// Copyright 2014 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "gpu/command_buffer/service/image_factory.h"

#include "gpu/command_buffer/common/capabilities.h"
#include "ui/gl/gl_bindings.h"

namespace gpu {

ImageFactory::ImageFactory() {
}

ImageFactory::~ImageFactory() {
}

// static
gfx::BufferFormat ImageFactory::ImageFormatToGpuMemoryBufferFormat(
    unsigned internalformat) {
  switch (internalformat) {
    case GL_R8:
      return gfx::BufferFormat::R_8;
    case GL_RGB:
      return gfx::BufferFormat::RGBX_8888;
    case GL_RGBA:
      return gfx::BufferFormat::RGBA_8888;
    case GL_BGRA_EXT:
      return gfx::BufferFormat::BGRA_8888;
    case GL_ATC_RGB_AMD:
      return gfx::BufferFormat::ATC;
    case GL_ATC_RGBA_INTERPOLATED_ALPHA_AMD:
      return gfx::BufferFormat::ATCIA;
    case GL_COMPRESSED_RGB_S3TC_DXT1_EXT:
      return gfx::BufferFormat::DXT1;
    case GL_COMPRESSED_RGBA_S3TC_DXT5_EXT:
      return gfx::BufferFormat::DXT5;
    case GL_ETC1_RGB8_OES:
      return gfx::BufferFormat::ETC1;
    case GL_RGB_YUV_420_CHROMIUM:
      return gfx::BufferFormat::YUV_420;
    default:
      NOTREACHED();
      return gfx::BufferFormat::RGBA_8888;
  }
}

// static
gfx::BufferUsage ImageFactory::ImageUsageToGpuMemoryBufferUsage(
    unsigned usage) {
  switch (usage) {
    case GL_MAP_CHROMIUM:
      return gfx::BufferUsage::MAP;
    case GL_SCANOUT_CHROMIUM:
      return gfx::BufferUsage::SCANOUT;
    default:
      NOTREACHED();
      return gfx::BufferUsage::MAP;
  }
}

// static
bool ImageFactory::IsImageFormatCompatibleWithGpuMemoryBufferFormat(
    unsigned internalformat,
    gfx::BufferFormat format) {
  return ImageFormatToGpuMemoryBufferFormat(internalformat) == format;
}

// static
bool ImageFactory::IsGpuMemoryBufferFormatSupported(
    gfx::BufferFormat format,
    const gpu::Capabilities& capabilities) {
  switch (format) {
    case gfx::BufferFormat::ATC:
    case gfx::BufferFormat::ATCIA:
      return capabilities.texture_format_atc;
    case gfx::BufferFormat::BGRA_8888:
      return capabilities.texture_format_bgra8888;
    case gfx::BufferFormat::DXT1:
      return capabilities.texture_format_dxt1;
    case gfx::BufferFormat::DXT5:
      return capabilities.texture_format_dxt5;
    case gfx::BufferFormat::ETC1:
      return capabilities.texture_format_etc1;
    case gfx::BufferFormat::R_8:
      return capabilities.texture_rg;
    case gfx::BufferFormat::RGBA_4444:
    case gfx::BufferFormat::RGBA_8888:
    case gfx::BufferFormat::RGBX_8888:
    case gfx::BufferFormat::YUV_420:
      return true;
  }

  NOTREACHED();
  return false;
}

// static
bool ImageFactory::IsImageSizeValidForGpuMemoryBufferFormat(
    const gfx::Size& size,
    gfx::BufferFormat format) {
  switch (format) {
    case gfx::BufferFormat::ATC:
    case gfx::BufferFormat::ATCIA:
    case gfx::BufferFormat::DXT1:
    case gfx::BufferFormat::DXT5:
    case gfx::BufferFormat::ETC1:
      // Compressed images must have a width and height that's evenly divisible
      // by the block size.
      return size.width() % 4 == 0 && size.height() % 4 == 0;
    case gfx::BufferFormat::R_8:
    case gfx::BufferFormat::RGBA_4444:
    case gfx::BufferFormat::RGBA_8888:
    case gfx::BufferFormat::BGRA_8888:
    case gfx::BufferFormat::RGBX_8888:
      return true;
    case gfx::BufferFormat::YUV_420:
      // U and V planes are subsampled by a factor of 2.
      return size.width() % 2 == 0 && size.height() % 2 == 0;
  }

  NOTREACHED();
  return false;
}

}  // namespace gpu