/* SPDX-License-Identifier: GPL-2.0-or-later
 * Copyright 2006 Blender Foundation. All rights reserved. */

/** \file
 * \ingroup render
 */

#include <cerrno>
#include <cstdio>
#include <cstdlib>
#include <cstring>

#include "MEM_guardedalloc.h"

#include "BLI_ghash.h"
#include "BLI_hash_md5.h"
#include "BLI_listbase.h"
#include "BLI_path_util.h"
#include "BLI_rect.h"
#include "BLI_string.h"
#include "BLI_string_utils.h"
#include "BLI_threads.h"
#include "BLI_utildefines.h"

#include "BKE_appdir.h"
#include "BKE_camera.h"
#include "BKE_global.h"
#include "BKE_image.h"
#include "BKE_image_format.h"
#include "BKE_image_save.h"
#include "BKE_main.h"
#include "BKE_report.h"
#include "BKE_scene.h"

#include "IMB_colormanagement.h"
#include "IMB_imbuf.h"
#include "IMB_imbuf_types.h"
#include "IMB_openexr.h"

#include "RE_engine.h"

#include "render_result.h"
#include "render_types.h"

/********************************** Free *************************************/

static void render_result_views_free(RenderResult *rr)
{
  while (rr->views.first) {
    RenderView *rv = static_cast<RenderView *>(rr->views.first);
    BLI_remlink(&rr->views, rv);

    if (rv->rect32) {
      MEM_freeN(rv->rect32);
    }

    if (rv->rectz) {
      MEM_freeN(rv->rectz);
    }

    if (rv->rectf) {
      MEM_freeN(rv->rectf);
    }

    MEM_freeN(rv);
  }

  rr->have_combined = false;
}

void render_result_free(RenderResult *rr)
{
  if (rr == nullptr) {
    return;
  }

  while (rr->layers.first) {
    RenderLayer *rl = static_cast<RenderLayer *>(rr->layers.first);

    while (rl->passes.first) {
      RenderPass *rpass = static_cast<RenderPass *>(rl->passes.first);
      if (rpass->rect) {
        MEM_freeN(rpass->rect);
      }
      BLI_remlink(&rl->passes, rpass);
      MEM_freeN(rpass);
    }
    BLI_remlink(&rr->layers, rl);
    MEM_freeN(rl);
  }

  render_result_views_free(rr);

  if (rr->rect32) {
    MEM_freeN(rr->rect32);
  }
  if (rr->rectz) {
    MEM_freeN(rr->rectz);
  }
  if (rr->rectf) {
    MEM_freeN(rr->rectf);
  }
  if (rr->text) {
    MEM_freeN(rr->text);
  }
  if (rr->error) {
    MEM_freeN(rr->error);
  }

  BKE_stamp_data_free(rr->stamp_data);

  MEM_freeN(rr);
}

void render_result_free_list(ListBase *lb, RenderResult *rr)
{
  RenderResult *rrnext;

  for (; rr; rr = rrnext) {
    rrnext = rr->next;

    if (lb && lb->first) {
      BLI_remlink(lb, rr);
    }

    render_result_free(rr);
  }
}

/********************************* multiview *************************************/

void render_result_views_shallowcopy(RenderResult *dst, RenderResult *src)
{
  if (dst == nullptr || src == nullptr) {
    return;
  }

  LISTBASE_FOREACH (RenderView *, rview, &src->views) {
    RenderView *rv;

    rv = MEM_cnew<RenderView>("new render view");
    BLI_addtail(&dst->views, rv);

    BLI_strncpy(rv->name, rview->name, sizeof(rv->name));
    rv->rectf = rview->rectf;
    rv->rectz = rview->rectz;
    rv->rect32 = rview->rect32;
  }
}

void render_result_views_shallowdelete(RenderResult *rr)
{
  if (rr == nullptr) {
    return;
  }

  while (rr->views.first) {
    RenderView *rv = static_cast<RenderView *>(rr->views.first);
    BLI_remlink(&rr->views, rv);
    MEM_freeN(rv);
  }
}

/********************************** New **************************************/

static void render_layer_allocate_pass(RenderResult *rr, RenderPass *rp)
{
  if (rp->rect != nullptr) {
    return;
  }

  const size_t rectsize = size_t(rr->rectx) * rr->recty * rp->channels;
  rp->rect = MEM_cnew_array<float>(rectsize, rp->name);

  if (STREQ(rp->name, RE_PASSNAME_VECTOR)) {
    /* initialize to max speed */
    float *rect = rp->rect;
    for (int x = rectsize - 1; x >= 0; x--) {
      rect[x] = PASS_VECTOR_MAX;
    }
  }
  else if (STREQ(rp->name, RE_PASSNAME_Z)) {
    float *rect = rp->rect;
    for (int x = rectsize - 1; x >= 0; x--) {
      rect[x] = 10e10;
    }
  }
}

