#!ruby -Ks
# -*- mode: ruby; encoding: sjis -*-
# Last updated: <2014/01/13 07:36:15 +0900>
#
# Shaderを使ってラスタスクロールのテスト
# 天井、壁、床をラスタースクロールさせるっぽい感じの処理

require 'dxruby'

hlsl = <<EOS
  float2 size;
  float d;
  float dd;
  texture tex0;

  sampler Samp0 = sampler_state
  {
    Texture =<tex0>;

    // こっちだと画面がチラチラする (´･ω･｀)
    // MinFilter = LINEAR;
    // MagFilter = LINEAR;
    // MipFilter = LINEAR;

    // こっちならチラチラしない
    MinFilter = POINT;
    MagFilter = POINT;
    MipFilter = NONE;

    AddressU = WRAP;
    AddressV = WRAP;
  };

  struct PixelIn
  {
    float2 UV : TEXCOORD0;
  };

  struct PixelOut
  {
    float4 Color : COLOR0;
  };

  PixelOut PS1(PixelIn input)
  {
    PixelOut output;
    input.UV.x = input.UV.x + ((d + (d * input.UV.y * dd)) / size.x);
    output.Color = tex2D( Samp0, input.UV );
    return output;
  }

  PixelOut PS2(PixelIn input)
  {
    PixelOut output;
    input.UV.x = input.UV.x + ((d + (d * (1.0 - input.UV.y) * dd)) / size.x);
    output.Color = tex2D( Samp0, input.UV );
    return output;
  }

  PixelOut PS3(PixelIn input)
  {
    PixelOut output;
    input.UV.x = input.UV.x + d / size.x;
    output.Color = tex2D( Samp0, input.UV );
    return output;
  }

//   float4 PS(float2 input : TEXCOORD0) : COLOR0
//   {
//     float4 output;
//     // input.x -= ((d / size.x) + ((d / size.x) * input.y * dd));
//     input.x = input.x - ((d + (d * input.y * dd)) / size.x);
//     output = tex2D( Samp0, input);
//     return output;
//   }

  technique FloorScroll
  {
    pass P0
    {
      PixelShader = compile ps_2_0 PS1();
    }
  }
  technique CeilingScroll
  {
    pass P0
    {
      PixelShader = compile ps_2_0 PS2();
    }
  }
  technique WallScroll
  {
    pass P0
    {
      PixelShader = compile ps_2_0 PS3();
    }
  }
EOS

core = Shader::Core.new(hlsl, {:size=>:float, :d=>:float, :dd=>:float})
shader1 = Shader.new(core, "CeilingScroll")
shader2 = Shader.new(core, "WallScroll")
shader3 = Shader.new(core, "FloorScroll")

# 画像に対してランダムにドットを打つ
def plot_random_dot(image)
  dt = [[10, [255, 0, 64, 255]],
    [5, [255, 0, 255, 255]],
    [3, [255, 255, 255, 255]]]
  srand(0)
  image.height.times do |y|
    # next if y % 2 != 0
    dt.each do |d|
      d[0].times {|i| image[rand(image.width), y] = d[1]}
    end
  end
end

image1 = Image.new(640, 150, [0, 0, 0, 0]) # 天井
image2 = Image.new(640, 180, [0, 0, 0, 0]) # 壁
image3 = Image.new(640, 150, [0, 0, 0, 0]) # 床
plot_random_dot(image1)
plot_random_dot(image2)
plot_random_dot(image3)

shader1.size = [image1.width, image1.height]
shader1.d = 0
shader1.dd = 2.0 # yが1ドット進むごとにつける角度

shader2.size = [image2.width, image2.height]
shader2.d = 0
shader2.dd = 0

shader3.size = [image3.width, image3.height]
shader3.d = 0
shader3.dd = 16.0

# Window.fps = 10
x = 0
Window.loop do
  break if Input.keyPush?(K_ESCAPE)
  x += 1
  shader1.d = x # スクロール量を指定
  shader2.d = x
  shader3.d = x

  y = 0
  Window.draw_shader(0, y, image1, shader1)
  y += image1.height
  Window.draw_shader(0, y, image2, shader2)
  y += image2.height
  Window.draw_shader(0, y, image3, shader3)
end