view3d_idx_view.py

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# <pep8 compliant>

bl_info = {
    'name': 'Index Visualiser (BMesh)',
    'author': 'Bartius Crouch, CoDEmanX, zeffii',
    'version': (2, 6, 14),
    'blender': (2, 65, 0),
    'location': 'View3D > Properties panel > Mesh Display tab (edit-mode)',
    'warning': '', # used for warning icon and text in addons panel
    'description': 'Display the indices of vertices, edges and faces '\
        'in the 3d-view',
    'wiki_url': 'http://wiki.blender.org/index.php/Extensions:2.5/Py/'\
        'Scripts/3D_interaction/Index_Visualiser',
    'tracker_url': 'http://projects.blender.org/tracker/index.php?'\
        'func=detail&aid=21557',
    'category': '3D View'}


"""
Display the indices of vertices, edges and faces in the 3d-view.

How to use:
- Select a mesh and go into editmode
- Display the properties panel (N-key)
- Go to the Mesh Display tab, it helps to fold the tabs above it
- Press the 'Visualise indices button'

"""

import bpy
import bgl
import blf
import mathutils
import bmesh
import math


def adjust_list(in_list, x, y):
    return [[old_x + x , old_y + y] for (old_x, old_y) in in_list]


def get_points(amp, center, index):
    '''
    amp:     radius of rounded edges
    center:  location on screen
    index:   string representation of the index number
    
    returns: rounded rect point_list used for background.
    '''

    cx, cy = center
    width, height = blf.dimensions(0, index) 
    width += 2
    height += 4
    width -= (2*amp)
    height -= (2*amp)
   
    pos_list, final_list = [], []

    n_points = 12
    seg_angle = 2*math.pi / n_points
    for i in range(n_points+1):
        angle = i * seg_angle
        x = math.cos(angle) * amp + cx
        y = -math.sin(angle) * amp + cy
        pos_list.append([x, y])
     
    w_list, h_list = [1,-1,-1,1], [-1,-1,1,1]
    slice_list = [[i,i+4] for i in range(0, n_points, 3)]

    for idx, (start, end) in enumerate(slice_list):
        point_array = pos_list[start:end]
        w = width * w_list[idx]
        h = height * h_list[idx]
        final_list += adjust_list(point_array, w, h)      

    return final_list


# calculate locations and store them as ID property in the mesh
def draw_callback_px(self, context):
    # polling
    if context.mode != "EDIT_MESH":
        return

    # get screen information
    region = context.region
    mid_x = region.width / 2
    mid_y = region.height / 2
    width = region.width
    height = region.height
    
    # get matrices
    view_mat = context.space_data.region_3d.perspective_matrix
    ob_mat = context.active_object.matrix_world
    total_mat = view_mat * ob_mat
    
    text_height = 13    
    blf.size(0, text_height, 72)
    
    def draw_index(rgb, index, center):
        
        vec = total_mat * center # order is important
        # dehomogenise
        vec = mathutils.Vector((vec[0] / vec[3], vec[1] / vec[3], vec[2] / vec[3]))
        x = int(mid_x + vec[0] * width / 2)
        y = int(mid_y + vec[1] * height / 2)

        index = str(index)
        polyline = get_points(amp=5, center=(x,y), index=index)

        ''' draw polygon '''
        bgl.glColor4f(0.103, 0.2, 0.2, 0.2)    
 
        bgl.glBegin(bgl.GL_POLYGON)
        for segment in polyline:
            bgl.glVertex2f(*segment)  
        bgl.glEnd()

        txt_width, txt_height = blf.dimensions(0, index) 
        ''' draw text '''
        bgl.glColor3f(*rgb)
        blf.position(0, x-(txt_width/2), y-(txt_height/2), 0)
        blf.draw(0, index)

    vert_idx_color = (1.0, 1.0, 1.0)
    edge_idx_color = (1.0, 1.0, 0.0)
    face_idx_color = (1.0, 0.8, 0.8)

    scene = context.scene
    me = context.active_object.data
    bm = bmesh.from_edit_mesh(me)
    
    if scene.live_mode:
        me.update()
    
    if scene.display_vert_index:
        for v in bm.verts:
            if not v.hide and \
            (v.select or not scene.display_sel_only):
                ## CoDEmanx: bm.verts.index_update()?
                draw_index(vert_idx_color, v.index, v.co.to_4d())

    if scene.display_edge_index:
        for e in bm.edges:
            if not e.hide and \
            (e.select or not scene.display_sel_only):
                v1 = e.verts[0].co
                v2 = e.verts[1].co
                loc = v1 + ((v2 - v1) / 2)
                draw_index(edge_idx_color, e.index, loc.to_4d())

    if scene.display_face_index:
        for f in bm.faces:
            if not f.hide and \
            (f.select or not scene.display_sel_only):
                draw_index(face_idx_color, f.index, f.calc_center_median().to_4d())


