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.