XNA how to draw some sprites tiled/wrapped and others not?

Question

I already have:

mySpriteBatch.Begin(SpriteSortMode.Immediate, BlendState.AlphaBlend); 

and take care to draw all my sprites in order.

I now want to draw some textures tiled. Do I have to create another SpriteBatch and call:

mySpriteBatch.Begin(SpriteSortMode.FrontToBack, BlendState.Opaque, SamplerState.LinearWrap, DepthStencilState.Default, RasterizerState.CullNone); 

To draw my tiled textures? But won't these tiled sprites be drawn on top the ones already drawn with the previous SpriteBatch?

What I would really like is to be able to do is draw some sprites normally and some tiled using the same SpriteBatch then my ordering wont be messed up. Is this possible? I tried:

GraphicsDevice.SamplerStates[0].AddressU = TextureAddressMode.Wrap; GraphicsDevice.SamplerStates[0].AddressV = TextureAddressMode.Wrap;

In my first and only SpriteBatch but got the InvalidOperationException:

Cannot change read-only SamplerState. State objects become read-only the first time they are bound to a GraphicsDevice. To change property values, create a new SamplerState instance.

Answer 1

Here's the problems you are having:

1. Sorting for sprite batches only applies within that batch. At End, everything in the batch gets drawn to screen and becomes pixels. The default depth state for SpriteBatch does not read the depth buffer.
2. State objects (eg: SamplerState) are read-only once they are used. In this case, you're accessing the state that the graphics device is currently using. You can create a new state of your own, if you like - or use different existing ones.

Here's what you need to do:

Fortunately you don't have to create a custom SamplerState, as you can just use the built-in SamplerState.LinearWrap. Pass it into SpriteBatch.Begin like so:

spriteBatch.Begin(SpriteSortMode.Deferred,
                  null, SamplerState.LinearWrap, null, null);

(Note the use of Deferred - this is the default. You should only use Immediate if you actually need that behaviour, as it is much, much slower. Passing null in for state objects causes SpriteBatch to use the default state object for that state.)

Then it's a simple matter of tiling your sprites. The trick to do this with SpriteBatch.Draw is the source rectangle parameter. You can specify a source rectangle that extends beyond the edge of your texture. If, for example, you wanted to draw your sprite tiled 3 times horizontally and 2 times vertically, here's how:

spriteBatch.Draw(myTexture, myPosition,
                 new Rectangle(0, 0, myTexture.Width * 3, myTexture.Height * 2),
                 Color.White);

Then, to draw a non-tiled sprite, simply don't specify a source rectangle.

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It is worth noting the reason for the existence of TextureAddressMode.Clamp: If you draw a tile with Wrap, and then position or scale your sprite it so that a pixel in the sprite's texture does not perfectly line up with a pixel on the screen, you will find that your sprite gets a fringe where blending is happening between two pixels on the opposite sides of the texture. Clamp prevents blending from doing this by extending the edge pixels of the texture out to infinity. To avoid this problem you must either have pixel-perfect sprite positioning, or ensure that your art assets look reasonable if it happens.

It's also worth noting that this wrapping technique precludes the use of texture atlases. So, if you have many different tile types, it can be better for performance to just draw the tile multiple times. (Details)