image_gpu.c

Go to the documentation of this file.

/*
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
 *
 * The Original Code is Copyright (C) 2001-2002 by NaN Holding BV.
 * All rights reserved.
 */
 
#include "MEM_guardedalloc.h"
 
#include "BLI_bitmap.h"
#include "BLI_boxpack_2d.h"
#include "BLI_linklist.h"
#include "BLI_listbase.h"
#include "BLI_threads.h"
 
#include "DNA_image_types.h"
#include "DNA_userdef_types.h"
 
#include "IMB_colormanagement.h"
#include "IMB_imbuf.h"
#include "IMB_imbuf_types.h"
 
#include "BKE_global.h"
#include "BKE_image.h"
#include "BKE_main.h"
 
#include "GPU_capabilities.h"
#include "GPU_state.h"
#include "GPU_texture.h"
 
#include "PIL_time.h"
 
/* Prototypes. */
static void gpu_free_unused_buffers(void);
static void image_free_gpu(Image *ima, const bool immediate);
static void image_update_gputexture_ex(
    Image *ima, ImageTile *tile, ImBuf *ibuf, int x, int y, int w, int h);
 
/* Internal structs. */
#define IMA_PARTIAL_REFRESH_TILE_SIZE 256
typedef struct ImagePartialRefresh {
  struct ImagePartialRefresh *next, *prev;
  int tile_x;
  int tile_y;
} ImagePartialRefresh;
 
/* Is the alpha of the `GPUTexture` for a given image/ibuf premultiplied. */
bool BKE_image_has_gpu_texture_premultiplied_alpha(Image *image, ImBuf *ibuf)
{
  if (image) {
    /* Render result and compositor output are always premultiplied */
    if (ELEM(image->type, IMA_TYPE_R_RESULT, IMA_TYPE_COMPOSITE)) {
      return true;
    }
    /* Generated images use pre multiplied float buffer, but straight alpha for byte buffers. */
    if (image->type == IMA_TYPE_UV_TEST && ibuf) {
      return ibuf->rect_float != NULL;
    }
  }
  if (ibuf) {
    if (ibuf->rect_float) {
      return image ? (image->alpha_mode != IMA_ALPHA_STRAIGHT) : false;
    }
 
    return image ? (image->alpha_mode == IMA_ALPHA_PREMUL) : true;
  }
  return false;
}
 
/* -------------------------------------------------------------------- */
static bool is_over_resolution_limit(int w, int h, bool limit_gl_texture_size)
{
  return (w > GPU_texture_size_with_limit(w, limit_gl_texture_size) ||
          h > GPU_texture_size_with_limit(h, limit_gl_texture_size));
}
 
static int smaller_power_of_2_limit(int num, bool limit_gl_texture_size)
{
  return power_of_2_min_i(GPU_texture_size_with_limit(num, limit_gl_texture_size));
}
 
static GPUTexture *gpu_texture_create_tile_mapping(Image *ima, const int multiview_eye)
{
  GPUTexture *tilearray = ima->gputexture[TEXTARGET_2D_ARRAY][multiview_eye];
 
  if (tilearray == NULL) {
    return 0;
  }
 
  float array_w = GPU_texture_width(tilearray);
  float array_h = GPU_texture_height(tilearray);
 
  ImageTile *last_tile = (ImageTile *)ima->tiles.last;
  /* Tiles are sorted by number. */
  int max_tile = last_tile->tile_number - 1001;
 
  /* create image */
  int width = max_tile + 1;
  float *data = (float *)MEM_callocN(width * 8 * sizeof(float), __func__);
  for (int i = 0; i < width; i++) {
    data[4 * i] = -1.0f;
  }
  LISTBASE_FOREACH (ImageTile *, tile, &ima->tiles) {
    int i = tile->tile_number - 1001;
    data[4 * i] = tile->runtime.tilearray_layer;
 
    float *tile_info = &data[4 * width + 4 * i];
    tile_info[0] = tile->runtime.tilearray_offset[0] / array_w;
    tile_info[1] = tile->runtime.tilearray_offset[1] / array_h;
    tile_info[2] = tile->runtime.tilearray_size[0] / array_w;
    tile_info[3] = tile->runtime.tilearray_size[1] / array_h;
  }
 
  GPUTexture *tex = GPU_texture_create_1d_array(ima->id.name + 2, width, 2, 1, GPU_RGBA32F, data);
  GPU_texture_mipmap_mode(tex, false, false);
 
