[PD] Gem line2D max line width

[Claude Heiland-Allen]

On 25/04/15 22:27, Peter P. wrote:
> In Gem I would like to make a 2D Bezier curve with the [line2D] object

I can't find any reference to [line2D] in my fresh GEM clone.  Do you 
mean [curve]?

> and give it a width bigger than 250, drawing it as "linestrip". But the
> line does not get thicker.

250 is quite high.

> Is there a limit to it,

Yes.

> if so why,

Defined by the underlying OpenGL implementation:
https://www.opengl.org/sdk/docs/man2/xhtml/glLineWidth.xml

Not sure if GEM exposes the query methods.

> and how could I work around this?

Draw wide lines as triangle strips - maybe look at [curve3d] for that?


It's possible in OpenGL 3.2 to use a geometry shader to convert line 
strips to triangle strips, using input layout lines_adjacency so that 
you can take into account the corners.  But that requires that you draw 
with GL_LINE_STRIP_ADJACENCY, which isn't supported by GemShape, and the 
polynomial evaluators used in [curve] were removed before OpenGL version 
3.2.


Claude
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