cc/base/math_util_unittest.cc

   1 // Copyright 2012 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #include "cc/base/math_util.h"
   6
   7 #include <cmath>
   8
   9 #include "cc/test/geometry_test_utils.h"
  10 #include "testing/gmock/include/gmock/gmock.h"
  11 #include "testing/gtest/include/gtest/gtest.h"
  12 #include "ui/gfx/geometry/rect.h"
  13 #include "ui/gfx/geometry/rect_f.h"
  14 #include "ui/gfx/transform.h"
  15
  16 namespace cc {
  17 namespace {
  18
  19 TEST(MathUtilTest, ProjectionOfPerpendicularPlane) {
  20   // In this case, the m33() element of the transform becomes zero, which could
  21   // cause a divide-by-zero when projecting points/quads.
  22
  23   gfx::Transform transform;
  24   transform.MakeIdentity();
  25   transform.matrix().set(2, 2, 0);
  26
  27   gfx::RectF rect = gfx::RectF(0, 0, 1, 1);
  28   gfx::RectF projected_rect = MathUtil::ProjectClippedRect(transform, rect);
  29
  30   EXPECT_EQ(0, projected_rect.x());
  31   EXPECT_EQ(0, projected_rect.y());
  32   EXPECT_TRUE(projected_rect.IsEmpty());
  33 }
  34
  35 TEST(MathUtilTest, ProjectionOfAlmostPerpendicularPlane) {
  36   // In this case, the m33() element of the transform becomes almost zero, which
  37   // could cause a divide-by-zero when projecting points/quads.
  38
  39   gfx::Transform transform;
  40   // The transform is from an actual test page:
  41   // [ +1.0000 +0.0000 -1.0000 +3144132.0000
  42   //   +0.0000 +1.0000 +0.0000 +0.0000
  43   //   +16331238407143424.0000 +0.0000 -0.0000 +51346917453137000267776.0000
  44   //   +0.0000 +0.0000 +0.0000 +1.0000 ]
  45   transform.MakeIdentity();
  46   transform.matrix().set(0, 2, static_cast<SkMScalar>(-1));
  47   transform.matrix().set(0, 3, static_cast<SkMScalar>(3144132.0));
  48   transform.matrix().set(2, 0, static_cast<SkMScalar>(16331238407143424.0));
  49   transform.matrix().set(2, 2, static_cast<SkMScalar>(-1e-33));
  50   transform.matrix().set(2, 3,
  51                          static_cast<SkMScalar>(51346917453137000267776.0));
  52
  53   gfx::RectF rect = gfx::RectF(0, 0, 1, 1);
  54   gfx::RectF projected_rect = MathUtil::ProjectClippedRect(transform, rect);
  55
  56   EXPECT_EQ(0, projected_rect.x());
  57   EXPECT_EQ(0, projected_rect.y());
  58   EXPECT_TRUE(projected_rect.IsEmpty()) << projected_rect.ToString();
  59 }
  60
  61 TEST(MathUtilTest, EnclosingClippedRectUsesCorrectInitialBounds) {
  62   HomogeneousCoordinate h1(-100, -100, 0, 1);
  63   HomogeneousCoordinate h2(-10, -10, 0, 1);
  64   HomogeneousCoordinate h3(10, 10, 0, -1);
  65   HomogeneousCoordinate h4(100, 100, 0, -1);
  66
  67   // The bounds of the enclosing clipped rect should be -100 to -10 for both x
  68   // and y. However, if there is a bug where the initial xmin/xmax/ymin/ymax are
  69   // initialized to numeric_limits<float>::min() (which is zero, not -flt_max)
  70   // then the enclosing clipped rect will be computed incorrectly.
  71   gfx::RectF result = MathUtil::ComputeEnclosingClippedRect(h1, h2, h3, h4);
  72
  73   // Due to floating point math in ComputeClippedPointForEdge this result
  74   // is fairly imprecise.  0.15f was empirically determined.
  75   EXPECT_RECT_NEAR(
  76       gfx::RectF(gfx::PointF(-100, -100), gfx::SizeF(90, 90)), result, 0.15f);
  77 }
  78
  79 TEST(MathUtilTest, EnclosingRectOfVerticesUsesCorrectInitialBounds) {
  80   gfx::PointF vertices[3];
  81   int num_vertices = 3;
  82
  83   vertices[0] = gfx::PointF(-10, -100);
  84   vertices[1] = gfx::PointF(-100, -10);
  85   vertices[2] = gfx::PointF(-30, -30);
  86
  87   // The bounds of the enclosing rect should be -100 to -10 for both x and y.
  88   // However, if there is a bug where the initial xmin/xmax/ymin/ymax are
  89   // initialized to numeric_limits<float>::min() (which is zero, not -flt_max)
  90   // then the enclosing clipped rect will be computed incorrectly.