  MEM_freeN(data);
 
  return tex;
}
 
typedef struct PackTile {
  FixedSizeBoxPack boxpack;
  ImageTile *tile;
  float pack_score;
} PackTile;
 
static int compare_packtile(const void *a, const void *b)
{
  const PackTile *tile_a = (const PackTile *)a;
  const PackTile *tile_b = (const PackTile *)b;
 
  return tile_a->pack_score < tile_b->pack_score;
}
 
static GPUTexture *gpu_texture_create_tile_array(Image *ima, ImBuf *main_ibuf)
{
  const bool limit_gl_texture_size = (ima->gpuflag & IMA_GPU_MAX_RESOLUTION) == 0;
  int arraywidth = 0, arrayheight = 0;
  ListBase boxes = {NULL};
 
  LISTBASE_FOREACH (ImageTile *, tile, &ima->tiles) {
    ImageUser iuser;
    BKE_imageuser_default(&iuser);
    iuser.tile = tile->tile_number;
    ImBuf *ibuf = BKE_image_acquire_ibuf(ima, &iuser, NULL);
 
    if (ibuf) {
      PackTile *packtile = (PackTile *)MEM_callocN(sizeof(PackTile), __func__);
      packtile->tile = tile;
      packtile->boxpack.w = ibuf->x;
      packtile->boxpack.h = ibuf->y;
 
      if (is_over_resolution_limit(
              packtile->boxpack.w, packtile->boxpack.h, limit_gl_texture_size)) {
        packtile->boxpack.w = smaller_power_of_2_limit(packtile->boxpack.w, limit_gl_texture_size);
        packtile->boxpack.h = smaller_power_of_2_limit(packtile->boxpack.h, limit_gl_texture_size);
      }
      arraywidth = max_ii(arraywidth, packtile->boxpack.w);
      arrayheight = max_ii(arrayheight, packtile->boxpack.h);
 
      /* We sort the tiles by decreasing size, with an additional penalty term
       * for high aspect ratios. This improves packing efficiency. */
      float w = packtile->boxpack.w, h = packtile->boxpack.h;
      packtile->pack_score = max_ff(w, h) / min_ff(w, h) * w * h;
 
      BKE_image_release_ibuf(ima, ibuf, NULL);
      BLI_addtail(&boxes, packtile);
    }
  }
 
  BLI_assert(arraywidth > 0 && arrayheight > 0);
 
  BLI_listbase_sort(&boxes, compare_packtile);
  int arraylayers = 0;
  /* Keep adding layers until all tiles are packed. */
  while (boxes.first != NULL) {
    ListBase packed = {NULL};
    BLI_box_pack_2d_fixedarea(&boxes, arraywidth, arrayheight, &packed);
    BLI_assert(packed.first != NULL);
 
    LISTBASE_FOREACH (PackTile *, packtile, &packed) {
      ImageTile *tile = packtile->tile;
      int *tileoffset = tile->runtime.tilearray_offset;
      int *tilesize = tile->runtime.tilearray_size;
 
      tileoffset[0] = packtile->boxpack.x;
      tileoffset[1] = packtile->boxpack.y;
      tilesize[0] = packtile->boxpack.w;
      tilesize[1] = packtile->boxpack.h;
      tile->runtime.tilearray_layer = arraylayers;
    }
 
    BLI_freelistN(&packed);
    arraylayers++;
  }
 
  const bool use_high_bitdepth = (ima->flag & IMA_HIGH_BITDEPTH);
  /* Create Texture without content. */
  GPUTexture *tex = IMB_touch_gpu_texture(
      ima->id.name + 2, main_ibuf, arraywidth, arrayheight, arraylayers, use_high_bitdepth);
 
  /* Upload each tile one by one. */
  LISTBASE_FOREACH (ImageTile *, tile, &ima->tiles) {
    int tilelayer = tile->runtime.tilearray_layer;
    int *tileoffset = tile->runtime.tilearray_offset;
    int *tilesize = tile->runtime.tilearray_size;
 
    if (tilesize[0] == 0 || tilesize[1] == 0) {
      continue;
    }
 
    ImageUser iuser;
    BKE_imageuser_default(&iuser);
    iuser.tile = tile->tile_number;
    ImBuf *ibuf = BKE_image_acquire_ibuf(ima, &iuser, NULL);
 
    if (ibuf) {
      const bool store_premultiplied = BKE_image_has_gpu_texture_premultiplied_alpha(ima, ibuf);
      IMB_update_gpu_texture_sub(tex,
                                 ibuf,
                                 UNPACK2(tileoffset),
                                 tilelayer,
                                 UNPACK2(tilesize),
                                 use_high_bitdepth,
                                 store_premultiplied);
    }
 
