From f123981a96c8ab7d7cb3e77ecbcf0048cb3b79e6 Mon Sep 17 00:00:00 2001
From: reduz <reduzio@gmail.com>
Date: Tue, 3 Nov 2020 16:51:53 -0300
Subject: Implement DirectionalLight2D

Also separated Light2D in PointLight2D and DirectionalLight2D.
Used PointLight2D because its more of a point, and it does not work
the same as OmniLight (as shape depends on texture).
Added a few utility methods to Rect2D I needed.
---
 core/math/rect2.h | 62 +++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 62 insertions(+)

(limited to 'core/math')

diff --git a/core/math/rect2.h b/core/math/rect2.h
index 7660db71eb..4e6cecaab2 100644
--- a/core/math/rect2.h
+++ b/core/math/rect2.h
@@ -244,6 +244,68 @@ struct Rect2 {
 		return Rect2(Point2(position.x + MIN(size.x, 0), position.y + MIN(size.y, 0)), size.abs());
 	}
 
+	Vector2 get_support(const Vector2 &p_normal) const {
+		Vector2 half_extents = size * 0.5;
+		Vector2 ofs = position + half_extents;
+		return Vector2(
+					   (p_normal.x > 0) ? -half_extents.x : half_extents.x,
+					   (p_normal.y > 0) ? -half_extents.y : half_extents.y) +
+			   ofs;
+	}
+
+	_FORCE_INLINE_ bool intersects_filled_polygon(const Vector2 *p_points, int p_point_count) const {
+		Vector2 center = position + size * 0.5;
+		int side_plus = 0;
+		int side_minus = 0;
+		Vector2 end = position + size;
+
+		int i_f = p_point_count - 1;
+		for (int i = 0; i < p_point_count; i++) {
+			const Vector2 &a = p_points[i_f];
+			const Vector2 &b = p_points[i];
+			i_f = i;
+
+			Vector2 r = (b - a);
+			float l = r.length();
+			if (l == 0.0) {
+				continue;
+			}
+
+			//check inside
+			Vector2 tg = r.tangent();
+			float s = tg.dot(center) - tg.dot(a);
+			if (s < 0.0) {
+				side_plus++;
+			} else {
+				side_minus++;
+			}
+
+			//check ray box
+			r /= l;
+			Vector2 ir(1.0 / r.x, 1.0 / r.y);
+
+			// lb is the corner of AABB with minimal coordinates - left bottom, rt is maximal corner
+			// r.org is origin of ray
+			Vector2 t13 = (position - a) * ir;
+			Vector2 t24 = (end - a) * ir;
+
+			float tmin = MAX(MIN(t13.x, t24.x), MIN(t13.y, t24.y));
+			float tmax = MIN(MAX(t13.x, t24.x), MAX(t13.y, t24.y));
+
+			// if tmax < 0, ray (line) is intersecting AABB, but the whole AABB is behind us
+			if (tmax < 0 || tmin > tmax || tmin >= l) {
+				continue;
+			}
+
+			return true;
+		}
+
+		if (side_plus * side_minus == 0) {
+			return true; //all inside
+		} else {
+			return false;
+		}
+	}
 	operator String() const { return String(position) + ", " + String(size); }
 
 	Rect2() {}
-- 
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