RenderPass *render_layer_add_pass(RenderResult *rr,
                                  RenderLayer *rl,
                                  int channels,
                                  const char *name,
                                  const char *viewname,
                                  const char *chan_id,
                                  const bool allocate)
{
  const int view_id = BLI_findstringindex(&rr->views, viewname, offsetof(RenderView, name));
  RenderPass *rpass = MEM_cnew<RenderPass>(name);

  rpass->channels = channels;
  rpass->rectx = rl->rectx;
  rpass->recty = rl->recty;
  rpass->view_id = view_id;

  BLI_strncpy(rpass->name, name, sizeof(rpass->name));
  BLI_strncpy(rpass->chan_id, chan_id, sizeof(rpass->chan_id));
  BLI_strncpy(rpass->view, viewname, sizeof(rpass->view));
  RE_render_result_full_channel_name(
      rpass->fullname, nullptr, rpass->name, rpass->view, rpass->chan_id, -1);

  if (rl->exrhandle) {
    int a;
    for (a = 0; a < channels; a++) {
      char passname[EXR_PASS_MAXNAME];
      RE_render_result_full_channel_name(
          passname, nullptr, rpass->name, nullptr, rpass->chan_id, a);
      IMB_exr_add_channel(rl->exrhandle, rl->name, passname, viewname, 0, 0, nullptr, false);
    }
  }

  BLI_addtail(&rl->passes, rpass);

  if (allocate) {
    render_layer_allocate_pass(rr, rpass);
  }
  else {
    /* The result contains non-allocated pass now, so tag it as such. */
    rr->passes_allocated = false;
  }

  return rpass;
}

RenderResult *render_result_new(Render *re,
                                rcti *partrct,
                                const char *layername,
                                const char *viewname)
{
  RenderResult *rr;
  RenderLayer *rl;
  int rectx, recty;

  rectx = BLI_rcti_size_x(partrct);
  recty = BLI_rcti_size_y(partrct);

  if (rectx <= 0 || recty <= 0) {
    return nullptr;
  }

  rr = MEM_cnew<RenderResult>("new render result");
  rr->rectx = rectx;
  rr->recty = recty;

  /* tilerect is relative coordinates within render disprect. do not subtract crop yet */
  rr->tilerect.xmin = partrct->xmin - re->disprect.xmin;
  rr->tilerect.xmax = partrct->xmax - re->disprect.xmin;
  rr->tilerect.ymin = partrct->ymin - re->disprect.ymin;
  rr->tilerect.ymax = partrct->ymax - re->disprect.ymin;

  rr->passes_allocated = false;

  render_result_views_new(rr, &re->r);

  /* Check render-data for amount of layers. */
  FOREACH_VIEW_LAYER_TO_RENDER_BEGIN (re, view_layer) {
    if (layername && layername[0]) {
      if (!STREQ(view_layer->name, layername)) {
        continue;
      }
    }

    rl = MEM_cnew<RenderLayer>("new render layer");
    BLI_addtail(&rr->layers, rl);

    BLI_strncpy(rl->name, view_layer->name, sizeof(rl->name));
    rl->layflag = view_layer->layflag;

    rl->passflag = view_layer->passflag;

    rl->rectx = rectx;
    rl->recty = recty;

    LISTBASE_FOREACH (RenderView *, rv, &rr->views) {
      const char *view = rv->name;

      if (viewname && viewname[0]) {
        if (!STREQ(view, viewname)) {
          continue;
        }
      }

      /* A render-layer should always have a "Combined" pass. */
      render_layer_add_pass(rr, rl, 4, "Combined", view, "RGBA", false);
    }
  }
  FOREACH_VIEW_LAYER_TO_RENDER_END;

  /* Preview-render doesn't do layers, so we make a default one. */
  if (BLI_listbase_is_empty(&rr->layers) && !(layername && layername[0])) {
    rl = MEM_cnew<RenderLayer>("new render layer");
    BLI_addtail(&rr->layers, rl);

    rl->rectx = rectx;
    rl->recty = recty;

    LISTBASE_FOREACH (RenderView *, rv, &rr->views) {
      const char *view = rv->name;

      if (viewname && viewname[0]) {
        if (!STREQ(view, viewname)) {
          continue;
        }
      }

      /* A render-layer should always have a "Combined" pass. */
      render_layer_add_pass(rr, rl, 4, RE_PASSNAME_COMBINED, view, "RGBA", false);
    }

