/*
 * 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) 2005 Blender Foundation.
 * All rights reserved.
 */

/** \file
 * \ingroup gpu
 *
 * Utility functions for dealing with OpenGL texture & material context,
 * mipmap generation and light objects.
 *
 * These are some obscure rendering functions shared between the game engine (not anymore)
 * and the blender, in this module to avoid duplication
 * and abstract them away from the rest a bit.
 */

#include <string.h>

#include "BLI_blenlib.h"
#include "BLI_linklist.h"
#include "BLI_math.h"
#include "BLI_threads.h"
#include "BLI_utildefines.h"

#include "DNA_light_types.h"
#include "DNA_material_types.h"
#include "DNA_mesh_types.h"
#include "DNA_meshdata_types.h"
#include "DNA_modifier_types.h"
#include "DNA_node_types.h"
#include "DNA_object_types.h"
#include "DNA_scene_types.h"
#include "DNA_smoke_types.h"
#include "DNA_view3d_types.h"
#include "DNA_particle_types.h"

#include "MEM_guardedalloc.h"

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

#include "BKE_colorband.h"
#include "BKE_global.h"
#include "BKE_image.h"
#include "BKE_main.h"
#include "BKE_material.h"
#include "BKE_movieclip.h"
#include "BKE_node.h"
#include "BKE_scene.h"

#include "GPU_draw.h"
#include "GPU_extensions.h"
#include "GPU_glew.h"
#include "GPU_texture.h"

#include "PIL_time.h"

#ifdef WITH_SMOKE
#  include "smoke_API.h"
#endif

static void gpu_free_image_immediate(Image *ima);

//* Checking powers of two for images since OpenGL ES requires it */
#ifdef WITH_DDS
static bool is_power_of_2_resolution(int w, int h)
{
  return is_power_of_2_i(w) && is_power_of_2_i(h);
}
#endif

static bool is_over_resolution_limit(GLenum textarget, int w, int h)
{
  int size = (textarget == GL_TEXTURE_2D) ? GPU_max_texture_size() : GPU_max_cube_map_size();
  int reslimit = (U.glreslimit != 0) ? min_ii(U.glreslimit, size) : size;

  return (w > reslimit || h > reslimit);
}

static int smaller_power_of_2_limit(int num)
{
  int reslimit = (U.glreslimit != 0) ? min_ii(U.glreslimit, GPU_max_texture_size()) :
                                       GPU_max_texture_size();
  /* take texture clamping into account */
  if (num > reslimit) {
    return reslimit;
  }

  return power_of_2_min_i(num);
}

/* Current OpenGL state caching for GPU_set_tpage */

static struct GPUTextureState {
  /* also controls min/mag filtering */
  bool domipmap;
  /* only use when 'domipmap' is set */
  bool linearmipmap;
  /* store this so that new images created while texture painting won't be set to mipmapped */
  bool texpaint;

  float anisotropic;
} GTS = {1, 0, 0, 1.0f};

/* Mipmap settings */

void GPU_set_mipmap(Main *bmain, bool mipmap)
{
  if (GTS.domipmap != mipmap) {
    GPU_free_images(bmain);
    GTS.domipmap = mipmap;
  }
}

void GPU_set_linear_mipmap(bool linear)
{
  if (GTS.linearmipmap != linear) {
    GTS.linearmipmap = linear;
  }
}

bool GPU_get_mipmap(void)
{
  return GTS.domipmap && !GTS.texpaint;
}

bool GPU_get_linear_mipmap(void)
{
  return GTS.linearmipmap;
}

static GLenum gpu_get_mipmap_filter(bool mag)
{
  /* linearmipmap is off by default *when mipmapping is off,
   * use unfiltered display */
  if (mag) {
    if (GTS.domipmap) {
      return GL_LINEAR;
    }
    else {
      return GL_NEAREST;
    }
  }
  else {
    if (GTS.domipmap) {
      if (GTS.linearmipmap) {
        return GL_LINEAR_MIPMAP_LINEAR;
      }
      else {
        return GL_LINEAR_MIPMAP_NEAREST;
      }
    }
    else {
      return GL_NEAREST;
    }
  }
}

/* Anisotropic filtering settings */
void GPU_set_anisotropic(Main *bmain, float value)
{
  if (GTS.anisotropic != value) {
    GPU_free_images(bmain);

    /* Clamp value to the maximum value the graphics card supports */
    const float max = GPU_max_texture_anisotropy();
    if (value > max) {
      value = max;
    }

