imageio.cpp

/*
    pbrt source code is Copyright(c) 1998-2016
                        Matt Pharr, Greg Humphreys, and Wenzel Jakob.

    This file is part of pbrt.

    Redistribution and use in source and binary forms, with or without
    modification, are permitted provided that the following conditions are
    met:

    - Redistributions of source code must retain the above copyright
      notice, this list of conditions and the following disclaimer.

    - Redistributions in binary form must reproduce the above copyright
      notice, this list of conditions and the following disclaimer in the
      documentation and/or other materials provided with the distribution.

    THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
    IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
    TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
    PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
    HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
    SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
    LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
    DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
    THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
    (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
    OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

 */

// core/imageio.cpp*
#include "imageio.h"
#include "ext/lodepng.h"
#include "ext/targa.h"
#include "fileutil.h"
#include "spectrum.h"

#include <ImfRgba.h>
#include <ImfRgbaFile.h>

// ImageIO Local Declarations
static void WriteImageEXR(const std::string &name, const Float *pixels,
                          int xRes, int yRes, int totalXRes, int totalYRes,
                          int xOffset, int yOffset);
static void WriteImageTGA(const std::string &name, const uint8_t *pixels,
                          int xRes, int yRes, int totalXRes, int totalYRes,
                          int xOffset, int yOffset);
static RGBSpectrum *ReadImageTGA(const std::string &name, int *w, int *h);
static RGBSpectrum *ReadImagePNG(const std::string &name, int *w, int *h);
static bool WriteImagePFM(const std::string &filename, const Float *rgb,
                          int xres, int yres);
static RGBSpectrum *ReadImagePFM(const std::string &filename, int *xres,
                                 int *yres);

// ImageIO Function Definitions
std::unique_ptr<RGBSpectrum[]> ReadImage(const std::string &name,
                                         Point2i *resolution) {
    if (HasExtension(name, ".exr"))
        return std::unique_ptr<RGBSpectrum[]>(
            ReadImageEXR(name, &resolution->x, &resolution->y));
    else if (HasExtension(name, ".tga"))
        return std::unique_ptr<RGBSpectrum[]>(
            ReadImageTGA(name, &resolution->x, &resolution->y));
    else if (HasExtension(name, ".png"))
        return std::unique_ptr<RGBSpectrum[]>(
            ReadImagePNG(name, &resolution->x, &resolution->y));
    else if (HasExtension(name, ".pfm"))
        return std::unique_ptr<RGBSpectrum[]>(
            ReadImagePFM(name, &resolution->x, &resolution->y));
    Error("Unable to load image stored in format \"%s\" for filename \"%s\".",
          strrchr(name.c_str(), '.') ? (strrchr(name.c_str(), '.') + 1)
                                     : "(unknown)",
          name.c_str());
    return nullptr;
}

void WriteImage(const std::string &name, const Float *rgb,
                const Bounds2i &outputBounds, const Point2i &totalResolution) {
    Vector2i resolution = outputBounds.Diagonal();
    if (HasExtension(name, ".exr")) {
        WriteImageEXR(name, rgb, resolution.x, resolution.y, totalResolution.x,
                      totalResolution.y, outputBounds.pMin.x,
                      outputBounds.pMin.y);
    } else if (HasExtension(name, ".pfm")) {
        WriteImagePFM(name, rgb, resolution.x, resolution.y);
    } else if (HasExtension(name, ".tga") || HasExtension(name, ".png")) {
        // 8-bit formats; apply gamma
        Vector2i resolution = outputBounds.Diagonal();
        std::unique_ptr<uint8_t[]> rgb8(
            new uint8_t[3 * resolution.x * resolution.y]);
        uint8_t *dst = rgb8.get();
        for (int y = 0; y < resolution.y; ++y) {
            for (int x = 0; x < resolution.x; ++x) {
#define TO_BYTE(v) (uint8_t) Clamp(255.f * GammaCorrect(v) + 0.5f, 0.f, 255.f)
                dst[0] = TO_BYTE(rgb[3 * (y * resolution.x + x) + 0]);
                dst[1] = TO_BYTE(rgb[3 * (y * resolution.x + x) + 1]);
                dst[2] = TO_BYTE(rgb[3 * (y * resolution.x + x) + 2]);
#undef TO_BYTE
                dst += 3;
            }
        }

        if (HasExtension(name, ".tga"))
            WriteImageTGA(name, rgb8.get(), resolution.x, resolution.y,
                          totalResolution.x, totalResolution.y,
                          outputBounds.pMin.x, outputBounds.pMin.y);
        else {
            unsigned int error = lodepng_encode24_file(
                name.c_str(), rgb8.get(), resolution.x, resolution.y);
            if (error != 0)
                Error("Error writing PNG \"%s\": %s", name.c_str(),
                      lodepng_error_text(error));
        }
    } else {
        Error("Can't determine image file type from suffix of filename \"%s\"",
              name.c_str());
    }
}