    BKE_image_release_ibuf(ima, ibuf, NULL);
  }
 
  if (GPU_mipmap_enabled()) {
    GPU_texture_generate_mipmap(tex);
    GPU_texture_mipmap_mode(tex, true, true);
    if (ima) {
      ima->gpuflag |= IMA_GPU_MIPMAP_COMPLETE;
    }
  }
  else {
    GPU_texture_mipmap_mode(tex, false, true);
  }
 
  return tex;
}
 
/* -------------------------------------------------------------------- */
static GPUTexture **get_image_gpu_texture_ptr(Image *ima,
                                              eGPUTextureTarget textarget,
                                              const int multiview_eye)
{
  const bool in_range = (textarget >= 0) && (textarget < TEXTARGET_COUNT);
  BLI_assert(in_range);
  BLI_assert(multiview_eye == 0 || multiview_eye == 1);
 
  if (in_range) {
    return &(ima->gputexture[textarget][multiview_eye]);
  }
  return NULL;
}
 
static GPUTexture *image_gpu_texture_error_create(eGPUTextureTarget textarget)
{
  fprintf(stderr, "GPUTexture: Blender Texture Not Loaded!\n");
  switch (textarget) {
    case TEXTARGET_2D_ARRAY:
      return GPU_texture_create_error(2, true);
    case TEXTARGET_TILE_MAPPING:
      return GPU_texture_create_error(1, true);
    case TEXTARGET_2D:
    default:
      return GPU_texture_create_error(2, false);
  }
}
 
static GPUTexture *image_get_gpu_texture(Image *ima,
                                         ImageUser *iuser,
                                         ImBuf *ibuf,
                                         eGPUTextureTarget textarget)
{
  if (ima == NULL) {
    return NULL;
  }
 
  /* Free any unused GPU textures, since we know we are in a thread with OpenGL
   * context and might as well ensure we have as much space free as possible. */
  gpu_free_unused_buffers();
 
  /* Free GPU textures when requesting a different render pass/layer.
   * When `iuser` isn't set (texture painting single image mode) we assume that
   * the current `pass` and `layer` should be 0. */
  short requested_pass = iuser ? iuser->pass : 0;
  short requested_layer = iuser ? iuser->layer : 0;
  short requested_view = iuser ? iuser->multi_index : 0;
  const bool limit_resolution = U.glreslimit != 0 &&
                                ((iuser && (iuser->flag & IMA_SHOW_MAX_RESOLUTION) == 0) ||
                                 (iuser == NULL));
  short requested_gpu_flags = limit_resolution ? 0 : IMA_GPU_MAX_RESOLUTION;
#define GPU_FLAGS_TO_CHECK (IMA_GPU_MAX_RESOLUTION)
  /* There is room for 2 multiview textures. When a higher number is requested we should always
   * target the first view slot. This is fine as multi view images aren't used together. */
  if (requested_view < 2) {
    requested_view = 0;
  }
  if (ima->gpu_pass != requested_pass || ima->gpu_layer != requested_layer ||
      ima->gpu_view != requested_view ||
      ((ima->gpuflag & GPU_FLAGS_TO_CHECK) != requested_gpu_flags)) {
    ima->gpu_pass = requested_pass;
    ima->gpu_layer = requested_layer;
    ima->gpu_view = requested_view;
    ima->gpuflag &= ~GPU_FLAGS_TO_CHECK;
    ima->gpuflag |= requested_gpu_flags | IMA_GPU_REFRESH;
  }
#undef GPU_FLAGS_TO_CHECK
 
