WIP gizmo for parametreic extrusion, see #1324

src/ifcblenderexport/blenderbim/bim/__init__.py

@@ -6,7 +6,7 @@ bpy = sys.modules.get("bpy")
 if bpy is not None:
     import bpy
     import importlib
-    from . import handler, ui, prop, operator
+    from . import handler, ui, prop, operator, gizmos
 
     modules = {
         "project": None,
@@ -145,6 +145,11 @@ if bpy is not None:
         ui.BIM_UL_drawinglist,
         ui.BIM_UL_topics,
         ui.BIM_ADDON_preferences,
+        gizmos.UglyDotGizmo,
+        gizmos.DotGizmo,
+        gizmos.DimensionLabelGizmo,
+        gizmos.ExtrusionGuidesGizmo,
+        gizmos.ExtrusionWidget
     ]
 
     for module in modules.values():

src/ifcblenderexport/blenderbim/bim/gizmos.py

@@ -0,0 +1,400 @@
+import bpy
+import blf
+from bpy import types
+import math
+from mathutils import Vector, Matrix
+from mathutils import geometry
+import gpu, bgl
+from bpy_extras import view3d_utils
+
+
+from .shaders import DotsGizmoShader, ExtrusionGuidesShader, BaseLinesShader
+
+
+"""Gizmos under the hood
+
+## Transforms:
+
+source/blender/windowmanager/gizmo/WM_gizmo_types.h
+matrix_basis -- "Transformation of this gizmo." = placement in scene
+matrix_offset -- "Custom offset from origin." = local transforms according to state/value
+matrix_space -- "The space this gizmo is being modified in." used by some gizmos for undefined purposes
+matrix_world -- final matrix, scaled according to viewport zoom and custom scale_basis
+
+source/blender/windowmanager/gizmo/intern/wm_gizmo.c:WM_gizmo_calc_matrix_final_params
+final = space @ (autoscale * (basis @ offset))
+final = space @ (basis @ offset) -- if gizmo.use_draw_scale == False
+final = space @ ((autoscale * basis) @ offset) -- if gizmo.use_draw_offset_scale
+
+source/blender/windowmanager/gizmo/intern/wm_gizmo.c:wm_gizmo_calculate_scale
+autoscale = gizmo.scale_basis * magic(preferences, matrix_space, matrix_basis, context.region_data)
+magic -- making 1.0 to match preferences.view.gizmo_size pixels (75 by default)
+
+
+## Selection
+
+select_id -- apparently, id of a selectable part
+test_select -- expected to return id of selection, doesn't seem to work
+draw_select -- fake-draw of selection geometry for gpu-side cursor tracking
+
+"""
+
+
+# some geometries for Gizmo.custom_shape shaders
+
+CUBE = (
+    (+1, +1, +1), (-1, +1, +1), (+1, -1, +1),  # top
+    (+1, -1, +1), (-1, +1, +1), (-1, -1, +1),
+    (+1, +1, +1), (+1, -1, +1), (+1, +1, -1),  # right
+    (+1, +1, -1), (+1, -1, +1), (+1, -1, -1),
+    (+1, +1, +1), (+1, +1, -1), (-1, +1, +1),  # back
+    (-1, +1, +1), (+1, +1, -1), (-1, +1, -1),
+    (-1, -1, -1), (-1, +1, -1), (+1, -1, -1),  # bot
+    (+1, -1, -1), (-1, +1, -1), (+1, +1, -1),
+    (-1, -1, -1), (-1, -1, +1), (-1, +1, -1),  # left
+    (-1, +1, -1), (-1, -1, +1), (-1, +1, +1),
+    (-1, -1, -1), (+1, -1, -1), (-1, -1, +1),  # front
+    (-1, -1, +1), (+1, -1, -1), (+1, -1, +1)
+)
+
+DISC = (
+    (0.0, 0.0, 0.0), (1.0, 0.0, 0), (0.8660254037844387, 0.49999999999999994, 0),