  91   gfx::RectF result =
  92       MathUtil::ComputeEnclosingRectOfVertices(vertices, num_vertices);
  93
  94   EXPECT_FLOAT_RECT_EQ(gfx::RectF(gfx::PointF(-100, -100), gfx::SizeF(90, 90)),
  95                        result);
  96 }
  97
  98 TEST(MathUtilTest, SmallestAngleBetweenVectors) {
  99   gfx::Vector2dF x(1, 0);
 100   gfx::Vector2dF y(0, 1);
 101   gfx::Vector2dF test_vector(0.5, 0.5);
 102
 103   // Orthogonal vectors are at an angle of 90 degress.
 104   EXPECT_EQ(90, MathUtil::SmallestAngleBetweenVectors(x, y));
 105
 106   // A vector makes a zero angle with itself.
 107   EXPECT_EQ(0, MathUtil::SmallestAngleBetweenVectors(x, x));
 108   EXPECT_EQ(0, MathUtil::SmallestAngleBetweenVectors(y, y));
 109   EXPECT_EQ(0, MathUtil::SmallestAngleBetweenVectors(test_vector, test_vector));
 110
 111   // Parallel but reversed vectors are at 180 degrees.
 112   EXPECT_FLOAT_EQ(180, MathUtil::SmallestAngleBetweenVectors(x, -x));
 113   EXPECT_FLOAT_EQ(180, MathUtil::SmallestAngleBetweenVectors(y, -y));
 114   EXPECT_FLOAT_EQ(
 115       180, MathUtil::SmallestAngleBetweenVectors(test_vector, -test_vector));
 116
 117   // The test vector is at a known angle.
 118   EXPECT_FLOAT_EQ(
 119       45, std::floor(MathUtil::SmallestAngleBetweenVectors(test_vector, x)));
 120   EXPECT_FLOAT_EQ(
 121       45, std::floor(MathUtil::SmallestAngleBetweenVectors(test_vector, y)));
 122 }
 123
 124 TEST(MathUtilTest, VectorProjection) {
 125   gfx::Vector2dF x(1, 0);
 126   gfx::Vector2dF y(0, 1);
 127   gfx::Vector2dF test_vector(0.3f, 0.7f);
 128
 129   // Orthogonal vectors project to a zero vector.
 130   EXPECT_VECTOR_EQ(gfx::Vector2dF(0, 0), MathUtil::ProjectVector(x, y));
 131   EXPECT_VECTOR_EQ(gfx::Vector2dF(0, 0), MathUtil::ProjectVector(y, x));
 132
 133   // Projecting a vector onto the orthonormal basis gives the corresponding
 134   // component of the vector.
 135   EXPECT_VECTOR_EQ(gfx::Vector2dF(test_vector.x(), 0),
 136                    MathUtil::ProjectVector(test_vector, x));
 137   EXPECT_VECTOR_EQ(gfx::Vector2dF(0, test_vector.y()),
 138                    MathUtil::ProjectVector(test_vector, y));
 139
 140   // Finally check than an arbitrary vector projected to another one gives a
 141   // vector parallel to the second vector.
 142   gfx::Vector2dF target_vector(0.5, 0.2f);
 143   gfx::Vector2dF projected_vector =
 144       MathUtil::ProjectVector(test_vector, target_vector);
 145   EXPECT_EQ(projected_vector.x() / target_vector.x(),
 146             projected_vector.y() / target_vector.y());
 147 }
 148
 149 TEST(MathUtilTest, MapEnclosedRectWith2dAxisAlignedTransform) {
 150   gfx::Rect input(1, 2, 3, 4);
 151   gfx::Rect output;
 152   gfx::Transform transform;
 153
 154   // Identity.
 155   output =
 156       MathUtil::MapEnclosedRectWith2dAxisAlignedTransform(transform, input);
 157   EXPECT_EQ(input, output);
 158
 159   // Integer translate.
 160   transform.Translate(2.0, 3.0);
 161   output =
 162       MathUtil::MapEnclosedRectWith2dAxisAlignedTransform(transform, input);
 163   EXPECT_EQ(gfx::Rect(3, 5, 3, 4), output);
 164
 165   // Non-integer translate.
 166   transform.Translate(0.5, 0.5);
 167   output =
 168       MathUtil::MapEnclosedRectWith2dAxisAlignedTransform(transform, input);
 169   EXPECT_EQ(gfx::Rect(4, 6, 2, 3), output);
 170
 171   // Scale.
 172   transform = gfx::Transform();
 173   transform.Scale(2.0, 3.0);
 174   output =
 175       MathUtil::MapEnclosedRectWith2dAxisAlignedTransform(transform, input);
 176   EXPECT_EQ(gfx::Rect(2, 6, 6, 12), output);
 177
 178   // Rotate Z.
 179   transform = gfx::Transform();
 180   transform.Translate(1.0, 2.0);
 181   transform.RotateAboutZAxis(90.0);
 182   transform.Translate(-1.0, -2.0);
 183   output =
 184       MathUtil::MapEnclosedRectWith2dAxisAlignedTransform(transform, input);
 185   EXPECT_EQ(gfx::Rect(-3, 2, 4, 3), output);
 186
 187   // Rotate X.
