cc/CCMathUtilTest.cpp

   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 "config.h"
   6
   7 #include "CCMathUtil.h"
   8
   9 #include "CCGeometryTestUtils.h"
  10 #include "FloatRect.h"
  11 #include "testing/gmock/include/gmock/gmock.h"
  12 #include "testing/gtest/include/gtest/gtest.h"
  13 #include <public/WebTransformationMatrix.h>
  14
  15 using namespace cc;
  16 using WebKit::WebTransformationMatrix;
  17
  18 namespace {
  19
  20 TEST(CCMathUtilTest, verifyBackfaceVisibilityBasicCases)
  21 {
  22     WebTransformationMatrix transform;
  23
  24     transform.makeIdentity();
  25     EXPECT_FALSE(transform.isBackFaceVisible());
  26
  27     transform.makeIdentity();
  28     transform.rotate3d(0, 80, 0);
  29     EXPECT_FALSE(transform.isBackFaceVisible());
  30
  31     transform.makeIdentity();
  32     transform.rotate3d(0, 100, 0);
  33     EXPECT_TRUE(transform.isBackFaceVisible());
  34
  35     // Edge case, 90 degree rotation should return false.
  36     transform.makeIdentity();
  37     transform.rotate3d(0, 90, 0);
  38     EXPECT_FALSE(transform.isBackFaceVisible());
  39 }
  40
  41 TEST(CCMathUtilTest, verifyBackfaceVisibilityForPerspective)
  42 {
  43     WebTransformationMatrix layerSpaceToProjectionPlane;
  44
  45     // This tests if isBackFaceVisible works properly under perspective transforms.
  46     // Specifically, layers that may have their back face visible in orthographic
  47     // projection, may not actually have back face visible under perspective projection.
  48
  49     // Case 1: Layer is rotated by slightly more than 90 degrees, at the center of the
  50     //         prespective projection. In this case, the layer's back-side is visible to
  51     //         the camera.
  52     layerSpaceToProjectionPlane.makeIdentity();
  53     layerSpaceToProjectionPlane.applyPerspective(1);
  54     layerSpaceToProjectionPlane.translate3d(0, 0, 0);
  55     layerSpaceToProjectionPlane.rotate3d(0, 100, 0);
  56     EXPECT_TRUE(layerSpaceToProjectionPlane.isBackFaceVisible());
  57
  58     // Case 2: Layer is rotated by slightly more than 90 degrees, but shifted off to the
  59     //         side of the camera. Because of the wide field-of-view, the layer's front
  60     //         side is still visible.
  61     //
  62     //                       |<-- front side of layer is visible to perspective camera
  63     //                    \  |            /
  64     //                     \ |           /
  65     //                      \|          /
  66     //                       |         /
  67     //                       |\       /<-- camera field of view
  68     //                       | \     /
  69     // back side of layer -->|  \   /
  70     //                           \./ <-- camera origin
  71     //
  72     layerSpaceToProjectionPlane.makeIdentity();
  73     layerSpaceToProjectionPlane.applyPerspective(1);
  74     layerSpaceToProjectionPlane.translate3d(-10, 0, 0);
  75     layerSpaceToProjectionPlane.rotate3d(0, 100, 0);
  76     EXPECT_FALSE(layerSpaceToProjectionPlane.isBackFaceVisible());
  77
  78     // Case 3: Additionally rotating the layer by 180 degrees should of course show the
  79     //         opposite result of case 2.
  80     layerSpaceToProjectionPlane.rotate3d(0, 180, 0);
  81     EXPECT_TRUE(layerSpaceToProjectionPlane.isBackFaceVisible());
  82 }
  83
  84 TEST(CCMathUtilTest, verifyProjectionOfPerpendicularPlane)
  85 {
  86     // In this case, the m33() element of the transform becomes zero, which could cause a
  87     // divide-by-zero when projecting points/quads.
  88
  89     WebTransformationMatrix transform;
  90     transform.makeIdentity();
  91     transform.setM33(0);
  92
  93     FloatRect rect = FloatRect(0, 0, 1, 1);
  94     FloatRect projectedRect = CCMathUtil::projectClippedRect(transform, rect);
  95
  96     EXPECT_EQ(0, projectedRect.x());
  97     EXPECT_EQ(0, projectedRect.y());
  98     EXPECT_TRUE(projectedRect.isEmpty());
  99 }
 100
 101 TEST(CCMathUtilTest, verifyEnclosingClippedRectUsesCorrectInitialBounds)
 102 {
 103     HomogeneousCoordinate h1(-100, -100, 0, 1);
 104     HomogeneousCoordinate h2(-10, -10, 0, 1);
 105     HomogeneousCoordinate h3(10, 10, 0, -1);
 106     HomogeneousCoordinate h4(100, 100, 0, -1);
 107
 108     // The bounds of the enclosing clipped rect should be -100 to -10 for both x and y.