+    (0.0, 0.0, 0.0), (0.8660254037844387, 0.49999999999999994, 0), (0.5000000000000001, 0.8660254037844386, 0),
+    (0.0, 0.0, 0.0), (0.5000000000000001, 0.8660254037844386, 0), (6.123233995736766e-17, 1.0, 0),
+    (0.0, 0.0, 0.0), (6.123233995736766e-17, 1.0, 0), (-0.4999999999999998, 0.8660254037844387, 0),
+    (0.0, 0.0, 0.0), (-0.4999999999999998, 0.8660254037844387, 0), (-0.8660254037844385, 0.5000000000000003, 0),
+    (0.0, 0.0, 0.0), (-0.8660254037844385, 0.5000000000000003, 0), (-1.0, 1.2246467991473532e-16, 0),
+    (0.0, 0.0, 0.0), (-1.0, 1.2246467991473532e-16, 0), (-0.8660254037844388, -0.4999999999999997, 0),
+    (0.0, 0.0, 0.0), (-0.8660254037844388, -0.4999999999999997, 0), (-0.5000000000000004, -0.8660254037844384, 0),
+    (0.0, 0.0, 0.0), (-0.5000000000000004, -0.8660254037844384, 0), (-1.8369701987210297e-16, -1.0, 0),
+    (0.0, 0.0, 0.0), (-1.8369701987210297e-16, -1.0, 0), (0.49999999999999933, -0.866025403784439, 0),
+    (0.0, 0.0, 0.0), (0.49999999999999933, -0.866025403784439, 0), (0.8660254037844384, -0.5000000000000004, 0),
+    (0.0, 0.0, 0.0), (0.8660254037844384, -0.5000000000000004, 0), (1.0, 0.0, 0),
+)
+
+X3DISC = (
+    (0.0, 0.0, 0.0), (1.0, 0.0, 0), (0.8660254037844387, 0.49999999999999994, 0),
+    (0.0, 0.0, 0.0), (0.8660254037844387, 0.49999999999999994, 0), (0.5000000000000001, 0.8660254037844386, 0),
+    (0.0, 0.0, 0.0), (0.5000000000000001, 0.8660254037844386, 0), (6.123233995736766e-17, 1.0, 0),
+    (0.0, 0.0, 0.0), (6.123233995736766e-17, 1.0, 0), (-0.4999999999999998, 0.8660254037844387, 0),
+    (0.0, 0.0, 0.0), (-0.4999999999999998, 0.8660254037844387, 0), (-0.8660254037844385, 0.5000000000000003, 0),
+    (0.0, 0.0, 0.0), (-0.8660254037844385, 0.5000000000000003, 0), (-1.0, 1.2246467991473532e-16, 0),
+    (0.0, 0.0, 0.0), (-1.0, 1.2246467991473532e-16, 0), (-0.8660254037844388, -0.4999999999999997, 0),
+    (0.0, 0.0, 0.0), (-0.8660254037844388, -0.4999999999999997, 0), (-0.5000000000000004, -0.8660254037844384, 0),
+    (0.0, 0.0, 0.0), (-0.5000000000000004, -0.8660254037844384, 0), (-1.8369701987210297e-16, -1.0, 0),
+    (0.0, 0.0, 0.0), (-1.8369701987210297e-16, -1.0, 0), (0.49999999999999933, -0.866025403784439, 0),
+    (0.0, 0.0, 0.0), (0.49999999999999933, -0.866025403784439, 0), (0.8660254037844384, -0.5000000000000004, 0),
+    (0.0, 0.0, 0.0), (0.8660254037844384, -0.5000000000000004, 0), (1.0, 0.0, 0),
+    (0.0, 0.0, 0.0), (0, 1.0, 0.0), (0, 0.8660254037844387, 0.49999999999999994),
+    (0.0, 0.0, 0.0), (0, 0.8660254037844387, 0.49999999999999994), (0, 0.5000000000000001, 0.8660254037844386),
+    (0.0, 0.0, 0.0), (0, 0.5000000000000001, 0.8660254037844386), (0, 6.123233995736766e-17, 1.0),
+    (0.0, 0.0, 0.0), (0, 6.123233995736766e-17, 1.0), (0, -0.4999999999999998, 0.8660254037844387),
+    (0.0, 0.0, 0.0), (0, -0.4999999999999998, 0.8660254037844387), (0, -0.8660254037844385, 0.5000000000000003),
+    (0.0, 0.0, 0.0), (0, -0.8660254037844385, 0.5000000000000003), (0, -1.0, 1.2246467991473532e-16),
+    (0.0, 0.0, 0.0), (0, -1.0, 1.2246467991473532e-16), (0, -0.8660254037844388, -0.4999999999999997),