    /* NOTE: this has to be in sync with `scene.cc`. */
    rl->layflag = SCE_LAY_FLAG_DEFAULT;
    rl->passflag = SCE_PASS_COMBINED;

    re->single_view_layer[0] = '\0';
  }

  /* Border render; calculate offset for use in compositor. compo is centralized coords. */
  /* XXX(ton): obsolete? I now use it for drawing border render offset. */
  rr->xof = re->disprect.xmin + BLI_rcti_cent_x(&re->disprect) - (re->winx / 2);
  rr->yof = re->disprect.ymin + BLI_rcti_cent_y(&re->disprect) - (re->winy / 2);

  return rr;
}

void render_result_passes_allocated_ensure(RenderResult *rr)
{
  if (rr == nullptr) {
    /* Happens when the result was not yet allocated for the current scene or slot configuration.
     */
    return;
  }

  LISTBASE_FOREACH (RenderLayer *, rl, &rr->layers) {
    LISTBASE_FOREACH (RenderPass *, rp, &rl->passes) {
      if (rl->exrhandle != nullptr && !STREQ(rp->name, RE_PASSNAME_COMBINED)) {
        continue;
      }

      render_layer_allocate_pass(rr, rp);
    }
  }

  rr->passes_allocated = true;
}

void render_result_clone_passes(Render *re, RenderResult *rr, const char *viewname)
{
  LISTBASE_FOREACH (RenderLayer *, rl, &rr->layers) {
    RenderLayer *main_rl = RE_GetRenderLayer(re->result, rl->name);
    if (!main_rl) {
      continue;
    }

    LISTBASE_FOREACH (RenderPass *, main_rp, &main_rl->passes) {
      if (viewname && viewname[0] && !STREQ(main_rp->view, viewname)) {
        continue;
      }

      /* Compare fullname to make sure that the view also is equal. */
      RenderPass *rp = static_cast<RenderPass *>(
          BLI_findstring(&rl->passes, main_rp->fullname, offsetof(RenderPass, fullname)));
      if (!rp) {
        render_layer_add_pass(
            rr, rl, main_rp->channels, main_rp->name, main_rp->view, main_rp->chan_id, false);
      }
    }
  }
}

void RE_create_render_pass(RenderResult *rr,
                           const char *name,
                           int channels,
                           const char *chan_id,
                           const char *layername,
                           const char *viewname,
                           const bool allocate)
{
  LISTBASE_FOREACH (RenderLayer *, rl, &rr->layers) {
    if (layername && layername[0] && !STREQ(rl->name, layername)) {
      continue;
    }

    LISTBASE_FOREACH (RenderView *, rv, &rr->views) {
      const char *view = rv->name;

      if (viewname && viewname[0] && !STREQ(view, viewname)) {
        continue;
      }

      /* Ensure that the pass doesn't exist yet. */
      bool pass_exists = false;
      LISTBASE_FOREACH (RenderPass *, rp, &rl->passes) {
        if (STREQ(rp->name, name) && STREQ(rp->view, view)) {
          pass_exists = true;
          break;
        }
      }

      if (!pass_exists) {
        render_layer_add_pass(rr, rl, channels, name, view, chan_id, allocate);
      }
    }
  }
}

void RE_render_result_full_channel_name(char *fullname,
                                        const char *layname,
                                        const char *passname,
                                        const char *viewname,
                                        const char *chan_id,
                                        const int channel)
{
  /* OpenEXR compatible full channel name. */
  const char *strings[4];
  int strings_len = 0;

  if (layname && layname[0]) {
    strings[strings_len++] = layname;
  }
  if (passname && passname[0]) {
    strings[strings_len++] = passname;
  }
  if (viewname && viewname[0]) {
    strings[strings_len++] = viewname;
  }

  char token[2];
  if (channel >= 0) {
    ARRAY_SET_ITEMS(token, chan_id[channel], '\0');
    strings[strings_len++] = token;
  }

  BLI_string_join_array_by_sep_char(fullname, EXR_PASS_MAXNAME, '.', strings, strings_len);
}

static int passtype_from_name(const char *name)
{
  const char delim[] = {'.', '\0'};
  const char *sep, *suf;
  int len = BLI_str_partition(name, delim, &sep, &suf);

#define CHECK_PASS(NAME) \
  if (STREQLEN(name, RE_PASSNAME_##NAME, len)) { \
    return SCE_PASS_##NAME; \
  } \
  ((void)0)

  CHECK_PASS(COMBINED);
  CHECK_PASS(Z);
  CHECK_PASS(VECTOR);
  CHECK_PASS(NORMAL);
  CHECK_PASS(UV);
  CHECK_PASS(EMIT);
  CHECK_PASS(SHADOW);
  CHECK_PASS(AO);
  CHECK_PASS(ENVIRONMENT);
  CHECK_PASS(INDEXOB);
  CHECK_PASS(INDEXMA);
  CHECK_PASS(MIST);
  CHECK_PASS(DIFFUSE_DIRECT);
  CHECK_PASS(DIFFUSE_INDIRECT);
  CHECK_PASS(DIFFUSE_COLOR);
  CHECK_PASS(GLOSSY_DIRECT);
  CHECK_PASS(GLOSSY_INDIRECT);
  CHECK_PASS(GLOSSY_COLOR);
  CHECK_PASS(TRANSM_DIRECT);
  CHECK_PASS(TRANSM_INDIRECT);
  CHECK_PASS(TRANSM_COLOR);
  CHECK_PASS(SUBSURFACE_DIRECT);
  CHECK_PASS(SUBSURFACE_INDIRECT);
  CHECK_PASS(SUBSURFACE_COLOR);

