fix: shaders on i off no afectaven a crtpi

source/core/input/global_inputs.cpp

@@ -78,8 +78,9 @@ namespace GlobalInputs {
         // F6 — Toggle supersampling
         bool ss = JI_KeyPressed(KeyConfig::scancode("toggle_supersampling"));
         if (ss && !ss_prev) {
-            Screen::get()->toggleSupersampling();
+            if (Screen::get()->toggleSupersampling()) {
-            Overlay::showNotification(Options::video.supersampling ? Locale::get("notifications.ss_on") : Locale::get("notifications.ss_off"));
+                Overlay::showNotification(Options::video.supersampling ? Locale::get("notifications.ss_on") : Locale::get("notifications.ss_off"));
+            }
         }
         if (ss) consumed = true;
         ss_prev = ss;
@@ -87,10 +88,11 @@ namespace GlobalInputs {
         // F7 — Canviar tipus de shader (PostFX ↔ CrtPi)
         bool next_shader = JI_KeyPressed(KeyConfig::scancode("next_shader"));
         if (next_shader && !next_shader_prev) {
-            Screen::get()->nextShaderType();
+            if (Screen::get()->nextShaderType()) {
-            char msg[64];
+                char msg[64];
-            snprintf(msg, sizeof(msg), "%s: %s", Screen::get()->getActiveShaderName(), Screen::get()->getCurrentPresetName());
+                snprintf(msg, sizeof(msg), "%s: %s", Screen::get()->getActiveShaderName(), Screen::get()->getCurrentPresetName());
-            Overlay::showNotification(msg);
+                Overlay::showNotification(msg);
+            }
         }
         if (next_shader) consumed = true;
         next_shader_prev = next_shader;
@@ -98,10 +100,11 @@ namespace GlobalInputs {
         // F8 — Pròxim preset del shader actiu
         bool next_preset = JI_KeyPressed(KeyConfig::scancode("next_shader_preset"));
         if (next_preset && !next_preset_prev) {
-            Screen::get()->nextPreset();
+            if (Screen::get()->nextPreset()) {
-            char msg[64];
+                char msg[64];
-            snprintf(msg, sizeof(msg), Locale::get("notifications.preset_fmt"), Screen::get()->getCurrentPresetName());
+                snprintf(msg, sizeof(msg), Locale::get("notifications.preset_fmt"), Screen::get()->getCurrentPresetName());
-            Overlay::showNotification(msg);
+                Overlay::showNotification(msg);
+            }
         }
         if (next_preset) consumed = true;
         next_preset_prev = next_preset;

source/core/rendering/screen.cpp

@@ -145,11 +145,22 @@ void Screen::present(Uint32* pixel_data) {
         shader_backend_->uploadPixels(pixel_data, GAME_WIDTH, GAME_HEIGHT);
         shader_backend_->render();
     } else if (shader_backend_ && shader_backend_->isHardwareAccelerated()) {
-        // GPU activa però shaders desactivats: renderitza net (sense efectes)
+        // GPU activa però shaders desactivats: renderitza net (sense efectes).
+        // Força POSTFX amb params zerats — altrament, si l'actiu és CRTPI,
+        // els seus efectes (scanlines, curvatura) seguirien aplicant-se encara
+        // que shader_enabled sigui false. Restaurem l'actiu al final per a
+        // no trencar la selecció de l'usuari.
         Rendering::PostFXParams clean{};
         shader_backend_->setPostFXParams(clean);
+        const auto prev_shader = shader_backend_->getActiveShader();
+        if (prev_shader != Rendering::ShaderType::POSTFX) {
+            shader_backend_->setActiveShader(Rendering::ShaderType::POSTFX);
+        }
         shader_backend_->uploadPixels(pixel_data, GAME_WIDTH, GAME_HEIGHT);
         shader_backend_->render();
+        if (prev_shader != Rendering::ShaderType::POSTFX) {
+            shader_backend_->setActiveShader(prev_shader);
+        }
     } else {
         // Fallback SDL_Renderer
         SDL_UpdateTexture(texture_, nullptr, pixel_data, GAME_WIDTH * sizeof(Uint32));
@@ -192,10 +203,16 @@ void Screen::toggleShaders() {
     }
 }
 
-void Screen::toggleSupersampling() {
+auto Screen::toggleSupersampling() -> bool {
-    if (!shader_backend_ || !shader_backend_->isHardwareAccelerated()) return;
+    // SS només té sentit amb shaders on i pipeline PostFX (el Lanczos downscale
+    // i el camí SS s'apliquen al pas de PostFX; CRTPI fa el seu propi
+    // submostreig intern i no usa aquesta via).
+    if (!shader_backend_ || !shader_backend_->isHardwareAccelerated()) return false;
+    if (!Options::video.shader_enabled) return false;
+    if (shader_backend_->getActiveShader() != Rendering::ShaderType::POSTFX) return false;
     Options::video.supersampling = !Options::video.supersampling;
     shader_backend_->setOversample(Options::video.supersampling ? 3 : 1);
+    return true;
 }
 
 void Screen::toggleAspectRatio() {
@@ -244,8 +261,9 @@ void Screen::cycleTextureFilter(int dir) {
     }
 }
 