+    (0.0, 0.0, 0.0), (0, -0.8660254037844388, -0.4999999999999997), (0, -0.5000000000000004, -0.8660254037844384),
+    (0.0, 0.0, 0.0), (0, -0.5000000000000004, -0.8660254037844384), (0, -1.8369701987210297e-16, -1.0),
+    (0.0, 0.0, 0.0), (0, -1.8369701987210297e-16, -1.0), (0, 0.49999999999999933, -0.866025403784439),
+    (0.0, 0.0, 0.0), (0, 0.49999999999999933, -0.866025403784439), (0, 0.8660254037844384, -0.5000000000000004),
+    (0.0, 0.0, 0.0), (0, 0.8660254037844384, -0.5000000000000004), (0, 1.0, 0.0),
+    (0.0, 0.0, 0.0), (0.0, 0, 1.0), (0.49999999999999994, 0, 0.8660254037844387),
+    (0.0, 0.0, 0.0), (0.49999999999999994, 0, 0.8660254037844387), (0.8660254037844386, 0, 0.5000000000000001),
+    (0.0, 0.0, 0.0), (0.8660254037844386, 0, 0.5000000000000001), (1.0, 0, 6.123233995736766e-17),
+    (0.0, 0.0, 0.0), (1.0, 0, 6.123233995736766e-17), (0.8660254037844387, 0, -0.4999999999999998),
+    (0.0, 0.0, 0.0), (0.8660254037844387, 0, -0.4999999999999998), (0.5000000000000003, 0, -0.8660254037844385),
+    (0.0, 0.0, 0.0), (0.5000000000000003, 0, -0.8660254037844385), (1.2246467991473532e-16, 0, -1.0),
+    (0.0, 0.0, 0.0), (1.2246467991473532e-16, 0, -1.0), (-0.4999999999999997, 0, -0.8660254037844388),
+    (0.0, 0.0, 0.0), (-0.4999999999999997, 0, -0.8660254037844388), (-0.8660254037844384, 0, -0.5000000000000004),
+    (0.0, 0.0, 0.0), (-0.8660254037844384, 0, -0.5000000000000004), (-1.0, 0, -1.8369701987210297e-16),
+    (0.0, 0.0, 0.0), (-1.0, 0, -1.8369701987210297e-16), (-0.866025403784439, 0, 0.49999999999999933),
+    (0.0, 0.0, 0.0), (-0.866025403784439, 0, 0.49999999999999933), (-0.5000000000000004, 0, 0.8660254037844384),
+    (0.0, 0.0, 0.0), (-0.5000000000000004, 0, 0.8660254037844384), (0.0, 0, 1.0),
+)
+
+
+class CustomGizmo():
+    # FIXME: highliting/selection doesnt work
+    def draw_very_custom_shape(self, ctx, custom_shape, select_id=None):
+        # similar to draw_custom_shape
+        shape, batch, shader = custom_shape
+
+        shader.bind()
+
+        if select_id is not None:
+            gpu.select.load_id(select_id)
+        else:
+            if self.is_highlight:
+                color = (*self.color_highlight, self.alpha_highlight)
+            else:
+                color = (*self.color, self.alpha)
+            shader.uniform_float('color', color)
+            shape.glenable()
+
+        shape.uniform_region(ctx)
+        # shader.uniform_float('modelMatrix', self.matrix_world)
+        with gpu.matrix.push_pop():
+            gpu.matrix.multiply_matrix(self.matrix_world)
+            batch.draw()
+
+        bgl.glDisable(bgl.GL_BLEND)
+
+
+class OffsetHandle():
+    """Handling mouse to offset gizmo from base along Z axis"""
+    # FIXME: works a bit weird for rotated objects
+
+    def invoke(self, ctx, event):
+        self.init_value = self.target_get_value('offset') / self.scale_value
+        coordz = self.project_mouse(ctx, event)
+        if coordz is None:
+            return {'CANCELLED'}
