From c553f22f1ec6d4694d39b70663ed1e23f97f4758 Mon Sep 17 00:00:00 2001
From: Mika Tuupola <tuupola@appelsiini.net>
Date: Fri, 3 Apr 2026 09:09:27 +0300
Subject: [PATCH 1/2] Change to insertion sort

In theory faster, but the effect is minimal until there is lot
of vertices.
---
 src/hagl_polygon.c | 20 ++++++++------------
 1 file changed, 8 insertions(+), 12 deletions(-)

diff --git a/src/hagl_polygon.c b/src/hagl_polygon.c
index 666c92a..d49040a 100644
--- a/src/hagl_polygon.c
+++ b/src/hagl_polygon.c
@@ -115,19 +115,15 @@ void hagl_fill_polygon(
             j = i;
         }
 
-        /* Sort the nodes, via a simple “Bubble” sort. */
-        int16_t i = 0;
-        while (i < count - 1) {
-            if (nodes[i] > nodes[i + 1]) {
-                int16_t swap = nodes[i];
-                nodes[i] = nodes[i + 1];
-                nodes[i + 1] = swap;
-                if (i) {
-                    i--;
-                }
-            } else {
-                i++;
+        /* Sort the nodes, via insertion sort. */
+        for (int16_t i = 1; i < count; i++) {
+            int16_t key = nodes[i];
+            int16_t j = i - 1;
+            while (j >= 0 && nodes[j] > key) {
+                nodes[j + 1] = nodes[j];
+                j--;
             }
+            nodes[j + 1] = key;
         }
 
         /* Draw lines between nodes. */

From bb071c2c404ce312a50bab4e11e0f18c2bb18d09 Mon Sep 17 00:00:00 2001
From: Mika Tuupola <tuupola@appelsiini.net>
Date: Wed, 16 Sep 2026 17:08:33 +0300
Subject: [PATCH 2/2] Clamp miny and maxy with clip window

---
 src/hagl_polygon.c | 26 +++++++++++++++++++-------
 1 file changed, 19 insertions(+), 7 deletions(-)

diff --git a/src/hagl_polygon.c b/src/hagl_polygon.c
index d49040a..e8f07b0 100644
--- a/src/hagl_polygon.c
+++ b/src/hagl_polygon.c
@@ -79,18 +79,30 @@ void hagl_fill_polygon(
         return;
     }
 
-    miny = surface->height;
-    maxy = 0;
+    miny = vertices[1];
+    maxy = vertices[1];
 
-    for (uint8_t i = 0; i < amount; i++) {
-        if (miny > vertices[(i << 1) + 1]) {
-            miny = vertices[(i << 1) + 1];
+    for (int16_t i = 1; i < amount; i++) {
+        int16_t vy = vertices[(i << 1) + 1];
+        if (miny > vy) {
+            miny = vy;
         }
-        if (maxy < vertices[(i << 1) + 1]) {
-            maxy = vertices[(i << 1) + 1];
+        if (maxy < vy) {
+            maxy = vy;
         }
     }
 
+    if ((maxy < surface->clip.y0) || (miny > surface->clip.y1)) {
+        return;
+    }
+
+    if (miny < surface->clip.y0) {
+        miny = surface->clip.y0;
+    }
+    if (maxy > surface->clip.y1) {
+        maxy = surface->clip.y1;
+    }
+
     /*  Loop through the rows of the image. */
     for (y = miny; y <= maxy; y++) {