Game Development Reference
In-Depth Information
using
System;
1
using
Microsoft.Xna.Framework;
2
using
Microsoft.Xna.Framework.Content;
3
using
Microsoft.Xna.Framework.Graphics;
4
using
Microsoft.Xna.Framework.Input;
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6
7
class
Cannon : ThreeColorGameObject
{
8
Texture2D cannonBarrel;
9
float
angle;
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11
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public
Cannon(ContentManager Content)
:
base
(Content.Load<Texture2D>("spr_cannon_red"),
13
Content.Load<Texture2D>("spr_cannon_green"),
14
Content.Load<Texture2D>("spr_cannon_blue"))
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{
this
.cannonBarrel = Content.Load<Texture2D>("spr_cannon_barrel");
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position =
new
Vector2(72, 405);
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}
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public override void
HandleInput(InputHelper inputHelper)
{
if
(inputHelper.KeyPressed(Keys.R))
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Color = Color.Red;
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else if
(inputHelper.KeyPressed(Keys.G))
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Color = Color.Green;
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else if
(inputHelper.KeyPressed(Keys.B))
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Color = Color.Blue;
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−
double
opposite = inputHelper.MousePosition.Y
position.Y;
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−
double
adjacent = inputHelper.MousePosition.X
position.X;
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angle = (
float
)Math.Atan2(opposite, adjacent);
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}
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public override void
Draw(GameTime gameTime, SpriteBatch spriteBatch)
{ spriteBatch.Draw(cannonBarrel, position,
null
, Color.White, angle,
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new
Vector2(34, 34), 1.0f, SpriteEffects.None, 0);
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−
spriteBatch.Draw(currentColor, position
new
Vector2(currentColor.Width,
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currentColor.Height) / 2, Color.White);
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}
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public override void
Reset()
{
base
.Reset();
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angle = 0.0f;
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}
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public
Vector2 BallPosition
{
get
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∗
∗
{
float
opposite = (
float
)Math.Sin(angle)
cannonBarrel.Width
0.5f;
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∗
∗
float
adjacent = (
float
)Math.Cos(angle)
cannonBarrel.Width
0.5f;
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return
position +
new
Vector2(adjacent, opposite);
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}
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}
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}
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Listing 10.1
The final
Cannon
class
