tile.cpp as of 2024-04-26

#include <tile.hpp>

using namespace kit;





void Scene::drawBg(){
  if(bmp_bg == nullptr) return;
  shape::point sizeBmp = bmp_bg->getSize();
  if(sizeBmp.x<1 || sizeBmp.y<1) return;


  if(stretch_bg){ //stretch entire background to entire canvas
    bmp_bg->blitRect();


  } else { //otherwise, repeat background bitmap in a tile pattern
    shape::rect dst; //destination rectangle
    dst.w = sizeBmp.x;
    dst.h = sizeBmp.y;

    shape::point sizeCanvas = gl_win->getCanvasSize();

    //increase x, then y until the entire canvas is drawn to
    for(dst.y = 0;  dst.y < sizeCanvas.y;  dst.y += dst.h)
    for(dst.x = 0;  dst.x < sizeCanvas.x;  dst.x += dst.w)
    {
      bmp_bg->blitRect(&dst, nullptr); //whole bitmap is used when src = nullptr
    }


  }

}





//note: if slowdown gets to a point where it's noticable,
 //implement a scene pattern cache
void Scene::drawTiles(bool drawForeground){
  Tile*              tiles = pat_mg;
  if(drawForeground) tiles = pat_fg;
  if(tiles == nullptr) return;

  if(tileset_a >= gl_tilesets_len  ||  tileset_b >= gl_tilesets_len)
    throw "tileset index is out of bounds";

  Bitmap* tileset[2];
  tileset[0] = gl_tilesets[tileset_a];
  tileset[1] = gl_tilesets[tileset_b];

  shape::rect src(0, 0, 24, 24); //determines section of tileset to copy from
  shape::rect dst(0, 0, 24, 24); //determines section of canvas to paste to

  shape::point sizeCanvas = gl_win->getCanvasSize();



  u32 tileindex = 0; //for accessing each tile independent of the 2 for loops

  //increase x, then y until the entire canvas is drawn to
  for(dst.y = 0;  dst.y < sizeCanvas.y;  dst.y += dst.h)
  for(dst.x = 0;  dst.x < sizeCanvas.x;  dst.x += dst.w)
  {
    Tile tile = tiles[tileindex++];
    if(!tile.id) continue; //tile 0 is always transparent, so it can be skipped
    src.x = ( tile.id    &0b1111) * src.w; //bits 0-3 are the tileset atlas' x
    src.y = ((tile.id>>4)& 0b111) * src.h; //bits 4-6 are the tileset atlas' y


    Bitmap* _tileset = tileset[tile.tileset]; //(tile.tileset is 1 bit in size)
    if(_tileset != nullptr){
      _tileset->blitRect(&dst, &src, 0xff00ff); //transparency color is magenta

    } else { //tileset doesn't exist; draw 'missing tileset' tile
      gl_tileset_missing->blitRect(&dst, nullptr); //transparency is not used

    }

  }

}