diff --git a/src/hardware/r_opengl/r_opengl.c b/src/hardware/r_opengl/r_opengl.c
index 92af4e127..2878a0bef 100644
--- a/src/hardware/r_opengl/r_opengl.c
+++ b/src/hardware/r_opengl/r_opengl.c
@@ -1603,7 +1603,7 @@ EXPORT void HWRAPI(ReadScreenFinalTexture) (UINT8 * restrict dest, INT32 scale)
 		image -= screen_width*scale*3;
 		if (scale == 1)
 			memcpy(dest, image, stride);
-		else for (size_t i = 0; i < stride; i += 3)
+		else for (INT32 i = 0; i < stride; i += 3)
 			memcpy(dest + i, image + i*scale, 3);
 		dest += stride;
 	}