    GTS.anisotropic = value;
  }
}

float GPU_get_anisotropic(void)
{
  return GTS.anisotropic;
}

/* Set OpenGL state for an MTFace */

static GPUTexture **gpu_get_image_gputexture(Image *ima, GLenum textarget)
{
  if (textarget == GL_TEXTURE_2D) {
    return &ima->gputexture[TEXTARGET_TEXTURE_2D];
  }
  else if (textarget == GL_TEXTURE_CUBE_MAP) {
    return &ima->gputexture[TEXTARGET_TEXTURE_CUBE_MAP];
  }

  return NULL;
}

static uint gpu_texture_create_from_ibuf(Image *ima, ImBuf *ibuf, int textarget)
{
  uint bindcode = 0;
  const bool mipmap = GPU_get_mipmap();

#ifdef WITH_DDS
  if (ibuf->ftype == IMB_FTYPE_DDS) {
    /* DDS is loaded directly in compressed form. */
    GPU_create_gl_tex_compressed(&bindcode, textarget, ima, ibuf);
    return bindcode;
  }
#endif

  /* Regular uncompressed texture. */
  float *rect_float = ibuf->rect_float;
  uchar *rect = (uchar *)ibuf->rect;
  bool compress_as_srgb = false;

  if (rect_float == NULL) {
    /* Byte image is in original colorspace from the file. If the file is sRGB
     * scene linear, or non-color data no conversion is needed. Otherwise we
     * compress as scene linear + sRGB transfer function to avoid precision loss
     * in common cases.
     *
     * We must also convert to premultiplied for correct texture interpolation
     * and consistency with float images. */
    if (!IMB_colormanagement_space_is_data(ibuf->rect_colorspace)) {
      compress_as_srgb = !IMB_colormanagement_space_is_scene_linear(ibuf->rect_colorspace);

      rect = MEM_mallocN(sizeof(uchar) * 4 * ibuf->x * ibuf->y, __func__);
      if (rect == NULL) {
        return bindcode;
      }

      /* Texture storage of images is defined by the alpha mode of the image. The
       * downside of this is that there can be artifacts near alpha edges. However,
       * this allows us to use sRGB texture formats and preserves color values in
       * zero alpha areas, and appears generally closer to what game engines that we
       * want to be compatible with do. */
      const bool store_premultiplied = ima ? (ima->alpha_mode == IMA_ALPHA_PREMUL) : true;
      IMB_colormanagement_imbuf_to_byte_texture(
          rect, 0, 0, ibuf->x, ibuf->y, ibuf, compress_as_srgb, store_premultiplied);
    }
  }
  else {
    /* Float image is already in scene linear colorspace or non-color data by
     * convention, no colorspace conversion needed. But we do require 4 channels
     * currently. */
    const bool store_premultiplied = ima ? (ima->alpha_mode != IMA_ALPHA_STRAIGHT) : false;

    if (ibuf->channels != 4 || !store_premultiplied) {
      rect_float = MEM_mallocN(sizeof(float) * 4 * ibuf->x * ibuf->y, __func__);
      if (rect_float == NULL) {
        return bindcode;
      }
      IMB_colormanagement_imbuf_to_float_texture(
          rect_float, 0, 0, ibuf->x, ibuf->y, ibuf, store_premultiplied);
    }
  }

  /* Create OpenGL texture. */
  GPU_create_gl_tex(&bindcode,
                    (uint *)rect,
                    rect_float,
                    ibuf->x,
                    ibuf->y,
                    textarget,
                    mipmap,
                    compress_as_srgb,
                    ima);

  /* 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);
  }

  return bindcode;
}

static GPUTexture **gpu_get_movieclip_gputexture(MovieClip *clip,
                                                 MovieClipUser *cuser,
                                                 GLenum textarget)
{
  MovieClip_RuntimeGPUTexture *tex;
  for (tex = clip->runtime.gputextures.first; tex; tex = tex->next) {
    if (memcmp(&tex->user, cuser, sizeof(MovieClipUser)) == 0) {
      break;
    }
  }

  if (tex == NULL) {
    tex = MEM_mallocN(sizeof(MovieClip_RuntimeGPUTexture), __func__);

    for (int i = 0; i < TEXTARGET_COUNT; i++) {
      tex->gputexture[i] = NULL;
    }

    memcpy(&tex->user, cuser, sizeof(MovieClipUser));
    BLI_addtail(&clip->runtime.gputextures, tex);
  }