 109     // However, if there is a bug where the initial xmin/xmax/ymin/ymax are initialized to
 110     // numeric_limits<float>::min() (which is zero, not -flt_max) then the enclosing
 111     // clipped rect will be computed incorrectly.
 112     FloatRect result = CCMathUtil::computeEnclosingClippedRect(h1, h2, h3, h4);
 113
 114     EXPECT_FLOAT_RECT_EQ(FloatRect(FloatPoint(-100, -100), FloatSize(90, 90)), result);
 115 }
 116
 117 TEST(CCMathUtilTest, verifyEnclosingRectOfVerticesUsesCorrectInitialBounds)
 118 {
 119     FloatPoint vertices[3];
 120     int numVertices = 3;
 121
 122     vertices[0] = FloatPoint(-10, -100);
 123     vertices[1] = FloatPoint(-100, -10);
 124     vertices[2] = FloatPoint(-30, -30);
 125
 126     // The bounds of the enclosing rect should be -100 to -10 for both x and y. However,
 127     // if there is a bug where the initial xmin/xmax/ymin/ymax are initialized to
 128     // numeric_limits<float>::min() (which is zero, not -flt_max) then the enclosing
 129     // clipped rect will be computed incorrectly.
 130     FloatRect result = CCMathUtil::computeEnclosingRectOfVertices(vertices, numVertices);
 131
 132     EXPECT_FLOAT_RECT_EQ(FloatRect(FloatPoint(-100, -100), FloatSize(90, 90)), result);
 133 }
 134
 135 TEST(CCMathUtilTest, smallestAngleBetweenVectors)
 136 {
 137     FloatSize x(1, 0);
 138     FloatSize y(0, 1);
 139     FloatSize testVector(0.5, 0.5);
 140
 141     // Orthogonal vectors are at an angle of 90 degress.
 142     EXPECT_EQ(90, CCMathUtil::smallestAngleBetweenVectors(x, y));
 143
 144     // A vector makes a zero angle with itself.
 145     EXPECT_EQ(0, CCMathUtil::smallestAngleBetweenVectors(x, x));
 146     EXPECT_EQ(0, CCMathUtil::smallestAngleBetweenVectors(y, y));
 147     EXPECT_EQ(0, CCMathUtil::smallestAngleBetweenVectors(testVector, testVector));
 148
 149     // Parallel but reversed vectors are at 180 degrees.
 150     EXPECT_FLOAT_EQ(180, CCMathUtil::smallestAngleBetweenVectors(x, -x));
 151     EXPECT_FLOAT_EQ(180, CCMathUtil::smallestAngleBetweenVectors(y, -y));
 152     EXPECT_FLOAT_EQ(180, CCMathUtil::smallestAngleBetweenVectors(testVector, -testVector));
 153
 154     // The test vector is at a known angle.
 155     EXPECT_FLOAT_EQ(45, floor(CCMathUtil::smallestAngleBetweenVectors(testVector, x)));
 156     EXPECT_FLOAT_EQ(45, floor(CCMathUtil::smallestAngleBetweenVectors(testVector, y)));
 157 }
 158
 159 TEST(CCMathUtilTest, vectorProjection)
 160 {
 161     FloatSize x(1, 0);
 162     FloatSize y(0, 1);
 163     FloatSize testVector(0.3f, 0.7f);
 164
 165     // Orthogonal vectors project to a zero vector.
 166     EXPECT_EQ(FloatSize(0, 0), CCMathUtil::projectVector(x, y));
 167     EXPECT_EQ(FloatSize(0, 0), CCMathUtil::projectVector(y, x));
 168
 169     // Projecting a vector onto the orthonormal basis gives the corresponding component of the
 170     // vector.
 171     EXPECT_EQ(FloatSize(testVector.width(), 0), CCMathUtil::projectVector(testVector, x));
 172     EXPECT_EQ(FloatSize(0, testVector.height()), CCMathUtil::projectVector(testVector, y));
 173
 174     // Finally check than an arbitrary vector projected to another one gives a vector parallel to
 175     // the second vector.
 176     FloatSize targetVector(0.5, 0.2f);
 177     FloatSize projectedVector = CCMathUtil::projectVector(testVector, targetVector);
 178     EXPECT_EQ(projectedVector.width() / targetVector.width(),
 179               projectedVector.height() / targetVector.height());
 180 }
 181
 182 } // namespace