From 5f6c8dd8e627c15d1b5889cb062abda2ace96495 Mon Sep 17 00:00:00 2001
From: veclavtalica <veclavtalica@tutamail.com>
Date: Mon, 13 Jan 2025 17:35:50 +0300
Subject: [PATCH] missing texture when loading fails

---
 src/twn_textures.c | 42 ++++++++++++++++++++++++++++++++++++++++--
 1 file changed, 40 insertions(+), 2 deletions(-)

diff --git a/src/twn_textures.c b/src/twn_textures.c
index c64527a..4b618dd 100644
--- a/src/twn_textures.c
+++ b/src/twn_textures.c
@@ -40,6 +40,43 @@ static int load_eof_callback(void *user) {
     return context->position == context->size;
 }
 
+
+static uint8_t *missing_texture_data;
+
+static SDL_Surface *gen_missing_texture_surface(void) {
+    Uint32 rmask, gmask, bmask, amask;
+
+    #if SDL_BYTEORDER == SDL_BIG_ENDIAN
+        rmask = 0xff000000;
+        gmask = 0x00ff0000;
+        bmask = 0x0000ff00;
+    #else
+        rmask = 0x000000ff;
+        gmask = 0x0000ff00;
+        bmask = 0x00ff0000;
+    #endif
+
+    if (!missing_texture_data) {
+        missing_texture_data = SDL_malloc(64 * 64 * 3);
+        for (int y = 0; y < 64; ++y)
+            for (int x = 0; x < 64; ++x) {
+                /* diagonal stripes, chosen so that asked pixel uvs are corresponding to final output */
+                missing_texture_data[(y * 64 + x) * 3 + 0] = (x / 2 + y / 2) % 2 == 0 ? 175 : 0;
+                missing_texture_data[(y * 64 + x) * 3 + 1] = (x / 2 + y / 2) % 2 == 0 ? 0 : 0;
+                missing_texture_data[(y * 64 + x) * 3 + 2] = (x / 2 + y / 2) % 2 == 0 ? 175 : 0;
+            }
+    }
+
+    /* same data is reused after being allocated/generated once */
+    SDL_Surface* surface = SDL_CreateRGBSurfaceFrom(missing_texture_data, 64, 64,
+                                                    3 * 8,
+                                                    64 * 3,
+                                                    rmask, gmask, bmask, 0);
+
+    return surface;
+}
+
+
 SDL_Surface *textures_load_surface(const char *path) {
     SDL_RWops *handle = PHYSFSRWOPS_openRead(path);
     if (handle == NULL)
@@ -93,8 +130,9 @@ ERR_CANNOT_CREATE_SURFACE:
 
 ERR_CANNOT_READ_IMAGE:
 ERR_CANNOT_OPEN_FILE:
-    CRY(path, "Failed to load image. Aborting...");
-    die_abruptly();
+    /* something didn't worked out, use a stub texture */
+    log_warn("Cannot open image: %s, using a stub", path);
+    return gen_missing_texture_surface();
 }