+        self.init_coordz = coordz
+        return {'RUNNING_MODAL'}
+
+    def modal(self, ctx, event, tweak):
+        coordz = self.project_mouse(ctx, event)
+        if coordz is None:
+            return {'CANCELLED'}
+        delta = coordz - self.init_coordz
+        if 'PRECISE' in tweak:
+            delta /= 10.0
+        value = max(0, self.init_value + delta)
+        value *= self.scale_value
+        # ctx.area.header_text_set(f"coords: {self.init_coordz} - {coordz}, delta: {delta}, value: {value}")
+        ctx.area.header_text_set(f"Depth: {value}")
+        self.target_set_value('offset', value)
+        return {'RUNNING_MODAL'}
+
+    def project_mouse(self, ctx, event):
+        """Projecting mouse coords to local axis Z"""
+        # logic from source/blender/editors/gizmo_library/gizmo_types/arrow3d_gizmo.c:gizmo_arrow_modal
+
+        mouse = Vector((event.mouse_region_x, event.mouse_region_y))
+        region = ctx.region
+        region3d = ctx.region_data
+        ray_orig = view3d_utils.region_2d_to_origin_3d(region, region3d, mouse)
+        ray_norm = view3d_utils.region_2d_to_vector_3d(region, region3d, mouse)
+
+        # 'arrow' origin and direction
+        base = Vector((0, 0, 0))
+        axis = Vector((0, 0, 1))
+
+        # projecttion of the arrow to a plane, perpendicular to view ray
+        axis_proj = axis - ray_norm * axis.dot(ray_norm)
+
+        # intersection of the axis with the plane through view origin perpendicular to the arrow projection
+        coords = geometry.intersect_line_plane(base, axis, ray_orig, axis_proj)
+
+        return coords.z
+
+    def exit(self, ctx, cancel):
+        if cancel:
+            self.target_set_value('offset', self.init_value)
+        else:
+            self.group.update(ctx)
+
+
+class UglyDotGizmo(OffsetHandle, types.Gizmo):
+    """three orthogonal circles"""
+    bl_idname = "BIM_GT_uglydot_3d"
+    bl_target_properties = (
+        {'id': 'offset', 'type': 'FLOAT', 'array_length': 1},
+    )
+
+    __slots__ = (
+        'scale_value',
+        'custom_shape',
+        'init_value',
+        'init_coordz',
+    )
+
+    def setup(self):
+        self.custom_shape = self.new_custom_shape(type='TRIS', verts=X3DISC)
+
+    def refresh(self):
+        offset = self.target_get_value('offset') / self.scale_value
+        self.matrix_offset.col[3][2] = offset  # z-shift
+
+    def draw(self, ctx):
+        self.refresh()
+        self.draw_custom_shape(self.custom_shape)
+
+    def draw_select(self, ctx, select_id):
+        self.refresh()
+        self.draw_custom_shape(self.custom_shape, select_id=select_id)
+
+
+class DotGizmo(CustomGizmo, OffsetHandle, types.Gizmo):
+    """Single dot viewport-aligned"""
+    # FIXME: make it selectable
+    bl_idname = "BIM_GT_dot_2d"
+    bl_target_properties = (
+        {'id': 'offset', 'type': 'FLOAT', 'array_length': 1},
+    )
+
+    __slots__ = (
+        'scale_value',
+        'custom_shape',
+    )
+
+    def setup(self):
+        shader = DotsGizmoShader()