#undef CHECK_PASS
  return 0;
}

/* callbacks for render_result_new_from_exr */
static void *ml_addlayer_cb(void *base, const char *str)
{
  RenderResult *rr = static_cast<RenderResult *>(base);

  RenderLayer *rl = MEM_cnew<RenderLayer>("new render layer");
  BLI_addtail(&rr->layers, rl);

  BLI_strncpy(rl->name, str, EXR_LAY_MAXNAME);
  return rl;
}

static void ml_addpass_cb(void *base,
                          void *lay,
                          const char *name,
                          float *rect,
                          int totchan,
                          const char *chan_id,
                          const char *view)
{
  RenderResult *rr = static_cast<RenderResult *>(base);
  RenderLayer *rl = static_cast<RenderLayer *>(lay);
  RenderPass *rpass = MEM_cnew<RenderPass>("loaded pass");

  BLI_addtail(&rl->passes, rpass);
  rpass->channels = totchan;
  rl->passflag |= passtype_from_name(name);

  /* channel id chars */
  BLI_strncpy(rpass->chan_id, chan_id, sizeof(rpass->chan_id));

  rpass->rect = rect;
  BLI_strncpy(rpass->name, name, EXR_PASS_MAXNAME);
  BLI_strncpy(rpass->view, view, sizeof(rpass->view));
  RE_render_result_full_channel_name(rpass->fullname, nullptr, name, view, rpass->chan_id, -1);

  if (view[0] != '\0') {
    rpass->view_id = BLI_findstringindex(&rr->views, view, offsetof(RenderView, name));
  }
  else {
    rpass->view_id = 0;
  }
}

static void *ml_addview_cb(void *base, const char *str)
{
  RenderResult *rr = static_cast<RenderResult *>(base);

  RenderView *rv = MEM_cnew<RenderView>("new render view");
  BLI_strncpy(rv->name, str, EXR_VIEW_MAXNAME);

  /* For stereo drawing we need to ensure:
   * STEREO_LEFT_NAME  == STEREO_LEFT_ID and
   * STEREO_RIGHT_NAME == STEREO_RIGHT_ID */

  if (STREQ(str, STEREO_LEFT_NAME)) {
    BLI_addhead(&rr->views, rv);
  }
  else if (STREQ(str, STEREO_RIGHT_NAME)) {
    RenderView *left_rv = static_cast<RenderView *>(
        BLI_findstring(&rr->views, STEREO_LEFT_NAME, offsetof(RenderView, name)));

    if (left_rv == nullptr) {
      BLI_addhead(&rr->views, rv);
    }
    else {
      BLI_insertlinkafter(&rr->views, left_rv, rv);
    }
  }
  else {
    BLI_addtail(&rr->views, rv);
  }

  return rv;
}

static int order_render_passes(const void *a, const void *b)
{
  /* 1 if `a` is after `b`. */
  RenderPass *rpa = (RenderPass *)a;
  RenderPass *rpb = (RenderPass *)b;
  uint passtype_a = passtype_from_name(rpa->name);
  uint passtype_b = passtype_from_name(rpb->name);

  /* Render passes with default type always go first. */
  if (passtype_b && !passtype_a) {
    return 1;
  }
  if (passtype_a && !passtype_b) {
    return 0;
  }

  if (passtype_a && passtype_b) {
    if (passtype_a > passtype_b) {
      return 1;
    }
    if (passtype_a < passtype_b) {
      return 0;
    }
  }
  else {
    int cmp = strncmp(rpa->name, rpb->name, EXR_PASS_MAXNAME);
    if (cmp > 0) {
      return 1;
    }
    if (cmp < 0) {
      return 0;
    }
  }

  /* they have the same type */
  /* left first */
  if (STREQ(rpa->view, STEREO_LEFT_NAME)) {
    return 0;
  }
  if (STREQ(rpb->view, STEREO_LEFT_NAME)) {
    return 1;
  }

  /* right second */
  if (STREQ(rpa->view, STEREO_RIGHT_NAME)) {
    return 0;
  }
  if (STREQ(rpb->view, STEREO_RIGHT_NAME)) {
    return 1;
  }

  /* remaining in ascending id order */
  return (rpa->view_id < rpb->view_id);
}

RenderResult *render_result_new_from_exr(
    void *exrhandle, const char *colorspace, bool predivide, int rectx, int recty)
{
  RenderResult *rr = MEM_cnew<RenderResult>(__func__);
  const char *to_colorspace = IMB_colormanagement_role_colorspace_name_get(
      COLOR_ROLE_SCENE_LINEAR);

  rr->rectx = rectx;
  rr->recty = recty;

