDo_ExpectVerts);
    // super high path
    tessellate_shadow(reporter, path, canvas.getTotalMatrix(), {0, 0, 4.0e+37f}, kDo_ExpectVerts);

    // This line segment has no area and no shadow.
    path = SkPathBuilder().lineTo(10.f, 10.f).detach();
    tessellate_shadow(reporter, path, canvas.getTotalMatrix(), {0, 0, 4}, kDont_ExpectVerts);

    // A series of collinear line segments
    SkPathBuilder builder;
    for (int i = 0; i < 10; ++i) {
        builder.lineTo((SkScalar)i, (SkScalar)i);
    }
    tessellate_shadow(reporter, builder.detach(), canvas.getTotalMatrix(),
                      {0, 0, 4}, kDont_ExpectVerts);

    // ugly degenerate path
    path = SkPathBuilder()
           .moveTo(-134217728, 2.22265153e+21f)
           .cubicTo(-2.33326106e+21f, 7.36298265e-41f, 3.72237738e-22f, 5.99502692e-36f,
                     1.13631943e+22f, 2.0890786e+33f)
           .cubicTo(1.03397626e-25f, 5.99502692e-36f, 9.18354962e-41f, 0,
                    4.6142745e-37f, -213558848)
           .lineTo(-134217728, 2.2226515e+21f)
           .detach();
    tessellate_shadow(reporter, path, canvas.getTotalMatrix(), {0, 0, 9}, kDont_ExpectVerts);

    // simple concave path (star of David)
    path = SkPathBuilder()
           .moveTo(0.0f, -50.0f)
           .lineTo(14.43f, -25.0f)
           .lineTo(43.30f, -25.0f)
           .lineTo(28.86f, 0.0f)
           .lineTo(43.30f, 25.0f)
           .lineTo(14.43f, 25.0f)
           .lineTo(0.0f, 50.0f)
           .lineTo(-14.43f, 25.0f)
           .lineTo(-43.30f, 25.0f)
           .lineTo(-28.86f, 0.0f)
           .lineTo(-43.30f, -25.0f)
           .lineTo(-14.43f, -25.0f)
           .detach();
// uncomment when transparent concave shadows are working
//    tessellate_shadow(reporter, path, canvas.getTotalMatrix(), {0, 0, 9}, kDo_ExpectVerts, true);

    // complex concave path (bowtie)
    builder.reset()
           .moveTo(-50, -50)
           .lineTo(-50, 50)
           .lineTo(50, -50)
           .lineTo(50, 50)
           .lineTo(-50, -50);
    tessellate_shadow(reporter, builder.snapshot(), canvas.getTotalMatrix(),
                      {0, 0, 9}, kDont_ExpectVerts);

    // multiple contour path
    path = builder
           .close()
           .moveTo(0, 0)
           .lineTo(1, 0)
           .lineTo(0, 1)
           .detach();
    tessellate_shadow(reporter, path, canvas.getTotalMatrix(), {0, 0, 9}, kDont_ExpectVerts);
}

void check_xformed_bounds(skiatest::Reporter* reporter, const SkPath& path, const SkMatrix& ctm) {
    SkDrawShadowRec rec = {
        SkPoint3::Make(0, 0, 4),
        SkPoint3::Make(100, 0, 600),
        800.f,
        0x08000000,
        0x40000000,
        0
    };
    // point light
    SkRect bounds;
    SkDrawShadowMetrics::GetLocalBounds(path, rec, ctm, &bounds);
    ctm.mapRect(&bounds);

    auto verts = SkShadowTessellator::MakeAmbient(path, ctm, rec.fZPlaneParams, true);
    if (verts) {
        REPORTER_ASSERT(reporter, bounds.contains(verts->bounds()));
    }

    SkPoint mapXY = ctm.mapPoint({rec.fLightPos.fX, rec.fLightPos.fY});
    SkPoint3 devLightPos = SkPoint3::Make(mapXY.fX, mapXY.fY, rec.fLightPos.fZ);
    verts = SkShadowTessellator::MakeSpot(path, ctm, rec.fZPlaneParams, devLightPos,
                                          rec.fLightRadius, false, false);
    if (verts) {
        REPORTER_ASSERT(reporter, bounds.contains(verts->bounds()));
    }

    // directional light
    rec.fFlags |= SkShadowFlags::kDirectionalLight_ShadowFlag;
    rec.fLightRadius = 2.0f;
    SkDrawShadowMetrics::GetLocalBounds(path, rec, ctm, &bounds);
    ctm.mapRect(&bounds);

    verts = SkShadowTessellator::MakeAmbient(path, ctm, rec.fZPlaneParams, true);
    if (verts) {
        REPORTER_ASSERT(reporter, bounds.contains(verts->bounds()));
    }

    devLightPos = rec.fLightPos;
    devLightPos.normalize();
    verts = SkShadowTessellator::MakeSpot(path, ctm, rec.fZPlaneParams, devLightPos,
                                          rec.fLightRadius, false, true);
    if (verts) {
        REPORTER_ASSERT(reporter, bounds.contains(verts->bounds()));
    }
}

void check_bounds(skiatest::Reporter* reporter, const SkPath& path) {
    const bool fixed_shadows_in_perspective = false;    // skbug.com/40041026

    SkMatrix ctm;
    ctm.setTranslate(100, 100);
    check_xformed_bounds(reporter, path, ctm);
    ctm.postScale(2, 2);
    check_xformed_bounds(reporter, path, ctm);
    ctm.preRotate(45);
    check_xformed_bounds(reporter, path, ctm);
    ctm.preSkew(40, -20);
    check_xformed_bounds(reporter, path, ctm);
    if (fixed_shadows_in_perspective) {
        ctm[SkMatrix::kMPersp0] = 0.0001f;
        ctm[SkMatrix::kMPersp1] = 12.f;
        check_xformed_bounds(reporter, path, ctm);
        ctm[SkMatrix::kMPersp0] = 0.0001f;
        ctm[SkMatrix::kMPersp1] = -12.f;
        check_xformed_bounds(reporter, path, ctm);
        ctm[SkMatrix::kMPersp0] = 12.f;
        ctm[SkMatrix::kMPersp1] = 0.0001f;
        check_xformed_bounds(reporter, path, ctm);
    }
}

DEF_TEST(ShadowBounds, reporter) {
    SkPath path = SkPath::RRect(SkRRect::MakeRectXY(SkRect::MakeLTRB(-50, -20, 40, 30), 4, 4));
    check_bounds(reporter, path);

    path = SkPath::Oval(SkRect::MakeLTRB(300, 300, 900, 900));
    check_bounds(reporter, path);

    path = SkPathBuilder().cubicTo(100, 50, 20, 100, 0, 0).detach();
    check_bounds(reporter, path);
}

#endif // !defined(SK_ENABLE_OPTIMIZE_SIZE)