  if (textarget == GL_TEXTURE_2D) {
    return &tex->gputexture[TEXTARGET_TEXTURE_2D];
  }
  else if (textarget == GL_TEXTURE_CUBE_MAP) {
    return &tex->gputexture[TEXTARGET_TEXTURE_CUBE_MAP];
  }

  return NULL;
}

static void gpu_texture_update_scaled(
    uchar *rect, float *rect_float, int full_w, int full_h, int x, int y, int w, int h)
{
  /* Partial update with scaling. */
  int limit_w = smaller_power_of_2_limit(full_w);
  int limit_h = smaller_power_of_2_limit(full_h);
  float xratio = limit_w / (float)full_w;
  float yratio = limit_h / (float)full_h;

  /* Find sub coordinates in scaled image. Take ceiling because we will be
   * losing 1 pixel due to rounding errors in x,y. */
  int sub_x = x * xratio;
  int sub_y = y * yratio;
  int sub_w = (int)ceil(xratio * w);
  int sub_h = (int)ceil(yratio * h);

  /* ...but take back if we are over the limit! */
  if (sub_w + sub_x > limit_w) {
    sub_w--;
  }
  if (sub_h + sub_y > limit_h) {
    sub_h--;
  }

  /* Scale pixels. */
  ImBuf *ibuf = IMB_allocFromBuffer((uint *)rect, rect_float, w, h, 4);
  IMB_scaleImBuf(ibuf, sub_w, sub_h);

  if (ibuf->rect_float) {
    glTexSubImage2D(
        GL_TEXTURE_2D, 0, sub_x, sub_y, sub_w, sub_h, GL_RGBA, GL_FLOAT, ibuf->rect_float);
  }
  else {
    glTexSubImage2D(
        GL_TEXTURE_2D, 0, sub_x, sub_y, sub_w, sub_h, GL_RGBA, GL_UNSIGNED_BYTE, ibuf->rect);
  }

  IMB_freeImBuf(ibuf);
}

static void gpu_texture_update_unscaled(
    uchar *rect, float *rect_float, int x, int y, int w, int h, GLint tex_stride, GLint tex_offset)
{
  /* Partial update without scaling. Stride and offset are used to copy only a
   * subset of a possible larger buffer than what we are updating. */
  GLint row_length;
  glGetIntegerv(GL_UNPACK_ROW_LENGTH, &row_length);
  glPixelStorei(GL_UNPACK_ROW_LENGTH, tex_stride);

  if (rect_float == NULL) {
    glTexSubImage2D(GL_TEXTURE_2D, 0, x, y, w, h, GL_RGBA, GL_UNSIGNED_BYTE, rect + tex_offset);
  }
  else {
    glTexSubImage2D(GL_TEXTURE_2D, 0, x, y, w, h, GL_RGBA, GL_FLOAT, rect_float + tex_offset);
  }

  glPixelStorei(GL_UNPACK_ROW_LENGTH, row_length);
}

static void gpu_texture_update_from_ibuf(Image *ima, ImBuf *ibuf, int x, int y, int w, int h)
{
  /* Partial update of texture for texture painting. This is often much
   * quicker than fully updating the texture for high resolution images.
   * Assumes the OpenGL texture is bound to 0. */
  const bool scaled = is_over_resolution_limit(GL_TEXTURE_2D, ibuf->x, 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;
  GLint tex_stride = ibuf->x;
  GLint tex_offset = ibuf->channels * (y * ibuf->x + x);

  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 = 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. */
      const bool store_premultiplied = (ima->alpha_mode == IMA_ALPHA_PREMUL);
      IMB_colormanagement_imbuf_to_byte_texture(
          rect, x, y, w, h, ibuf, compress_as_srgb, store_premultiplied);
    }
  }
  else {
    /* Float pixels. */
    const bool store_premultiplied = (ima->alpha_mode != IMA_ALPHA_STRAIGHT);

    if (ibuf->channels != 4 || scaled || !store_premultiplied) {
      rect_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. */
    gpu_texture_update_scaled(rect, rect_float, ibuf->x, ibuf->y, x, y, w, h);
  }
  else {
    /* Fast update at same resolution. */
    gpu_texture_update_unscaled(rect, rect_float, x, y, 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);
  }
}

GPUTexture *GPU_texture_from_blender(Image *ima, ImageUser *iuser, int textarget)
{
  if (ima == NULL) {
    return NULL;
  }

