kc3-lang/angle/scripts/bmp_to_nv12.py

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• Hash : bda75597
  Author :
  Date : 2016-04-18T17:25:54
  

  Finish NV12 support via streams.
  
  The main functionality for NV12 texture support through EGL streams has
  been added. Updates to the compiler, texture code, and stream code were
  added to support binding to external D3D11 NV12 textures. An end2end test
  was also added to test sampling of YUV textures and converting to RGB.
  There is also a new script to convert BMP files to an NV12 texture ready
  to load into D3D11 for testing purposes.
  
  BUG=angleproject:1332
  
  Change-Id: I39b6ec393ea338e2c843fb911acc1b36cd1158a0
  Reviewed-on: https://chromium-review.googlesource.com/339454
  Reviewed-by: Jamie Madill <jmadill@chromium.org>
  Commit-Queue: Ian Ewell <ewell@google.com>
  Reviewed-on: https://chromium-review.googlesource.com/341254
  Reviewed-by: Ian Ewell <ewell@google.com>
  

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• scripts/bmp_to_nv12.py

• #!/usr/bin/python
  #
  # Copyright 2016 The ANGLE Project Authors. All rights reserved.
  # Use of this source code is governed by a BSD-style license that can be
  # found in the LICENSE file.
  #
  # bmp_to_nv12.py:
  #   Script to convert a simple BMP file to an NV12 format. Used to create
  #   test images for the NV12 texture stream end to end tests
  
  import sys
  import struct
  
  if len(sys.argv) != 4:
      print("Usage: bmp_to_nv12.py input output prefix")
      exit(0)
  
  bmp_file = open(sys.argv[1], "rb")
  
  magic = bmp_file.read(2)
  if (magic != "BM"):
      print("Invalid BMP magic")
      exit(1)
  
  file_size, = struct.unpack("I", bmp_file.read(4))
  
  # eat reserved bytes
  bmp_file.read(4)
  
  offset, = struct.unpack("I", bmp_file.read(4))
  
  headersize, = struct.unpack("I", bmp_file.read(4))
  width, = struct.unpack("i", bmp_file.read(4))
  height, = struct.unpack("i", bmp_file.read(4))
  planes, = struct.unpack("H", bmp_file.read(2))
  bpp, = struct.unpack("H", bmp_file.read(2))
  compression, = struct.unpack("i", bmp_file.read(4))
  image_size, = struct.unpack("i", bmp_file.read(4))
  
  if (bpp != 24 or compression != 0):
      print("Unsupported BMP file")
      bmp_file.close()
      exit(1)
  
  bmp_file.seek(offset, 0)
  pixels = bmp_file.read(width * height * 3)
  bmp_file.close()
  
  # convert to YUV 4:4:4
  converted_pixels = bytearray(pixels)
  for i in range(0, width * height):
      R, = struct.unpack("B", pixels[i*3+2])
      G, = struct.unpack("B", pixels[i*3+1])
      B, = struct.unpack("B", pixels[i*3])
      converted_pixels[i*3] = ((66*R + 129*G + 25*B + 128) >> 8) + 16
      converted_pixels[i*3+1] = ((-38*R - 74*G + 112*B + 128) >> 8) + 128
      converted_pixels[i*3+2] = ((112*R - 94*G - 18*B + 128) >> 8) + 128
  
  # downsample to packed UV buffer
  uv_buffer = bytearray(width * height / 2)
  for i in range(0, width * height / 2, 2):
      U1 = converted_pixels[((((i / width) * 2) * width) + (i % width)) * 3 + 1]
      U2 = converted_pixels[((((i / width) * 2) * width) + width + (i % width)) * 3 + 1]
      V1 = converted_pixels[((((i / width) * 2) * width) + (i % width)) * 3 + 2]
      V2 = converted_pixels[((((i / width) * 2) * width) + width + (i % width)) * 3 + 2]
      uv_buffer[i] = (U1 + U2) / 2
      uv_buffer[i + 1] = (V1 + V2) / 2
  
  # extract the Y buffer
  y_buffer = bytearray(width * height)
  for i in range(0, width * height):
      y_buffer[i] = converted_pixels[i * 3]
  
  # write out the file as a C header
  nv12_file = open(sys.argv[2], "w")
  nv12_file.write("// Automatically generated from " + sys.argv[1] + "\n")
  nv12_file.write("static const size_t " + sys.argv[3] + "_width = " + str(width) + ";\n")
  nv12_file.write("static const size_t " + sys.argv[3] + "_height = " + str(height) + ";\n")
  nv12_file.write("static const unsigned char " + sys.argv[3] + "_data[] = \n{")
  for i in range(0, width * height):
      if (i % 16) == 0:
          nv12_file.write("\n    ")
      nv12_file.write(str(y_buffer[i]) + ",")
  for i in range(0, width * height / 2):
      if (i % 16) == 0:
          nv12_file.write("\n    ")
      nv12_file.write(str(uv_buffer[i]) + ",")
  nv12_file.write("\n};")
  nv12_file.close()

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