skia2/tests/M44Test.cpp
Michael Ludwig 423990db1b Decrease w epsilon to avoid incorrect bounds calculations
Bug: skia:12335
Change-Id: I0106c30d875a7a88431a6e068a82d2d987fc62b9
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/438738
Commit-Queue: Florin Malita <fmalita@google.com>
Auto-Submit: Michael Ludwig <michaelludwig@google.com>
Reviewed-by: Florin Malita <fmalita@google.com>
2021-08-12 13:19:39 +00:00

361 lines
15 KiB
C++

/*
* Copyright 2020 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/SkM44.h"
#include "include/utils/SkRandom.h"
#include "src/core/SkMatrixPriv.h"
#include "tests/Test.h"
static bool eq(const SkM44& a, const SkM44& b, float tol) {
float fa[16], fb[16];
a.getColMajor(fa);
b.getColMajor(fb);
for (int i = 0; i < 16; ++i) {
if (!SkScalarNearlyEqual(fa[i], fb[i], tol)) {
return false;
}
}
return true;
}
DEF_TEST(M44, reporter) {
SkM44 m, im;
REPORTER_ASSERT(reporter, SkM44(1, 0, 0, 0,
0, 1, 0, 0,
0, 0, 1, 0,
0, 0, 0, 1) == m);
REPORTER_ASSERT(reporter, SkM44() == m);
REPORTER_ASSERT(reporter, m.invert(&im));
REPORTER_ASSERT(reporter, SkM44() == im);
m.setTranslate(3, 4, 2);
REPORTER_ASSERT(reporter, SkM44(1, 0, 0, 3,
0, 1, 0, 4,
0, 0, 1, 2,
0, 0, 0, 1) == m);
const float f[] = { 1, 0, 0, 2, 3, 1, 2, 5, 0, 5, 3, 0, 0, 1, 0, 2 };
m = SkM44::ColMajor(f);
REPORTER_ASSERT(reporter, SkM44(f[0], f[4], f[ 8], f[12],
f[1], f[5], f[ 9], f[13],
f[2], f[6], f[10], f[14],
f[3], f[7], f[11], f[15]) == m);
{
SkM44 t = m.transpose();
REPORTER_ASSERT(reporter, t != m);
REPORTER_ASSERT(reporter, t.rc(1,0) == m.rc(0,1));
SkM44 tt = t.transpose();
REPORTER_ASSERT(reporter, tt == m);
}
m = SkM44::RowMajor(f);
REPORTER_ASSERT(reporter, SkM44(f[ 0], f[ 1], f[ 2], f[ 3],
f[ 4], f[ 5], f[ 6], f[ 7],
f[ 8], f[ 9], f[10], f[14],
f[12], f[13], f[14], f[15]) == m);
REPORTER_ASSERT(reporter, m.invert(&im));
m = m * im;
// m should be identity now, but our calc is not perfect...
REPORTER_ASSERT(reporter, eq(SkM44(), m, 0.0000005f));
REPORTER_ASSERT(reporter, SkM44() != m);
}
DEF_TEST(M44_v3, reporter) {
SkV3 a = {1, 2, 3},
b = {1, 2, 2};
REPORTER_ASSERT(reporter, a.lengthSquared() == 1 + 4 + 9);
REPORTER_ASSERT(reporter, b.length() == 3);
REPORTER_ASSERT(reporter, a.dot(b) == 1 + 4 + 6);
REPORTER_ASSERT(reporter, b.dot(a) == 1 + 4 + 6);
REPORTER_ASSERT(reporter, (a.cross(b) == SkV3{-2, 1, 0}));
REPORTER_ASSERT(reporter, (b.cross(a) == SkV3{ 2, -1, 0}));
SkM44 m = {
2, 0, 0, 3,
0, 1, 0, 5,
0, 0, 3, 1,
0, 0, 0, 1
};
SkV3 c = m * a;
REPORTER_ASSERT(reporter, (c == SkV3{2, 2, 9}));
SkV4 d = m.map(4, 3, 2, 1);
REPORTER_ASSERT(reporter, (d == SkV4{11, 8, 7, 1}));
}
DEF_TEST(M44_v4, reporter) {
SkM44 m( 1, 2, 3, 4,
5, 6, 7, 8,
9, 10, 11, 12,
13, 14, 15, 16);
SkV4 r0 = m.row(0),
r1 = m.row(1),
r2 = m.row(2),
r3 = m.row(3);
REPORTER_ASSERT(reporter, (r0 == SkV4{ 1, 2, 3, 4}));
REPORTER_ASSERT(reporter, (r1 == SkV4{ 5, 6, 7, 8}));
REPORTER_ASSERT(reporter, (r2 == SkV4{ 9, 10, 11, 12}));
REPORTER_ASSERT(reporter, (r3 == SkV4{13, 14, 15, 16}));