-void Screen::nextShaderType() {
+auto Screen::nextShaderType() -> bool {
-    if (!shader_backend_ || !shader_backend_->isHardwareAccelerated()) return;
+    if (!shader_backend_ || !shader_backend_->isHardwareAccelerated()) return false;
+    if (!Options::video.shader_enabled) return false;
 
     if (shader_backend_->getActiveShader() == Rendering::ShaderType::POSTFX) {
         shader_backend_->setActiveShader(Rendering::ShaderType::CRTPI);
@@ -256,45 +274,50 @@ void Screen::nextShaderType() {
         Options::video.current_shader = "postfx";
         applyCurrentPostFXPreset();
     }
+    return true;
 }
 
-void Screen::nextPreset() {
+auto Screen::nextPreset() -> bool {
-    if (!shader_backend_ || !shader_backend_->isHardwareAccelerated()) return;
+    if (!shader_backend_ || !shader_backend_->isHardwareAccelerated()) return false;
+    if (!Options::video.shader_enabled) return false;
 
     if (shader_backend_->getActiveShader() == Rendering::ShaderType::POSTFX) {
-        if (Options::postfx_presets.empty()) return;
+        if (Options::postfx_presets.empty()) return false;
         Options::current_postfx_preset = (Options::current_postfx_preset + 1) % static_cast<int>(Options::postfx_presets.size());
         Options::video.current_postfx_preset = Options::postfx_presets[Options::current_postfx_preset].name;
         applyCurrentPostFXPreset();
     } else {
-        if (Options::crtpi_presets.empty()) return;
+        if (Options::crtpi_presets.empty()) return false;
         Options::current_crtpi_preset = (Options::current_crtpi_preset + 1) % static_cast<int>(Options::crtpi_presets.size());
         Options::video.current_crtpi_preset = Options::crtpi_presets[Options::current_crtpi_preset].name;
         applyCurrentCrtPiPreset();
     }
+    return true;
 }
 
-void Screen::prevShaderType() {
+auto Screen::prevShaderType() -> bool {
     // Només dues opcions — prev == next
-    nextShaderType();
+    return nextShaderType();
 }
 
-void Screen::prevPreset() {
+auto Screen::prevPreset() -> bool {
-    if (!shader_backend_ || !shader_backend_->isHardwareAccelerated()) return;
+    if (!shader_backend_ || !shader_backend_->isHardwareAccelerated()) return false;
+    if (!Options::video.shader_enabled) return false;
 
     if (shader_backend_->getActiveShader() == Rendering::ShaderType::POSTFX) {
-        if (Options::postfx_presets.empty()) return;
+        if (Options::postfx_presets.empty()) return false;
         int n = static_cast<int>(Options::postfx_presets.size());
         Options::current_postfx_preset = (Options::current_postfx_preset - 1 + n) % n;
         Options::video.current_postfx_preset = Options::postfx_presets[Options::current_postfx_preset].name;
         applyCurrentPostFXPreset();
     } else {
-        if (Options::crtpi_presets.empty()) return;
+        if (Options::crtpi_presets.empty()) return false;
         int n = static_cast<int>(Options::crtpi_presets.size());
         Options::current_crtpi_preset = (Options::current_crtpi_preset - 1 + n) % n;
         Options::video.current_crtpi_preset = Options::crtpi_presets[Options::current_crtpi_preset].name;
         applyCurrentCrtPiPreset();
     }
+    return true;
 }
 
 auto Screen::getCurrentPresetName() const -> const char* {

source/core/rendering/screen.hpp

@@ -23,16 +23,20 @@ class Screen {
     void setZoom(int zoom);
 
     // Shaders i vídeo
+    // Mètodes que depenen d'una precondició (GPU present, shaders on, etc.)
+    // retornen `bool`: true si l'acció s'ha aplicat, false si la precondició
+    // no es complia. Els callers (F-keys, menú) poden suprimir notificacions
+    // o feedback quan la crida no ha tingut efecte.
     void toggleShaders();
-    void toggleSupersampling();
+    auto toggleSupersampling() -> bool;                 // false si GPU off / shaders off / actiu != POSTFX
     void toggleAspectRatio();
-    void cycleScalingMode(int dir);    // Cicla DISABLED/STRETCH/LETTERBOX/OVERSCAN/INTEGER
+    void cycleScalingMode(int dir);                     // Cicla DISABLED/STRETCH/LETTERBOX/OVERSCAN/INTEGER
     void toggleVSync();
-    void cycleTextureFilter(int dir);  // Cicla NEAREST/LINEAR
+    void cycleTextureFilter(int dir);                   // Cicla NEAREST/LINEAR
-    void nextShaderType();  // Cicla PostFX ↔ CrtPi (F7)
+    auto nextShaderType() -> bool;                      // false si GPU off / shaders off
-    void prevShaderType();  // Cicla al revés
+    auto prevShaderType() -> bool;                      // idem
-    void nextPreset();      // Cicla presets del shader actiu (F8)
+    auto nextPreset() -> bool;                          // false si GPU off / shaders off
-    void prevPreset();      // Cicla presets al revés
+    auto prevPreset() -> bool;                          // idem
     [[nodiscard]] auto getCurrentPresetName() const -> const char*;
     void setActiveShader(Rendering::ShaderType type);
     void applyCurrentPostFXPreset();