  /* currently, gpu refresh tagging is used by ima sequences */
  if (ima->gpuflag & IMA_GPU_REFRESH) {
    gpu_free_image_immediate(ima);
    ima->gpuflag &= ~IMA_GPU_REFRESH;
  }

  /* Tag as in active use for garbage collector. */
  BKE_image_tag_time(ima);

  /* Test if we already have a texture. */
  GPUTexture **tex = gpu_get_image_gputexture(ima, textarget);
  if (*tex) {
    return *tex;
  }

  /* Check if we have a valid image. If not, we return a dummy
   * texture with zero bindcode so we don't keep trying. */
  uint bindcode = 0;
  if (ima->ok == 0) {
    *tex = GPU_texture_from_bindcode(textarget, bindcode);
    return *tex;
  }

  /* check if we have a valid image buffer */
  ImBuf *ibuf = BKE_image_acquire_ibuf(ima, iuser, NULL);
  if (ibuf == NULL) {
    *tex = GPU_texture_from_bindcode(textarget, bindcode);
    return *tex;
  }

  bindcode = gpu_texture_create_from_ibuf(ima, ibuf, textarget);

  BKE_image_release_ibuf(ima, ibuf, NULL);

  *tex = GPU_texture_from_bindcode(textarget, bindcode);

  GPU_texture_orig_size_set(*tex, ibuf->x, ibuf->y);

  return *tex;
}

GPUTexture *GPU_texture_from_movieclip(MovieClip *clip, MovieClipUser *cuser, int textarget)
{
  if (clip == NULL) {
    return NULL;
  }

  GPUTexture **tex = gpu_get_movieclip_gputexture(clip, cuser, textarget);
  if (*tex) {
    return *tex;
  }

  /* check if we have a valid image buffer */
  uint bindcode = 0;
  ImBuf *ibuf = BKE_movieclip_get_ibuf(clip, cuser);
  if (ibuf == NULL) {
    *tex = GPU_texture_from_bindcode(textarget, bindcode);
    return *tex;
  }

  bindcode = gpu_texture_create_from_ibuf(NULL, ibuf, textarget);
  IMB_freeImBuf(ibuf);

  *tex = GPU_texture_from_bindcode(textarget, bindcode);
  return *tex;
}

void GPU_free_texture_movieclip(struct MovieClip *clip)
{
  /* number of gpu textures to keep around as cache
   * We don't want to keep too many GPU textures for
   * movie clips around, as they can be large.*/
  const int MOVIECLIP_NUM_GPUTEXTURES = 1;

  while (BLI_listbase_count(&clip->runtime.gputextures) > MOVIECLIP_NUM_GPUTEXTURES) {
    MovieClip_RuntimeGPUTexture *tex = BLI_pophead(&clip->runtime.gputextures);
    for (int i = 0; i < TEXTARGET_COUNT; i++) {
      /* free glsl image binding */
      if (tex->gputexture[i]) {
        GPU_texture_free(tex->gputexture[i]);
        tex->gputexture[i] = NULL;
      }
    }
    MEM_freeN(tex);
  }
}

static void **gpu_gen_cube_map(uint *rect, float *frect, int rectw, int recth)
{
  size_t block_size = frect ? sizeof(float[4]) : sizeof(uchar[4]);
  void **sides = NULL;
  int h = recth / 2;
  int w = rectw / 3;

  if (w != h) {
    return sides;
  }

  /* PosX, NegX, PosY, NegY, PosZ, NegZ */
  sides = MEM_mallocN(sizeof(void *) * 6, "");
  for (int i = 0; i < 6; i++) {
    sides[i] = MEM_mallocN(block_size * w * h, "");
  }

  /* divide image into six parts */
  /* ______________________
   * |      |      |      |
   * | NegX | NegY | PosX |
   * |______|______|______|
   * |      |      |      |
   * | NegZ | PosZ | PosY |
   * |______|______|______|
   */
  if (frect) {
    float(*frectb)[4] = (float(*)[4])frect;
    float(**fsides)[4] = (float(**)[4])sides;

    for (int y = 0; y < h; y++) {
      for (int x = 0; x < w; x++) {
        memcpy(&fsides[0][x * h + y], &frectb[(recth - y - 1) * rectw + 2 * w + x], block_size);
        memcpy(&fsides[1][x * h + y], &frectb[(y + h) * rectw + w - 1 - x], block_size);
        memcpy(
            &fsides[3][y * w + x], &frectb[(recth - y - 1) * rectw + 2 * w - 1 - x], block_size);
        memcpy(&fsides[5][y * w + x], &frectb[(h - y - 1) * rectw + w - 1 - x], block_size);
      }
      memcpy(&fsides[2][y * w], frectb[y * rectw + 2 * w], block_size * w);
      memcpy(&fsides[4][y * w], frectb[y * rectw + w], block_size * w);
    }
  }
  else {
    uint **isides = (uint **)sides;