+        self.custom_shape = shader, shader.batch(pos=((0, 0, 0),)), shader.prog
+        self.use_draw_scale = False
+
+    def refresh(self):
+        offset = self.target_get_value('offset') / self.scale_value
+        self.matrix_offset.col[3][2] = offset  # z-shifted
+
+    def draw(self, ctx):
+        self.refresh()
+        self.draw_very_custom_shape(ctx, self.custom_shape)
+
+    def draw_select(self, ctx, select_id):
+        self.refresh()
+        self.draw_very_custom_shape(ctx, self.custom_shape, select_id=select_id)
+
+    # doesn't get called
+    # def test_select(self, ctx, location):
+    #     pass
+
+
+class ExtrusionGuidesGizmo(CustomGizmo, types.Gizmo):
+    """Extrusion guides
+
+    Noninteractive gizmo to indicate extrusion depth and planes.
+    Draws main segment and orthogonal cross at endpoints.
+    """
+    bl_idname = "BIM_GT_extrusion_guides"
+    bl_target_properties = (
+        {'id': 'depth', 'type': 'FLOAT', 'array_length': 1},
+    )
+
+    __slots__ = (
+        'scale_value',
+        'custom_shape'
+    )
+
+    def setup(self):
+        shader = ExtrusionGuidesShader()
+        self.custom_shape = shader, shader.batch(pos=((0, 0, 0), (0, 0, 1))), shader.prog
+        self.use_draw_scale = False
+
+    def refresh(self):
+        depth = self.target_get_value('depth') / self.scale_value
+        self.matrix_offset.col[2][2] = depth  # z-scaled
+
+    def draw(self, ctx):
+        self.refresh()
+        self.draw_very_custom_shape(ctx, self.custom_shape)
+
+
+class DimensionLabelGizmo(types.Gizmo):
+    """Text label for a dimension"""
+    # does not work properly, fonts are totally screwed up
+
+    bl_idname = "BIM_GT_dimension_label"
+    bl_target_properties = (
+        {'id': 'value', 'type': 'FLOAT', 'array_length': 1},
+    )
+
+    __slots__ = (
+        'text_label'
+    )
+
+    def setup(self):
+        pass
+
+    def refresh(self, ctx):
+        value = self.target_get_value('value')
+        self.matrix_offset.col[3][2] = value * .5
+        unit_system = ctx.scene.unit_settings.system
+        self.text_label = bpy.utils.units.to_string(unit_system, 'LENGTH', value, 3, split_unit=False)
+
+    def draw(self, ctx):
+        self.refresh(ctx)
+        self.draw_text(ctx)
+
+    def draw_text(self, ctx):
+        font_id = 0
+        font_size = 16
+        dpi = ctx.preferences.system.dpi
+
+        # pos = self.matrix_world @ Vector((0, 0, 0, 1))
+        # pos = Vector((0, 0, 0.5))
+        # region = ctx.region
+        # region3d = ctx.region_data
+        # pos = view3d_utils.location_3d_to_region_2d(region, region3d, pos)
+
+        # text = self.text_label
+
+        blf.size(font_id, font_size, dpi)
+        blf.position(font_id, 0, 0, 0)
+        blf.color(font_id, *self.color, self.alpha)
+        blf.draw(font_id, "ABC")
+
+
+class ExtrusionWidget(types.GizmoGroup):
+    bl_idname = "bim.extrusion_widget"
+    bl_label = "Extrusion Gizmos"
+    bl_space_type = 'VIEW_3D'
+    bl_region_type = 'WINDOW'
+    bl_options = {'3D', 'PERSISTENT'}
+