  /* Check if image has been updated and tagged to be updated (full or partial). */
  ImageTile *tile = BKE_image_get_tile(ima, 0);
  if (((ima->gpuflag & IMA_GPU_REFRESH) != 0) ||
      ((ibuf == NULL || tile == NULL || !tile->ok) &&
       ((ima->gpuflag & IMA_GPU_PARTIAL_REFRESH) != 0))) {
    image_free_gpu(ima, true);
    BLI_freelistN(&ima->gpu_refresh_areas);
    ima->gpuflag &= ~(IMA_GPU_REFRESH | IMA_GPU_PARTIAL_REFRESH);
  }
  else if (ima->gpuflag & IMA_GPU_PARTIAL_REFRESH) {
    BLI_assert(ibuf);
    BLI_assert(tile && tile->ok);
    ImagePartialRefresh *refresh_area;
    while ((refresh_area = BLI_pophead(&ima->gpu_refresh_areas))) {
      const int tile_offset_x = refresh_area->tile_x * IMA_PARTIAL_REFRESH_TILE_SIZE;
      const int tile_offset_y = refresh_area->tile_y * IMA_PARTIAL_REFRESH_TILE_SIZE;
      const int tile_width = MIN2(IMA_PARTIAL_REFRESH_TILE_SIZE, ibuf->x - tile_offset_x);
      const int tile_height = MIN2(IMA_PARTIAL_REFRESH_TILE_SIZE, ibuf->y - tile_offset_y);
      image_update_gputexture_ex(
          ima, tile, ibuf, tile_offset_x, tile_offset_y, tile_width, tile_height);
      MEM_freeN(refresh_area);
    }
    ima->gpuflag &= ~IMA_GPU_PARTIAL_REFRESH;
  }
 
  /* Tag as in active use for garbage collector. */
  BKE_image_tag_time(ima);
 
  /* Test if we already have a texture. */
  int current_view = iuser ? iuser->multi_index : 0;
  if (current_view >= 2) {
    current_view = 0;
  }
  GPUTexture **tex = get_image_gpu_texture_ptr(ima, textarget, current_view);
  if (*tex) {
    return *tex;
  }
 
  /* Check if we have a valid image. If not, we return a dummy
   * texture with zero bind-code so we don't keep trying. */
  if (tile == NULL || tile->ok == 0) {
    *tex = image_gpu_texture_error_create(textarget);
    return *tex;
  }
 
  /* check if we have a valid image buffer */
  ImBuf *ibuf_intern = ibuf;
  if (ibuf_intern == NULL) {
    ibuf_intern = BKE_image_acquire_ibuf(ima, iuser, NULL);
    if (ibuf_intern == NULL) {
      *tex = image_gpu_texture_error_create(textarget);
      return *tex;
    }
  }
 
  if (textarget == TEXTARGET_2D_ARRAY) {
    *tex = gpu_texture_create_tile_array(ima, ibuf_intern);
  }
  else if (textarget == TEXTARGET_TILE_MAPPING) {
    *tex = gpu_texture_create_tile_mapping(ima, iuser ? iuser->multiview_eye : 0);
  }
  else {
    const bool use_high_bitdepth = (ima->flag & IMA_HIGH_BITDEPTH);
    const bool store_premultiplied = BKE_image_has_gpu_texture_premultiplied_alpha(ima,
                                                                                   ibuf_intern);
    const bool limit_gl_texture_size = (ima->gpuflag & IMA_GPU_MAX_RESOLUTION) == 0;
 
    *tex = IMB_create_gpu_texture(ima->id.name + 2,
                                  ibuf_intern,
                                  use_high_bitdepth,
                                  store_premultiplied,
                                  limit_gl_texture_size);
 
    if (*tex) {
      GPU_texture_wrap_mode(*tex, true, false);
 
      if (GPU_mipmap_enabled()) {
        GPU_texture_generate_mipmap(*tex);
        if (ima) {
          ima->gpuflag |= IMA_GPU_MIPMAP_COMPLETE;
        }
        GPU_texture_mipmap_mode(*tex, true, true);
      }
      else {
        GPU_texture_mipmap_mode(*tex, false, true);
      }
    }
  }
 
  /* if `ibuf` was given, we don't own the `ibuf_intern` */
  if (ibuf == NULL) {
    BKE_image_release_ibuf(ima, ibuf_intern, NULL);
  }
 
  if (*tex) {
    GPU_texture_orig_size_set(*tex, ibuf_intern->x, ibuf_intern->y);
  }
 
  return *tex;
}
 
GPUTexture *BKE_image_get_gpu_texture(Image *image, ImageUser *iuser, ImBuf *ibuf)
{
  return image_get_gpu_texture(image, iuser, ibuf, TEXTARGET_2D);
}
 
GPUTexture *BKE_image_get_gpu_tiles(Image *image, ImageUser *iuser, ImBuf *ibuf)
{
  return image_get_gpu_texture(image, iuser, ibuf, TEXTARGET_2D_ARRAY);
}
 
GPUTexture *BKE_image_get_gpu_tilemap(Image *image, ImageUser *iuser, ImBuf *ibuf)
{
  return image_get_gpu_texture(image, iuser, ibuf, TEXTARGET_TILE_MAPPING);
}
 