  IMB_exr_multilayer_convert(exrhandle, rr, ml_addview_cb, ml_addlayer_cb, ml_addpass_cb);

  LISTBASE_FOREACH (RenderLayer *, rl, &rr->layers) {
    rl->rectx = rectx;
    rl->recty = recty;

    BLI_listbase_sort(&rl->passes, order_render_passes);

    LISTBASE_FOREACH (RenderPass *, rpass, &rl->passes) {
      rpass->rectx = rectx;
      rpass->recty = recty;

      if (rpass->channels >= 3) {
        IMB_colormanagement_transform(rpass->rect,
                                      rpass->rectx,
                                      rpass->recty,
                                      rpass->channels,
                                      colorspace,
                                      to_colorspace,
                                      predivide);
      }
    }
  }

  return rr;
}

void render_result_view_new(RenderResult *rr, const char *viewname)
{
  RenderView *rv = MEM_cnew<RenderView>("new render view");
  BLI_addtail(&rr->views, rv);
  BLI_strncpy(rv->name, viewname, sizeof(rv->name));
}

void render_result_views_new(RenderResult *rr, const RenderData *rd)
{
  /* clear previously existing views - for sequencer */
  render_result_views_free(rr);

  /* check renderdata for amount of views */
  if (rd->scemode & R_MULTIVIEW) {
    LISTBASE_FOREACH (SceneRenderView *, srv, &rd->views) {
      if (BKE_scene_multiview_is_render_view_active(rd, srv) == false) {
        continue;
      }
      render_result_view_new(rr, srv->name);
    }
  }

  /* we always need at least one view */
  if (BLI_listbase_count_at_most(&rr->views, 1) == 0) {
    render_result_view_new(rr, "");
  }
}

/*********************************** Merge ***********************************/

static void do_merge_tile(
    RenderResult *rr, RenderResult *rrpart, float *target, float *tile, int pixsize)
{
  int y, tilex, tiley;
  size_t ofs, copylen;

  copylen = tilex = rrpart->rectx;
  tiley = rrpart->recty;

  ofs = (size_t(rrpart->tilerect.ymin) * rr->rectx + rrpart->tilerect.xmin);
  target += pixsize * ofs;

  copylen *= sizeof(float) * pixsize;
  tilex *= pixsize;
  ofs = pixsize * rr->rectx;

  for (y = 0; y < tiley; y++) {
    memcpy(target, tile, copylen);
    target += ofs;
    tile += tilex;
  }
}

void render_result_merge(RenderResult *rr, RenderResult *rrpart)
{
  LISTBASE_FOREACH (RenderLayer *, rl, &rr->layers) {
    RenderLayer *rlp = RE_GetRenderLayer(rrpart, rl->name);

    if (rlp) {
      /* Passes are allocated in sync. */
      for (RenderPass *rpass = static_cast<RenderPass *>(rl->passes.first),
                      *rpassp = static_cast<RenderPass *>(rlp->passes.first);
           rpass && rpassp;
           rpass = rpass->next) {
        /* For save buffers, skip any passes that are only saved to disk. */
        if (rpass->rect == nullptr || rpassp->rect == nullptr) {
          continue;
        }
        /* Render-result have all passes, render-part only the active view's passes. */
        if (!STREQ(rpassp->fullname, rpass->fullname)) {
          continue;
        }

        do_merge_tile(rr, rrpart, rpass->rect, rpassp->rect, rpass->channels);

        /* manually get next render pass */
        rpassp = rpassp->next;
      }
    }
  }
}

/**************************** Single Layer Rendering *************************/

void render_result_single_layer_begin(Render *re)
{
  /* all layers except the active one get temporally pushed away */

  /* officially pushed result should be nullptr... error can happen with do_seq */
  RE_FreeRenderResult(re->pushedresult);

  re->pushedresult = re->result;
  re->result = nullptr;
}

void render_result_single_layer_end(Render *re)
{
  if (re->result == nullptr) {
    printf("pop render result error; no current result!\n");
    return;
  }

  if (!re->pushedresult) {
    return;
  }

  if (re->pushedresult->rectx == re->result->rectx &&
      re->pushedresult->recty == re->result->recty) {
    /* find which layer in re->pushedresult should be replaced */
    RenderLayer *rl = static_cast<RenderLayer *>(re->result->layers.first);

    /* render result should be empty after this */
    BLI_remlink(&re->result->layers, rl);

