- changed the stencil cap drawer to only cover the area which is actually used by the portal.

This will now both exclude floor caps when only ceiling elements are used and everything outside the bounding box of active portal lines.
Hopefully this is enough to fix the issues with portal caps but of course it is not foolproof if someone just makes the right setup.

src/r_data/r_sections.cpp

@@ -495,9 +495,9 @@ public:
 			auto &section = sections[i];
 			auto &work = triangles[i];
 
-			BoundingRect bounds = { 1e32, 1e32, -1e32, -1e32 };
-			BoundingRect loopBounds = { 1e32, 1e32, -1e32, -1e32 };
-			BoundingRect outermostBounds = { 1e32, 1e32, -1e32, -1e32 };
+			BoundingRect bounds(false);
+			BoundingRect loopBounds(false);
+			BoundingRect outermostBounds(false);
 			unsigned outermoststart = ~0u;
 			unsigned loopstart = 0;
 			bool ispolyorg = false;
@@ -519,7 +519,7 @@ public:
 						outermoststart = loopstart;
 						loopstart = i + 1;
 					}
-					loopBounds = { 1e32, 1e32, -1e32, -1e32 };
+					loopBounds.setEmpty();
 				}
 			}
 			work.boundingLoopStart = outermoststart;
@@ -716,7 +716,7 @@ public:
 			dest.subsectors.Set(&output.allSubsectors[numsubsectors], group.subsectors.Size());
 			dest.vertexindex = -1;
 			dest.vertexcount = 0;
-			dest.bounds = {1e32, 1e32, -1e32, -1e32};
+			dest.bounds.setEmpty();
 			numsegments += group.segments.Size();
 
 			if (output.firstSectionForSectorPtr[dest.sector->Index()] == -1)

src/r_data/r_sections.h

@@ -25,12 +25,35 @@ struct BoundingRect
 {
 	double left, top, right, bottom;
 
-	bool contains(const BoundingRect & other)
+	BoundingRect() = default;
+	BoundingRect(bool)
+	{
+		setEmpty();
+	}
+
+	void setEmpty()
+	{
+		left = top = 1e38;
+		bottom = right = -1e38;
+	}
+
+	bool contains(const BoundingRect & other) const
 	{
 		return left <= other.left && top <= other.top && right >= other.right && bottom >= other.bottom;
 	}
 
-	bool intersects(const BoundingRect & other)
+	bool contains(double x, double y) const
+	{
+		return left <= x && top <= y && right >= x && bottom >= y;
+	}
+
+	template <class T>
+	bool contains(const T &vec) const
+	{
+		return left <= vec.X && top <= vec.Y && right >= vec.X && bottom >= vec.Y;
+	}
+
+	bool intersects(const BoundingRect & other) const
 	{
 		return !(other.left > right ||
 			other.right < left ||
@@ -46,7 +69,7 @@ struct BoundingRect
 		if (other.bottom > bottom) bottom = other.bottom;
 	}
 
-	double distanceTo(const BoundingRect &other)
+	double distanceTo(const BoundingRect &other) const
 	{
 		if (intersects(other)) return 0;
 		return std::max(std::min(fabs(left - other.right), fabs(right - other.left)),
@@ -61,10 +84,11 @@ struct BoundingRect
 		if (y > bottom) bottom = y;
 	}
 
-	bool operator == (const BoundingRect &other)
+	bool operator == (const BoundingRect &other) const
 	{
 		return left == other.left && top == other.top && right == other.right && bottom == other.bottom;
 	}
+
 };