+    # FIXME: use proper scale from ifc value to blender units
+
+    @classmethod
+    def poll(cls, ctx):
+        obj = ctx.object
+        return (obj and obj.type == 'MESH'
+                and obj.data.BIMMeshProperties.ifc_parameters.get('IfcExtrudedAreaSolid/Depth') is not None)
+
+    def setup(self, ctx):
+        target = ctx.object
+        prop = target.data.BIMMeshProperties.ifc_parameters.get('IfcExtrudedAreaSolid/Depth')
+
+        basis = target.matrix_world.normalized()
+        theme = ctx.preferences.themes[0].user_interface
+
+        gz = self.handle = self.gizmos.new('BIM_GT_uglydot_3d')
+        gz.matrix_basis = basis
+        gz.scale_basis = 0.1
+        gz.color = gz.color_highlight = tuple(theme.gizmo_primary)
+        gz.alpha = 0.5
+        gz.alpha_highlight = 1.0
+        gz.use_draw_modal = True
+        gz.target_set_prop('offset', prop, 'value')
+        gz.scale_value = 1000
+
+        gz = self.guides = self.gizmos.new('BIM_GT_extrusion_guides')
+        gz.matrix_basis = basis
+        gz.color = gz.color_highlight = tuple(theme.gizmo_secondary)
+        gz.alpha = gz.alpha_highlight = 0.5
+        gz.use_draw_modal = True
+        gz.target_set_prop('depth', prop, 'value')
+        gz.scale_value = 1000
+
+        # gz = self.label = self.gizmos.new('GIZMO_GT_dimension_label')
+        # gz.matrix_basis = basis
+        # gz.color = tuple(theme.gizmo_secondary)
+        # gz.alpha = 0.5
+        # gz.use_draw_modal = True
+        # gz.target_set_prop('value', target.demo, 'depth')
+
+    def refresh(self, ctx):
+        """updating gizmos"""
+        target = ctx.object
+        basis = target.matrix_world.normalized()
+        self.handle.matrix_basis = basis
+        self.guides.matrix_basis = basis
+
+    def update(self, ctx):
+        """updating object"""
+        bpy.ops.bim.update_parametric_representation()
+        # parameters disappear after update
+        # need to retrieve and rebind them again
+        bpy.ops.bim.get_representation_ifc_parameters()
+        target = ctx.object
+        prop = target.data.BIMMeshProperties.ifc_parameters.get('IfcExtrudedAreaSolid/Depth')
+        self.handle.target_set_prop('offset', prop, 'value')
+        self.guides.target_set_prop('depth', prop, 'value')

src/ifcblenderexport/blenderbim/bim/shaders.py

@@ -0,0 +1,268 @@
+from mathutils import Matrix
+import bgl
+from gpu.types import GPUShader
+from gpu_extras.batch import batch_for_shader
+
+
+class BaseShader():
+    """Wrapepr for GPUShader
+    To use for viewport decorations with geometry generated on GPU side.
+
+    The Geometry shader works in clipping coords (aftre projecting before division and window scaling).
+    To make window-scale geometry, vectors should be calculated in window space and than back-projected to clipping spae.
+    Provide `winSize` uniform vector with halfsize of window, and use W2C and C2W macros.
+
+    Replace glsl code in derived classes.
+    Beware of unused attributes and uniforms: glsl compiler will optimize them out and blender fail with an exception.