/* -------------------------------------------------------------------- */
static LinkNode *gpu_texture_free_queue = NULL;
static ThreadMutex gpu_texture_queue_mutex = BLI_MUTEX_INITIALIZER;
 
static void gpu_free_unused_buffers(void)
{
  if (gpu_texture_free_queue == NULL) {
    return;
  }
 
  BLI_mutex_lock(&gpu_texture_queue_mutex);
 
  while (gpu_texture_free_queue != NULL) {
    GPUTexture *tex = BLI_linklist_pop(&gpu_texture_free_queue);
    GPU_texture_free(tex);
  }
 
  BLI_mutex_unlock(&gpu_texture_queue_mutex);
}
 
void BKE_image_free_unused_gpu_textures()
{
  if (BLI_thread_is_main()) {
    gpu_free_unused_buffers();
  }
}
 
/* -------------------------------------------------------------------- */
static void image_free_gpu(Image *ima, const bool immediate)
{
  for (int eye = 0; eye < 2; eye++) {
    for (int i = 0; i < TEXTARGET_COUNT; i++) {
      if (ima->gputexture[i][eye] != NULL) {
        if (immediate) {
          GPU_texture_free(ima->gputexture[i][eye]);
        }
        else {
          BLI_mutex_lock(&gpu_texture_queue_mutex);
          BLI_linklist_prepend(&gpu_texture_free_queue, ima->gputexture[i][eye]);
          BLI_mutex_unlock(&gpu_texture_queue_mutex);
        }
 
        ima->gputexture[i][eye] = NULL;
      }
    }
  }
 
  ima->gpuflag &= ~IMA_GPU_MIPMAP_COMPLETE;
}
 
void BKE_image_free_gputextures(Image *ima)
{
  image_free_gpu(ima, BLI_thread_is_main());
}
 
void BKE_image_free_all_gputextures(Main *bmain)
{
  if (bmain) {
    LISTBASE_FOREACH (Image *, ima, &bmain->images) {
      BKE_image_free_gputextures(ima);
    }
  }
}
 
/* same as above but only free animated images */
void BKE_image_free_anim_gputextures(Main *bmain)
{
  if (bmain) {
    LISTBASE_FOREACH (Image *, ima, &bmain->images) {
      if (BKE_image_is_animated(ima)) {
        BKE_image_free_gputextures(ima);
      }
    }
  }
}
 
void BKE_image_free_old_gputextures(Main *bmain)
{
  static int lasttime = 0;
  int ctime = (int)PIL_check_seconds_timer();
 
  /*
   * Run garbage collector once for every collecting period of time
   * if textimeout is 0, that's the option to NOT run the collector
   */
  if (U.textimeout == 0 || ctime % U.texcollectrate || ctime == lasttime) {
    return;
  }
 
  /* of course not! */
  if (G.is_rendering) {
    return;
  }
 
  lasttime = ctime;
 
  LISTBASE_FOREACH (Image *, ima, &bmain->images) {
    if ((ima->flag & IMA_NOCOLLECT) == 0 && ctime - ima->lastused > U.textimeout) {
      /* If it's in GL memory, deallocate and set time tag to current time
       * This gives textures a "second chance" to be used before dying. */
      if (BKE_image_has_opengl_texture(ima)) {
        BKE_image_free_gputextures(ima);
        ima->lastused = ctime;
      }
      /* Otherwise, just kill the buffers */
      else {
        BKE_image_free_buffers(ima);
      }
    }
  }
}
/* -------------------------------------------------------------------- */
static ImBuf *update_do_scale(uchar *rect,
                              float *rect_float,
                              int *x,
                              int *y,
                              int *w,
                              int *h,
                              int limit_w,
                              int limit_h,
                              int full_w,
                              int full_h)
{
  /* Partial update with scaling. */
  float xratio = limit_w / (float)full_w;
  float yratio = limit_h / (float)full_h;
 
  int part_w = *w, part_h = *h;
 
  /* Find sub coordinates in scaled image. Take ceiling because we will be
   * losing 1 pixel due to rounding errors in x,y. */
  *x *= xratio;
  *y *= yratio;
  *w = (int)ceil(xratio * (*w));
  *h = (int)ceil(yratio * (*h));
 
  /* ...but take back if we are over the limit! */
  if (*x + *w > limit_w) {
    (*w)--;
  }
  if (*y + *h > limit_h) {
    (*h)--;
  }
 
