GL_EXT_fragment_shader_barycentric: Wireframe – Wunk

[utterances-bot]

GL_EXT_fragment_shader_barycentric: Wireframe – Wunk

https://wunkolo.github.io/post/2022/07/gl_ext_fragment_shader_barycentric-wireframe/

[kajott]

Very nice writeup, and wonderfully illustrated, thanks! Two additional remarks:

• Most of this is also possible without GL_EXT_fragment_shader_barycentric, but it requires adding an explicit vec3 vertex attribute that's (1,0,0) on one vertex of each triangle, (0,1,0) on another, and (0,0,1) on the third. (The order doesn't matter though.) This makes it hard to use on general meshes since you may need to duplicate vertices in some places in order to ensure that each vertex of a triangle has a different "color", but if you're preparing your mesh with wireframe rendering in mind, that's a possible solution.
• A fundamental issue with this approach to wireframe rendering is that all lines on the outer edges of an object are rendered with half the normal width. So while it's a nice and simple approach to rendering wireframes, it's (unfortunately) not a "correct", general-purpose one.