There are a few ways to do this! The simplest would be to forgo triangles and just size up your GL points:
Try a few different values (it takes in a float value) and see how that works for you. At larger sizes, it may get a little slow depending on your machine.
Another route is to use a geometry shader. Check out the built in example of/examples/gl/geometryShaderExample, which converts lines to triangle strips. Below is a small shader I wrote to convert gl points into circles; you can try changing the “circleRes” to 3 to make it emit triangles.