Stencil testing in XNA 4

问题

I was able to do this in XNA 3.1, however I see that we now use state objects in XNA 4, which is certainly an improvement, although I can't accomplish what I want so far :)

I am trying to:

Clear the stencil buffer to 0.

Draw a texture to the stencil buffer, setting the stencil buffer to 1 where the texture is drawn.

Draw another texture that will only appear where the stencil buffer is not 1.

Here is what I have so far, which appears to have no effect on the drawing of texture 2:

BlendState blend = new BlendState();
blend.ColorWriteChannels = ColorWriteChannels.None;


_preSparkStencil = new DepthStencilState();
_preSparkStencil.StencilEnable = true;
_preSparkStencil.StencilFunction = CompareFunction.Always;
_preSparkStencil.ReferenceStencil = 1;
_preSparkStencil.DepthBufferEnable = true;

_sparkStencil = new DepthStencilState();
_sparkStencil.StencilEnable = true;
_sparkStencil.StencilFunction = CompareFunction.NotEqual;
_sparkStencil.ReferenceStencil = 1;
_sparkStencil.DepthBufferEnable = true;

gd.DepthStencilState = _preSparkStencil;

gd.Clear(ClearOptions.Stencil, Color.Black, 0, 0);

sb.Begin(SpriteSortMode.Deferred, blend);

DrawTexture1();

sb.End();

gd.DepthStencilState = _sparkStencil;

sb.Begin(SpriteSortMode.Deferred, BlendState.NonPremultiplied);
DrawTexture2();
sb.End();

gd.DepthStencilState = old;

回答1:

The problem was that the RenderState needs to be passed into SpriteBatch, or else the SpriteBatch will use it's own RenderState.

    sb.Begin(SpriteSortMode.Deferred, BlendState.Opaque, 
        SamplerState.LinearWrap, _preSparkStencil, 
        RasterizerState.CullCounterClockwise, CLM.AlphaClip);

来源：https://stackoverflow.com/questions/5054839/stencil-testing-in-xna-4

标签

xna-4.0