globalCompositeOperation

[WeslleyDeSouza]

is this now supported?

[jagenjo]

no, I haven't figure out the equivalent of the globalcompositeoperation modes with the blend modes of opengl

[andrewdevcup]

What about creating custom shaders for it?

[jagenjo]

thats not how global composite operation works, as it doesnt involve shaders but blending operations

[andrewdevcup]

thats not how global composite operation works, as it doesnt involve shaders but blending operations

I'm not an expert at glsl programming, but i've always used shaders to do color math, i'm sure you can emulate almost all composite operations

[jagenjo]

shaders are not allowed to read the destination pixel. it can be overpass by rendering all to a texture, but that makes it way slower.
there is a extension proposed to solve this but it is not supported yet by browsers.