Question

WebGL is supporting ADD, SUBTRACT and REVERSE_SUBTRACT. link: http://www.khronos.org/opengles/sdk/docs/man/xhtml/glBlendEquation.xml

I need support for MAX and MIN too in WebGL. idea link: http://leri.univ-reims.fr/~bittar/cours/OpenGL/opengl/glBlendEquationEXT.html

Is there any workaround ?

Answer 1

You can use the shader to do the custom-blending. The basic approach for doing this is:

1. Render your scene (without the geometry you want to blend) to a texture
2. Render your texture to the screen
3. Render the ‘blending’-geometry with a shader that takes in the screen texture as input and performs the custom blending.

For a list of blending modes possible in the shader see:

http://devmaster.net/posts/shader-effects-blend-modes