public void Draw(string backgroundKey,
SpriteBatch batch)
{
ScrollingBackground sb = backgrounds[backgroundKey];
Texture2D texture = textures[sb.TextureName];
//Draw the main texture
batch.Draw(texture, sb.Position, sb.SourceRect,
sb.Color, 0, Vector2.Zero, 1.0f, SpriteEffects.None, 0f);
//Determine if we need to scroll left or right
Vector2 offset;
if (sb.Positive)
{
offset = sb.Position - (new Vector2(texture.Width, 0));
}
else
{
offset = new Vector2(texture.Width, 0) + sb.Position;
}
//now draw the background again at the appropriate offset
//NOTE: If our Width is larger than two times the size of our
//texture then the code will need to be modified
batch.Draw(texture, offset, sb.SourceRect,
sb.Color, 0, Vector2.Zero, 1.0f, SpriteEffects.None, 0f);
}
public void Draw(string backgroundKey,
SpriteBatch batch)
{
ScrollingBackground sb = backgrounds[backgroundKey];
Texture2D texture = textures[sb.TextureName];
//Draw the main texture
batch.Draw(texture, sb.Position, sb.SourceRect, sb.Color, 0, Vector2.Zero, 1.0f, SpriteEffects.None, sb.LayerDepth);
// Repeat as necessary
int offsetFromZero = (int)(sb.Position.X);
// To the right
int repeatRight = Game.GraphicsDevice.Viewport.Width / (texture.Width + offsetFromZero);
for (int i = 1; i <= repeatRight; i++)
{
Vector2 offsetPos = sb.Position;
offsetPos.X = offsetPos.X + (texture.Width * i);
batch.Draw(texture, offsetPos, sb.SourceRect, sb.Color, 0, Vector2.Zero, 1.0f, SpriteEffects.None, sb.LayerDepth);
}
// To the left
if (offsetFromZero > 0)
{
int repeatLeft = offsetFromZero / (texture.Width) + 1;
for (int i = 1; i <= repeatLeft; i++)
{
Vector2 offsetPos = sb.Position;
offsetPos.X = offsetPos.X - (texture.Width * i);
batch.Draw(texture, offsetPos, sb.SourceRect, sb.Color, 0, Vector2.Zero, 1.0f, SpriteEffects.None, sb.LayerDepth);
}
}
}
public override void Update(GameTime gameTime)
{
foreach (KeyValuePair <string, ScrollingBackground> background in backgrounds)
{
ScrollingBackground sb = background.Value;
sb.Position.X += (sb.ScrollRate * (float)gameTime.ElapsedGameTime.TotalSeconds);
sb.Position.X = sb.Position.X % textures[sb.TextureName].Width;
}
base.Update(gameTime);
}
public void AddBackground(string backgroundKey, string textureName,
Vector2 position, Rectangle sourceRect, float scrollRateRatio, float layerDepth,
Color color)
{
ScrollingBackground background = new ScrollingBackground(textureName, position, sourceRect, scrollRateRatio, layerDepth, color);
background.ScrollRate = scrollRate * scrollRateRatio;
if (!textures.ContainsKey(textureName))
{
textures.Add(textureName, Game.Content.Load <Texture2D>(contentPath + textureName));
}
if (backgrounds.ContainsKey(backgroundKey))
{
backgrounds[backgroundKey] = background;
}
else
{
backgrounds.Add(backgroundKey, background);
}
}
