as @CoDEmanX noted you can disable the depth test with bgl.glDisable(bgl.GL_DEPTH_TEST)
while drawing and use the POST_VIEW
.
here is an example code of a modified draw modal operator :
import bpy
import bgl
import blf
from mathutils import Vector
from bpy_extras import view3d_utils
def draw_callback_px(self, context, points):
bgl.glEnable(bgl.GL_BLEND)
bgl.glColor4f(1.0, 1.0, 1.0, 1.0)
bgl.glLineWidth(2)
bgl.glDisable(bgl.GL_DEPTH_TEST)
bgl.glBegin(bgl.GL_LINE_STRIP)
for x, y, z in self.points:
bgl.glVertex3f(x, y, z)
bgl.glEnd()
# restore opengl defaults
bgl.glLineWidth(1)
bgl.glDisable(bgl.GL_BLEND)
bgl.glEnable(bgl.GL_DEPTH_TEST)
bgl.glColor4f(0.0, 0.0, 0.0, 1.0)
class ModalDrawOperator(bpy.types.Operator):
"""Draw a line with the mouse"""
bl_idname = "view3d.modal_operator"
bl_label = "Simple Modal View3D Operator"
def modal(self, context, event):
context.area.tag_redraw()
if event.type == 'LEFTMOUSE':
if event.value == 'RELEASE':
co_2d = Vector((event.mouse_region_x, event.mouse_region_y))
viewport = context.area.regions[4]
r3d = context.area.spaces[0].region_3d
nor = view3d_utils.region_2d_to_vector_3d(viewport, r3d, co_2d)
v3 = view3d_utils.region_2d_to_location_3d(viewport, r3d, co_2d, nor)
self.points.append(v3)
elif event.type in {'RIGHTMOUSE', 'ESC'}:
bpy.types.SpaceView3D.draw_handler_remove(self._handle, 'WINDOW')
return {'CANCELLED'}
return {'RUNNING_MODAL'}
def invoke(self, context, event):
if context.area.type == 'VIEW_3D':
self.points = []
args = (self, context, self.points)
self._handle = bpy.types.SpaceView3D.draw_handler_add(draw_callback_px, args, 'WINDOW', 'POST_VIEW')
context.window_manager.modal_handler_add(self)
return {'RUNNING_MODAL'}
else:
self.report({'WARNING'}, "View3D not found, cannot run operator")
return {'CANCELLED'}
def register():
bpy.utils.register_class(ModalDrawOperator)
def unregister():
bpy.utils.unregister_class(ModalDrawOperator)
if __name__ == "__main__":
register()
POST_PIXEL
is the only way AFAIK, but some OpenGL guru might prove me wrong (disable depth test?). $\endgroup$