RGBSpectrum *ReadImageEXR(const std::string &name, int *width, int *height,
                          Bounds2i *dataWindow, Bounds2i *displayWindow) {
    using namespace Imf;
    using namespace Imath;
    try {
        RgbaInputFile file(name.c_str());
        Box2i dw = file.dataWindow();

        // OpenEXR uses inclusive pixel bounds; adjust to non-inclusive
        // (the convention pbrt uses) in the values returned.
        if (dataWindow)
            *dataWindow = {{dw.min.x, dw.min.y}, {dw.max.x + 1, dw.max.y + 1}};
        if (displayWindow) {
            Box2i dispw = file.displayWindow();
            *displayWindow = {{dispw.min.x, dispw.min.y},
                              {dispw.max.x + 1, dispw.max.y + 1}};
        }
        *width = dw.max.x - dw.min.x + 1;
        *height = dw.max.y - dw.min.y + 1;

        std::vector<Rgba> pixels(*width * *height);
        file.setFrameBuffer(&pixels[0] - dw.min.x - dw.min.y * *width, 1,
                            *width);
        file.readPixels(dw.min.y, dw.max.y);

        RGBSpectrum *ret = new RGBSpectrum[*width * *height];
        for (int i = 0; i < *width * *height; ++i) {
            Float frgb[3] = {pixels[i].r, pixels[i].g, pixels[i].b};
            ret[i] = RGBSpectrum::FromRGB(frgb);
        }
        Info("Read EXR image %s (%d x %d)", name.c_str(), *width, *height);
        return ret;
    } catch (const std::exception &e) {
        Error("Unable to read image file \"%s\": %s", name.c_str(), e.what());
    }

    return NULL;
}

static void WriteImageEXR(const std::string &name, const Float *pixels,
                          int xRes, int yRes, int totalXRes, int totalYRes,
                          int xOffset, int yOffset) {
    using namespace Imf;
    using namespace Imath;

    Rgba *hrgba = new Rgba[xRes * yRes];
    for (int i = 0; i < xRes * yRes; ++i)
        hrgba[i] = Rgba(pixels[3 * i], pixels[3 * i + 1], pixels[3 * i + 2]);

    // OpenEXR uses inclusive pixel bounds.
    Box2i displayWindow(V2i(0, 0), V2i(totalXRes - 1, totalYRes - 1));
    Box2i dataWindow(V2i(xOffset, yOffset),
                     V2i(xOffset + xRes - 1, yOffset + yRes - 1));

    try {
        RgbaOutputFile file(name.c_str(), displayWindow, dataWindow,
                            WRITE_RGBA);
        file.setFrameBuffer(hrgba - xOffset - yOffset * xRes, 1, xRes);
        file.writePixels(yRes);
    } catch (const std::exception &exc) {
        Error("Error writing \"%s\": %s", name.c_str(), exc.what());
    }

    delete[] hrgba;
}

// TGA Function Definitions
void WriteImageTGA(const std::string &name, const uint8_t *pixels, int xRes,
                   int yRes, int totalXRes, int totalYRes, int xOffset,
                   int yOffset) {
    // Reformat to BGR layout.
    std::unique_ptr<uint8_t[]> outBuf(new uint8_t[3 * xRes * yRes]);
    uint8_t *dst = outBuf.get();
    const uint8_t *src = pixels;
    for (int y = 0; y < yRes; ++y) {
        for (int x = 0; x < xRes; ++x) {
            dst[0] = src[2];
            dst[1] = src[1];
            dst[2] = src[0];
            dst += 3;
            src += 3;
        }
    }

