blend overlapping triangles in opengl

Question

I'm building a thick line from triangles. The problem i'm having is that when the curve is semi transparent and some triangles overlap i get the effect in the picture. I would like for the triangles alphas to not get added.

I'm using this blend function:

glBlendFuncSeparate(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA, GL_CONSTANT_ALPHA, GL_CONSTANT_ALPHA);

Answer 1

You may render the curve to separate render target with full opacity and then draw that target with custom alpha. Otherwise you should avoid overlapping.

Answer 2

您可以使用模板测试来阻止已经绘制的碎片的绘制（这样可以防止从第一个位置混合）