 188   transform = gfx::Transform();
 189   transform.RotateAboutXAxis(90.0);
 190   output =
 191       MathUtil::MapEnclosedRectWith2dAxisAlignedTransform(transform, input);
 192   EXPECT_TRUE(output.IsEmpty());
 193
 194   transform = gfx::Transform();
 195   transform.RotateAboutXAxis(180.0);
 196   output =
 197       MathUtil::MapEnclosedRectWith2dAxisAlignedTransform(transform, input);
 198   EXPECT_EQ(gfx::Rect(1, -6, 3, 4), output);
 199
 200   // Rotate Y.
 201   transform = gfx::Transform();
 202   transform.RotateAboutYAxis(90.0);
 203   output =
 204       MathUtil::MapEnclosedRectWith2dAxisAlignedTransform(transform, input);
 205   EXPECT_TRUE(output.IsEmpty());
 206
 207   transform = gfx::Transform();
 208   transform.RotateAboutYAxis(180.0);
 209   output =
 210       MathUtil::MapEnclosedRectWith2dAxisAlignedTransform(transform, input);
 211   EXPECT_EQ(gfx::Rect(-4, 2, 3, 4), output);
 212
 213   // Translate Z.
 214   transform = gfx::Transform();
 215   transform.ApplyPerspectiveDepth(10.0);
 216   transform.Translate3d(0.0, 0.0, 5.0);
 217   output =
 218       MathUtil::MapEnclosedRectWith2dAxisAlignedTransform(transform, input);
 219   EXPECT_EQ(gfx::Rect(2, 4, 6, 8), output);
 220 }
 221
 222 TEST(MathUtilTest, RoundUp) {
 223   for (int multiplier = 1; multiplier <= 10; ++multiplier) {
 224     // Try attempts in descending order, so that we can
 225     // determine the correct value before it's needed.
 226     int correct;
 227     for (int attempt = 5 * multiplier; attempt >= -5 * multiplier; --attempt) {
 228       if ((attempt % multiplier) == 0)
 229         correct = attempt;
 230       EXPECT_EQ(correct, MathUtil::UncheckedRoundUp(attempt, multiplier))
 231           << "attempt=" << attempt << " multiplier=" << multiplier;
 232     }
 233   }
 234
 235   for (unsigned multiplier = 1; multiplier <= 10; ++multiplier) {
 236     // Try attempts in descending order, so that we can
 237     // determine the correct value before it's needed.
 238     unsigned correct;
 239     for (unsigned attempt = 5 * multiplier; attempt > 0; --attempt) {
 240       if ((attempt % multiplier) == 0)
 241         correct = attempt;
 242       EXPECT_EQ(correct, MathUtil::UncheckedRoundUp(attempt, multiplier))
 243           << "attempt=" << attempt << " multiplier=" << multiplier;
 244     }
 245     EXPECT_EQ(0u, MathUtil::UncheckedRoundUp(0u, multiplier))
 246         << "attempt=0 multiplier=" << multiplier;
 247   }
 248 }
 249
 250 TEST(MathUtilTest, RoundUpOverflow) {
 251   // Rounding up 123 by 50 is 150, which overflows int8_t, but fits in uint8_t.
 252   EXPECT_FALSE(MathUtil::VerifyRoundup<int8_t>(123, 50));
 253   EXPECT_TRUE(MathUtil::VerifyRoundup<uint8_t>(123, 50));
 254 }
 255
 256 TEST(MathUtilTest, RoundDown) {
 257   for (int multiplier = 1; multiplier <= 10; ++multiplier) {
 258     // Try attempts in ascending order, so that we can
 259     // determine the correct value before it's needed.
 260     int correct;
 261     for (int attempt = -5 * multiplier; attempt <= 5 * multiplier; ++attempt) {
 262       if ((attempt % multiplier) == 0)
 263         correct = attempt;
 264       EXPECT_EQ(correct, MathUtil::UncheckedRoundDown(attempt, multiplier))
 265           << "attempt=" << attempt << " multiplier=" << multiplier;
 266     }
 267   }
 268
 269   for (unsigned multiplier = 1; multiplier <= 10; ++multiplier) {
 270     // Try attempts in ascending order, so that we can
 271     // determine the correct value before it's needed.
 272     unsigned correct;
 273     for (unsigned attempt = 0; attempt <= 5 * multiplier; ++attempt) {
 274       if ((attempt % multiplier) == 0)
 275         correct = attempt;
 276       EXPECT_EQ(correct, MathUtil::UncheckedRoundDown(attempt, multiplier))
 277           << "attempt=" << attempt << " multiplier=" << multiplier;
 278     }
 279   }
 280 }
 281
 282 TEST(MathUtilTest, RoundDownUnderflow) {
 283   // Rounding down -123 by 50 is -150, which underflows int8_t, but fits in
 284   // int16_t.
 285   EXPECT_FALSE(MathUtil::VerifyRoundDown<int8_t>(-123, 50));
 286   EXPECT_TRUE(MathUtil::VerifyRoundDown<int16_t>(-123, 50));
 287 }
 288
 289 }  // namespace
 290 }  // namespace cc