    tga_result result;
    if ((result = tga_write_bgr(name.c_str(), outBuf.get(), xRes, yRes, 24)) !=
        TGA_NOERR)
        Error("Unable to write output file \"%s\" (%s)", name.c_str(),
              tga_error(result));
}

static RGBSpectrum *ReadImageTGA(const std::string &name, int *width,
                                 int *height) {
    tga_image img;
    tga_result result;
    if ((result = tga_read(&img, name.c_str())) != TGA_NOERR) {
        Error("Unable to read from TGA file \"%s\" (%s)", name.c_str(),
              tga_error(result));
        return nullptr;
    }

    if (tga_is_right_to_left(&img)) tga_flip_horiz(&img);
    if (!tga_is_top_to_bottom(&img)) tga_flip_vert(&img);
    if (tga_is_colormapped(&img)) tga_color_unmap(&img);

    *width = img.width;
    *height = img.height;

    // "Unpack" the pixels (origin in the lower left corner).
    // TGA pixels are in BGRA format.
    RGBSpectrum *ret = new RGBSpectrum[*width * *height];
    RGBSpectrum *dst = ret;
    for (int y = 0; y < *height; y++)
        for (int x = 0; x < *width; x++) {
            uint8_t *src = tga_find_pixel(&img, x, y);
            if (tga_is_mono(&img))
                *dst++ = RGBSpectrum(*src / 255.f);
            else {
                Float c[3];
                c[2] = src[0] / 255.f;
                c[1] = src[1] / 255.f;
                c[0] = src[2] / 255.f;
                *dst++ = RGBSpectrum::FromRGB(c);
            }
        }

    tga_free_buffers(&img);
    Info("Read TGA image %s (%d x %d)", name.c_str(), *width, *height);

    return ret;
}

static RGBSpectrum *ReadImagePNG(const std::string &name, int *width,
                                 int *height) {
    unsigned char *rgb;
    unsigned w, h;
    unsigned int error = lodepng_decode24_file(&rgb, &w, &h, name.c_str());
    if (error != 0) {
        Error("Error reading PNG \"%s\": %s", name.c_str(),
              lodepng_error_text(error));
        return nullptr;
    }
    *width = w;
    *height = h;

    RGBSpectrum *ret = new RGBSpectrum[*width * *height];
    unsigned char *src = rgb;
    for (int y = 0; y < h; ++y) {
        for (int x = 0; x < w; ++x, src += 3) {
            Float c[3];
            c[0] = src[0] / 255.f;
            c[1] = src[1] / 255.f;
            c[2] = src[2] / 255.f;
            ret[y * *width + x] = RGBSpectrum::FromRGB(c);
        }
    }

    free(rgb);
    return ret;
}

// PFM Function Definitions
/*
 * PFM reader/writer code courtesy Jiawen "Kevin" Chen
 * (http://people.csail.mit.edu/jiawen/)
 */

static bool hostLittleEndian =
#if defined(__BYTE_ORDER__)
  #if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
    true
  #elif __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__
    false
  #else
    #error "__BYTE_ORDER__ defined but has unexpected value"
  #endif
#else
  #if defined(__LITTLE_ENDIAN__) || defined(__i386__) || defined(__x86_64__) || \
      defined(WIN32)
    true
  #elif defined(__BIG_ENDIAN__)
    false
  #elif defined(__sparc) || defined(__sparc__)
    false
  #else
    #error "Can't detect machine endian-ness at compile-time."
  #endif
#endif
    ;

#define BUFFER_SIZE 80

static inline int isWhitespace(char c) {
    return c == ' ' || c == '\n' || c == '\t';
}

// reads a "word" from the fp and puts it into buffer
// and adds a null terminator
// i.e. it keeps reading until a whitespace is reached
// returns the number of characters read
// *not* including the whitespace
// return -1 on an error
static int readWord(FILE *fp, char *buffer, int bufferLength) {
    int n;
    int c;

    if (bufferLength < 1) return -1;

    n = 0;
    c = fgetc(fp);
    while (c != EOF && !isWhitespace(c) && n < bufferLength) {
        buffer[n] = c;
        ++n;
        c = fgetc(fp);
    }

    if (n < bufferLength) {
        buffer[n] = '\0';
        return n;
    }

    return -1;
}

static RGBSpectrum *ReadImagePFM(const std::string &filename, int *xres,
                                 int *yres) {
    float *data = nullptr;
    RGBSpectrum *rgb = nullptr;
    char buffer[BUFFER_SIZE];
    unsigned int nFloats;
    int nChannels, width, height;
    float scale;
    bool fileLittleEndian;