REPORTER_ASSERT(reporter, SkM44::Rows(r0, r1, r2, r3) == m);
SkV4 c0 = m.col(0),
c1 = m.col(1),
c2 = m.col(2),
c3 = m.col(3);
REPORTER_ASSERT(reporter, (c0 == SkV4{1, 5, 9, 13}));
REPORTER_ASSERT(reporter, (c1 == SkV4{2, 6, 10, 14}));
REPORTER_ASSERT(reporter, (c2 == SkV4{3, 7, 11, 15}));
REPORTER_ASSERT(reporter, (c3 == SkV4{4, 8, 12, 16}));
REPORTER_ASSERT(reporter, SkM44::Cols(c0, c1, c2, c3) == m);
// implement matrix * vector using column vectors
SkV4 v = {1, 2, 3, 4};
SkV4 v1 = m * v;
SkV4 v2 = c0 * v.x + c1 * v.y + c2 * v.z + c3 * v.w;
REPORTER_ASSERT(reporter, v1 == v2);
REPORTER_ASSERT(reporter, (c0 + r0 == SkV4{c0.x+r0.x, c0.y+r0.y, c0.z+r0.z, c0.w+r0.w}));
REPORTER_ASSERT(reporter, (c0 - r0 == SkV4{c0.x-r0.x, c0.y-r0.y, c0.z-r0.z, c0.w-r0.w}));
REPORTER_ASSERT(reporter, (c0 * r0 == SkV4{c0.x*r0.x, c0.y*r0.y, c0.z*r0.z, c0.w*r0.w}));
}
DEF_TEST(M44_rotate, reporter) {
const SkV3 x = {1, 0, 0},
y = {0, 1, 0},
z = {0, 0, 1};
// We have radians version of setRotateAbout methods, but even with our best approx
// for PI, sin(SK_ScalarPI) != 0, so to make the comparisons in the unittest clear,
// I'm using the variants that explicitly take the sin,cos values.
struct {
SkScalar sinAngle, cosAngle;
SkV3 aboutAxis;
SkV3 expectedX, expectedY, expectedZ;
} recs[] = {
{ 0, 1, x, x, y, z}, // angle = 0
{ 0, 1, y, x, y, z}, // angle = 0
{ 0, 1, z, x, y, z}, // angle = 0
{ 0,-1, x, x,-y,-z}, // angle = 180
{ 0,-1, y, -x, y,-z}, // angle = 180
{ 0,-1, z, -x,-y, z}, // angle = 180
// Skia coordinate system is right-handed
{ 1, 0, x, x, z,-y}, // angle = 90
{ 1, 0, y, -z, y, x}, // angle = 90
{ 1, 0, z, y,-x, z}, // angle = 90
{-1, 0, x, x,-z, y}, // angle = -90
{-1, 0, y, z, y,-x}, // angle = -90
{-1, 0, z, -y, x, z}, // angle = -90
};
for (const auto& r : recs) {
SkM44 m(SkM44::kNaN_Constructor);
m.setRotateUnitSinCos(r.aboutAxis, r.sinAngle, r.cosAngle);
auto mx = m * x;
auto my = m * y;
auto mz = m * z;
REPORTER_ASSERT(reporter, mx == r.expectedX);
REPORTER_ASSERT(reporter, my == r.expectedY);
REPORTER_ASSERT(reporter, mz == r.expectedZ);
// flipping the axis-of-rotation should flip the results
mx = m * -x;
my = m * -y;
mz = m * -z;
REPORTER_ASSERT(reporter, mx == -r.expectedX);
REPORTER_ASSERT(reporter, my == -r.expectedY);
REPORTER_ASSERT(reporter, mz == -r.expectedZ);
}
}
DEF_TEST(M44_rectToRect, reporter) {
SkV2 dstScales[] = {
{1.f, 1.f}, // no aspect ratio change, nor up/down scaling
{0.25f, 0.5f}, // aspect ratio narrows, downscale x and y
{0.5f, 0.25f}, // aspect ratio widens, downscale x and y
{0.5f, 0.5f}, // no aspect ratio change, downscale x and y
{2.f, 3.f}, // aspect ratio narrows, upscale x and y
{3.f, 2.f}, // aspect ratio widens, upscale x and y
{2.f, 2.f}, // no aspect ratio change, upscale x and y
{0.5f, 2.f}, // aspect ratio narrows, downscale x and upscale y
{2.f, 0.5f} // aspect ratio widens, upscale x and downscale y
};
auto map2d = [&](const SkM44& m, SkV2 p) {
SkV4 mapped = m.map(p.x, p.y, 0.f, 1.f);
REPORTER_ASSERT(reporter, mapped.z == 0.f);
REPORTER_ASSERT(reporter, mapped.w == 1.f);
