Changing the PlatformTarget in Visual C# Express

January 18, 2010 .net msbuild

Some project types in Visual C# Express (Empty Project) will not allow you to change the PlatformTarget from the UI. You can still change the target platform though by editing the .csproj file in a text editor. Close the project and open it up in your favorite text editor (I use Notpad++). The .csproj file is really just a XML file. You should see somewhere in the file something like:

<PropertyGroup Condition=" '$(Configuration)|$(Platform)' == 'Debug|AnyCPU' ">
		....
	</PropertyGroup>
	<PropertyGroup Condition=" '$(Configuration)|$(Platform)' == 'Release|AnyCPU' ">
		....
	</PropertyGroup>

Inside the PropertyGroup elements, add the PlatformTarget element:

<PropertyGroup Condition=" '$(Configuration)|$(Platform)' == 'Debug|AnyCPU' ">
		....
		<PlatformTarget>x86</PlatformTarget>
	</PropertyGroup>
	<PropertyGroup Condition=" '$(Configuration)|$(Platform)' == 'Release|AnyCPU' ">
		....
		<PlatformTarget>x86</PlatformTarget>
	</PropertyGroup>

Save the file and open your project back up. Your project's output should now target only x86.

Calculating an angle from a Vector2

February 28, 2009 .net vectors xna

When you need to calculate an angle from a Vector2 structure, you can use this piece of code:

public static class Vector2Helper
{
	public static float CalculateAngle(Vector2 v)
	{
		float angle = 0.0f;

		if(v != Vector2.Zero)
		{
			v.Normalize();

			angle = (float)Math.Acos(v.Y);

			if(v.X &lt; 0.0f)
			angle = -angle;
		}

		return angle;
	}
}

I used this to calculate an angle from the Vector2 of the Left Stick.

The original credit for this source code comes from here.

Drawing 2D Lines as Rotated Quads

February 07, 2009 .net

I haven't had much time lately with work but one question I've seen asked many many times is how to draw lines of different widths. So, to cut to the chase I'll share the code I've used to do it.

public void DrawLine(Vector3 p1, Color c1, Vector3 p2, Color c2, int width)
{
	float distance = Vector3.Distance(p1, p2);
	float halfDistance = distance / 2.0f;
	float halfWidth = width / 2.0f;

	Vector3 difference = p2 - p1;
	Vector3 destination = new Vector3(p1.X + difference.X / 2.0f, p1.Y + difference.Y / 2.0f, p1.Z + difference.Z);

	// Calculate angle between two points
	float angle = (float)Math.Atan2(difference.Y, difference.X);

	Vector3 v1, v2, v3, v4;

	v1 = new Vector3(-halfDistance, -halfWidth, 0); // Top Left
	v2 = new Vector3(halfDistance, -halfWidth, 0); // Top Right
	v3 = new Vector3(halfDistance, halfWidth, 0); // Bottom Right
	v4 = new Vector3(-halfDistance, halfWidth, 0); // Bottom Left

	Matrix m =
		Matrix.Identity *
		Matrix.CreateRotationZ(angle) *
		Matrix.CreateTranslation(destination);

	v1 = Vector3.Transform(v1, m);
	v2 = Vector3.Transform(v2, m);
	v3 = Vector3.Transform(v3, m);
	v4 = Vector3.Transform(v4, m);

	DrawQuad(v1, c1, v2, c2, v3, c2, v4, c1);
}

I've left a lot of fluff code out. I usually check if the line is a width of 1 and draw a normal line. I also left out the code on how to draw a quad as that can be found many other places already.

SpriteSheet Class

January 09, 2009 .net xna

I've been talking with a guy on the creator forums lately about SpriteSheets and so I decided it might be a good idea to post my SpriteSheet class.

It's very simple. Only reads sprites from left to right and assumes all Sprites are the same width and height.

