Fix axis aligned cpBB segment query test.

slembcke · Oct 3, 2016 · d342fb3 · d342fb3
1 parent f5e696c
commit d342fb3
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Showing 2 changed files with 123 additions and 4 deletions.
diff --git a/include/chipmunk/cpBB.h b/include/chipmunk/cpBB.h
@@ -117,14 +117,18 @@ static inline cpFloat cpBBSegmentQuery(cpBB bb, cpVect a, cpVect b)
 	cpVect delta = cpvsub(b, a);
 	cpFloat tmin = -INFINITY, tmax = INFINITY;
 
-	if(delta.x != 0.0f){
+	if(delta.x == 0.0f){
+		if(a.x < bb.l || bb.r < a.x) return INFINITY;
+	} else {
 		cpFloat t1 = (bb.l - a.x)/delta.x;
 		cpFloat t2 = (bb.r - a.x)/delta.x;
 		tmin = cpfmax(tmin, cpfmin(t1, t2));
 		tmax = cpfmin(tmax, cpfmax(t1, t2));
 	}
 
-	if(delta.y != 0.0f){
+	if(delta.y == 0.0f){
+		if(a.y < bb.b || bb.t < a.y) return INFINITY;
+	} else {
 		cpFloat t1 = (bb.b - a.y)/delta.y;
 		cpFloat t2 = (bb.t - a.y)/delta.y;
 		tmin = cpfmax(tmin, cpfmin(t1, t2));
@@ -133,9 +137,9 @@ static inline cpFloat cpBBSegmentQuery(cpBB bb, cpVect a, cpVect b)
 
 	if(tmin <= tmax && 0.0f <= tmax && tmin <= 1.0f){
 		return cpfmax(tmin, 0.0f);
+	} else {
+		return INFINITY;
 	}
-
-	return INFINITY;
 }
 
 /// Return true if the bounding box intersects the line segment with ends @c a and @c b.

diff --git a/xcode/ObjectiveChipmunkTests/MiscTest.m b/xcode/ObjectiveChipmunkTests/MiscTest.m
@@ -132,6 +132,121 @@ -(void)testSlerp {
 	}
 }
 
+-(void)testBBSegmentQuery
+{
+	{ // left
+		cpVect a = cpv(-2, 0);
+		cpVect b = cpv( 0, 0);
+		cpBB bb = cpBBNew(-1, -1, 1, 1);
+		cpFloat t = cpBBSegmentQuery(bb, a, b);
+		XCTAssertEqualWithAccuracy(t, 0.5, 1e-5);
+	}
+
+	{ // right
+		cpVect a = cpv( 2, 0);
+		cpVect b = cpv( 0, 0);
+		cpBB bb = cpBBNew(-1, -1, 1, 1);
+		cpFloat t = cpBBSegmentQuery(bb, a, b);
+		XCTAssertEqualWithAccuracy(t, 0.5, 1e-5);
+	}
+
+	{ // bottom
+		cpVect a = cpv(0, -2);
+		cpVect b = cpv(0,  0);
+		cpBB bb = cpBBNew(-1, -1, 1, 1);
+		cpFloat t = cpBBSegmentQuery(bb, a, b);
+		XCTAssertEqualWithAccuracy(t, 0.5, 1e-5);
+	}
+
+	{ // top
+		cpVect a = cpv(0,  2);
+		cpVect b = cpv(0,  0);
+		cpBB bb = cpBBNew(-1, -1, 1, 1);
+		cpFloat t = cpBBSegmentQuery(bb, a, b);
+		XCTAssertEqualWithAccuracy(t, 0.5, 1e-5);
+	}
+
+	{ // diagonal corner
+		cpVect a = cpv(-2, -2);
+		cpVect b = cpv( 0,  0);
+		cpBB bb = cpBBNew(-1, -1, 1, 1);
+		cpFloat t = cpBBSegmentQuery(bb, a, b);
+		XCTAssertEqualWithAccuracy(t, 0.5, 1e-5);
+	}
+
+	{ // diagonal edge
+		cpVect a = cpv(-2, -1);
+		cpVect b = cpv( 0,  1);
+		cpBB bb = cpBBNew(-1, -1, 1, 1);
+		cpFloat t = cpBBSegmentQuery(bb, a, b);
+		XCTAssertEqualWithAccuracy(t, 0.5, 1e-5);
+	}
+
+	{ // x-aligned low.
+		cpVect a = cpv(-2, -1);
+		cpVect b = cpv( 0, -1);
+		cpBB bb = cpBBNew(-1, -1, 1, 1);
+		cpFloat t = cpBBSegmentQuery(bb, a, b);
+		XCTAssertEqual(t, 0.5);
+	}
+
+	{ // x-aligned high.
+		cpVect a = cpv(-2, 1);
+		cpVect b = cpv( 0, 1);
+		cpBB bb = cpBBNew(-1, -1, 1, 1);
+		cpFloat t = cpBBSegmentQuery(bb, a, b);
+		XCTAssertEqual(t, 0.5);
+	}
+
+	{ // y-aligned low.
+		cpVect a = cpv(-1, -2);
+		cpVect b = cpv(-1,  0);
+		cpBB bb = cpBBNew(-1, -1, 1, 1);
+		cpFloat t = cpBBSegmentQuery(bb, a, b);
+		XCTAssertEqual(t, 0.5);
+	}
+
+	{ // y-aligned high.
+		cpVect a = cpv(1, -2);
+		cpVect b = cpv(1,  0);
+		cpBB bb = cpBBNew(-1, -1, 1, 1);
+		cpFloat t = cpBBSegmentQuery(bb, a, b);
+		XCTAssertEqual(t, 0.5);
+	}
+
+	{ // Miss, x-aligned low.
+		cpVect a = cpv( 2, -2);
+		cpVect b = cpv( 0, -2);
+		cpBB bb = cpBBNew(-1, -1, 1, 1);
+		cpFloat t = cpBBSegmentQuery(bb, a, b);
+		XCTAssertEqual(t, INFINITY);
+	}
+
+	{ // Miss, x-aligned high.
+		cpVect a = cpv( 2, 2);
+		cpVect b = cpv( 0, 2);
+		cpBB bb = cpBBNew(-1, -1, 1, 1);
+		cpFloat t = cpBBSegmentQuery(bb, a, b);
+		XCTAssertEqual(t, INFINITY);
+	}
+
+	{ // Miss, y-aligned low.
+		cpVect a = cpv(-2, 2);
+		cpVect b = cpv(-2, 0);
+		cpBB bb = cpBBNew(-1, -1, 1, 1);
+		cpFloat t = cpBBSegmentQuery(bb, a, b);
+		XCTAssertEqual(t, INFINITY);
+	}
+
+	{ // Miss, y-aligned high.
+		cpVect a = cpv(2, 2);
+		cpVect b = cpv(2, 0);
+		cpBB bb = cpBBNew(-1, -1, 1, 1);
+		cpFloat t = cpBBSegmentQuery(bb, a, b);
+		XCTAssertEqual(t, INFINITY);
+	}
+}
+
 -(void)testImageSamplerLA
 {
 	{