    /* reconstruct render result layers */
    int nr = 0;
    LISTBASE_FOREACH (ViewLayer *, view_layer, &re->scene->view_layers) {
      if (STREQ(view_layer->name, re->single_view_layer)) {
        BLI_addtail(&re->result->layers, rl);
      }
      else {
        RenderLayer *rlpush = RE_GetRenderLayer(re->pushedresult, view_layer->name);
        if (rlpush) {
          BLI_remlink(&re->pushedresult->layers, rlpush);
          BLI_addtail(&re->result->layers, rlpush);
        }
      }
      nr++;
    }
  }

  RE_FreeRenderResult(re->pushedresult);
  re->pushedresult = nullptr;
}

int render_result_exr_file_read_path(RenderResult *rr,
                                     RenderLayer *rl_single,
                                     const char *filepath)
{
  void *exrhandle = IMB_exr_get_handle();
  int rectx, recty;

  if (!IMB_exr_begin_read(exrhandle, filepath, &rectx, &recty, false)) {
    printf("failed being read %s\n", filepath);
    IMB_exr_close(exrhandle);
    return 0;
  }

  if (rr == nullptr || rectx != rr->rectx || recty != rr->recty) {
    if (rr) {
      printf("error in reading render result: dimensions don't match\n");
    }
    else {
      printf("error in reading render result: nullptr result pointer\n");
    }
    IMB_exr_close(exrhandle);
    return 0;
  }

  LISTBASE_FOREACH (RenderLayer *, rl, &rr->layers) {
    if (rl_single && rl_single != rl) {
      continue;
    }

    /* passes are allocated in sync */
    LISTBASE_FOREACH (RenderPass *, rpass, &rl->passes) {
      const int xstride = rpass->channels;
      int a;
      char fullname[EXR_PASS_MAXNAME];

      for (a = 0; a < xstride; a++) {
        RE_render_result_full_channel_name(
            fullname, nullptr, rpass->name, rpass->view, rpass->chan_id, a);
        IMB_exr_set_channel(
            exrhandle, rl->name, fullname, xstride, xstride * rectx, rpass->rect + a);
      }

      RE_render_result_full_channel_name(
          rpass->fullname, nullptr, rpass->name, rpass->view, rpass->chan_id, -1);
    }
  }

  IMB_exr_read_channels(exrhandle);
  IMB_exr_close(exrhandle);

  return 1;
}

#define FILE_CACHE_MAX (FILE_MAXFILE + FILE_MAXFILE + MAX_ID_NAME + 100)

static void render_result_exr_file_cache_path(Scene *sce,
                                              const char *root,
                                              char r_path[FILE_CACHE_MAX])
{
  char filename_full[FILE_MAX + MAX_ID_NAME + 100], filename[FILE_MAXFILE], dirname[FILE_MAXDIR];
  char path_digest[16] = {0};
  char path_hexdigest[33];

  /* If root is relative, use either current .blend file dir, or temp one if not saved. */
  const char *blendfile_path = BKE_main_blendfile_path_from_global();
  if (blendfile_path[0] != '\0') {
    BLI_split_dirfile(blendfile_path, dirname, filename, sizeof(dirname), sizeof(filename));
    BLI_path_extension_replace(filename, sizeof(filename), ""); /* strip '.blend' */
    BLI_hash_md5_buffer(blendfile_path, strlen(blendfile_path), path_digest);
  }
  else {
    BLI_strncpy(dirname, BKE_tempdir_base(), sizeof(dirname));
    BLI_strncpy(filename, "UNSAVED", sizeof(filename));
  }
  BLI_hash_md5_to_hexdigest(path_digest, path_hexdigest);

  /* Default to *non-volatile* temp dir. */
  if (*root == '\0') {
    root = BKE_tempdir_base();
  }

  BLI_snprintf(filename_full,
               sizeof(filename_full),
               "cached_RR_%s_%s_%s.exr",
               filename,
               sce->id.name + 2,
               path_hexdigest);

  BLI_path_join(r_path, FILE_CACHE_MAX, root, filename_full);
  if (BLI_path_is_rel(r_path)) {
    BLI_path_abs(r_path, dirname);
  }
}

void render_result_exr_file_cache_write(Render *re)
{
  RenderResult *rr = re->result;
  char str[FILE_CACHE_MAX];
  char *root = U.render_cachedir;

  render_result_passes_allocated_ensure(rr);

  render_result_exr_file_cache_path(re->scene, root, str);
  printf("Caching exr file, %dx%d, %s\n", rr->rectx, rr->recty, str);

  BKE_image_render_write_exr(nullptr, rr, str, nullptr, true, nullptr, -1);
}

bool render_result_exr_file_cache_read(Render *re)
{
  /* File path to cache. */
  char filepath[FILE_CACHE_MAX] = "";
  char *root = U.render_cachedir;
  render_result_exr_file_cache_path(re->scene, root, filepath);

  printf("read exr cache file: %s\n", filepath);