return SkV2{mapped.x, mapped.y};
};
auto assertNearlyEqual = [&](float actual, float expected) {
REPORTER_ASSERT(reporter, SkScalarNearlyEqual(actual, expected),
"Expected %g == %g", actual, expected);
};
auto assertEdges = [&](float actualLow, float actualHigh,
float expectedLow, float expectedHigh) {
SkASSERT(expectedLow < expectedHigh);
REPORTER_ASSERT(reporter, actualLow < actualHigh,
"Expected %g < %g", actualLow, actualHigh);
assertNearlyEqual(actualLow, expectedLow);
assertNearlyEqual(actualHigh, expectedHigh);
};
SkRandom rand;
for (const auto& r : dstScales) {
SkRect src = SkRect::MakeXYWH(rand.nextRangeF(-10.f, 10.f),
rand.nextRangeF(-10.f, 10.f),
rand.nextRangeF(1.f, 10.f),
rand.nextRangeF(1.f, 10.f));
SkRect dst = SkRect::MakeXYWH(rand.nextRangeF(-10.f, 10.f),
rand.nextRangeF(-10.f, 10.f),
r.x * src.width(),
r.y * src.height());
SkM44 m = SkM44::RectToRect(src, dst);
// Regardless of the factory, center of src maps to center of dst
SkV2 center = map2d(m, {src.centerX(), src.centerY()});
assertNearlyEqual(center.x, dst.centerX());
assertNearlyEqual(center.y, dst.centerY());
// Map the four corners of src and validate against expected edge mapping
SkV2 tl = map2d(m, {src.fLeft, src.fTop});
SkV2 tr = map2d(m, {src.fRight, src.fTop});
SkV2 br = map2d(m, {src.fRight, src.fBottom});
SkV2 bl = map2d(m, {src.fLeft, src.fBottom});
assertEdges(tl.x, tr.x, dst.fLeft, dst.fRight);
assertEdges(bl.x, br.x, dst.fLeft, dst.fRight);
assertEdges(tl.y, bl.y, dst.fTop, dst.fBottom);
assertEdges(tr.y, br.y, dst.fTop, dst.fBottom);
}
}
DEF_TEST(M44_mapRect, reporter) {
auto assertRectsNearlyEqual = [&](const SkRect& actual, const SkRect& expected,
const SkRect& e) {
REPORTER_ASSERT(reporter, SkScalarNearlyEqual(actual.fLeft, expected.fLeft, e.fLeft),
"Expected %g == %g", actual.fLeft, expected.fLeft);
REPORTER_ASSERT(reporter, SkScalarNearlyEqual(actual.fTop, expected.fTop, e.fTop),
"Expected %g == %g", actual.fTop, expected.fTop);
REPORTER_ASSERT(reporter, SkScalarNearlyEqual(actual.fRight, expected.fRight, e.fRight),
"Expected %g == %g", actual.fRight, expected.fRight);
REPORTER_ASSERT(reporter, SkScalarNearlyEqual(actual.fBottom, expected.fBottom, e.fBottom),
"Expected %g == %g", actual.fBottom, expected.fBottom);
};
auto assertMapRect = [&](const SkM44& m, const SkRect& src, const SkRect* expected) {
SkRect epsilon = {1e-5f, 1e-5f, 1e-5f, 1e-5f};
SkRect actual = SkMatrixPriv::MapRect(m, src);
REPORTER_ASSERT(reporter, !actual.isEmpty());
if (expected) {
assertRectsNearlyEqual(actual, *expected, epsilon);
}
SkV4 corners[4] = {{src.fLeft, src.fTop, 0.f, 1.f},
{src.fRight, src.fTop, 0.f, 1.f},
{src.fRight, src.fBottom, 0.f, 1.f},
{src.fLeft, src.fBottom, 0.f, 1.f}};
bool leftFound = false;
bool topFound = false;
bool rightFound = false;
bool bottomFound = false;
bool clipped = false;
for (int i = 0; i < 4; ++i) {
SkV4 mapped = m * corners[i];
if (mapped.w > 0.f) {
// Should be contained in actual and might be on one or two of actual's edges
float x = mapped.x / mapped.w;
