#unity #blender A script for Blender that allows you to swap values of vertex colors with uv coordinates so that a custom Unity shader can make use of two sets of vertex colors.

SwapVertexColorsWithUVs.py

# Copyright (c) Rotorz Limited. All rights reserved.
# License: MIT

import bpy

bl_info = {
    'name': 'Swap Vertex Colors with UVs',
    'author': 'Rotorz Limited',
    'version': (0, 1),
    'blender': (2, 7, 7),
    'description': 'Swaps vertex color data with uv1/uv2 data',
    'category': 'Vertex Paint'
}

class SwapVertexColorsWithUVs(bpy.types.Operator):
    bl_label = "Swap Vertex Colors with UVs"
    bl_idname = "object.swap_vertex_colors_with_uvs"
    bl_description = "Swaps vertex color data with uv1/uv2 data"

    def execute(self, context):
        self.report({'INFO'}, "Swapping vertex color data with uv1/uv2 data")

        # start in object mode
        obj = context.scene.objects.active
        mesh = obj.data

        # make sure that the object has vertex colors
        if not mesh.vertex_colors:
            mesh.vertex_colors.new()
        # make sure that the object has uv data
        while len(mesh.uv_textures.values()) < 2:
            mesh.uv_textures.new()

        # grab the active vertex color data layer
        color_layer = mesh.vertex_colors.active
        # grab the active uv data layer
        uv_layers = mesh.uv_layers.values()

        i = 0
        for poly in mesh.polygons:
            for idx in poly.loop_indices:
                tempR = color_layer.data[i].color.r
                tempG = color_layer.data[i].color.g
                tempB = color_layer.data[i].color.b
                #tempA = color_layer.data[i].color.a

                color_layer.data[i].color.r = uv_layers[0].data[i].uv.x
                color_layer.data[i].color.g = uv_layers[0].data[i].uv.y
                color_layer.data[i].color.b = uv_layers[1].data[i].uv.x
                #color_layer.data[i].color.a = uv_layers[1].data[i].uv.y

                uv_layers[0].data[i].uv.x = tempR
                uv_layers[0].data[i].uv.y = tempG
                uv_layers[1].data[i].uv.x = tempB
                #uv_layers[1].data[i].uv.y = tempA

                i += 1

        # set to vertex paint mode to see the result
        bpy.ops.object.mode_set(mode='VERTEX_PAINT')

        return {'FINISHED'}

def register():
    bpy.utils.register_class(SwapVertexColorsWithUVs)
    bpy.context.window_manager.keyconfigs.active.keymaps['Vertex Paint'].keymap_items.new('object.swap_vertex_colors_with_uvs',value='PRESS',type='F1',ctrl=True,alt=False,shift=True,oskey=False)

def unregister():
    bpy.utils.unregister_class(SwapVertexColorsWithUVs)

if __name__ == "__main__":
    register()