# operator
class IndexVisualiser(bpy.types.Operator):
    bl_idname = "view3d.index_visualiser"
    bl_label = "Index Visualiser"
    bl_description = "Toggle the visualisation of indices"
    
    _handle = None
    
    @classmethod
    def poll(cls, context):
        return context.mode=="EDIT_MESH"
    
    def modal(self, context, event):
        if context.area:
            context.area.tag_redraw()

        # removal of callbacks when operator is called again
        if context.scene.display_indices == -1:
            bpy.types.SpaceView3D.draw_handler_remove(self._handle, 'WINDOW')
            context.scene.display_indices = 0
            return {"CANCELLED"}
        
        return {"PASS_THROUGH"}
    
    def invoke(self, context, event):
        if context.area.type == "VIEW_3D":
            if context.scene.display_indices < 1:
                # operator is called for the first time, start everything
                context.scene.display_indices = 1
                self._handle = bpy.types.SpaceView3D.draw_handler_add(draw_callback_px,
                    (self, context), 'WINDOW', 'POST_PIXEL')
                context.window_manager.modal_handler_add(self)
                return {"RUNNING_MODAL"}
            else:
                # operator is called again, stop displaying
                context.scene.display_indices = -1
                return {'RUNNING_MODAL'}
        else:
            self.report({"WARNING"}, "View3D not found, can't run operator")
            return {"CANCELLED"}


# defining the panel
def menu_func(self, context):
    self.layout.separator()
    col = self.layout.column(align=True)
    col.operator(IndexVisualiser.bl_idname, text="Visualize indices")
    row = col.row(align=True)
    row.active = (context.mode=="EDIT_MESH" and \
        context.scene.display_indices==1)
    row.prop(context.scene, "display_vert_index", toggle=True)
    row.prop(context.scene, "display_edge_index", toggle=True)
    row.prop(context.scene, "display_face_index", toggle=True)
    row = col.row(align=True)
    row.active = context.mode == "EDIT_MESH" and \
                 context.scene.display_indices == 1
    row.prop(context.scene, "display_sel_only")
    #row.prop(context.scene, "live_mode")


def register_properties():
    bpy.types.Scene.display_indices = bpy.props.IntProperty(
        name="Display indices",
        default=0)
    #context.scene.display_indices = 0
    bpy.types.Scene.display_sel_only = bpy.props.BoolProperty(
        name="Selected only",
        description="Only display indices of selected vertices/edges/faces",
        default=True)
    bpy.types.Scene.display_vert_index = bpy.props.BoolProperty(
        name="Vertices",
        description="Display vertex indices", default=True)
    bpy.types.Scene.display_edge_index = bpy.props.BoolProperty(
        name="Edges",
        description="Display edge indices")
    bpy.types.Scene.display_face_index = bpy.props.BoolProperty(
        name="Faces",
        description="Display face indices")
    bpy.types.Scene.live_mode = bpy.props.BoolProperty(
        name="Live",
        description="Toggle live update of the selection, can be slow",
        default=False)
        
def unregister_properties():
    del bpy.types.Scene.display_indices
    del bpy.types.Scene.display_sel_only
    del bpy.types.Scene.display_vert_index
    del bpy.types.Scene.display_edge_index
    del bpy.types.Scene.display_face_index
    del bpy.types.Scene.live_mode


def register():
    register_properties()
    bpy.utils.register_class(IndexVisualiser)
    bpy.types.VIEW3D_PT_view3d_meshdisplay.append(menu_func)


def unregister():
    bpy.utils.unregister_class(IndexVisualiser)
    unregister_properties()
    bpy.types.VIEW3D_PT_view3d_meshdisplay.remove(menu_func)


if __name__ == "__main__":
    register()