1 files changed, 14 insertions, 28 deletions

diff --git a/src/renderer.c b/src/renderer.c
index 0ce3107..07d79d6 100644
--- a/src/renderer.c
+++ b/src/renderer.c
@@ -128,35 +128,21 @@ draw_line(size_t x0, size_t y0, size_t x1, size_t y1, u8 clr) {
         }
     } else {
         // Diagonal line.
-        int x_step = x0 > x1 ? -1 : 1;
-        int y_step = y0 > y1 ? -1 : 1;
-        size_t dx = x0 > x1 ? x0 - x1 : x1 - x0;
-        size_t dy = y0 > y1 ? y0 - y1 : y1 - y0;
-        size_t x = x0;
-        size_t y = y0;
-        if (dx >= dy) {
-            // Positive slope.
-            int diff = 2 * dy - dx;
-            for (size_t i = 0; i <= dx; ++i) {
-                draw_pixel(x, y, clr);
-                if (diff >= 0) {
-                    y += y_step;
-                    diff -= 2 * dx;
-                }
-                x += x_step;
-                diff += 2 * dy;
+        int dx = x0 > x1 ? x0 - x1 : x1 - x0;
+        int dy = y0 > y1 ? y1 - y0 : y0 - y1;
+        int x_step = x0 < x1 ? 1 : -1;
+        int y_step = y0 < y1 ? 1 : -1;
+        int err = dx + dy;
+        while (!(x0 == x1 && y0 == y1)) {
+            draw_pixel(x0, y0, clr);
+            int diff = 2 * err;
+            if (diff >= dy) {
+                err += dy;
+                x0 += x_step;
             }
-        } else {
-            // Negative slope.
-            int diff = 2 * dx - dy;
-            for (size_t i = 0; i <= dy; ++i) {
-                draw_pixel(x, y, clr);
-                if (diff >= 0) {
-                    x += x_step;
-                    diff -= 2 * dy;
-                }
-                y -= y_step;
-                diff += 2 * dx;
+            if (diff <= dx) {
+                err += dx;
+                y0 += y_step;
             }
         }
     }