XNA 2D Spritesheet drawing rendering problem

Question

I'm making a tile-based game, using one spritesheet containing all tile graphics.

Each tile has a size of 32x32 pixels.

The main problem is: when I draw the tile to the screen, if the tile position x and y are not rounded or if scale is activated in spriteBatch.Draw() method (scale != 1.0f), I get some lines of adjacent tiles on the spritesheet into the current tile drawed.

I already tried setting SamplerState to PointClamp, removing AntiAlias, but still doesn't work.

Here I'll show images of some tests that I made, with a test sprite sheet that I've created (I made a 9x9 spritesheet, with each sprite of size 32x32 containing a unique solid color).

Tests:

SpriteSheet used:

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Already tried to remove anti-alias, set PointClamp as sampler state, but still getting this issue, XNA keeps drawing part of the adjacent pixels of the texture on the screen.

What I want is to get the correct area of the tilesheet texture (as seen in the first test, that gets just the yellow pixels).

My question is: Is there any way that I can fix this, WITHOUT adding tile spacing or any other modification involving the tilesheet?

Maybe disabling a texture filtering that is done by XNA, or something like that.

Answer 1

From my experience, this seems like you aren't setting your SamplerState to PointClamp correctly. This is indicated by the "blending" at the top left corner. Have you tried rendering on different hardware?

First, Your texture isn't a power-of-two Although some wouldn't agree, I always use textures^2. On some older hardware it was a requirement. I would suggesting sizing up to 128x128 (4*32, 4*32)

Second, have you tried setting GraphicsDevice.SamplerState[0] directly? (source)

Answer 2

Based on the images you're showing, it is very clear that the renderer is interpolating, so you have to disable this interpolation. This has little to do with half pixels.

Now, I'm not really knowledgeable in XNA, but a quick google of "xna nearest neighbor interpolation" shows that there are at least two places you can try to disable interpolation:

This one suggests using PointClamp as a parameter for SpriteBatch.Begin(), while this other one suggests setting it at GraphicsDevice.SamplerStates.

You mention you tried setting the sampler state to PointClamp, so how about trying at SpriteBatch.Begin()?

Answer 3

I had exactly the same problem that User24092, and I tried all those suggestions with no result. Finally the solution suggested by Panda Pajama made the trick!

Just set the PointClamp sampler state when you begin the spriteBatch:

spriteBatch.Begin(SpriteSortMode.Immediate, null, SamplerState.PointClamp, null,null);

It worked like a charm!

Answer 4

The best way to fix this is to round your X and Y values before drawing them.

The "usual" way I handle this in XNA is to keep X and Y internally as a float, and to expose them externally (eg. to SpriteBatch) as an int. You should, of course, use Math.Floor to get you the correct tile.

The code would look something like this:

float x, y = 0f;
// ...
public int X { get { return (int)Math.Floor(this.x); } }
public int Y { get { return (int)Math.Floor(this.y); } }
spriteBatch.Draw(this.texture, new Vector2(this.X, this.Y), Color.White);

Answer 5

I know it may be a bit extreme, but try to apply a pixel shader with filter point to force that the exact pixels are rendered. I'm really curious with this problem.

Texture Sprite;
sampler SamplerSprite = sampler_state {
    texture = <Sprite>;
    filter = POINT;
};

float4 Ps_Main(float2 coord : TEXCOORD0) : COLOR {
    return tex2D(SamplerSprite, coord);
}

technique Tech_0 {
    pass Pass_0 {
            pixelshader = compile ps_2_0 Ps_Main();
    }
}