    for (int y = 0; y < h; y++) {
      for (int x = 0; x < w; x++) {
        isides[0][x * h + y] = rect[(recth - y - 1) * rectw + 2 * w + x];
        isides[1][x * h + y] = rect[(y + h) * rectw + w - 1 - x];
        isides[3][y * w + x] = rect[(recth - y - 1) * rectw + 2 * w - 1 - x];
        isides[5][y * w + x] = rect[(h - y - 1) * rectw + w - 1 - x];
      }
      memcpy(&isides[2][y * w], &rect[y * rectw + 2 * w], block_size * w);
      memcpy(&isides[4][y * w], &rect[y * rectw + w], block_size * w);
    }
  }

  return sides;
}

static void gpu_del_cube_map(void **cube_map)
{
  int i;
  if (cube_map == NULL) {
    return;
  }
  for (i = 0; i < 6; i++) {
    MEM_freeN(cube_map[i]);
  }
  MEM_freeN(cube_map);
}

/* Image *ima can be NULL */
void GPU_create_gl_tex(uint *bind,
                       uint *rect,
                       float *frect,
                       int rectw,
                       int recth,
                       int textarget,
                       bool mipmap,
                       bool use_srgb,
                       Image *ima)
{
  ImBuf *ibuf = NULL;

  if (textarget == GL_TEXTURE_2D && is_over_resolution_limit(textarget, rectw, recth)) {
    int tpx = rectw;
    int tpy = recth;
    rectw = smaller_power_of_2_limit(rectw);
    recth = smaller_power_of_2_limit(recth);

    if (frect) {
      ibuf = IMB_allocFromBuffer(NULL, frect, tpx, tpy, 4);
      IMB_scaleImBuf(ibuf, rectw, recth);

      frect = ibuf->rect_float;
    }
    else {
      ibuf = IMB_allocFromBuffer(rect, NULL, tpx, tpy, 4);
      IMB_scaleImBuf(ibuf, rectw, recth);

      rect = ibuf->rect;
    }
  }

  /* create image */
  glGenTextures(1, (GLuint *)bind);
  glBindTexture(textarget, *bind);

  GLenum internal_format = (frect) ? GL_RGBA16F : (use_srgb) ? GL_SRGB8_ALPHA8 : GL_RGBA8;

  if (textarget == GL_TEXTURE_2D) {
    if (frect) {
      glTexImage2D(GL_TEXTURE_2D, 0, internal_format, rectw, recth, 0, GL_RGBA, GL_FLOAT, frect);
    }
    else {
      glTexImage2D(
          GL_TEXTURE_2D, 0, internal_format, rectw, recth, 0, GL_RGBA, GL_UNSIGNED_BYTE, rect);
    }

    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, gpu_get_mipmap_filter(1));

    if (GPU_get_mipmap() && mipmap) {
      glGenerateMipmap(GL_TEXTURE_2D);
      glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, gpu_get_mipmap_filter(0));
      if (ima) {
        ima->gpuflag |= IMA_GPU_MIPMAP_COMPLETE;
      }
    }
    else {
      glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
    }
  }
  else if (textarget == GL_TEXTURE_CUBE_MAP) {
    int w = rectw / 3, h = recth / 2;

    if (h == w && is_power_of_2_i(h) && !is_over_resolution_limit(textarget, h, w)) {
      void **cube_map = gpu_gen_cube_map(rect, frect, rectw, recth);
      GLenum type = frect ? GL_FLOAT : GL_UNSIGNED_BYTE;

      if (cube_map) {
        for (int i = 0; i < 6; i++) {
          glTexImage2D(GL_TEXTURE_CUBE_MAP_POSITIVE_X + i,
                       0,
                       internal_format,
                       w,
                       h,
                       0,
                       GL_RGBA,
                       type,
                       cube_map[i]);
        }
      }

      glTexParameteri(GL_TEXTURE_CUBE_MAP, GL_TEXTURE_MAG_FILTER, gpu_get_mipmap_filter(1));

