postfx: scanlines analítiques amb smoothstep a l'estil crtpi, exposant forma per preset YAML

source/game/options.cpp

@@ -224,6 +224,9 @@ namespace {
         readField(node, "curvature", preset.curvature);
         readField(node, "bleeding", preset.bleeding);
         readField(node, "flicker", preset.flicker);
+        readField(node, "scan_dark_ratio", preset.scan_dark_ratio);
+        readField(node, "scan_dark_floor", preset.scan_dark_floor);
+        readField(node, "scan_edge_soft", preset.scan_edge_soft);
     }
 
     void writePostFXPreset(std::ostringstream& out, const Options::PostFXPreset& preset) {
@@ -236,6 +239,9 @@ namespace {
         out << "    curvature: " << preset.curvature << "\n";
         out << "    bleeding: " << preset.bleeding << "\n";
         out << "    flicker: " << preset.flicker << "\n";
+        out << "    scan_dark_ratio: " << preset.scan_dark_ratio << "\n";
+        out << "    scan_dark_floor: " << preset.scan_dark_floor << "\n";
+        out << "    scan_edge_soft: " << preset.scan_edge_soft << "\n";
     }
 
     // Presets per defecte del shader CRT-Pi, portats de projecte_2026.
@@ -642,6 +648,9 @@ namespace Options {
             .curvature = IT->curvature,
             .bleeding = IT->bleeding,
             .flicker = IT->flicker,
+            .scan_dark_ratio = IT->scan_dark_ratio,
+            .scan_dark_floor = IT->scan_dark_floor,
+            .scan_edge_soft = IT->scan_edge_soft,
         };
     }
 

source/game/options.hpp

@@ -53,6 +53,10 @@ namespace Options {
         float curvature{0.0F};
         float bleeding{0.0F};
         float flicker{0.0F};
+        // Forma de les scanlines (3 subpíxels per fila lògica per defecte).
+        float scan_dark_ratio{0.333F};
+        float scan_dark_floor{0.42F};
+        float scan_edge_soft{1.0F};
     };
 
     // Preset del shader CRT-Pi (un per entrada a crtpi.yaml).