Lights does not render when diffuse is disabled and blur is enabled

[fgnm]

I've noticed that on some hardware configurations Lights are not rendered when RayHandler.useDiffuseLight(false); and blur is enabled. This is what happens on the same laptop running the same code both on IGPU HD Graphics 620 and external Nividia GeForce MX150:

MX150 with RayHandler.useDiffuseLight(false); and blurNum = 3

MX150 with RayHandler.useDiffuseLight(false); and blurNum = 0

IGPU HD Graphics 620 with RayHandler.useDiffuseLight(false); and blurNum = 3 Same with blurNum = 0

When RayHandler.useDiffuseLight(true); everything works as expected.

I've noticed also that on OnePlus 6T (Adreno 630) I've got the same result that happens on MX150.

[fgnm]

I've finally found the reason of this bug, and it's a my mistake plus a missing warning in Box2DLights docs. In my scenario diffuse lights can be enabled and disabled at runtime, this causes the issue because blurShader depends on RayHandler.isDiffuse value: https://github.com/libgdx/box2dlights/blob/29a84c7d5cbcd183049e7d62c134f6ad9c842b7b/src/shaders/Gaussian.java#L13 This shader is created only once, in the constructor of LightMap: https://github.com/libgdx/box2dlights/blob/29a84c7d5cbcd183049e7d62c134f6ad9c842b7b/src/box2dLight/LightMap.java#L130

So if I try to change RayHandler.isDiffuse after new RayHandler(world), shaders are messed up, on some GPUs works, on others not. So to fix this issue a possible workaround could be recreate the LightMap object when isDiffuse changes, in order to do that resizeFBO() function could be called.

Changing RayHandler.isDiffuse might not be a common situation, that's why this workaround could be enough without modify anything in box2dLights, so if this is not relevant please feel free to close this issue.

Thanks