+
+
+    Vertex topology attribute to use with line segments:
+    - 0 = inner
+    - 1 = starting
+    - 2 = ending
+    - 3 = isolated
+    """
+
+    TYPE = None  # should be LINES|POINTS|etc
+
+    DEF_GLSL = """
+    #define PI 3.141592653589793
+    """
+
+    VERT_GLSL = """
+    uniform mat4 viewMatrix;
+    uniform mat4 modelMatrix;
+
+    in vec3 pos;
+    in uint topology;
+    out vec4 gl_Position;
+    out uint topo;
+
+    void main() {
+        gl_Position = viewMatrix * modelMatrix * vec4(pos, 1.0);
+        topo = topology;
+    }
+    """
+
+    # prepended to geom_glsl
+    LIB_GLSL = """
+    uniform vec2 winSize;
+    // convert camera to window
+    #define C2W(v) vec4(v.x * winSize.x / v.w, v.y * winSize.y / v.w, v.z / v.w, 1)
+    // convert window to camera
+    #define W2C(v) vec4(v.x * v.w / winSize.x, v.y * v.w / winSize.y, v.z * v.w, 1)
+
+    void emitSegment(vec4 p0, vec4 p1) {
+        gl_Position = p0;
+        EmitVertex();
+        gl_Position = p1;
+        EmitVertex();
+        EndPrimitive();
+    }
+
+    void emitTriangle(vec4 p1, vec4 p2, vec4 p3) {
+        gl_Position = p1;
+        EmitVertex();
+        gl_Position = p2;
+        EmitVertex();
+        gl_Position = p3;
+        EmitVertex();
+        EndPrimitive();
+    }
+    """
+
+    GEOM_GLSL = """
+    """
+
+    FRAG_GLSL = """
+    uniform vec4 color;
+    out vec4 fragColor;
+
+    void main() {
+        fragColor = color;
+    }
+    """
+
+    def __init__(self):
+        # NB: libcode arg doesn't work
+        self.prog = GPUShader(vertexcode=self.VERT_GLSL,
+                              fragcode=self.FRAG_GLSL,
+                              geocode=self.LIB_GLSL + self.GEOM_GLSL,
+                              defines=self.DEF_GLSL)
+
+    def batch(self, indices=None, **data):
+        """Returns automatic GPUBatch filled with provided parameters
+        """
+        batch = batch_for_shader(self.prog, self.TYPE, data, indices=indices)
+        batch.program_set(self.prog)
+        return batch
+
+    def bind(self):
+        self.prog.bind()
+
+    def glenable(self):
+        bgl.glEnable(bgl.GL_BLEND)
+        bgl.glBlendFunc(bgl.GL_SRC_ALPHA, bgl.GL_ONE_MINUS_SRC_ALPHA)
+        bgl.glBlendEquation(bgl.GL_FUNC_ADD)
+
+        # bgl.glEnable(bgl.GL_DEPTH_TEST)
+        # bgl.glDepthFunc(bgl.GL_LEQUAL)
+        # bgl.glDepthMask(True)
+
+    def uniform_region(self, ctx):
+        region = ctx.region
+        region3d = ctx.region_data
+        try:
+            self.prog.uniform_float('viewMatrix', region3d.perspective_matrix)
+        except ValueError:  # unused uniform
+            pass
+        try:
+            self.prog.uniform_float('winSize', (region.width / 2, region.height / 2))
+        except ValueError:  # unused uniform
+            pass
+
+
+class BaseLinesShader(BaseShader):
+    """Draws line segments with gaps around vertices at endpoints
+    """
+    TYPE = 'LINES'
+
+    DEF_GLSL = BaseShader.DEF_GLSL + """
+    #define GAP_SIZE {gap_size}
+    """
+
+    GEOM_GLSL = """
+    layout(lines) in;
+    in uint topo[];
+    layout(line_strip, max_vertices=2) out;
+
+    void main() {
+        vec4 p0 = gl_in[0].gl_Position, p1 = gl_in[1].gl_Position;
+        uint t0 = topo[0], t1 = topo[1];
+
+        vec4 p0w = C2W(p0), p1w = C2W(p1);
+        vec4 edge = p1w - p0w, dir = normalize(edge);
+        vec4 gap = dir * GAP_SIZE;
+
+        vec4 p0_ = p0w, p1_ = p1w;
+
+        if (t0 == 1u) {
+            p0_ += gap;
+        }
+
+        if (t1 == 2u) {
+            p1_ -= gap;
+        }
+
+        emitSegment(W2C(p0_), W2C(p1_));
+    }
+    """
+
+    def __init__(self, gap_size=16):
+        super().__init__(gap_size=gap_size)
+
+    def glenable(self):
+        super().glenable()
+        bgl.glEnable(bgl.GL_LINE_SMOOTH)
+
+
+class GizmoShader(BaseShader):
+    """Gizmo 2D shader
+
+    Scaling to match viewport is partially controlled by user preferences and gizmo code.
