feat(transitions): mosaic dissolve fade-out al final de la fase STARTING (configurable a ui.yaml)

source/core/rendering/transitions/mosaic.cpp

@@ -0,0 +1,71 @@
+#include "core/rendering/transitions/mosaic.hpp"
+
+#include <algorithm>
+#include <cmath>
+#include <cstdint>
+
+#include "core/rendering/screen.hpp"
+
+namespace Transitions {
+
+    Mosaic::Mosaic(Params params)
+        : params_(params) {}
+
+    void Mosaic::begin(int duration_ms) {
+        duration_ms_ = duration_ms;
+        elapsed_ms_ = 0;
+    }
+
+    void Mosaic::tick(int delta_ms) {
+        if (duration_ms_ <= 0) { return; }
+        elapsed_ms_ = std::min(elapsed_ms_ + delta_ms, duration_ms_);
+    }
+
+    auto Mosaic::progress() const -> float {
+        if (duration_ms_ <= 0) { return 0.0F; }
+        return std::clamp(static_cast<float>(elapsed_ms_) / static_cast<float>(duration_ms_), 0.0F, 1.0F);
+    }
+
+    void Mosaic::render() const {
+        if (duration_ms_ <= 0) { return; }
+        const float P = progress();
+        const int MAX_BLOCK = std::max(1, params_.max_block_size);
+        // Blocs de mida creixent al llarg del fade. A p=0 → 1 px (sense
+        // efecte visible); a p=1 → max_block. Es fa cap-amunt amb ceil
+        // perquè el primer increment arribi aviat (el salt visual de
+        // 1→2 ja es nota).
+        const int BLOCK = std::clamp(static_cast<int>(std::ceil(static_cast<float>(MAX_BLOCK) * P)), 1, MAX_BLOCK);
+
+        auto& screen = Screen::get();
+        std::uint32_t* canvas = screen.getCanvasArgb();
+        const int W = screen.getCanvasWidth();
+        const int H = screen.getCanvasHeight();
+
+        if (BLOCK > 1) {
+            // Sample-and-fill in-place. Per a cada bloc, mostregem el
+            // píxel central (les vores poden caure fora del canvas en
+            // blocs de la última columna/fila → clamp).
+            for (int by = 0; by < H; by += BLOCK) {
+                const int Y_END = std::min(by + BLOCK, H);
+                const int SY = std::min(by + (BLOCK / 2), H - 1);
+                for (int bx = 0; bx < W; bx += BLOCK) {
+                    const int X_END = std::min(bx + BLOCK, W);
+                    const int SX = std::min(bx + (BLOCK / 2), W - 1);
+                    const std::uint32_t COLOR = canvas[(SY * W) + SX];
+                    for (int yy = by; yy < Y_END; ++yy) {
+                        std::uint32_t* row = canvas + (static_cast<std::ptrdiff_t>(yy) * W);
+                        std::fill(row + bx, row + X_END, COLOR);
+                    }
+                }
+            }
+        }
+
+        // Fade-to-black quadràtic per damunt: la mascara fosca arriba
+        // tard (a p=0.5 només 25% d'alpha) perquè es vegin els blocs.
+        const auto ALPHA = static_cast<std::uint8_t>(std::round(255.0F * P * P));
+        if (ALPHA > 0) {
+            screen.blendRect(0, 0, W, H, 0x00000000U, ALPHA);
+        }
+    }
+
+}  // namespace Transitions