A quick solution for OpenGLES lack of wireframe fill mode
24 September 2020
If you have ever worked with OpenGL you might be familiar with glPolygonMode. It allows you to specify GL_LINE, GL_POINT or GL_FILL, where fill is typically what we use to rasterise solid triangles, using lines allows us to achieve a wireframe effect. If you have ever then switched to OpenGLES (mobile or web platforms) you may have encountered GL_LINE being undefined and there is no way to get a wireframe fill mode.