feat: post-processing effects

src/graphics/core/PostEffect.cpp

@@ -8,10 +8,19 @@ PostEffect::Param::Param(Type type, Value defValue)
     : type(type), defValue(std::move(defValue)) {
 }
 
-PostEffect::PostEffect(std::unique_ptr<Shader> shader)
-    : shader(std::move(shader)) {
+PostEffect::PostEffect(
+    std::unique_ptr<Shader> shader,
+    std::unordered_map<std::string, Param> params
+)
+    : shader(std::move(shader)), params(std::move(params)) {
 }
 
-void PostEffect::use() {
+Shader& PostEffect::use() {
     shader->use();
+    shader->uniform1f("u_intensity", intensity);
+    return *shader;
+}
+
+void PostEffect::setIntensity(float value) {
+    intensity = value;
 }