  /* Scale pixels. */
  ImBuf *ibuf = IMB_allocFromBuffer((uint *)rect, rect_float, part_w, part_h, 4);
  IMB_scaleImBuf(ibuf, *w, *h);
 
  return ibuf;
}
 
static void gpu_texture_update_scaled(GPUTexture *tex,
                                      uchar *rect,
                                      float *rect_float,
                                      int full_w,
                                      int full_h,
                                      int x,
                                      int y,
                                      int layer,
                                      const int *tile_offset,
                                      const int *tile_size,
                                      int w,
                                      int h)
{
  ImBuf *ibuf;
  if (layer > -1) {
    ibuf = update_do_scale(
        rect, rect_float, &x, &y, &w, &h, tile_size[0], tile_size[1], full_w, full_h);
 
    /* Shift to account for tile packing. */
    x += tile_offset[0];
    y += tile_offset[1];
  }
  else {
    /* Partial update with scaling. */
    int limit_w = GPU_texture_width(tex);
    int limit_h = GPU_texture_height(tex);
 
    ibuf = update_do_scale(rect, rect_float, &x, &y, &w, &h, limit_w, limit_h, full_w, full_h);
  }
 
  void *data = (ibuf->rect_float) ? (void *)(ibuf->rect_float) : (void *)(ibuf->rect);
  eGPUDataFormat data_format = (ibuf->rect_float) ? GPU_DATA_FLOAT : GPU_DATA_UBYTE;
 
  GPU_texture_update_sub(tex, data_format, data, x, y, layer, w, h, 1);
 
  IMB_freeImBuf(ibuf);
}
 
static void gpu_texture_update_unscaled(GPUTexture *tex,
                                        uchar *rect,
                                        float *rect_float,
                                        int x,
                                        int y,
                                        int layer,
                                        const int tile_offset[2],
                                        int w,
                                        int h,
                                        int tex_stride,
                                        int tex_offset)
{
  if (layer > -1) {
    /* Shift to account for tile packing. */
    x += tile_offset[0];
    y += tile_offset[1];
  }
 
  void *data = (rect_float) ? (void *)(rect_float + tex_offset) : (void *)(rect + tex_offset);
  eGPUDataFormat data_format = (rect_float) ? GPU_DATA_FLOAT : GPU_DATA_UBYTE;
 
  /* Partial update without scaling. Stride and offset are used to copy only a
   * subset of a possible larger buffer than what we are updating. */
  GPU_unpack_row_length_set(tex_stride);
 
  GPU_texture_update_sub(tex, data_format, data, x, y, layer, w, h, 1);
  /* Restore default. */
  GPU_unpack_row_length_set(0);
}
 
static void gpu_texture_update_from_ibuf(
    GPUTexture *tex, Image *ima, ImBuf *ibuf, ImageTile *tile, int x, int y, int w, int h)
{
  bool scaled;
  if (tile != NULL) {
    int *tilesize = tile->runtime.tilearray_size;
    scaled = (ibuf->x != tilesize[0]) || (ibuf->y != tilesize[1]);
  }
  else {
    scaled = (GPU_texture_width(tex) != ibuf->x) || (GPU_texture_height(tex) != ibuf->y);
  }
 
  if (scaled) {
    /* Extra padding to account for bleed from neighboring pixels. */
    const int padding = 4;
    const int xmax = min_ii(x + w + padding, ibuf->x);
    const int ymax = min_ii(y + h + padding, ibuf->y);
    x = max_ii(x - padding, 0);
    y = max_ii(y - padding, 0);
    w = xmax - x;
    h = ymax - y;
  }
 
  /* Get texture data pointers. */
  float *rect_float = ibuf->rect_float;
  uchar *rect = (uchar *)ibuf->rect;
  int tex_stride = ibuf->x;
  int tex_offset = ibuf->channels * (y * ibuf->x + x);
 
  const bool store_premultiplied = BKE_image_has_gpu_texture_premultiplied_alpha(ima, ibuf);
  if (rect_float == NULL) {
    /* Byte pixels. */
    if (!IMB_colormanagement_space_is_data(ibuf->rect_colorspace)) {
      const bool compress_as_srgb = !IMB_colormanagement_space_is_scene_linear(
          ibuf->rect_colorspace);
 
      rect = (uchar *)MEM_mallocN(sizeof(uchar[4]) * w * h, __func__);
      if (rect == NULL) {
        return;
      }
 
      tex_stride = w;
      tex_offset = 0;
 
