Elixirでraylibを使ってグラフィック描画してみる その3 〜 raylibの定義から円を描く 〜

前回

無理やり円を描きました

今回

raylib本来の円を描く命令を使います
rayexには円を描く命令が定義してないので追加したいと思います

rayexを改造して円を描く命令を定義する

draw_lineを真似してdraw_circleを追加します

c_src/rayex/rayex.c

//　省略

 UNIFEX_TERM draw_line(UnifexEnv *env, int start_x, int start_y, int end_x,
                       int end_y, color c) {
   DrawLine(start_x, start_y, end_x, end_y, COLOR(c));
   return draw_pixel_result_ok(env);
 }

+ UNIFEX_TERM draw_circle(UnifexEnv *env, int center_x, int center_y, double radius,
+                        color c) {
+  DrawCircle(center_x, center_y, radius, COLOR(c));
+  return draw_pixel_result_ok(env);
+ }

// 省略

c_src/rayex/rayex.spec.exs

spec draw_line(start_x :: int, start_y :: int, end_x :: int, end_y :: int, color :: color) ::
       :ok :: label

+ spec draw_circle(center_x :: int, center_y :: int, radius :: float, color :: color) ::
+       :ok :: label

lib/rayex/shapes.ex

 # 省略
   @spec draw_line(integer(), integer(), integer(), integer(), S.Color.t()) :: :ok
   defdelegate draw_line(start_x, start_y, end_x, end_y, color), to: Raylib

+  @doc "Draw a circle"
+  @spec draw_circle(integer(), integer(), float(), S.Color.t()) :: :ok
+  defdelegate draw_circle(center_x, center_y, radius, color), to: Raylib
# 省略

実行側のプログラムを作る

ローカルにあるrayexに変更します

mix.exs

defmodule RayexExperiment.MixProject do
  use Mix.Project

  def project do
    [
      app: :rayex_experiment,
      version: "0.1.0",
      elixir: "~> 1.17",
      start_permanent: Mix.env() == :prod,
      deps: deps()
    ]
  end

  # Run "mix help compile.app" to learn about applications.
  def application do
    [
      extra_applications: [:logger]
    ]
  end

  # Run "mix help deps" to learn about dependencies.
  defp deps do
    [
-      {:rayex, "~> 0.0.3"}
+      {:rayex, path: "../rayex", override: true}
      # {:dep_from_hexpm, "~> 0.3.0"},
      # {:dep_from_git, git: "https://github.com/elixir-lang/my_dep.git", tag: "0.1.0"}
    ]
  end
end

円を描くプログラム
draw_circleを呼び出します

lib/rayex_circle.ex

defmodule RayexCircle do
  use Rayex

  def main() do
    init_window(800, 800, "window name")
    main_loop(true)
  end

  defp main_loop(true) do
    begin_drawing()
    draw_circle(400, 400, 100.0, %{r: 255, g: 161, b: 0, a: 255})

    end_drawing()

    Process.sleep(1000)
    main_loop(!window_should_close())
  end

  defp main_loop(_), do: nil
end

mix exeコマンド追加

lib/mix/tasks/exe.ex

defmodule Mix.Tasks.Exe do
  use Mix.Task

  def run(_arg) do
    RayexCircle.main()
  end
end

実行

$ mix exe