tetris: swap colors on level change

src/tetris/main.h

@@ -10,7 +10,7 @@ bool IOLoop(ncpp::NotCurses& nc, Tetris& t, std::atomic_bool& gameover) {
     switch(input){
       case NCKEY_LEFT: case 'h': t.MoveLeft(); break;
       case NCKEY_RIGHT: case 'l': t.MoveRight(); break;
-      case NCKEY_DOWN: case 'j': t.MoveDown(); break;
+      case NCKEY_DOWN: case 'j': { if(t.MoveDown()){ gameover = true; } break; }
       case 'L': if(ni.ctrl){ nc.refresh(nullptr, nullptr); } break;
       case 'z': t.RotateCcw(); break;
       case 'x': t.RotateCw(); break;
@@ -32,7 +32,7 @@ int main(void) {
   srand(time(nullptr));
   std::atomic_bool gameover = false;
   notcurses_options ncopts{};
-  ncopts.flags = NCOPTION_INHIBIT_SETLOCALE;
+  ncopts.flags = NCOPTION_INHIBIT_SETLOCALE | NCOPTION_NO_ALTERNATE_SCREEN;
   ncpp::NotCurses nc(ncopts);
   {
     Tetris t{nc, gameover};

src/tetris/stain.h

@@ -1,10 +1,17 @@
 void StainBoard(int dimy, int dimx){
   board_->cursor_move(0, 1);
-  int high = 0xff - level_ * 16, low = level_ * 16; // rgb calculation limits us to 16 levels (0--15)
+  const int l = level_ - 1;
+  int high = 0xff - l * 0x10, low = l * 0x20; // rgb calculation limits us to 16 levels (1--16)
+  int green = 0;
+  if(low >= 0x100){
+    low = low % 0x100;
+    green = (l - 8) * 0x20;
+  }
   uint64_t tl = 0, tr = 0, bl = 0, br = 0;
-  channels_set_fg_rgb(&tl, high, 0xff, low); channels_set_bg_alpha(&tl, CELL_ALPHA_TRANSPARENT);
-  channels_set_fg_rgb(&tr, low, high, 0xff); channels_set_bg_alpha(&tr, CELL_ALPHA_TRANSPARENT);
-  channels_set_fg_rgb(&bl, 0xff, low, high); channels_set_bg_alpha(&bl, CELL_ALPHA_TRANSPARENT);
-  channels_set_fg_rgb(&br, 0xff, high, low); channels_set_bg_alpha(&br, CELL_ALPHA_TRANSPARENT);
+  const int c1 = level_ % 2 ? high : low; const int c2 = level_ % 2 ? low : high;
+  channels_set_fg_rgb(&tl, c1, green, c2); channels_set_bg_alpha(&tl, CELL_ALPHA_TRANSPARENT);
+  channels_set_fg_rgb(&tr, c2, green, c1); channels_set_bg_alpha(&tr, CELL_ALPHA_TRANSPARENT);
+  channels_set_fg_rgb(&bl, c2, green, c1); channels_set_bg_alpha(&bl, CELL_ALPHA_TRANSPARENT);
+  channels_set_fg_rgb(&br, c1, green, c2); channels_set_bg_alpha(&br, CELL_ALPHA_TRANSPARENT);
   board_->stain(dimy - 2, dimx - 2, tl, tr, bl, br);
 }