External/HIP/workload/ray-tracing/InOneWeekend/rtw_stb_image.h

#ifndef RTW_STB_IMAGE_H
#define RTW_STB_IMAGE_H

//==============================================================================================
// Originally written in 2016 by Peter Shirley <ptrshrl@gmail.com>
//
// To the extent possible under law, the author(s) have dedicated all copyright
// and related and neighboring rights to this software to the public domain
// worldwide. This software is distributed without any warranty.
//
// You should have received a copy (see file COPYING.txt) of the CC0 Public
// Domain Dedication along with this software. If not, see
// <http://creativecommons.org/publicdomain/zero/1.0/>.
//
// The original source code is from
//    https://github.com/RayTracing/raytracing.github.io/tree/release/src/InOneWeekend
//
// Changes to the original code follow the following license.
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//==============================================================================================

// Disable strict warnings for this header from the Microsoft Visual C++
// compiler.
#ifdef _MSC_VER
#pragma warning(push, 0)
#endif

#define STB_IMAGE_IMPLEMENTATION
#include "external/stb_image.h"

#include <cstdlib>
#include <iostream>

class rtw_image {
public:
  rtw_image() : data(nullptr) {}

  rtw_image(const char *image_filename) {
    // Loads image data from the specified file. If the RTW_IMAGES environment
    // variable is defined, looks only in that directory for the image file. If
    // the image was not found, searches for the specified image file first from
    // the current directory, then in the images/ subdirectory, then the
    // _parent's_ images/ subdirectory, and then _that_ parent, on so on, for
    // six levels up. If the image was not loaded successfully, width() and
    // height() will return 0.

    auto filename = std::string(image_filename);
    auto imagedir = getenv("RTW_IMAGES");

    // Hunt for the image file in some likely locations.
    if (imagedir && load(std::string(imagedir) + "/" + image_filename))
      return;
    if (load(filename))
      return;
    if (load("images/" + filename))
      return;
    if (load("../images/" + filename))
      return;
    if (load("../../images/" + filename))
      return;
    if (load("../../../images/" + filename))
      return;
    if (load("../../../../images/" + filename))
      return;
    if (load("../../../../../images/" + filename))
      return;
    if (load("../../../../../../images/" + filename))
      return;

    std::cerr << "ERROR: Could not load image file '" << image_filename
              << "'.\n";
  }

  ~rtw_image() { STBI_FREE(data); }

  bool load(const std::string filename) {
    // Loads image data from the given file name. Returns true if the load
    // succeeded.
    auto n =
        bytes_per_pixel; // Dummy out parameter: original components per pixel
    data = stbi_load(filename.c_str(), &image_width, &image_height, &n,
                     bytes_per_pixel);
    bytes_per_scanline = image_width * bytes_per_pixel;
    return data != nullptr;
  }

  int width() const { return (data == nullptr) ? 0 : image_width; }
  int height() const { return (data == nullptr) ? 0 : image_height; }

  const unsigned char *pixel_data(int x, int y) const {
    // Return the address of the three bytes of the pixel at x,y (or magenta if
    // no data).
    static unsigned char magenta[] = {255, 0, 255};
    if (data == nullptr)
      return magenta;

    x = clamp(x, 0, image_width);
    y = clamp(y, 0, image_height);

    return data + y * bytes_per_scanline + x * bytes_per_pixel;
  }

private:
  const int bytes_per_pixel = 3;
  unsigned char *data;
  int image_width, image_height;
  int bytes_per_scanline;

  static int clamp(int x, int low, int high) {
    // Return the value clamped to the range [low, high).
    if (x < low)
      return low;
    if (x < high)
      return x;
    return high - 1;
  }
};

// Restore MSVC compiler warnings
#ifdef _MSC_VER
#pragma warning(pop)
#endif

#endif