// https://gist.github.com/mmp/21ea8ac6d7f682b6252b

// https://gist.github.com/mmp/21ea8ac6d7f682b6252b

#include "tinyexr/tinyexr.h"
#include "tinyexr/tinyexr.cc"
#include <stdio.h>
#include <assert.h>
#include <vector>
#include <algorithm>
#include <ImfInputFile.h>
#include <ImfRgbaFile.h>
#include <ImfChannelList.h>
#include <ImfFrameBuffer.h>
#include <half.h>
using namespace Imf;
using namespace Imath;

static float *OpenExrLoad(const char *name, int *width, int *height) {
try {
RgbaInputFile file (name);
Box2i dw = file.dataWindow();
*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);

printf("OpenExr\n datawindow: (%d %d) - (%d %d)\n", dw.min.x, dw.min.y,
dw.max.x, dw.max.y);
printf(" line order %s\n", (file.lineOrder() == INCREASING_Y) ?
"increasing y" : ((file.lineOrder() == DECREASING_Y) ? "decreasing y"
: "random y"));
printf(" compression: ");
switch (file.compression()) {
case NO_COMPRESSION: printf("none"); break;
case RLE_COMPRESSION: printf("RLE"); break;
case ZIPS_COMPRESSION: printf("zip"); break;
case ZIP_COMPRESSION: printf("zips"); break;
case PIZ_COMPRESSION: printf("piz"); break;
case PXR24_COMPRESSION: printf("pxr24"); break;
case B44_COMPRESSION: printf("b44"); break;
case B44A_COMPRESSION: printf("b44a"); break;
default: printf("unknown!");
}
printf("\n");

printf(" channels: ");
RgbaChannels channels = file.channels();
if (channels & WRITE_R) printf("R");
if (channels & WRITE_G) printf("G");
if (channels & WRITE_B) printf("B");
if (channels & WRITE_A) printf("A");
if (channels & WRITE_Y) printf("Y");
if (channels & WRITE_C) printf("C");
printf("\n");

float *ret = new float[4 * *width * *height];
for (int i = 0; i < *width * *height; ++i) {
ret[4*i] = pixels[i].r;
ret[4*i+1] = pixels[i].g;
ret[4*i+2] = pixels[i].b;
ret[4*i+3] = pixels[i].a;
}
return ret;
} catch (const std::exception &e) {
return NULL;
}
}

static void WriteImageEXR(const char *name, float *rgba,
int xRes, int yRes) {
Rgba *hrgba = new Rgba[xRes * yRes];
for (int i = 0; i < xRes * yRes; ++i)
hrgba[i] = Rgba(rgba[4*i], rgba[4*i+1], rgba[4*i+2], rgba[4*i+3]);

Box2i displayWindow(V2i(0,0), V2i(xRes-1, yRes-1));
Box2i dataWindow(V2i(0, 0), V2i(xRes - 1, yRes - 1));

try {
RgbaOutputFile file(name, displayWindow, dataWindow, WRITE_RGBA);
file.setFrameBuffer(hrgba, 1, xRes);
file.writePixels(yRes);
}
catch (const std::exception &e) {
fprintf(stderr, "Unable to write image file \"%s\": %s", name,
e.what());
}

delete[] hrgba;
}

int main(int argc, char *argv[]) {
if (argc != 3) {
fprintf(stderr, "usage: exrwritetest <tinyexr-filename.exr> <openexr-filename.exr>\n");
return 1;
}

int w = 1;
int h = 2;
float *rgba = new float[4 * w * h];
for (int i = 0; i < 4 * w * h; ++i) {
rgba[i] = drand48();
}

WriteImageEXR(argv[2], rgba, w, h);
const char *err;
SaveEXR(rgba, w, h, argv[1], /* fp16 */1, &err);

int ow, oh;
float *orgba = OpenExrLoad(argv[2], &ow, &oh);

int tw, th;
float *trgba;
if (LoadEXR(&trgba, &tw, &th, argv[1], &err) != 0) {
fprintf(stderr, "exrwritetest: %s %s\n", argv[2], err);
return 1;
}

int offset = 0;
for (int y = 0; y < h; ++y) {
for (int x = 0; x < w; ++x)
for (int c = 0; c < 4; ++c, ++offset)
if (orgba[offset] != trgba[offset])
fprintf(stderr, "Mismatch at (%d,%d), component %d: "
"orig %g, OpenEXR %g (err %g), tinyexr %g (err %g)\n",
x, y, c, rgba[offset],
orgba[offset], fabsf(rgba[offset] - orgba[offset]),
trgba[offset], fabsf(rgba[offset] - trgba[offset]));
}

return 0;
}