diff --git a/small3dlib.h b/small3dlib.h
index b6d93ec..bc5eb73 100644
--- a/small3dlib.h
+++ b/small3dlib.h
@@ -1531,7 +1531,8 @@ void S3L_drawTriangle(
                                                   loop */
 #endif
 
-      if (rXClipped < lXClipped)
+      if (rXClipped < lXClipped &&
+          lXClipped < S3L_RESOLUTION_X && rXClipped >= 0)
       {
         /* This can sometimes happen because of numerical errors in sorting
         left vs right triangle point, which are compared based on SLOPE, not
diff --git a/testSDL.c b/testSDL.c
index 0ef8922..31567f2 100644
--- a/testSDL.c
+++ b/testSDL.c
@@ -18,8 +18,8 @@
 
 #define S3L_PIXEL_FUNCTION drawPixel
 
-#define S3L_RESOLUTION_X 110
-#define S3L_RESOLUTION_Y 88
+#define S3L_RESOLUTION_X 640
+#define S3L_RESOLUTION_Y 480
 
 #include "small3dlib.h"