randomvertexcolors.py

# ##### BEGIN GPL LICENSE BLOCK #####
#
#  Random vertex colors, a Blender addon
#  (c) 2013 Michel J. Anders (varkenvarken)
#
#  This program is free software; you can redistribute it and/or
#  modify it under the terms of the GNU General Public License
#  as published by the Free Software Foundation; either version 2
#  of the License, or (at your option) any later version.
#
#  This program is distributed in the hope that it will be useful,
#  but WITHOUT ANY WARRANTY; without even the implied warranty of
#  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
#  GNU General Public License for more details.
#
#  You should have received a copy of the GNU General Public License
#  along with this program; if not, write to the Free Software Foundation,
#  Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
#
# ##### END GPL LICENSE BLOCK #####

# a special thank you to Linus Yng and @ambi for their feedback on the
# numpy related changes.

# <pep8 compliant>

from random import random
import bpy

from time import process_time as time

from bpy.props import BoolProperty
import numpy as np

bl_info = {
	"name": "Random vertex colors",
	"author": "michel anders (varkenvarken)",
	"version": (0, 0, 201602071043),
	"blender": (2, 68, 0),
	"location": "View3D > Paint > Add random vertex colors",
	"description": "Add random vertex colors to individual faces.",
	"warning": "",
	"wiki_url": "http://blenderthings.blogspot.com/2013/08/random-vertex-colors-simple-addon.html",
	"tracker_url": "",
	"category": "Paint"}


class RandomVertexColors(bpy.types.Operator):

	bl_idname = "mesh.random_vertex_colors"
	bl_label = "RandomVertexColors"
	bl_options = {'REGISTER', 'UNDO', 'PRESET'}

	timeit = BoolProperty(name="Log timing in console", default=False)
	usenumpy = BoolProperty(name="Use Numpy", default=False)

	@classmethod
	def poll(self, context):
		# Check if we have a mesh object active and are in vertex paint mode
		p = (context.mode == 'PAINT_VERTEX' and
			 isinstance(context.scene.objects.active, bpy.types.Object) and
			 isinstance(context.scene.objects.active.data, bpy.types.Mesh))
		return p

	def execute(self, context):
		bpy.ops.object.mode_set(mode='OBJECT')
		mesh = context.scene.objects.active.data
		vertex_colors = mesh.vertex_colors.active.data
		polygons = mesh.polygons
		verts = mesh.vertices
		npolygons = len(polygons)
		nverts = len(verts)
		nloops = len(vertex_colors)

		if self.usenumpy:
			start = time()

			startloop = np.empty(npolygons, dtype=np.int32)
			numloops = np.empty(npolygons, dtype=np.int32)
			polygon_indices = np.empty(npolygons, dtype=np.int32)

			polygons.foreach_get('index', polygon_indices)
			polygons.foreach_get('loop_start', startloop)
			polygons.foreach_get('loop_total', numloops)

			colors = np.random.random_sample((npolygons,3)).astype(np.float32)
			loopcolors = np.empty((nloops,3), dtype=np.float32)

			#the following code is *much* slower than doing everrything in numpy
			#for s,n,pi in np.nditer([startloop, numloops, polygon_indices]):
			#	loopcolors[slice(s,s+n)] = colors[pi]

			loopcolors[startloop] = colors[polygon_indices]
			numloops -= 1
			nz = np.flatnonzero(numloops)
			while len(nz):
				startloop[nz] += 1
				loopcolors[startloop[nz]] = colors[polygon_indices[nz]]
				numloops[nz] -= 1
				nz = np.flatnonzero(numloops)

			loopcolors = loopcolors.flatten()
			vertex_colors.foreach_set("color", loopcolors)
		else:
			start = time()
			for poly in polygons:
				color = [random(), random(), random()]
				for loop_index in range(poly.loop_start, poly.loop_start + poly.loop_total):
					vertex_colors[loop_index].color = color
		if self.timeit:
			print("%s: %d/%d (verts/polys) in %.2f seconds"%("numpy" if self.usenumpy else "plain", nverts, npolygons, time()-start))
		bpy.ops.object.mode_set(mode='VERTEX_PAINT')
		bpy.ops.object.mode_set(mode='EDIT')
		bpy.ops.object.mode_set(mode='VERTEX_PAINT')
		context.scene.update()
		return {'FINISHED'}


def menu_func(self, context):
	self.layout.operator(RandomVertexColors.bl_idname, text=bl_info['description'],
						 icon='PLUGIN')


def register():
	bpy.utils.register_module(__name__)
	bpy.types.VIEW3D_MT_paint_vertex.append(menu_func)


def unregister():
	bpy.types.VIEW3D_MT_paint_vertex.remove(menu_func)
	bpy.utils.unregister_module(__name__)


if __name__ == "__main__":
	register()