feat: post-processing effects

src/assets/assetload_funcs.cpp

@@ -60,13 +60,7 @@ assetload::postfunc assetload::texture(
     }
 }
 
-assetload::postfunc assetload::shader(
-    AssetsLoader*,
-    const ResPaths& paths,
-    const std::string& filename,
-    const std::string& name,
-    const std::shared_ptr<AssetCfg>&
-) {
+static auto process_program(const ResPaths& paths, const std::string& filename) {
     io::path vertexFile = paths.find(filename + ".glslv");
     io::path fragmentFile = paths.find(filename + ".glslf");
 
@@ -75,8 +69,25 @@ assetload::postfunc assetload::shader(
 
     auto& preprocessor = *Shader::preprocessor;
 
-    vertexSource = preprocessor.process(vertexFile, vertexSource).code;
-    fragmentSource = preprocessor.process(fragmentFile, fragmentSource).code;
+    auto vertex = preprocessor.process(vertexFile, vertexSource);
+    auto fragment = preprocessor.process(fragmentFile, fragmentSource);
+    return std::make_pair(vertex, fragment);
+}
+
+assetload::postfunc assetload::shader(
+    AssetsLoader*,
+    const ResPaths& paths,
+    const std::string& filename,
+    const std::string& name,
+    const std::shared_ptr<AssetCfg>&
+) {
+    auto [vertex, fragment] = process_program(paths, filename);
+
+    io::path vertexFile = paths.find(filename + ".glslv");
+    io::path fragmentFile = paths.find(filename + ".glslf");
+
+    std::string vertexSource = std::move(vertex.code);
+    std::string fragmentSource = std::move(fragment.code);
 
     return [=](auto assets) {
         assets->store(
@@ -91,6 +102,40 @@ assetload::postfunc assetload::shader(
     };
 }
 
+assetload::postfunc assetload::posteffect(
+    AssetsLoader*,
+    const ResPaths& paths,
+    const std::string& file,
+    const std::string& name,
+    const std::shared_ptr<AssetCfg>& settings
+) {
+    io::path effectFile = paths.find(file + ".glsl");
+    std::string effectSource = io::read_string(effectFile);
+
+    auto& preprocessor = *Shader::preprocessor;
+    preprocessor.addHeader(
+        "__effect__", preprocessor.process(effectFile, effectSource, true)
+    );
+
+    auto [vertex, fragment] = process_program(paths, SHADERS_FOLDER + "/effect");
+    auto params = std::move(fragment.params);
+
+    std::string vertexSource = std::move(vertex.code);
+    std::string fragmentSource = std::move(fragment.code);
+
+    return [=](auto assets) {
+        auto program = Shader::create(
+            effectFile.string(),
+            effectFile.string(),
+            vertexSource,
+            fragmentSource
+        );
+        assets->store(
+            std::make_shared<PostEffect>(std::move(program), params), name
+        );
+    };
+}
+
 static bool append_atlas(AtlasBuilder& atlas, const io::path& file) {
     std::string name = file.stem();
     // skip duplicates