VCS/XnaShader2 - Sample is best!

開発環境	Microsoft Visual C# 2010 Express (SP1)
実行環境	Microsoft Windows XP Home Edition (SP3)
プロジェクトの種類	Windows Game (4.0)
プロジェクト名	XnaShader

参考

• プログラマブル・シェーダによる積極的なGPUの活用 － ＠IT

Program_2.cs

// #2
using System;
using Microsoft.Xna.Framework;
using Microsoft.Xna.Framework.Graphics;
using Microsoft.Xna.Framework.Input;
 
class Game1 : Game
{
	GraphicsDeviceManager graphics;
	VertexBuffer vb;
	Effect effect;
	Vector2 offset = new Vector2(-0.25f, 0.0f);
	float zoom = 3.0f;
 
	// 頂点構造体
	struct MyVertex : IVertexType
	{
		Vector2 Position;
		Vector2 UV;
		public MyVertex(Vector2 position, Vector2 uv)
		{
			Position = position;
			UV = uv;
		}
		public readonly static VertexDeclaration VertexDeclaration = new VertexDeclaration(
			new VertexElement[] {
				new VertexElement(0, VertexElementFormat.Vector2,
					VertexElementUsage.Position, 0),
				new VertexElement(8, VertexElementFormat.Vector2,
					VertexElementUsage.TextureCoordinate, 0),
			});
		VertexDeclaration IVertexType.VertexDeclaration { get { return VertexDeclaration;} }
	}
 
	public Game1()
	{
		graphics = new GraphicsDeviceManager(this);
		Content.RootDirectory = "Content";
		Window.AllowUserResizing = true;
	}
 
	protected override void LoadContent()
	{
		const int numVertices = 4;
		vb = new VertexBuffer(GraphicsDevice, typeof(MyVertex), numVertices,
			BufferUsage.None);
		MyVertex[] vertices = new MyVertex[numVertices] {
			new MyVertex(new Vector2(-1.0f,  1.0f), new Vector2(0.0f, 1.0f)), // LT
			new MyVertex(new Vector2( 1.0f,  1.0f), new Vector2(1.0f, 1.0f)), // RT
			new MyVertex(new Vector2(-1.0f, -1.0f), new Vector2(0.0f, 0.0f)), // LB
			new MyVertex(new Vector2( 1.0f, -1.0f), new Vector2(1.0f, 0.0f)), // RB
		};
		vb.SetData(vertices);
 
		// ContentにMandelbrot.fxを追加しておく
		effect = Content.Load<Effect>("Mandelbrot");
 
		base.LoadContent();
	}
 
	protected override void Update(GameTime gameTime)
	{
		// 移動量
		float offsetMove = 0.01f * (float)Math.Log(zoom + 1.0f);
 
		KeyboardState key = Keyboard.GetState();
		if (key.IsKeyDown(Keys.Left)) {
			offset.X -= offsetMove;
		}
		if (key.IsKeyDown(Keys.Right)) {
			offset.X += offsetMove;
		}
		if (key.IsKeyDown(Keys.Down)) {
			offset.Y -= offsetMove;
		}
		if (key.IsKeyDown(Keys.Up)) {
			offset.Y += offsetMove;
		}
		if (key.IsKeyDown(Keys.PageDown)) {
			zoom *= 1.05f;
		}
		if (key.IsKeyDown(Keys.PageUp))
		{
			zoom /= 1.05f;
		}
		if (key.IsKeyDown(Keys.Escape)) {
			Exit();
		}
 
		base.Update(gameTime);
	}
 
	protected override void Draw(GameTime gameTime)
	{
		GraphicsDevice.Clear(Color.CornflowerBlue);
 
		// エフェクトのパラメータ更新
		effect.Parameters["Zoom"].SetValue(zoom);
		effect.Parameters["Aspect"].SetValue(GraphicsDevice.Viewport.AspectRatio);
		effect.Parameters["Offset"].SetValue(offset);
 
		GraphicsDevice.SetVertexBuffer(vb);
		foreach(EffectPass pass in effect.CurrentTechnique.Passes) {
			pass.Apply();
			GraphicsDevice.DrawPrimitives(PrimitiveType.TriangleStrip, 0, 2);
		}
 
		base.Draw(gameTime);
	}
}
 
class Program
{
	static void Main()
	{
		using (Game1 game = new Game1()) {
			game.IsMouseVisible = true;
			game.Run();
		}
	}
}
 

Mandelbrot_2.fx

float Aspect = 1.0f;
float Zoom = 1.0f;
float2 Offset = float2(0.0f, 0.0f);
 
// 頂点シェーダ
struct VertexIn
{
	float2 Pos : POSITION;
	float2 UV : TEXCOORD0;
};
 
struct VertexOut
{
	float4 ScreenPos : POSITION;
	float2 UV : TEXCOORD0;
};
 
VertexOut MyVertexShader(VertexIn input)
{
	VertexOut output;
	output.ScreenPos = float4(input.Pos, 0.0f, 1.0f);
	output.UV = input.UV;
	return output;
}
 
// ピクセルシェーダ
struct PixelIn
{
	float2 UV : TEXCOORD0;
};
 
struct PixelOut
{
	float4 Color : COLOR0;
};
 
PixelOut MandelbrotShader(PixelIn input, uniform int MaxIterate)
{
	const float2 c = (input.UV - 0.5f) * float2(1.0f, Aspect) * Zoom + Offset;
 
	float2 p = 0;
	int n;
	for (n = 0; n < MaxIterate && dot(p, p) < 4.0f; n++) {
		p = float2(p.x * p.x - p.y * p.y, 2.0f * p.x * p.y) + c;
	}
 
	PixelOut output;
	if (n < MaxIterate) {
		float u = (float)n / (float)MaxIterate;
		output.Color.rgb = float3(u, u, 1.0f - u);
	} else {
		output.Color.rgb = 0.0f;
	}
	output.Color.a = 1.0f;
	return output;
}
 
// レンダー
technique Render
{
	pass Pass0
	{
		VertexShader = compile vs_3_0 MyVertexShader();
		PixelShader = compile ps_3_0 MandelbrotShader(254);
	}
}