Loading core/graphics/intersect.cc +79 −0 Original line number Diff line number Diff line Loading @@ -88,5 +88,84 @@ bool intersect_line_line( return true; } bool intersect_line_lineseg( vec2 p0, vec2 v0, vec2 s1, vec2 e1, vec2* p /* = nullptr */) { // find the intersection between the infinite lines given by {p0, v1} and the // infinite line that passes through {s0, e0} vec2 pt; auto pt_exists = intersect_line_line( p0, v0, s1, vec2_normalize(vec2_sub(e1, s1)), &pt); if (!pt_exists) { return false; } // check if the intersection point is outside of the line segment if (pt.x < std::min(s1.x, e1.x) || pt.x > std::max(s1.x, e1.x) || pt.y < std::min(s1.y, e1.y) || pt.y > std::max(s1.y, e1.y)) { return false; } // we found a point of intersection that is located on the line segment, // return it if (p) { *p = pt; } return true; } bool intersect_lineseg_lineseg( vec2 s0, vec2 e0, vec2 s1, vec2 e1, vec2* p /* = nullptr */) { // find the intersection between the infinite lines that pass through {s0, e0} // and {s1, e1} respectively vec2 pt; auto pt_exists = intersect_line_line( s0, vec2_sub(e0, s0), s1, vec2_normalize(vec2_sub(e1, s1)), &pt); if (!pt_exists) { return false; } // check if the intersection point is outside of one of the lines segments if (pt.x < std::min(s0.x, e0.x) || pt.x > std::max(s0.x, e0.x) || pt.y < std::min(s0.y, e0.y) || pt.y > std::max(s0.y, e0.y) || pt.x < std::min(s1.x, e1.x) || pt.x > std::max(s1.x, e1.x) || pt.y < std::min(s1.y, e1.y) || pt.y > std::max(s1.y, e1.y)) { return false; } // we found a point of intersection that is located on both line segments, // return it if (p) { *p = pt; } return true; } } // namespace fviz core/graphics/intersect.h +24 −0 Original line number Diff line number Diff line Loading @@ -35,5 +35,29 @@ bool intersect_line_line( vec2 v1, vec2* p = nullptr); /** * Given an infinite line defined by a point on the line and a direction vector * and a line segment defined by its start and end point, compute their point of * intersection if any. Returns false if the two lines are parallel. */ bool intersect_line_lineseg( vec2 p0, vec2 v0, vec2 s1, vec2 e1, vec2* p = nullptr); /** * Given two line sgements defined by the two start and end points of the two * line segments s0, s1 and e1, e2, compute their point of intersection if any. * Returns false if the two line segements are parallel or coincident. */ bool intersect_lineseg_lineseg( vec2 s0, vec2 e0, vec2 s1, vec2 e1, vec2* p = nullptr); } // namespace fviz tests/unit/test_graphics_intersect.cc +42 −0 Original line number Diff line number Diff line Loading @@ -162,8 +162,50 @@ void test_intersect_point() { EXPECT_EQ(p.y, 4); } void test_intersect_linesegs() { { Point p; EXPECT_EQ( intersect_lineseg_lineseg( {1, 1}, {3, 1}, {1, 4}, {3, 4}, &p), false); } { Point p; EXPECT_EQ( intersect_lineseg_lineseg( {1, 1}, {4, 4}, {1, 4}, {4, 1}, &p), true); EXPECT_EQ(p.x, 2.5); EXPECT_EQ(p.y, 2.5); } { Point p; EXPECT_EQ( intersect_lineseg_lineseg( {1, 1}, {4, 2}, {1, 4}, {4, 3}, &p), false); } } int main(int argc, char** argv) { test_intersect_parallel(); test_intersect_point(); test_intersect_linesegs(); } Loading
core/graphics/intersect.cc +79 −0 Original line number Diff line number Diff line Loading @@ -88,5 +88,84 @@ bool intersect_line_line( return true; } bool intersect_line_lineseg( vec2 p0, vec2 v0, vec2 s1, vec2 e1, vec2* p /* = nullptr */) { // find the intersection between the infinite lines given by {p0, v1} and the // infinite line that passes through {s0, e0} vec2 pt; auto pt_exists = intersect_line_line( p0, v0, s1, vec2_normalize(vec2_sub(e1, s1)), &pt); if (!pt_exists) { return false; } // check if the intersection point is outside of the line segment if (pt.x < std::min(s1.x, e1.x) || pt.x > std::max(s1.x, e1.x) || pt.y < std::min(s1.y, e1.y) || pt.y > std::max(s1.y, e1.y)) { return false; } // we found a point of intersection that is located on the line segment, // return it if (p) { *p = pt; } return true; } bool intersect_lineseg_lineseg( vec2 s0, vec2 e0, vec2 s1, vec2 e1, vec2* p /* = nullptr */) { // find the intersection between the infinite lines that pass through {s0, e0} // and {s1, e1} respectively vec2 pt; auto pt_exists = intersect_line_line( s0, vec2_sub(e0, s0), s1, vec2_normalize(vec2_sub(e1, s1)), &pt); if (!pt_exists) { return false; } // check if the intersection point is outside of one of the lines segments if (pt.x < std::min(s0.x, e0.x) || pt.x > std::max(s0.x, e0.x) || pt.y < std::min(s0.y, e0.y) || pt.y > std::max(s0.y, e0.y) || pt.x < std::min(s1.x, e1.x) || pt.x > std::max(s1.x, e1.x) || pt.y < std::min(s1.y, e1.y) || pt.y > std::max(s1.y, e1.y)) { return false; } // we found a point of intersection that is located on both line segments, // return it if (p) { *p = pt; } return true; } } // namespace fviz
core/graphics/intersect.h +24 −0 Original line number Diff line number Diff line Loading @@ -35,5 +35,29 @@ bool intersect_line_line( vec2 v1, vec2* p = nullptr); /** * Given an infinite line defined by a point on the line and a direction vector * and a line segment defined by its start and end point, compute their point of * intersection if any. Returns false if the two lines are parallel. */ bool intersect_line_lineseg( vec2 p0, vec2 v0, vec2 s1, vec2 e1, vec2* p = nullptr); /** * Given two line sgements defined by the two start and end points of the two * line segments s0, s1 and e1, e2, compute their point of intersection if any. * Returns false if the two line segements are parallel or coincident. */ bool intersect_lineseg_lineseg( vec2 s0, vec2 e0, vec2 s1, vec2 e1, vec2* p = nullptr); } // namespace fviz
tests/unit/test_graphics_intersect.cc +42 −0 Original line number Diff line number Diff line Loading @@ -162,8 +162,50 @@ void test_intersect_point() { EXPECT_EQ(p.y, 4); } void test_intersect_linesegs() { { Point p; EXPECT_EQ( intersect_lineseg_lineseg( {1, 1}, {3, 1}, {1, 4}, {3, 4}, &p), false); } { Point p; EXPECT_EQ( intersect_lineseg_lineseg( {1, 1}, {4, 4}, {1, 4}, {4, 1}, &p), true); EXPECT_EQ(p.x, 2.5); EXPECT_EQ(p.y, 2.5); } { Point p; EXPECT_EQ( intersect_lineseg_lineseg( {1, 1}, {4, 2}, {1, 4}, {4, 3}, &p), false); } } int main(int argc, char** argv) { test_intersect_parallel(); test_intersect_point(); test_intersect_linesegs(); }