      /* Convert to scene linear with sRGB compression, and premultiplied for
       * correct texture interpolation. */
      IMB_colormanagement_imbuf_to_byte_texture(
          rect, x, y, w, h, ibuf, compress_as_srgb, store_premultiplied);
    }
  }
  else {
    /* Float pixels. */
    if (ibuf->channels != 4 || scaled || !store_premultiplied) {
      rect_float = (float *)MEM_mallocN(sizeof(float[4]) * w * h, __func__);
      if (rect_float == NULL) {
        return;
      }
 
      tex_stride = w;
      tex_offset = 0;
 
      IMB_colormanagement_imbuf_to_float_texture(
          rect_float, x, y, w, h, ibuf, store_premultiplied);
    }
  }
 
  if (scaled) {
    /* Slower update where we first have to scale the input pixels. */
    if (tile != NULL) {
      int *tileoffset = tile->runtime.tilearray_offset;
      int *tilesize = tile->runtime.tilearray_size;
      int tilelayer = tile->runtime.tilearray_layer;
      gpu_texture_update_scaled(
          tex, rect, rect_float, ibuf->x, ibuf->y, x, y, tilelayer, tileoffset, tilesize, w, h);
    }
    else {
      gpu_texture_update_scaled(
          tex, rect, rect_float, ibuf->x, ibuf->y, x, y, -1, NULL, NULL, w, h);
    }
  }
  else {
    /* Fast update at same resolution. */
    if (tile != NULL) {
      int *tileoffset = tile->runtime.tilearray_offset;
      int tilelayer = tile->runtime.tilearray_layer;
      gpu_texture_update_unscaled(
          tex, rect, rect_float, x, y, tilelayer, tileoffset, w, h, tex_stride, tex_offset);
    }
    else {
      gpu_texture_update_unscaled(
          tex, rect, rect_float, x, y, -1, NULL, w, h, tex_stride, tex_offset);
    }
  }
 
  /* Free buffers if needed. */
  if (rect && rect != (uchar *)ibuf->rect) {
    MEM_freeN(rect);
  }
  if (rect_float && rect_float != ibuf->rect_float) {
    MEM_freeN(rect_float);
  }
 
  if (GPU_mipmap_enabled()) {
    GPU_texture_generate_mipmap(tex);
  }
  else {
    ima->gpuflag &= ~IMA_GPU_MIPMAP_COMPLETE;
  }
 
  GPU_texture_unbind(tex);
}
 
static void image_update_gputexture_ex(
    Image *ima, ImageTile *tile, ImBuf *ibuf, int x, int y, int w, int h)
{
  GPUTexture *tex = ima->gputexture[TEXTARGET_2D][0];
  /* Check if we need to update the main gputexture. */
  if (tex != NULL && tile == ima->tiles.first) {
    gpu_texture_update_from_ibuf(tex, ima, ibuf, NULL, x, y, w, h);
  }
 
  /* Check if we need to update the array gputexture. */
  tex = ima->gputexture[TEXTARGET_2D_ARRAY][0];
  if (tex != NULL) {
    gpu_texture_update_from_ibuf(tex, ima, ibuf, tile, x, y, w, h);
  }
}
 
/* Partial update of texture for texture painting. This is often much
 * quicker than fully updating the texture for high resolution images. */
void BKE_image_update_gputexture(Image *ima, ImageUser *iuser, int x, int y, int w, int h)
{
  ImBuf *ibuf = BKE_image_acquire_ibuf(ima, iuser, NULL);
  ImageTile *tile = BKE_image_get_tile_from_iuser(ima, iuser);
 
  if ((ibuf == NULL) || (w == 0) || (h == 0)) {
    /* Full reload of texture. */
    BKE_image_free_gputextures(ima);
  }
  image_update_gputexture_ex(ima, tile, ibuf, x, y, w, h);
  BKE_image_release_ibuf(ima, ibuf, NULL);
}
 
/* Mark areas on the GPUTexture that needs to be updated. The areas are marked in chunks.
 * The next time the GPUTexture is used these tiles will be refreshes. This saves time
 * when writing to the same place multiple times This happens for during foreground
 * rendering. */
void BKE_image_update_gputexture_delayed(
    struct Image *ima, struct ImBuf *ibuf, int x, int y, int w, int h)
{
  /* Check for full refresh. */
  if (ibuf && x == 0 && y == 0 && w == ibuf->x && h == ibuf->y) {
    ima->gpuflag |= IMA_GPU_REFRESH;
  }
  /* Check if we can promote partial refresh to a full refresh. */
  if ((ima->gpuflag & (IMA_GPU_REFRESH | IMA_GPU_PARTIAL_REFRESH)) ==
      (IMA_GPU_REFRESH | IMA_GPU_PARTIAL_REFRESH)) {
    ima->gpuflag &= ~IMA_GPU_PARTIAL_REFRESH;
    BLI_freelistN(&ima->gpu_refresh_areas);
  }
  /* Image is already marked for complete refresh. */
  if (ima->gpuflag & IMA_GPU_REFRESH) {
    return;
  }
 
