tetris: different colors for different levels

src/tetris/lock.h

@@ -1,22 +1,27 @@
+void StainBoard(int dimy, int dimx){
+  if(!board_->cursor_move(0, 1)){
+    throw TetrisNotcursesErr("cursor_move()");
+  }
+  int high = 0xff - level_ * 16, low = level_ * 16; // rgb calculation limits us to 16 levels (0--15)
+  uint64_t tl = 0, tr = 0, bl = 0, br = 0;
+  channels_set_fg_rgb(&tl, high, 0, low); channels_set_bg_alpha(&tl, CELL_ALPHA_TRANSPARENT);
+  channels_set_fg_rgb(&tr, low, high, 0); channels_set_bg_alpha(&tr, CELL_ALPHA_TRANSPARENT);
+  channels_set_fg_rgb(&bl, 0, low, high); channels_set_bg_alpha(&bl, CELL_ALPHA_TRANSPARENT);
+  channels_set_fg_rgb(&br, 0, high, low); channels_set_bg_alpha(&br, CELL_ALPHA_TRANSPARENT);
+  if(!board_->stain(dimy - 2, dimx - 2, tl, tr, bl, br)){
+    throw TetrisNotcursesErr("stain()");
+  }
+}
+
 void LockPiece(){
   curpiece_->mergedown(*board_);
   int bdimy, bdimx;
   board_->get_dim(&bdimy, &bdimx);
   int cleared; // how many contiguous lines were cleared
   do{
-    uint64_t tl = 0, tr = 0, bl = 0, br = 0;
-    channels_set_fg(&tl, 0xff0000); channels_set_bg_alpha(&tl, CELL_ALPHA_TRANSPARENT);
-    channels_set_fg(&tr, 0x00ff00); channels_set_bg_alpha(&tr, CELL_ALPHA_TRANSPARENT);
-    channels_set_fg(&bl, 0x0000ff); channels_set_bg_alpha(&bl, CELL_ALPHA_TRANSPARENT);
-    channels_set_fg(&br, 0x00ffff); channels_set_bg_alpha(&br, CELL_ALPHA_TRANSPARENT);
-    if(!board_->cursor_move(0, 1)){
-      throw TetrisNotcursesErr("cursor_move()");
-    }
-    if(!board_->stain(bdimy - 2, bdimx - 2, tl, tr, bl, br)){
-      throw TetrisNotcursesErr("stain()");
-    }
     cleared = 0;
     int y;
+    StainBoard(bdimy, bdimx);
     for(y = bdimy - 2 ; y > 0 ; --y){ // get the lowest cleared area
       if(LineClear(y)){
         ++cleared;
@@ -44,6 +49,7 @@ void LockPiece(){
       static constexpr int points[] = {50, 150, 350, 1000};
       score_ += (level_ + 1) * points[cleared - 1];
       level_ = linescleared_ / 10;
+      StainBoard(bdimy, bdimx);
       UpdateScore();
     }
   }while(cleared);