Glow filter differences in html5 and linux

[Shallowmallow]

Thank you for the extension! :)

In linux, these lines make the filter crash

openfl-shaders/openfl/shaders/Glow.hx

Lines 33 to 34 in 715b5fd

	const float ANGLE_STEP_SIZE = min(__ANGLE_STEP_SIZE__, PI * 2.0);
	const float ANGLE_STEP_NUM = ceil(PI * 2. / ANGLE_STEP_SIZE);

It corks correctly if you remove const. But then it crashes on html5 :(

[loudoweb]

Thanks for your report.
Do you have a log on these crashes?

[Shallowmallow]

On linux I have this ```Error : [openfl.display.Shader] ERROR: Error compiling fragment shader 0:32(32): error: initializer of const variable `ANGLE_STEP_SIZE' must be a constant expression 0:33(31): error: initializer of const variable `ANGLE_STEP_NUM' must be a constant expression``` Personally , I duplicated the glfragment, removed the const, and surrounded it by #if linux #else to make it work on both html5 and linux on my computer