Take the 2-minute tour ×
Game Development Stack Exchange is a question and answer site for professional and independent game developers. It's 100% free, no registration required.

I have a "lighting" texture (black background with white or colours for lights) that I want to draw as a multiplcation operation. SpriteBatch.Begin can specify BlendState.Additive, but there's no BlendState.Multiplicative.

I also tried the solution in this answer, but it didn't work -- even when I (incorrectly?) changed the code to work with XNA 4 style ColorDestinationBlend, I ended up with the final solution being inverted (black area where the light is, everything else is visible).

I initially thought of a shader, but I couldn't get shaders to work with MonoGame, so I'm falling back to SpriteBatch.

share|improve this question

1 Answer 1

up vote 4 down vote accepted

Create your own BlendState, eg:

BlendState blend = new BlendState();
blend.ColorBlendFunction = BlendFunction.Add;
blend.ColorSourceBlend = Blend.DestinationColor;
blend.ColorDestinationBlend = Blend.Zero;

This will result in out.rgb = source.rgb * destination.rgb + 0;

Edits by questioner: I had to also set the drawing mode to SpriteSortMode.Immediate before this worked.

share|improve this answer
1  
Whoa, you're a genius!! Thanks! (Again lol) –  ashes999 Dec 16 '12 at 16:28

Your Answer

 
discard

By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.