float y = mapped.y / mapped.w;
// Can't use SkRect::contains() since it treats right and bottom edges as exclusive
REPORTER_ASSERT(reporter, actual.fLeft <= x && x <= actual.fRight,
"Expected %g contained in [%g, %g]",
x, actual.fLeft, actual.fRight);
REPORTER_ASSERT(reporter, actual.fTop <= y && y <= actual.fBottom,
"Expected %g contained in [%g, %g]",
y, actual.fTop, actual.fBottom);
leftFound |= SkScalarNearlyEqual(x, actual.fLeft);
topFound |= SkScalarNearlyEqual(y, actual.fTop);
rightFound |= SkScalarNearlyEqual(x, actual.fRight);
bottomFound |= SkScalarNearlyEqual(y, actual.fBottom);
} else {
// The mapped point would be clipped so the clipped mapped bounds don't necessarily
// contain it
clipped = true;
}
}
if (clipped) {
// At least one of the mapped corners should have contributed to the rect
REPORTER_ASSERT(reporter, leftFound || topFound || rightFound || bottomFound);
// For any edge that came from a clipped corner, increase its error tolerance relative
// to what SkPath::ApplyPerspectiveClip calculates.
// TODO(michaelludwig): skbug.com/12335 required updating the w epsilon distance which
// greatly increased noise for coords projecting to infinity. They aren't "wrong", since
// the intent was clearly to pick a big number that's definitely offscreen, but
// MapRect should have a more robust solution than a fixed w > epsilon and when it does,
// these expectations for clipped points should be more accurate.
if (!leftFound) { epsilon.fLeft = .01f * actual.fLeft; }
if (!topFound) { epsilon.fTop = .01f * actual.fTop; }
if (!rightFound) { epsilon.fRight = .01f * actual.fRight; }
if (!bottomFound) { epsilon.fBottom = .01f * actual.fBottom; }
} else {
// The mapped corners should have contributed to all four edges of the returned rect
REPORTER_ASSERT(reporter, leftFound && topFound && rightFound && bottomFound);
}
SkPath path = SkPath::Rect(src);
path.transform(m.asM33(), SkApplyPerspectiveClip::kYes);
assertRectsNearlyEqual(actual, path.getBounds(), epsilon);
};
// src chosen arbitrarily
const SkRect src = SkRect::MakeLTRB(4.83f, -0.48f, 5.53f, 30.68f);
// Identity maps src to src
assertMapRect(SkM44(), src, &src);
// Scale+Translate just offsets src
SkRect st = SkRect::MakeLTRB(10.f + 2.f * src.fLeft, 8.f + 4.f * src.fTop,
10.f + 2.f * src.fRight, 8.f + 4.f * src.fBottom);
assertMapRect(SkM44::Scale(2.f, 4.f).postTranslate(10.f, 8.f), src, &st);
// Rotate 45 degrees about center
assertMapRect(SkM44::Rotate({0.f, 0.f, 1.f}, SK_ScalarPI / 4.f)
.preTranslate(-src.centerX(), -src.centerY())
.postTranslate(src.centerX(), src.centerY()),
src, nullptr);
// Perspective matrix where src does not need to be clipped w > 0
SkM44 p = SkM44::Perspective(0.01f, 10.f, SK_ScalarPI / 3.f);
p.preTranslate(0.f, 5.f, -0.1f);
p.preConcat(SkM44::Rotate({0.f, 1.f, 0.f}, 0.008f /* radians */));
assertMapRect(p, src, nullptr);
// Perspective matrix where src *does* need to be clipped w > 0
p.setIdentity();
p.setRow(3, {-.2f, -.6f, 0.f, 8.f});
assertMapRect(p, src, nullptr);
}