require 'gosu'

class Map
    def initialize(width, height)
        @width = width
        @height = height
        @origin_x = width / 2
        @origin_y = height / 2
    end

    def transform_x(x, y, z)
        cart_x = (x - z) * Math.cos(0.46365)
        cart_x + @origin_x
    end

    def transform_y(x, y, z)
        cart_y = y + (x + z) * Math.sin(0.46365)
        -cart_y + @origin_y
    end
end

class GameWindow < Gosu::Window
    def initialize
        super(640, 480, false)
        self.caption = "Iso"
        @map = Map.new(640, 480)
    end

    def draw
        draw_box(0, 0, 0, 100, 100, 100, Gosu::Color::BLUE)
        draw_box(0, 0, 200, 40, 80, 40, Gosu::Color::RED)
        draw_axes
    end

    def draw_axes
        draw_line_to(0, 0, 0, 200, 0, 0, Gosu::Color::GREEN)
        draw_line_to(0, 0, 0, 0, 200, 0, Gosu::Color::RED)
        draw_line_to(0, 0, 0, 0, 0, 200, Gosu::Color::YELLOW)
    end

    def draw_line_to(x1, y1, z1, x2, y2, z2, color)
        draw_line(@map.transform_x(x1, y1, z1),
                  @map.transform_y(x1, y1, z1),
                  color,
                  @map.transform_x(x2, y2, z2),
                  @map.transform_y(x2, y2, z2),
                  color)
    end

    def draw_box(x, y, z, width, height, depth, color)
        draw_line_to(x, y, z, x+width, y, z, color)
        draw_line_to(x, y, z, x, y+depth, z, color)
        draw_line_to(x, y, z, x, y, z+height, color)
        draw_line_to(x, y+depth, z, x+width, y+depth, z, color)
        draw_line_to(x+width, y, z, x+width, y+depth, z, color)
        draw_line_to(x, y+depth, z, x, y+depth, z+height, color)
        draw_line_to(x, y, z+height, x, y+depth, z+height, color)
        draw_line_to(x, y, z+height, x+width, y, z+height, color)
        draw_line_to(x, y+depth, z+height, x+width, y+depth, z+height, color)
        draw_line_to(x+width, y, z+height, x+width, y+depth, z+height, color)
        draw_line_to(x+width, y+depth, z+height, x+width, y+depth, z, color)
        draw_line_to(x+width, y, z+height, x+width, y, z, color)
    end
end

window = GameWindow.new
window.show