  /* Try opening the file. */
  void *exrhandle = IMB_exr_get_handle();
  int rectx, recty;

  if (!IMB_exr_begin_read(exrhandle, filepath, &rectx, &recty, true)) {
    printf("cannot read: %s\n", filepath);
    IMB_exr_close(exrhandle);
    return false;
  }

  /* Read file contents into render result. */
  const char *colorspace = IMB_colormanagement_role_colorspace_name_get(COLOR_ROLE_SCENE_LINEAR);
  RE_FreeRenderResult(re->result);

  IMB_exr_read_channels(exrhandle);
  re->result = render_result_new_from_exr(exrhandle, colorspace, false, rectx, recty);

  IMB_exr_close(exrhandle);

  return true;
}

/*************************** Combined Pixel Rect *****************************/

ImBuf *RE_render_result_rect_to_ibuf(RenderResult *rr,
                                     const ImageFormatData *imf,
                                     const float dither,
                                     const int view_id)
{
  ImBuf *ibuf = IMB_allocImBuf(rr->rectx, rr->recty, imf->planes, 0);
  RenderView *rv = RE_RenderViewGetById(rr, view_id);

  /* if not exists, BKE_imbuf_write makes one */
  ibuf->rect = (uint *)rv->rect32;
  ibuf->rect_float = rv->rectf;
  ibuf->zbuf_float = rv->rectz;

  /* float factor for random dither, imbuf takes care of it */
  ibuf->dither = dither;

  /* prepare to gamma correct to sRGB color space
   * note that sequence editor can generate 8bpc render buffers
   */
  if (ibuf->rect) {
    if (BKE_imtype_valid_depths(imf->imtype) &
        (R_IMF_CHAN_DEPTH_12 | R_IMF_CHAN_DEPTH_16 | R_IMF_CHAN_DEPTH_24 | R_IMF_CHAN_DEPTH_32)) {
      if (imf->depth == R_IMF_CHAN_DEPTH_8) {
        /* Higher depth bits are supported but not needed for current file output. */
        ibuf->rect_float = nullptr;
      }
      else {
        IMB_float_from_rect(ibuf);
      }
    }
    else {
      /* ensure no float buffer remained from previous frame */
      ibuf->rect_float = nullptr;
    }
  }

  /* Color -> gray-scale. */
  /* editing directly would alter the render view */
  if (imf->planes == R_IMF_PLANES_BW && imf->imtype != R_IMF_IMTYPE_MULTILAYER) {
    ImBuf *ibuf_bw = IMB_dupImBuf(ibuf);
    IMB_color_to_bw(ibuf_bw);
    IMB_freeImBuf(ibuf);
    ibuf = ibuf_bw;
  }

  return ibuf;
}

void RE_render_result_rect_from_ibuf(RenderResult *rr, const ImBuf *ibuf, const int view_id)
{
  RenderView *rv = RE_RenderViewGetById(rr, view_id);

  if (ibuf->rect_float) {
    rr->have_combined = true;

    if (!rv->rectf) {
      rv->rectf = MEM_cnew_array<float>(4 * rr->rectx * rr->recty, "render_seq rectf");
    }

    memcpy(rv->rectf, ibuf->rect_float, sizeof(float[4]) * rr->rectx * rr->recty);

    /* TSK! Since sequence render doesn't free the *rr render result, the old rect32
     * can hang around when sequence render has rendered a 32 bits one before */
    MEM_SAFE_FREE(rv->rect32);
  }
  else if (ibuf->rect) {
    rr->have_combined = true;

    if (!rv->rect32) {
      rv->rect32 = MEM_cnew_array<int>(rr->rectx * rr->recty, "render_seq rect");
    }

    memcpy(rv->rect32, ibuf->rect, sizeof(int) * rr->rectx * rr->recty);

    /* Same things as above, old rectf can hang around from previous render. */
    MEM_SAFE_FREE(rv->rectf);
  }
}

void render_result_rect_fill_zero(RenderResult *rr, const int view_id)
{
  RenderView *rv = RE_RenderViewGetById(rr, view_id);

  if (rv->rectf) {
    memset(rv->rectf, 0, sizeof(float[4]) * rr->rectx * rr->recty);
  }
  else if (rv->rect32) {
    memset(rv->rect32, 0, 4 * rr->rectx * rr->recty);
  }
  else {
    rv->rect32 = MEM_cnew_array<int>(rr->rectx * rr->recty, "render_seq rect");
  }
}

void render_result_rect_get_pixels(RenderResult *rr,
                                   uint *rect,
                                   int rectx,
                                   int recty,
                                   const ColorManagedViewSettings *view_settings,
                                   const ColorManagedDisplaySettings *display_settings,
                                   const int view_id)
{
  RenderView *rv = RE_RenderViewGetById(rr, view_id);

  if (rv && rv->rect32) {
    memcpy(rect, rv->rect32, sizeof(int) * rr->rectx * rr->recty);
  }
  else if (rv && rv->rectf) {
    IMB_display_buffer_transform_apply(
        (uchar *)rect, rv->rectf, rr->rectx, rr->recty, 4, view_settings, display_settings, true);
  }
  else {
    /* else fill with black */
    memset(rect, 0, sizeof(int) * rectx * recty);
  }
}

