| /* |
| * Copyright 2023 Google LLC |
| * |
| * Use of this source code is governed by a BSD-style license that can be |
| * found in the LICENSE file. |
| */ |
| |
| #include "include/core/SkSpan.h" |
| #include "include/core/SkTypes.h" |
| #include "include/private/base/SkFloatingPoint.h" |
| #include "src/base/SkQuads.h" |
| #include "src/pathops/SkPathOpsQuad.h" |
| #include "tests/Test.h" |
| |
| #include <algorithm> |
| #include <cstddef> |
| #include <iterator> |
| #include <string> |
| |
| static void testQuadRootsReal(skiatest::Reporter* reporter, std::string name, |
| double A, double B, double C, |
| SkSpan<const double> expectedRoots) { |
| skiatest::ReporterContext subtest(reporter, name); |
| // Validate test case |
| REPORTER_ASSERT(reporter, expectedRoots.size() <= 2, |
| "Invalid test case, up to 2 roots allowed"); |
| |
| for (size_t i = 0; i < expectedRoots.size(); i++) { |
| double x = expectedRoots[i]; |
| // A*x^2 + B*x + C should equal 0 |
| double y = A * x * x + B * x + C; |
| REPORTER_ASSERT(reporter, sk_double_nearly_zero(y), |
| "Invalid test case root %zu. %.16f != 0", i, y); |
| |
| if (i > 0) { |
| REPORTER_ASSERT(reporter, expectedRoots[i-1] <= expectedRoots[i], |
| "Invalid test case root %zu. Roots should be sorted in ascending order", i); |
| } |
| } |
| |
| { |
| skiatest::ReporterContext subsubtest(reporter, "Pathops Implementation"); |
| double roots[2] = {0, 0}; |
| int rootCount = SkDQuad::RootsReal(A, B, C, roots); |
| REPORTER_ASSERT(reporter, expectedRoots.size() == size_t(rootCount), |
| "Wrong number of roots returned %zu != %d", expectedRoots.size(), |
| rootCount); |
| |
| // We don't care which order the roots are returned from the algorithm. |
| // For determinism, we will sort them (and ensure the provided solutions are also sorted). |
| std::sort(std::begin(roots), std::begin(roots) + rootCount); |
| for (int i = 0; i < rootCount; i++) { |
| if (sk_double_nearly_zero(expectedRoots[i])) { |
| REPORTER_ASSERT(reporter, sk_double_nearly_zero(roots[i]), |
| "0 != %.16f at index %d", roots[i], i); |
| } else { |
| REPORTER_ASSERT(reporter, |
| sk_doubles_nearly_equal_ulps(expectedRoots[i], roots[i], 64), |
| "%.16f != %.16f at index %d", expectedRoots[i], roots[i], i); |
| } |
| } |
| } |
| { |
| skiatest::ReporterContext subsubtest(reporter, "SkQuads Implementation"); |
| double roots[2] = {0, 0}; |
| int rootCount = SkQuads::RootsReal(A, B, C, roots); |
| REPORTER_ASSERT(reporter, expectedRoots.size() == size_t(rootCount), |
| "Wrong number of roots returned %zu != %d", expectedRoots.size(), |
| rootCount); |
| |
| // We don't care which order the roots are returned from the algorithm. |
| // For determinism, we will sort them (and ensure the provided solutions are also sorted). |
| std::sort(std::begin(roots), std::begin(roots) + rootCount); |
| for (int i = 0; i < rootCount; i++) { |
| if (sk_double_nearly_zero(expectedRoots[i])) { |
| REPORTER_ASSERT(reporter, sk_double_nearly_zero(roots[i]), |
| "0 != %.16f at index %d", roots[i], i); |
| } else { |
| REPORTER_ASSERT(reporter, |
| sk_doubles_nearly_equal_ulps(expectedRoots[i], roots[i], 64), |
| "%.16f != %.16f at index %d", expectedRoots[i], roots[i], i); |
| } |
| } |
| } |
| } |
| |
| DEF_TEST(QuadRootsReal_ActualQuadratics, reporter) { |
| // All answers are given with 16 significant digits (max for a double) or as an integer |
| // when the answer is exact. |
| testQuadRootsReal(reporter, "two roots 3x^2 - 20x - 40", |
| 3, -20, -40, |
| {-1.610798991397109, |
| //-1.610798991397108632474265 from Wolfram Alpha |
| 8.277465658063775, |
| // 8.277465658063775299140932 from Wolfram Alpha |
| }); |
| |
| // (2x - 4)(x + 17) |
| testQuadRootsReal(reporter, "two roots 2x^2 + 30x - 68", |
| 2, 30, -68, |
| {-17, 2}); |
| |
| testQuadRootsReal(reporter, "two roots x^2 - 5", |
| 1, 0, -5, |
| {-2.236067977499790, |
| //-2.236067977499789696409174 from Wolfram Alpha |
| 2.236067977499790, |
| // 2.236067977499789696409174 from Wolfram Alpha |
| }); |
| |
| testQuadRootsReal(reporter, "one root x^2 - 2x + 1", |
| 1, -2, 1, |
| {1}); |
| |
| testQuadRootsReal(reporter, "no roots 5x^2 + 6x + 7", |
| 5, 6, 7, |
| {}); |
| } |
| |
| DEF_TEST(QuadRootsReal_Linear, reporter) { |
| testQuadRootsReal(reporter, "positive slope 5x + 6", |
| 0, 5, 6, |
| {-1.2}); |
| |
| testQuadRootsReal(reporter, "negative slope -3x - 9", |
| 0, -3, -9, |
| {-3.}); |
| } |
| |
| DEF_TEST(QuadRootsReal_Constant, reporter) { |
| testQuadRootsReal(reporter, "No intersections y = -10", |
| 0, 0, -10, |
| {}); |
| |
| testQuadRootsReal(reporter, "Infinite solutions y = 0", |
| 0, 0, 0, |
| {0.}); |
| } |