io_mesh_uv_layout/export_uv_png.py

   1 # ##### BEGIN GPL LICENSE BLOCK #####
   2 #
   3 #  This program is free software; you can redistribute it and/or
   4 #  modify it under the terms of the GNU General Public License
   5 #  as published by the Free Software Foundation; either version 2
   6 #  of the License, or (at your option) any later version.
   7 #
   8 #  This program is distributed in the hope that it will be useful,
   9 #  but WITHOUT ANY WARRANTY; without even the implied warranty of
  10 #  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  11 #  GNU General Public License for more details.
  12 #
  13 #  You should have received a copy of the GNU General Public License
  14 #  along with this program; if not, write to the Free Software Foundation,
  15 #  Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
  16 #
  17 # ##### END GPL LICENSE BLOCK #####
  18
  19 # <pep8-80 compliant>
  20
  21 import bpy
  22 import gpu
  23 import bgl
  24 from mathutils import Vector, Matrix
  25 from mathutils.geometry import tessellate_polygon
  26 from gpu_extras.batch import batch_for_shader
  27
  28 def export(filepath, face_data, colors, width, height, opacity):
  29     offscreen = gpu.types.GPUOffScreen(width, height)
  30     offscreen.bind()
  31
  32     try:
  33         bgl.glClear(bgl.GL_COLOR_BUFFER_BIT)
  34         draw_image(face_data, opacity)
  35
  36         pixel_data = get_pixel_data_from_current_back_buffer(width, height)
  37         save_pixels(filepath, pixel_data, width, height)
  38     finally:
  39         offscreen.unbind()
  40         offscreen.free()
  41
  42 def draw_image(face_data, opacity):
  43     bgl.glLineWidth(1)
  44     bgl.glEnable(bgl.GL_BLEND)
  45     bgl.glEnable(bgl.GL_LINE_SMOOTH)
  46     bgl.glHint(bgl.GL_LINE_SMOOTH_HINT, bgl.GL_NICEST)
  47
  48     with gpu.matrix.push_pop():
  49         gpu.matrix.load_matrix(get_normalize_uvs_matrix())
  50         gpu.matrix.load_projection_matrix(Matrix.Identity(4))
  51
  52         draw_background_colors(face_data, opacity)
  53         draw_lines(face_data)
  54
  55     bgl.glDisable(bgl.GL_BLEND)
  56     bgl.glDisable(bgl.GL_LINE_SMOOTH)
  57
  58 def get_normalize_uvs_matrix():
  59     '''matrix maps x and y coordinates from [0, 1] to [-1, 1]'''
  60     matrix = Matrix.Identity(4)
  61     matrix.col[3][0] = -1
  62     matrix.col[3][1] = -1
  63     matrix[0][0] = 2
  64     matrix[1][1] = 2
  65     return matrix
  66
  67 def draw_background_colors(face_data, opacity):
  68     coords = [uv for uvs, _ in face_data for uv in uvs]
  69     colors = [(*color, opacity) for uvs, color in face_data for _ in range(len(uvs))]
  70
  71     indices = []
  72     offset = 0
  73     for uvs, _ in face_data:
  74         triangles = tessellate_uvs(uvs)
  75         indices.extend([index + offset for index in triangle] for triangle in triangles)
  76         offset += len(uvs)
  77
  78     shader = gpu.shader.from_builtin('2D_FLAT_COLOR')
  79     batch = batch_for_shader(shader, 'TRIS',
  80         {"pos" : coords,
  81          "color" : colors},
  82         indices=indices)
  83     batch.draw(shader)
  84
  85 def tessellate_uvs(uvs):
  86     return tessellate_polygon([uvs])
  87
  88 def draw_lines(face_data):
  89     coords = []
  90     for uvs, _ in face_data:
  91         for i in range(len(uvs)):
  92             start = uvs[i]
  93             end = uvs[(i+1) % len(uvs)]
  94             coords.append((start[0], start[1]))
  95             coords.append((end[0], end[1]))
  96
  97     shader = gpu.shader.from_builtin('2D_UNIFORM_COLOR')
  98     batch = batch_for_shader(shader, 'LINES', {"pos" : coords})
  99     shader.bind()
 100     shader.uniform_float("color", (0, 0, 0, 1))
 101     batch.draw(shader)
 102
 103 def get_pixel_data_from_current_back_buffer(width, height):
 104     buffer = bgl.Buffer(bgl.GL_BYTE, width * height * 4)
 105     bgl.glReadBuffer(bgl.GL_BACK)
 106     bgl.glReadPixels(0, 0, width, height, bgl.GL_RGBA, bgl.GL_UNSIGNED_BYTE, buffer)
 107     return buffer
 108
 109 def save_pixels(filepath, pixel_data, width, height):
 110     image = bpy.data.images.new("temp", width, height, alpha=True)
 111     image.filepath = filepath
 112     image.pixels = [v / 255 for v in pixel_data]
 113     image.save()
 114     bpy.data.images.remove(image)