/*************************** multiview functions *****************************/

bool RE_HasCombinedLayer(const RenderResult *result)
{
  if (result == nullptr) {
    return false;
  }

  const RenderView *rv = static_cast<RenderView *>(result->views.first);
  if (rv == nullptr) {
    return false;
  }

  return (rv->rect32 || rv->rectf);
}

bool RE_HasFloatPixels(const RenderResult *result)
{
  LISTBASE_FOREACH (const RenderView *, rview, &result->views) {
    if (rview->rect32 && !rview->rectf) {
      return false;
    }
  }

  return true;
}

bool RE_RenderResult_is_stereo(const RenderResult *result)
{
  if (!BLI_findstring(&result->views, STEREO_LEFT_NAME, offsetof(RenderView, name))) {
    return false;
  }

  if (!BLI_findstring(&result->views, STEREO_RIGHT_NAME, offsetof(RenderView, name))) {
    return false;
  }

  return true;
}

RenderView *RE_RenderViewGetById(RenderResult *rr, const int view_id)
{
  RenderView *rv = static_cast<RenderView *>(BLI_findlink(&rr->views, view_id));
  BLI_assert(rr->views.first);
  return rv ? rv : static_cast<RenderView *>(rr->views.first);
}

RenderView *RE_RenderViewGetByName(RenderResult *rr, const char *viewname)
{
  RenderView *rv = static_cast<RenderView *>(
      BLI_findstring(&rr->views, viewname, offsetof(RenderView, name)));
  BLI_assert(rr->views.first);
  return rv ? rv : static_cast<RenderView *>(rr->views.first);
}

static RenderPass *duplicate_render_pass(RenderPass *rpass)
{
  RenderPass *new_rpass = MEM_cnew("new render pass", *rpass);
  new_rpass->next = new_rpass->prev = nullptr;
  if (new_rpass->rect != nullptr) {
    new_rpass->rect = static_cast<float *>(MEM_dupallocN(new_rpass->rect));
  }
  return new_rpass;
}

static RenderLayer *duplicate_render_layer(RenderLayer *rl)
{
  RenderLayer *new_rl = MEM_cnew("new render layer", *rl);
  new_rl->next = new_rl->prev = nullptr;
  new_rl->passes.first = new_rl->passes.last = nullptr;
  new_rl->exrhandle = nullptr;
  LISTBASE_FOREACH (RenderPass *, rpass, &rl->passes) {
    RenderPass *new_rpass = duplicate_render_pass(rpass);
    BLI_addtail(&new_rl->passes, new_rpass);
  }
  return new_rl;
}

static RenderView *duplicate_render_view(RenderView *rview)
{
  RenderView *new_rview = MEM_cnew("new render view", *rview);
  if (new_rview->rectf != nullptr) {
    new_rview->rectf = static_cast<float *>(MEM_dupallocN(new_rview->rectf));
  }
  if (new_rview->rectz != nullptr) {
    new_rview->rectz = static_cast<float *>(MEM_dupallocN(new_rview->rectz));
  }
  if (new_rview->rect32 != nullptr) {
    new_rview->rect32 = static_cast<int *>(MEM_dupallocN(new_rview->rect32));
  }
  return new_rview;
}

RenderResult *RE_DuplicateRenderResult(RenderResult *rr)
{
  RenderResult *new_rr = MEM_cnew("new duplicated render result", *rr);
  new_rr->next = new_rr->prev = nullptr;
  new_rr->layers.first = new_rr->layers.last = nullptr;
  new_rr->views.first = new_rr->views.last = nullptr;
  LISTBASE_FOREACH (RenderLayer *, rl, &rr->layers) {
    RenderLayer *new_rl = duplicate_render_layer(rl);
    BLI_addtail(&new_rr->layers, new_rl);
  }
  LISTBASE_FOREACH (RenderView *, rview, &rr->views) {
    RenderView *new_rview = duplicate_render_view(rview);
    BLI_addtail(&new_rr->views, new_rview);
  }
  if (new_rr->rectf != nullptr) {
    new_rr->rectf = static_cast<float *>(MEM_dupallocN(new_rr->rectf));
  }
  if (new_rr->rectz != nullptr) {
    new_rr->rectz = static_cast<float *>(MEM_dupallocN(new_rr->rectz));
  }
  if (new_rr->rect32 != nullptr) {
    new_rr->rect32 = static_cast<int *>(MEM_dupallocN(new_rr->rect32));
  }
  new_rr->stamp_data = BKE_stamp_data_copy(new_rr->stamp_data);
  return new_rr;
}