    FILE *fp = fopen(filename.c_str(), "rb");
    if (!fp) goto fail;

    // read either "Pf" or "PF"
    if (readWord(fp, buffer, BUFFER_SIZE) == -1) goto fail;

    if (strcmp(buffer, "Pf") == 0)
        nChannels = 1;
    else if (strcmp(buffer, "PF") == 0)
        nChannels = 3;
    else
        goto fail;

    // read the rest of the header
    // read width
    if (readWord(fp, buffer, BUFFER_SIZE) == -1) goto fail;
    width = atoi(buffer);
    *xres = width;

    // read height
    if (readWord(fp, buffer, BUFFER_SIZE) == -1) goto fail;
    height = atoi(buffer);
    *yres = height;

    // read scale
    if (readWord(fp, buffer, BUFFER_SIZE) == -1) goto fail;
    sscanf(buffer, "%f", &scale);

    // read the data
    nFloats = nChannels * width * height;
    data = new float[nFloats];
    // Flip in Y, as P*M has the origin at the lower left.
    for (int y = height - 1; y >= 0; --y) {
        if (fread(&data[y * nChannels * width], sizeof(float),
                  nChannels * width, fp) != nChannels * width)
            goto fail;
    }

    // apply endian conversian and scale if appropriate
    fileLittleEndian = (scale < 0.f);
    if (hostLittleEndian ^ fileLittleEndian) {
        uint8_t bytes[4];
        for (unsigned int i = 0; i < nFloats; ++i) {
            memcpy(bytes, &data[i], 4);
            std::swap(bytes[0], bytes[3]);
            std::swap(bytes[1], bytes[2]);
            memcpy(&data[i], bytes, 4);
        }
    }
    if (std::abs(scale) != 1.f)
        for (unsigned int i = 0; i < nFloats; ++i) data[i] *= std::abs(scale);

    // create RGBs...
    rgb = new RGBSpectrum[width * height];
    if (nChannels == 1) {
        for (int i = 0; i < width * height; ++i) rgb[i] = RGBSpectrum(data[i]);
    } else {
        for (int i = 0; i < width * height; ++i) {
            Float frgb[3] = {data[3 * i], data[3 * i + 1], data[3 * i + 2]};
            rgb[i] = RGBSpectrum::FromRGB(frgb);
        }
    }

    delete[] data;
    fclose(fp);
    return rgb;

fail:
    Error("Error reading PFM file \"%s\"", filename.c_str());
    if (fp) fclose(fp);
    delete[] data;
    delete[] rgb;
    return nullptr;
}

static bool WriteImagePFM(const std::string &filename, const Float *rgb,
                          int width, int height) {
    FILE *fp;
    float scale;

    fp = fopen(filename.c_str(), "wb");
    if (!fp) {
        Error("Unable to open output PFM file \"%s\"", filename.c_str());
        return false;
    }

    std::unique_ptr<float[]> scanline(new float[3 * width]);

    // only write 3 channel PFMs here...
    if (fprintf(fp, "PF\n") < 0) goto fail;

    // write the width and height, which must be positive
    if (fprintf(fp, "%d %d\n", width, height) < 0) goto fail;

    // write the scale, which encodes endianness
    scale = hostLittleEndian ? -1.f : 1.f;
    if (fprintf(fp, "%f\n", scale) < 0) goto fail;

    // write the data from bottom left to upper right as specified by
    // http://netpbm.sourceforge.net/doc/pfm.html
    // The raster is a sequence of pixels, packed one after another, with no
    // delimiters of any kind. They are grouped by row, with the pixels in each
    // row ordered left to right and the rows ordered bottom to top.
    for (int y = height - 1; y >= 0; y--) {
        // in case Float is 'double', copy into a staging buffer that's
        // definitely a 32-bit float...
        for (int x = 0; x < 3 * width; ++x)
            scanline[x] = rgb[y * width * 3 + x];
        if (fwrite(&scanline[0], sizeof(float), width * 3, fp) <
            (size_t)(width * 3))
            goto fail;
    }

    fclose(fp);
    return true;

fail:
    Error("Error writing PFM file \"%s\"", filename.c_str());
    fclose(fp);
    return false;
}