Hi to all,
i am trying to write a script for applying gradient vertex colors to the active mesh.
What i actually want to achieve is to apply gradient white/black colors to a mesh, in more details the top vertices to have pure white color and the bottom vertices to have pure black color. All the vertices in the middle should have a gray scale value based on the normalized height of the mesh bounds for example.
I absolutely don’t understand the Blender API and python and i’m having difficulties to achieve this. I found an add-on from internet which i am trying to alter now in a way that will suite my needs but i am confused. So could you point me on how i have to get the mesh bound, create the interpolated color and apply it to the vertices. Here i have the altered code but it can only apply a constant color to a vertex:
import bpy
import random
bl_info = {
'author': 'v',
'category': '3D View',
'description': 'Set model vertex color using a black/white gradient - used in game engine to bend trees',
'name': 'Apply gradient mesh vertex colors'
}
def set_verts_colors():
white = (1, 1, 1)
black = (0, 0, 0)
# must switch to Object Mode briefly to get the new set of selected elements
# and then change the vertex_color layer
bpy.ops.object.mode_set(mode='OBJECT')
obj = bpy.context.active_object
mesh = obj.data
color_layer = mesh.vertex_colors.active
selected = set(v.index for v in obj.data.vertices if v.select)
verts = mesh.vertices
i = 0
for poly in mesh.polygons:
for loop_index in poly.loop_indices:
vidx = mesh.loops[loop_index].vertex_index
if vidx in selected:
# How to apply gradient color
# pure white color on the highest vertices
# black color on the bottom vertices
# and of cource interpolated grayscale values for all verts in the middle
color_layer.data[i].color = (1, 1, 1)
i += 1
# set to vertex paint mode to see the result
# bpy.ops.object.mode_set(mode='VERTEX_PAINT')
bpy.ops.object.mode_set(mode='EDIT')
class BSEVtexSetter(bpy.types.Operator):
bl_idname = "object.vertex_color_setter"
bl_label = "Apply gradient Vertex Color to mesh"
def draw(self, context):
layout = self.layout
def execute(self, context):
set_verts_colors()
return {'FINISHED'}
def invoke(self, context, event):
return context.window_manager.invoke_props_dialog(self)
def register():
bpy.utils.register_class(BSEVtexSetter)
def unregister():
bpy.utils.unregister_class(BSEVtexSetter)
del bpy.types.Scene.BSE_new_color
if __name__ == "__main__":
register()