+    """
+    # TODO: add some magic to respect gizmo settings/params
+
+    VERT_GLSL = """
+    uniform mat4 ModelViewProjectionMatrix;
+
+    in vec3 pos;
+
+    void main() {
+        gl_Position = ModelViewProjectionMatrix * vec4(pos, 1.0);
+    }
+    """
+
+
+class DotsGizmoShader(GizmoShader):
+    """Draws circles of radius 1 around points"""
+
+    TYPE = 'POINTS'
+
+    DEF_GLSL = BaseShader.DEF_GLSL + """
+    #define CIRCLE_SEGMENTS 12
+    #define CIRCLE_RADIUS 8
+    """
+
+    GEOM_GLSL = """
+    layout(points) in;
+    layout(triangle_strip, max_vertices=36) out;
+
+    // apparently can be precalculated
+    void makeCircle(out vec4 circle[CIRCLE_SEGMENTS+1]) {
+        float angle_d = PI * 2 / CIRCLE_SEGMENTS;
+        for(int i = 0; i<=CIRCLE_SEGMENTS; i++) {
+            float angle = angle_d * i;
+            circle[i] = vec4(cos(angle), sin(angle), 0, 0) * CIRCLE_RADIUS;
+        }
+    }
+
+    void main() {
+        vec4 p0 = gl_in[0].gl_Position;
+        vec4 p0w = C2W(p0);
+
+        vec4 circle[CIRCLE_SEGMENTS+1];
+        makeCircle(circle);
+
+        vec4 p1w, p2w;
+
+        for(int i = 0; i<=CIRCLE_SEGMENTS; i++) {
+            p1w = p0w + circle[i];
+            p2w = p0w + circle[i+1];
+            emitTriangle(p0, W2C(p1w), W2C(p2w));
+        }
+/*
+        for(int i = 0; i<=CIRCLE_SEGMENTS; i++) {
+            p1w = p0 + circle[i];
+            p2w = p0 + circle[i+1];
+            emitTriangle(p0, p1w, p2w);
+        }
+*/
+    }
+    """
+
+
+class ExtrusionGuidesShader(GizmoShader):
+    """Draws lines and add cross in XY plane at endpoints"""
+
+    TYPE = 'LINES'
+
+    DEF_GLSL = BaseShader.DEF_GLSL + """
+    #define CROSS_SIZE .5
+    """
+
+    GEOM_GLSL = """
+    uniform mat4 ModelViewProjectionMatrix;
+
+    layout(lines) in;
+    layout(line_strip, max_vertices=10) out;
+
+    void main() {
+        vec4 p0 = gl_in[0].gl_Position, p1 = gl_in[1].gl_Position;
+        vec4 p0w = C2W(p0), p1w = C2W(p1);
+
+        emitSegment(p0, p1);
+
+        vec4 bx = ModelViewProjectionMatrix[0] * CROSS_SIZE;
+        vec4 by = ModelViewProjectionMatrix[1] * CROSS_SIZE;
+
+        emitSegment(p0 - bx, p0 + bx);
+        emitSegment(p0 - by, p0 + by);
+        emitSegment(p1 - bx, p1 + bx);
+        emitSegment(p1 - by, p1 + by);
+    }
+    """
+
+    def glenable(self):
+        super().glenable()
+        bgl.glEnable(bgl.GL_LINE_SMOOTH)