Simple gizmo drawer for blender 2.80

BlenderGpuGizmos.py

import bpy
import gpu
from random import random
from mathutils import Vector
from gpu_extras.batch import batch_for_shader

gizmos_line_vert = '''
    uniform mat4 u_ViewProjectionMatrix;
    in vec3 position;
    in vec4 color;
    out vec4 vertex_color;
    void main()
    {
        vertex_color = color;
        gl_Position = u_ViewProjectionMatrix * vec4(position, 1.0f);
    }
'''

gizmos_line_frag = '''
    in vec4 vertex_color;
    void main()
    {
        gl_FragColor = vertex_color;
    }
'''

#
class QuickGizmosStub:
    __GizmosHandlers__    = {};
    __GizmosInitialized__ = False;

    # data for line gizmos
    __LineGizmosCoords__  = [];
    __LineGizmosColors__  = [];
    __LineGizmosShader__  = None;
    __LineGizmosDrawer__  = None;
    __LineGizmosDirty__   = True;
    
    @staticmethod
    def __create_drawer__(stub, key, fn, vs, ps):
        shader = gpu.types.GPUShader(vs, ps);
        stub.__GizmosHandlers__[key] = bpy.types.SpaceView3D.draw_handler_add(fn,(), 'WINDOW', 'POST_PIXEL');        
        return shader;
                
    @staticmethod
    def get_stub():
        stub = None;
        if 'QUICKGIZMOS' in bpy.app.driver_namespace:
            stub = bpy.app.driver_namespace['QUICKGIZMOS'];
            
        if stub == None:
            stub = QuickGizmosStub();
            
            # initialize for line gizmo
            stub.__LineGizmosShader__ = QuickGizmosStub.__create_drawer__(stub, 'GIZMO_LINE_DRAWER', QuickGizmos.__draw_lines__, gizmos_line_vert, gizmos_line_frag);
           
            # TODO
            bpy.app.driver_namespace['QUICKGIZMOS'] = stub;
            
        return stub;


#
class QuickGizmos:    
    @staticmethod
    def __draw_lines__():
        stub = QuickGizmosStub.get_stub();
        
        if len(stub.__LineGizmosCoords__) > 0 and len(stub.__LineGizmosColors__) > 0:
            stub.__LineGizmosShader__.bind();
            matrix = bpy.context.region_data.perspective_matrix;
            stub.__LineGizmosShader__.uniform_float("u_ViewProjectionMatrix", matrix);

            # update batch if dirty
            if stub.__LineGizmosDirty__ == True:
                stub.__LineGizmosDirty__ = False;
                stub.__LineGizmosDrawer__ = batch_for_shader(stub.__LineGizmosShader__, 'LINES',
                    {"position": stub.__LineGizmosCoords__, "color": stub.__LineGizmosColors__});    			

            stub.__LineGizmosDrawer__.draw(stub.__LineGizmosShader__);


    @classmethod
    def draw_line(cls, v1, v2, color):
        stub = QuickGizmosStub.get_stub();
        stub.__LineGizmosCoords__.append(v1);
        stub.__LineGizmosCoords__.append(v2);
        stub.__LineGizmosColors__.append(color);
        stub.__LineGizmosColors__.append(color);
        stub.__LineGizmosDirty__ = True;
        
    @classmethod
    def clear_lines(cls):
        stub = QuickGizmosStub.get_stub();
        stub.__LineGizmosCoords__ = [];
        stub.__LineGizmosColors__ = [];
        stub.__LineGizmosDirty__  = True;
        
#
def draw_gizmo_line(v1, v2, clr=[1,0,0,1]):
    QuickGizmos.draw_line(v1, v2, clr);
    
#
def clear_gizmo_lines():
    QuickGizmos.clear_lines();