From 9dd37f6d4013311640a9e09742bb459da539eeae Mon Sep 17 00:00:00 2001
From: Sven Balzer <4653051+Kyuusokuna@users.noreply.github.com>
Date: Thu, 2 Apr 2026 17:02:16 +0200
Subject: [PATCH] replace the x64 specific change_map_tile() with a generic c
 implementation

---
 src/main.cpp | 31 +++++++++++++++++--------------
 1 file changed, 17 insertions(+), 14 deletions(-)

diff --git a/src/main.cpp b/src/main.cpp
index 2fce5f9..6e7fdce 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -1230,28 +1230,31 @@ static Uint32 find_matching_tile(Uint32 corner_info) {
 }
 
 static void change_map_tile(Sint32 pos_x, Sint32 pos_y, TileKind kind) {
-    __m128i corner_infos = _mm_setr_epi32(get_corner_info(pos_x, pos_y + 1), get_corner_info(pos_x + 1, pos_y + 1), get_corner_info(pos_x + 1, pos_y), get_corner_info(pos_x, pos_y));
-    __m128i none_mask    = _mm_cmpeq_epi8(corner_infos, _mm_set1_epi8(TILEKIND_NONE));
-    __m128i error_mask   = _mm_cmpeq_epi8(corner_infos, _mm_set1_epi8(TILEKIND_ERROR));
-    __m128i kind_mask    = _mm_setr_epi32(0x0000ff00, 0x000000ff, 0xff000000, 0x00ff0000);
-    __m128i replace_mask = _mm_or_si128(_mm_or_si128(none_mask, kind_mask), error_mask);
-    corner_infos = _mm_andnot_si128(replace_mask, corner_infos);
-    corner_infos = _mm_or_si128(corner_infos, _mm_and_si128(replace_mask, _mm_set1_epi8(kind)));
+    const Uint32 INFO_NONE     = ((TILEKIND_NONE  << 24) | (TILEKIND_NONE  << 16) | (TILEKIND_NONE  << 8) | TILEKIND_NONE);
+    const Uint32 INFO_ERROR    = ((TILEKIND_ERROR << 24) | (TILEKIND_ERROR << 16) | (TILEKIND_ERROR << 8) | TILEKIND_ERROR);
+    const Uint32 INFO_MASKS[4] = { 0x0000ff00, 0x000000ff, 0xff000000, 0x00ff0000 };
 
-    Uint32 corner_infos_u32[4];
-    _mm_storeu_si128((__m128i *)&corner_infos_u32, corner_infos);
+    Uint32 corner_infos[4] = { get_corner_info(pos_x + 0, pos_y + 1), get_corner_info(pos_x + 1, pos_y + 1), get_corner_info(pos_x + 1, pos_y + 0), get_corner_info(pos_x + 0, pos_y + 0) };
 
-    if (0 <= pos_x + 0 && pos_x + 0 < current_map.width && 0 <= pos_y + 1 && pos_y + 1 < current_map.height)
-        current_map.tiles[(pos_y + 1) * current_map.width + pos_x + 0] = find_matching_tile(corner_infos_u32[0]);
+    for (int i = 0; i < 4; i++) {
+        Uint32 replace_mask = INFO_MASKS[i];
+        if ((corner_infos[i] == INFO_NONE) | (corner_infos[i] == INFO_ERROR))
+            replace_mask = 0xffffffff;
+        
+        corner_infos[i] = corner_infos[i] ^ ((corner_infos[i] ^ ((kind << 24) | (kind << 16) | (kind << 8) | kind)) & replace_mask);
+    }
     
+    if (0 <= pos_x + 0 && pos_x + 0 < current_map.width && 0 <= pos_y + 1 && pos_y + 1 < current_map.height)
+        current_map.tiles[(pos_y + 1) * current_map.width + pos_x + 0] = find_matching_tile(corner_infos[0]);
+
     if (0 <= pos_x + 1 && pos_x + 1 < current_map.width && 0 <= pos_y + 1 && pos_y + 1 < current_map.height)
-        current_map.tiles[(pos_y + 1) * current_map.width + pos_x + 1] = find_matching_tile(corner_infos_u32[1]);
+        current_map.tiles[(pos_y + 1) * current_map.width + pos_x + 1] = find_matching_tile(corner_infos[1]);
     
     if (0 <= pos_x + 1 && pos_x + 1 < current_map.width && 0 <= pos_y + 0 && pos_y + 0 < current_map.height)
-        current_map.tiles[(pos_y + 0) * current_map.width + pos_x + 1] = find_matching_tile(corner_infos_u32[2]);
+        current_map.tiles[(pos_y + 0) * current_map.width + pos_x + 1] = find_matching_tile(corner_infos[2]);
     
     if (0 <= pos_x + 0 && pos_x + 0 < current_map.width && 0 <= pos_y + 0 && pos_y + 0 < current_map.height)
-        current_map.tiles[(pos_y + 0) * current_map.width + pos_x + 0] = find_matching_tile(corner_infos_u32[3]);
+        current_map.tiles[(pos_y + 0) * current_map.width + pos_x + 0] = find_matching_tile(corner_infos[3]);
 
     update_buffer(current_map.gpu_buffer, 0, current_map.width * current_map.height * sizeof(Uint32), current_map.tiles);
 }