void Window::RenderLine(Renderer &renderer, const TileSet &tileset, TileSet::Number tileset_number,
const TileMap &tilemap, const Palette &window_palette, uint8_t current_line) const
{
// When a new frame begins, reset to beginning of Window
if (0 == current_line)
{
line_to_be_rendered_ = 0;
}
if (window_on_)
{
// There is nothing to draw for lines before the vertical position of the window
if (current_line < window_position_y_)
{
return;
}
// The line (of the tiles) to be drawn, depending on the vertical scroll of the background and the current line being drawn (last 3 bits, 0-7)
const uint8_t line_in_tile{ static_cast<uint8_t>(line_to_be_rendered_ & 0x07) };
// There is nothing to draw for pixels before the horizontal position of the window
size_t pixels_drawn = window_position_x_;
while (pixels_drawn < screen_width_)
{
const auto tile_number = tilemap.GetTileNumber(line_to_be_rendered_, pixels_drawn);
const auto& tile = tileset.GetTile(tileset_number, tile_number);
for (auto x_in_tile = 0; (x_in_tile < tile.GetWidth()) && (pixels_drawn < screen_width_); x_in_tile++)
{
try
{
const auto color = window_palette.GetColor(tile.ReadPixel(x_in_tile, line_in_tile));
renderer.RenderPixel(pixels_drawn, current_line, color);
}
catch (std::out_of_range &)
{
throw std::runtime_error("Trying to access invalid palette");
}
pixels_drawn += 1;
}
}
// Only increase the line to be rendered if the window is enabled
line_to_be_rendered_ += 1;
}
}
void Background::RenderLine(Renderer &renderer, const TileSet &tileset, TileSet::Number tileset_number,
const TileMap &tilemap, const Palette &bg_palette, uint8_t current_line) const
{
if (background_on_)
{
// The pixel offset inside the first tile to be drawn, depending on the horizontal scroll of the background (last 3 bits, 0-7)
size_t x_offset_in_tile = bg_scroll_x_ & 0x07;
// The line (of the tiles) to be drawn, depending on the vertical scroll of the background and the current line being drawn (last 3 bits, 0-7)
const uint8_t line_in_tile{ static_cast<uint8_t>((current_line + bg_scroll_y_) & 0x07) };
size_t pixels_rendered = 0;
while (pixels_rendered < screen_width_)
{
const auto tile_number = tilemap.GetTileNumber(current_line + bg_scroll_y_, pixels_rendered + bg_scroll_x_);
const auto& tile = tileset.GetTile(tileset_number, tile_number);
for (auto x_in_tile = x_offset_in_tile; (x_in_tile < tile.GetWidth()) && (pixels_rendered < screen_width_); x_in_tile++)
{
try
{
const auto color = bg_palette.GetColor(tile.ReadPixel(x_in_tile, line_in_tile));
renderer.RenderPixel(pixels_rendered, current_line, color);
}
catch (std::out_of_range &)
{
throw std::runtime_error("Trying to access invalid palette");
}
pixels_rendered += 1;
}
// For all tiles except the first one, the whole tile is to be rendered, so there is no offset whatsoever
x_offset_in_tile = 0;
}
}
}
