Enhances audio effects.Adds TitleScene.

src/GlitchPosteffect.h

@@ -0,0 +1,48 @@
+#pragma once
+
+#include <cstring>
+#include <cmath>
+
+#include "iDrawable.h"
+
+
+namespace gj {
+
+
+class GlitchPosteffect : public iDrawable {
+ public:
+  GlitchPosteffect(GlitchPosteffect&&) = delete;
+  GlitchPosteffect(const GlitchPosteffect&) = delete;
+
+  GlitchPosteffect& operator=(GlitchPosteffect&&) = delete;
+  GlitchPosteffect& operator=(const GlitchPosteffect&) = delete;
+  
+  GlitchPosteffect() {
+  }
+
+  void Draw(Colorbuffer& fb) const override {
+    const int32_t w = static_cast<int32_t>(fb.width());
+    const int32_t h = static_cast<int32_t>(fb.height());
+
+    float* ptr = fb.ptr();
+
+    for (int32_t y = 0; y < h; ++y) {
+      const double shift = (XorShift(seed+y)%100/100.*2-1)*maxShift;
+      const int32_t s = static_cast<int32_t>(w*shift);
+      if (std::abs(shift) > 1) continue;
+      
+      const size_t offset = static_cast<size_t>(y) * w;
+      float* src = ptr + offset;
+      float* dst = ptr + offset + s;
+      if (src > dst) std::swap(src, dst);
+
+      std::memmove(dst, src, static_cast<size_t>(w) - std::abs(s));
+    }
+  }
+
+  uint64_t seed     = 1;
+  double   maxShift = 0;
+};
+
+
+}