#region Using
using System;
using Microsoft.Xna.Framework;
using Microsoft.Xna.Framework.Graphics;
#endregion

namespace Snow.Xna.Graphics
{
	/// <summary>
	/// Spritesheet class.
	/// </summary>
	public class SpriteSheet
	{
		#region Fields

		string name;

		Texture2D texture;

		Rectangle[] rectangles;

		int spriteWidth, spriteHeight;

		#endregion

		#region Properties

		/// <summary>
		/// The name of this SpriteSheet.
		/// </summary>
		public string Name
		{
			get { return name; }
		}

		/// <summary>
		/// The texture for this SpriteSheet.
		/// </summary>
		public Texture2D Texture
		{
			get { return texture; }
		}

		/// <summary>
		/// Returns a rectangle for a sprite in the SpriteSheet.
		/// </summary>
		/// <param name="i">index</param>
		/// <returns></returns>
		public Rectangle this[int i]
		{
			get { return rectangles[i]; }
		}

		/// <summary>
		/// The number of sprites in this SpriteSheet.
		/// </summary>
		public int Count
		{
			get { return rectangles.Length; }
		}

		/// <summary>
		/// The width of the texture.
		/// </summary>
		public int Width
		{
			get { return texture.Width; }
		}

		/// <summary>
		/// The width of each sprite in the SpriteSheet.
		/// </summary>
		public int SpriteWidth
		{
			get { return spriteWidth; }
		}

		/// <summary>
		/// The height of the texture.
		/// </summary>
		public int Height
		{
			get { return texture.Height; }
		}

		/// <summary>
		/// The height of each sprite in the SpriteSheet.
		/// </summary>
		public int SpriteHeight
		{
			get { return spriteHeight; }
		}

		#endregion

		/// <summary>
		/// Create a new SpriteSheet and determine the number of sprites in the sheet.
		/// </summary>
		/// <param name="texture"></param>
		/// <param name="spriteWidth">Width of each sprite.</param>
		/// <param name="spriteHeight">Height of each sprite.</param>
		public SpriteSheet(string name, Texture2D texture, int spriteWidth, int spriteHeight)
			: this(name, texture, spriteWidth, spriteHeight, 0)
		{
		}

		/// <summary>
		/// Create a new SpriteSheet.
		/// </summary>
		/// <param name="texture"></param>
		/// <param name="spriteWidth">Width of each sprite.</param>
		/// <param name="spriteHeight">Height of each sprite.</param>
		/// <param name="count">The number of sprites in the sheet.</param>
		public SpriteSheet(string name, Texture2D texture, int spriteWidth, int spriteHeight, int count)
		{
			this.name = name;
			this.texture = texture;
			this.spriteWidth = spriteWidth;
			this.spriteHeight = spriteHeight;

			if(count == 0)
			{
				int numX = texture.Width / spriteWidth;
				int numY = texture.Height / spriteHeight;

				rectangles = new Rectangle[numX * numY];
			}
			else
			{
				rectangles = new Rectangle[count];
			}

			int x = 0, y = 0;
			for(int i = 0; i < rectangles.Length; i++)
			{
				rectangles[i] = new Rectangle(x, y, spriteWidth, spriteHeight);

				x += spriteWidth;
				if(x >= texture.Width)
				{
					x = 0;
					y += spriteHeight;
				}
			}
		}

		public static implicit operator Texture2D(SpriteSheet spriteSheet)
		{
			return spriteSheet.Texture;
		}
	}
}

You can create a new SpriteSheet and use it like this:

`

SpriteSheet spriteSheet = new SpriteSheet("tiles", Content.Load<texture2D>("tiles"), 64, 64);

spriteBatch.Begin();

spriteBatch.Draw(spriteSheet,
		        new Rectangle(0, 0, spriteSheet.SpriteWidth, spriteSheet.SpriteHeight),
			spriteSheet[0],
			Color.White);

spriteBatch.End();

`

Which loads a spritesheet with sprites of size 64x64. It then draws the first Sprite in the SpriteSheet. You of course wouldn't want to load the spritesheet every frame as well.

Feel free to use this code without restriction.

Edit: I copied and pasted the second piece of code from somewhere else so I fixed two typos.

Colors and Hex

December 21, 2008 .net xna

I recently needed to write out Color(s) as an xml attribute. I wrote 2 methods to read and write the Color(s) as Hex strings. Here ya go:

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