refactor textures access

src/assets/assets_util.cpp

@@ -0,0 +1,24 @@
+#include "assets_util.hpp"
+
+#include "assets/Assets.hpp"
+#include "graphics/core/Atlas.hpp"
+#include "graphics/core/Texture.hpp"
+
+util::TextureRegion util::getTextureRegion(
+    const Assets& assets, const std::string& name, const std::string& fallback
+) {
+    size_t sep = name.find(':');
+    if (sep == std::string::npos) {
+        return {assets.get<Texture>(name), UVRegion(0,0,1,1)};
+    } else {
+        auto atlas = assets.get<Atlas>(name.substr(0, sep));
+        if (atlas) {
+            if (auto reg = atlas->getIf(name.substr(sep+1))) {
+                return {atlas->getTexture(), *reg};
+            } else if (!fallback.empty()){
+                return util::getTextureRegion(assets, fallback, "");
+            }
+        }
+    }
+    return {nullptr, UVRegion()};
+}