Better Steam path detection and build guide

1 files changed, 30 insertions, 4 deletions

diff --git a/src/engine/renderer.cpp b/src/engine/renderer.cpp
index 0be0e53..0ec6371 100644
--- a/src/engine/renderer.cpp
+++ b/src/engine/renderer.cpp
@@ -10,6 +10,35 @@
 #include <cmath>
 #include <vector>
 #include <algorithm>
+#include <string>
+#include <filesystem>
+
+namespace {
+
+// Root of a bring-your-own Forts install, used to resolve "forts:REL" texture
+// paths. Tries known developer install locations first, then the FORTS_DATA
+// override, and returns the first that exists on disk. Resolved once, cached.
+const std::string& forts_data_root() {
+    static const std::string root = [] {
+        std::vector<std::string> candidates = {
+            "/opt/steam/steamapps/common/Forts/data",              // Emil
+            "/mnt/games/SteamLibrary/steamapps/common/Forts/data", // Vaino
+        };
+        if (const char* env = std::getenv("FORTS_DATA")) {
+            candidates.emplace_back(env);
+        }
+        for (const auto& c : candidates) {
+            std::error_code ec;
+            if (std::filesystem::is_directory(c, ec)) return c;
+        }
+        // None present; return the override if set, else the first guess, so the
+        // failed-load message at least points somewhere meaningful.
+        return candidates.back();
+    }();
+    return root;
+}
+
+}  // namespace
 
 bool Renderer::init(SDL_Window* window, int width, int height) {
     width_  = width;
@@ -140,10 +169,7 @@ SDL_Texture* Renderer::load_texture(const std::string& path) {
     // files, like a Doom source port + WAD). Nothing is copied into the repo.
     std::string file = path;
     if (path.rfind("forts:", 0) == 0) {
-        const char* env = std::getenv("FORTS_DATA");
-        std::string root = env ? env
-            : "/mnt/games/SteamLibrary/steamapps/common/Forts/data";
-        file = root + "/" + path.substr(6);
+        file = forts_data_root() + "/" + path.substr(6);
     }
 
     int w = 0, h = 0, n = 0;