What should I expect the value of gl_in to be if the drawing array only has three vertices to draw? Is there a default value chosen by OpenGL?
gl_in is sized by the
layout declaration which declares the input primitive type. So if the input primitive type is
gl_in will only have three elements and accessing
gl_in is invalid. If a geometry shader is active but the input primitive type doesn’t match the primitives which are actually generated, the drawing command will generate a