fix: pantalla completa, integer scale i vsync

source/core/rendering/sdl3gpu/sdl3gpu_shader.cpp

@@ -2,7 +2,9 @@
 
 #include <SDL3/SDL_log.h>
 
-#include <cstring>  // memcpy, strlen
+#include <algorithm>  // std::min, std::max, std::floor
+#include <cmath>      // std::floor
+#include <cstring>    // memcpy, strlen
 
 #ifndef __APPLE__
 #include "core/rendering/sdl3gpu/postfx_frag_spv.h"
@@ -218,7 +220,7 @@ auto SDL3GPUShader::init(SDL_Window* window,
         }
         SDL_SetGPUSwapchainParameters(device_, window_,
             SDL_GPU_SWAPCHAINCOMPOSITION_SDR,
-            SDL_GPU_PRESENTMODE_VSYNC);
+            vsync_ ? SDL_GPU_PRESENTMODE_VSYNC : SDL_GPU_PRESENTMODE_IMMEDIATE);
     }
 
     // ----------------------------------------------------------------
@@ -410,6 +412,29 @@ void SDL3GPUShader::render() {
     if (pass != nullptr) {
         SDL_BindGPUGraphicsPipeline(pass, pipeline_);
 
+        // Calcular viewport para mantener relación de aspecto (letterbox o integer scale)
+        float vx = 0.0F;
+        float vy = 0.0F;
+        float vw = 0.0F;
+        float vh = 0.0F;
+        if (integer_scale_) {
+            const int scale = std::max(1, std::min(
+                static_cast<int>(sw) / tex_width_,
+                static_cast<int>(sh) / tex_height_));
+            vw = static_cast<float>(tex_width_ * scale);
+            vh = static_cast<float>(tex_height_ * scale);
+        } else {
+            const float scale = std::min(
+                static_cast<float>(sw) / static_cast<float>(tex_width_),
+                static_cast<float>(sh) / static_cast<float>(tex_height_));
+            vw = static_cast<float>(tex_width_) * scale;
+            vh = static_cast<float>(tex_height_) * scale;
+        }
+        vx = std::floor((static_cast<float>(sw) - vw) * 0.5F);
+        vy = std::floor((static_cast<float>(sh) - vh) * 0.5F);
+        SDL_GPUViewport vp = {vx, vy, vw, vh, 0.0F, 1.0F};
+        SDL_SetGPUViewport(pass, &vp);
+
         SDL_GPUTextureSamplerBinding binding = {};
         binding.texture = scene_texture_;
         binding.sampler = sampler_;
@@ -525,4 +550,17 @@ void SDL3GPUShader::setPostFXParams(const PostFXParams& p) {
     uniforms_.bleeding          = p.bleeding;
 }
 
+void SDL3GPUShader::setVSync(bool vsync) {
+    vsync_ = vsync;
+    if (device_ != nullptr && window_ != nullptr) {
+        SDL_SetGPUSwapchainParameters(device_, window_,
+            SDL_GPU_SWAPCHAINCOMPOSITION_SDR,
+            vsync_ ? SDL_GPU_PRESENTMODE_VSYNC : SDL_GPU_PRESENTMODE_IMMEDIATE);
+    }
+}
+
+void SDL3GPUShader::setScaleMode(bool integer_scale) {
+    integer_scale_ = integer_scale;
+}
+
 }  // namespace Rendering

source/core/rendering/sdl3gpu/sdl3gpu_shader.hpp

@@ -50,6 +50,12 @@ class SDL3GPUShader : public ShaderBackend {
         // Actualiza los parámetros de intensidad de los efectos PostFX
         void setPostFXParams(const PostFXParams& p) override;
 
+        // Activa/desactiva VSync en el swapchain
+        void setVSync(bool vsync) override;
+
+        // Activa/desactiva escalado entero (integer scale)
+        void setScaleMode(bool integer_scale) override;
+
     private:
         static auto createShaderMSL(SDL_GPUDevice* device,
             const char* msl_source,
@@ -80,6 +86,8 @@ class SDL3GPUShader : public ShaderBackend {
         int tex_width_ = 0;
         int tex_height_ = 0;
         bool is_initialized_ = false;
+        bool vsync_ = true;
+        bool integer_scale_ = false;
 };
 
 }  // namespace Rendering