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/*
* Copyright 2011 Google Inc.
*
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*/
// Unit tests for src/core/SkPoint.cpp and its header
#include "SkPoint.h"
#include "SkRect.h"
#include "Test.h"
static void test_casts(skiatest::Reporter* reporter) {
SkPoint p = { 0, 0 };
SkRect r = { 0, 0, 0, 0 };
const SkScalar* pPtr = SkTCast<const SkScalar*>(&p);
const SkScalar* rPtr = SkTCast<const SkScalar*>(&r);
REPORTER_ASSERT(reporter, p.asScalars() == pPtr);
REPORTER_ASSERT(reporter, r.asScalars() == rPtr);
}
// Tests SkPoint::Normalize() for this (x,y)
static void test_Normalize(skiatest::Reporter* reporter,
SkScalar x, SkScalar y) {
SkPoint point;
point.set(x, y);
SkScalar oldLength = point.length();
SkScalar returned = SkPoint::Normalize(&point);
SkScalar newLength = point.length();
REPORTER_ASSERT(reporter, SkScalarNearlyEqual(returned, oldLength));
REPORTER_ASSERT(reporter, SkScalarNearlyEqual(newLength, SK_Scalar1));
}
// Tests that SkPoint::length() and SkPoint::Length() both return
// approximately expectedLength for this (x,y).
static void test_length(skiatest::Reporter* reporter, SkScalar x, SkScalar y,
SkScalar expectedLength) {
SkPoint point;
point.set(x, y);
SkScalar s1 = point.length();
SkScalar s2 = SkPoint::Length(x, y);
//The following should be exactly the same, but need not be.
//See http://gcc.gnu.org/bugzilla/show_bug.cgi?id=323
REPORTER_ASSERT(reporter, SkScalarNearlyEqual(s1, s2));
REPORTER_ASSERT(reporter, SkScalarNearlyEqual(s1, expectedLength));
test_Normalize(reporter, x, y);
}
// Ugh. Windows compiler can dive into other .cpp files, and sometimes
// notices that I will generate an overflow... which is exactly the point
// of this test!
//
// To avoid this warning, I need to convince the compiler that I might not
// use that big value, hence this hacky helper function: reporter is
// ALWAYS non-null. (shhhhhh, don't tell the compiler that).
template <typename T> T get_value(skiatest::Reporter* reporter, T value) {
return reporter ? value : 0;
}
// On linux gcc, 32bit, we are seeing the compiler propagate up the value
// of SkPoint::length() as a double (which we use sometimes to avoid overflow
// during the computation), even though the signature says float (SkScalar).
//
// force_as_float is meant to capture our latest technique (horrible as
// it is) to force the value to be a float, so we can test whether it was
// finite or not.
static float force_as_float(skiatest::Reporter* reporter, float value) {
uint32_t storage;
memcpy(&storage, &value, 4);
// even the pair of memcpy calls are not sufficient, since those seem to
// be no-op'd, so we add a runtime tests (just like get_value) to force
// the compiler to give us an actual float.
if (nullptr == reporter) {
storage = ~storage;
}
memcpy(&value, &storage, 4);
return value;
}
// test that we handle very large values correctly. i.e. that we can
// successfully normalize something whose mag overflows a float.
static void test_overflow(skiatest::Reporter* reporter) {
SkScalar bigFloat = get_value(reporter, 3.4e38f);
SkPoint pt = { bigFloat, bigFloat };
SkScalar length = pt.length();
length = force_as_float(reporter, length);
// expect this to be non-finite, but dump the results if not.
if (SkScalarIsFinite(length)) {
SkDebugf("length(%g, %g) == %g\n", pt.fX, pt.fY, length);
REPORTER_ASSERT(reporter, !SkScalarIsFinite(length));
}
// this should succeed, even though we can't represent length
REPORTER_ASSERT(reporter, pt.setLength(SK_Scalar1));
// now that pt is normalized, we check its length
length = pt.length();
REPORTER_ASSERT(reporter, SkScalarNearlyEqual(length, SK_Scalar1));
}
// test that we handle very small values correctly. i.e. that we can
// report failure if we try to normalize them.
static void test_underflow(skiatest::Reporter* reporter) {
SkPoint pt = { 1.0e-37f, 1.0e-37f };
const SkPoint empty = { 0, 0 };
REPORTER_ASSERT(reporter, 0 == SkPoint::Normalize(&pt));
REPORTER_ASSERT(reporter, pt == empty);
REPORTER_ASSERT(reporter, !pt.setLength(SK_Scalar1));
REPORTER_ASSERT(reporter, pt == empty);
}
DEF_TEST(Point, reporter) {
test_casts(reporter);
static const struct {
SkScalar fX;
SkScalar fY;
SkScalar fLength;
} gRec[] = {
{ SkIntToScalar(3), SkIntToScalar(4), SkIntToScalar(5) },
{ 0.6f, 0.8f, SK_Scalar1 },
};
for (size_t i = 0; i < SK_ARRAY_COUNT(gRec); ++i) {
test_length(reporter, gRec[i].fX, gRec[i].fY, gRec[i].fLength);
}
test_underflow(reporter);
test_overflow(reporter);
}
DEF_TEST(Point_setLengthFast, reporter) {
// Scale a (1,1) point to a bunch of different lengths,
// making sure the slow and fast paths are within 0.1%.
const float tests[] = { 1.0f, 0.0f, 1.0e-37f, 3.4e38f, 42.0f, 0.00012f };
const SkPoint kOne = {1.0f, 1.0f};
for (unsigned i = 0; i < SK_ARRAY_COUNT(tests); i++) {
SkPoint slow = kOne, fast = kOne;
slow.setLength(tests[i]);
fast.setLengthFast(tests[i]);
if (slow.length() < FLT_MIN && fast.length() < FLT_MIN) continue;
SkScalar ratio = slow.length() / fast.length();
REPORTER_ASSERT(reporter, ratio > 0.999f);
REPORTER_ASSERT(reporter, ratio < 1.001f);
}
}
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