1 files changed, 96 insertions, 0 deletions
diff --git a/rect.c b/rect.c
new file mode 100644
index 0000000..bcc95cd
--- /dev/null
+++ b/rect.c
@@ -0,0 +1,96 @@
+#include "maths.h"
+#include "rect.h"
+
+Rectangle make_rect(int x, int y, int w, int h) {
+	Rectangle r;
+	r.x = x;
+	r.y = y;
+	r.w = w;
+	r.h = h;
+	return r;
+}
+
+int rects_overlap(const Rectangle* a, const Rectangle* b) {
+	return
+		a->x + a->w > b->x &&
+		a->y + a->h > b->y &&
+		a->x < b->x + b->w &&
+		a->y < b->y + b->h;
+}
+
+int rects_overlap2(
+	int x0,
+	int y0,
+	int w0,
+	int h0,
+	int x1,
+	int y1,
+	int w1,
+	int h1
+) {
+	return
+		x0 + w0 > x1 &&
+		y0 + h0 > y1 &&
+		x0 < x1 + w1 &&
+		y0 < y1 + h1;
+}
+
+int point_rect_overlap(
+	const Rectangle* r,
+	int px,
+	int py
+) {
+	return
+		px >= r->x &&
+		py >= r->y &&
+		px <= r->x + r->w &&
+		py <= r->y + r->h;
+}
+
+int point_rect_overlap2(
+	int x,
+	int y,
+	int w,
+	int h,
+	int px,
+	int py
+) {
+	return
+		px > x &&
+		py > y &&
+		px < x + w &&
+		py < y + h;
+}
+
+Rectangle rect_intersect(
+	const Rectangle* a,
+	const Rectangle* b
+) {
+	int x1, y1, x2, y2;
+	Rectangle r;
+  x1 = maxi(a->x, b->x);
+  y1 = maxi(a->y, b->y);
+  x2 = mini(a->x + a->w, b->x + b->w);
+  y2 = mini(a->y + a->h, b->y + b->h);
+  r.x = x1;
+  r.y = y1;
+  r.w = maxi(0, x2 - x1);
+  r.h = maxi(0, y2 - y1);
+  return r;
+}
+
+Rectangle* rect_merge(
+	Rectangle* d,
+	const Rectangle* r
+) {
+	int x1, y1, x2, y2;
+	x1 = mini(d->x, r->x);
+	y1 = mini(d->y, r->y);
+	x2 = maxi(d->x + d->w, r->x + r->w);
+	y2 = maxi(d->y + d->h, r->y + r->h);
+	d->x = x1;
+	d->y = y1;
+	d->w = x2 - x1;
+	d->h = y2 - y1;
+	return d;
+}