  /* Schedule the tiles that covers the requested area. */
  const int start_tile_x = x / IMA_PARTIAL_REFRESH_TILE_SIZE;
  const int start_tile_y = y / IMA_PARTIAL_REFRESH_TILE_SIZE;
  const int end_tile_x = (x + w) / IMA_PARTIAL_REFRESH_TILE_SIZE;
  const int end_tile_y = (y + h) / IMA_PARTIAL_REFRESH_TILE_SIZE;
  const int num_tiles_x = (end_tile_x + 1) - (start_tile_x);
  const int num_tiles_y = (end_tile_y + 1) - (start_tile_y);
  const int num_tiles = num_tiles_x * num_tiles_y;
  const bool allocate_on_heap = BLI_BITMAP_SIZE(num_tiles) > 16;
  BLI_bitmap *requested_tiles = NULL;
  if (allocate_on_heap) {
    requested_tiles = BLI_BITMAP_NEW(num_tiles, __func__);
  }
  else {
    requested_tiles = BLI_BITMAP_NEW_ALLOCA(num_tiles);
  }
 
  /* Mark the tiles that have already been requested. They don't need to be requested again. */
  int num_tiles_not_scheduled = num_tiles;
  LISTBASE_FOREACH (ImagePartialRefresh *, area, &ima->gpu_refresh_areas) {
    if (area->tile_x < start_tile_x || area->tile_x > end_tile_x || area->tile_y < start_tile_y ||
        area->tile_y > end_tile_y) {
      continue;
    }
    int requested_tile_index = (area->tile_x - start_tile_x) +
                               (area->tile_y - start_tile_y) * num_tiles_x;
    BLI_BITMAP_ENABLE(requested_tiles, requested_tile_index);
    num_tiles_not_scheduled--;
    if (num_tiles_not_scheduled == 0) {
      break;
    }
  }
 
  /* Schedule the tiles that aren't requested yet. */
  if (num_tiles_not_scheduled) {
    int tile_index = 0;
    for (int tile_y = start_tile_y; tile_y <= end_tile_y; tile_y++) {
      for (int tile_x = start_tile_x; tile_x <= end_tile_x; tile_x++) {
        if (!BLI_BITMAP_TEST_BOOL(requested_tiles, tile_index)) {
          ImagePartialRefresh *area = MEM_mallocN(sizeof(ImagePartialRefresh), __func__);
          area->tile_x = tile_x;
          area->tile_y = tile_y;
          BLI_addtail(&ima->gpu_refresh_areas, area);
        }
        tile_index++;
      }
    }
    ima->gpuflag |= IMA_GPU_PARTIAL_REFRESH;
  }
  if (allocate_on_heap) {
    MEM_freeN(requested_tiles);
  }
}
 
/* these two functions are called on entering and exiting texture paint mode,
 * temporary disabling/enabling mipmapping on all images for quick texture
 * updates with glTexSubImage2D. images that didn't change don't have to be
 * re-uploaded to OpenGL */
void BKE_image_paint_set_mipmap(Main *bmain, bool mipmap)
{
  LISTBASE_FOREACH (Image *, ima, &bmain->images) {
    if (BKE_image_has_opengl_texture(ima)) {
      if (ima->gpuflag & IMA_GPU_MIPMAP_COMPLETE) {
        for (int eye = 0; eye < 2; eye++) {
          for (int a = 0; a < TEXTARGET_COUNT; a++) {
            if (ELEM(a, TEXTARGET_2D, TEXTARGET_2D_ARRAY)) {
              GPUTexture *tex = ima->gputexture[a][eye];
              if (tex != NULL) {
                GPU_texture_mipmap_mode(tex, mipmap, true);
              }
            }
          }
        }
      }
      else {
        BKE_image_free_gputextures(ima);
      }
    }
    else {
      ima->gpuflag &= ~IMA_GPU_MIPMAP_COMPLETE;
    }
  }
}