afegit flicker a postfx

source/core/rendering/screen.cpp

@@ -475,7 +475,7 @@ void Screen::applyCurrentPostFXPreset() {
         // setOversample primero: puede recrear texturas antes de que setPostFXParams
         // decida si hornear scanlines en CPU o aplicarlas en GPU.
         shader_backend_->setOversample(Options::video.supersampling ? 3 : 1);
-        Rendering::PostFXParams params{.vignette = p.vignette, .scanlines = p.scanlines, .chroma = p.chroma, .mask = p.mask, .gamma = p.gamma, .curvature = p.curvature, .bleeding = p.bleeding};
+        Rendering::PostFXParams params{.vignette = p.vignette, .scanlines = p.scanlines, .chroma = p.chroma, .mask = p.mask, .gamma = p.gamma, .curvature = p.curvature, .bleeding = p.bleeding, .flicker = p.flicker};
         shader_backend_->setPostFXParams(params);
     }
 }

source/core/rendering/sdl3gpu/sdl3gpu_shader.cpp

@@ -57,7 +57,7 @@ struct PostFXUniforms {
     float pixel_scale;
     float time;
     float oversample;  // 1.0 = sin SS, 3.0 = 3× supersampling
-    float pad1;
+    float flicker;     // 0 = off, 1 = phosphor flicker ~50 Hz
 };
 
 // YCbCr helpers for NTSC bleeding
@@ -119,8 +119,8 @@ fragment float4 postfx_fs(PostVOut                 in    [[stage_in]],
         colour = base;
     }
 
-    // Aberración cromática
-    float ca = u.chroma_strength * 0.005f;
+    // Aberración cromática (drift animado con time para efecto NTSC real)
+    float ca = u.chroma_strength * 0.005f * (1.0f + 0.15f * sin(u.time * 7.3f));
     colour.r = scene.sample(samp, uv + float2(ca, 0.0f)).r;
     colour.b = scene.sample(samp, uv - float2(ca, 0.0f)).b;
 
@@ -165,6 +165,12 @@ fragment float4 postfx_fs(PostVOut                 in    [[stage_in]],
         colour = mix(colour, colour * mask, u.mask_strength);
     }
 
+    // Parpadeo de fósforo CRT (~50 Hz)
+    if (u.flicker > 0.0f) {
+        float flicker_wave = sin(u.time * 100.0f) * 0.5f + 0.5f;
+        colour *= 1.0f - u.flicker * 0.04f * flicker_wave;
+    }
+
     return float4(colour, 1.0f);
 }
 )";
@@ -627,6 +633,7 @@ namespace Rendering {
         uniforms_.gamma_strength    = p.gamma;
         uniforms_.curvature         = p.curvature;
         uniforms_.bleeding          = p.bleeding;
+        uniforms_.flicker           = p.flicker;
 
         // Con supersampling las scanlines se hornean en CPU (uploadPixels).
         // El shader recibe strength=0 para no aplicarlas de nuevo en GPU.

source/core/rendering/sdl3gpu/sdl3gpu_shader.hpp

@@ -20,7 +20,7 @@ struct PostFXUniforms {
     float pixel_scale;        // physical pixels per logical pixel (vh / tex_height_)
     float time;               // seconds since SDL init (SDL_GetTicks() / 1000.0f)
     float oversample;         // supersampling factor (1.0 = off, 3.0 = 3×SS)
-    float pad1;               // padding — keep struct at 48 bytes (3 × 16)
+    float flicker;            // 0 = off, 1 = phosphor flicker ~50 Hz — keep struct at 48 bytes (3 × 16)
 };
 
 namespace Rendering {

source/core/rendering/shader_backend.hpp

@@ -18,6 +18,7 @@ namespace Rendering {
         float gamma = 0.0F;       // Corrección gamma (blend 0=off, 1=full)
         float curvature = 0.0F;   // Curvatura barrel CRT
         float bleeding = 0.0F;    // Sangrado de color NTSC
+        float flicker = 0.0F;    // Parpadeo de fósforo CRT ~50 Hz
     };
 
     /**