Module: Doom::Game::FramebufferBlitter

Included in:
Intermission, Menu
Defined in:
lib/doom/game/framebuffer_blitter.rb

Overview

Shared framebuffer blitting for the full-screen menu and intermission screens. Both draw palette-index sprites into a flat 320x240 framebuffer, so the clipping loop lived duplicated in each. It lives here once and uses the renderer's screen constants instead of hardcoded 320/240.

A "sprite" here is anything exposing #width and #column_pixels(x), where a column is an array of palette indices (nil = transparent).

Instance Method Summary collapse

Instance Method Details

#blit_sprite(framebuffer, sprite, x, y) ⇒ Object

Blit a sprite's opaque pixels at (x, y), clipping to the screen.



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# File 'lib/doom/game/framebuffer_blitter.rb', line 14

def blit_sprite(framebuffer, sprite, x, y)
  return unless sprite

  w = Render::SCREEN_WIDTH
  h = Render::SCREEN_HEIGHT
  sprite.width.times do |col_x|
    sx = x + col_x
    next if sx < 0 || sx >= w

    col = sprite.column_pixels(col_x)
    next unless col

    col.each_with_index do |color, col_y|
      next unless color

      sy = y + col_y
      next if sy < 0 || sy >= h

      framebuffer[(sy * w) + sx] = color
    end
  end
end