// Copyright (C) 2016 The Android Open Source Project
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//      http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

package image

import (
  "bytes"

  "android.googlesource.com/platform/tools/gpu/framework/binary"
  "android.googlesource.com/platform/tools/gpu/framework/binary/endian"
  "android.googlesource.com/platform/tools/gpu/framework/device"
)

type fmtRedF16 struct{ binary.Generate }

func (f *fmtRedF16) Key() interface{}             { return *f }
func (*fmtRedF16) String() string                 { return "RedF16" }
func (*fmtRedF16) Size(w, h int) int              { return w * h * 2 }
func (*fmtRedF16) Check(d []byte, w, h int) error { return checkSize(d, w, h, 16) }

// RedF16 returns a format containing a single 16-bit floating point red channel
// per pixel.
func RedF16() Format { return &fmtRedF16{} }

func init() {
  RegisterConverter(RedF16(), RGBA(),
    func(src []byte, width, height int) ([]byte, error) {
      r := endian.Reader(bytes.NewBuffer(src), device.LittleEndian)
      dst, i := make([]byte, width*height*4), 0
      for y := 0; y < height; y++ {
        for x := 0; x < width; x++ {
          dst[i+0], dst[i+1], dst[i+2], dst[i+3] = f16ToByte(r.Float16()), 0, 0, 255
          i += 4
        }
      }
      return dst, nil
    })
}