      if (GPU_get_mipmap() && mipmap) {
        glGenerateMipmap(GL_TEXTURE_CUBE_MAP);
        glTexParameteri(GL_TEXTURE_CUBE_MAP, GL_TEXTURE_MIN_FILTER, gpu_get_mipmap_filter(0));

        if (ima) {
          ima->gpuflag |= IMA_GPU_MIPMAP_COMPLETE;
        }
      }
      else {
        glTexParameteri(GL_TEXTURE_CUBE_MAP, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
      }
      glTexParameteri(GL_TEXTURE_CUBE_MAP, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
      glTexParameteri(GL_TEXTURE_CUBE_MAP, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
      glTexParameteri(GL_TEXTURE_CUBE_MAP, GL_TEXTURE_WRAP_R, GL_CLAMP_TO_EDGE);

      gpu_del_cube_map(cube_map);
    }
    else {
      printf("Incorrect envmap size\n");
    }
  }

  if (GLEW_EXT_texture_filter_anisotropic) {
    glTexParameterf(textarget, GL_TEXTURE_MAX_ANISOTROPY_EXT, GPU_get_anisotropic());
  }

  glBindTexture(textarget, 0);

  if (ibuf) {
    IMB_freeImBuf(ibuf);
  }
}

/**
 * GPU_upload_dxt_texture() assumes that the texture is already bound and ready to go.
 * This is so the viewport and the BGE can share some code.
 * Returns false if the provided ImBuf doesn't have a supported DXT compression format
 */
bool GPU_upload_dxt_texture(ImBuf *ibuf, bool use_srgb)
{
#ifdef WITH_DDS
  GLint format = 0;
  int blocksize, height, width, i, size, offset = 0;

  width = ibuf->x;
  height = ibuf->y;

  if (GLEW_EXT_texture_compression_s3tc) {
    if (ibuf->dds_data.fourcc == FOURCC_DXT1) {
      format = (use_srgb) ? GL_COMPRESSED_SRGB_ALPHA_S3TC_DXT1_EXT :
                            GL_COMPRESSED_RGBA_S3TC_DXT1_EXT;
    }
    else if (ibuf->dds_data.fourcc == FOURCC_DXT3) {
      format = (use_srgb) ? GL_COMPRESSED_SRGB_ALPHA_S3TC_DXT3_EXT :
                            GL_COMPRESSED_RGBA_S3TC_DXT3_EXT;
    }
    else if (ibuf->dds_data.fourcc == FOURCC_DXT5) {
      format = (use_srgb) ? GL_COMPRESSED_SRGB_ALPHA_S3TC_DXT5_EXT :
                            GL_COMPRESSED_RGBA_S3TC_DXT5_EXT;
    }
  }

  if (format == 0) {
    fprintf(stderr, "Unable to find a suitable DXT compression, falling back to uncompressed\n");
    return false;
  }

  if (!is_power_of_2_resolution(width, height)) {
    fprintf(
        stderr,
        "Unable to load non-power-of-two DXT image resolution, falling back to uncompressed\n");
    return false;
  }

  glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, gpu_get_mipmap_filter(0));
  glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, gpu_get_mipmap_filter(1));

  if (GLEW_EXT_texture_filter_anisotropic) {
    glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MAX_ANISOTROPY_EXT, GPU_get_anisotropic());
  }

  blocksize = (ibuf->dds_data.fourcc == FOURCC_DXT1) ? 8 : 16;
  for (i = 0; i < ibuf->dds_data.nummipmaps && (width || height); i++) {
    if (width == 0) {
      width = 1;
    }
    if (height == 0) {
      height = 1;
    }

    size = ((width + 3) / 4) * ((height + 3) / 4) * blocksize;

    glCompressedTexImage2D(
        GL_TEXTURE_2D, i, format, width, height, 0, size, ibuf->dds_data.data + offset);

    offset += size;
    width >>= 1;
    height >>= 1;
  }

  /* set number of mipmap levels we have, needed in case they don't go down to 1x1 */
  glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAX_LEVEL, i - 1);

  return true;
#else
  UNUSED_VARS(ibuf, use_srgb);
  return false;
#endif
}

void GPU_create_gl_tex_compressed(unsigned int *bind, int textarget, Image *ima, ImBuf *ibuf)
{
  /* For DDS we only support data, scene linear and sRGB. Converting to
   * different colorspace would break the compression. */
  const bool use_srgb = !(IMB_colormanagement_space_is_data(ibuf->rect_colorspace) ||
                          IMB_colormanagement_space_is_scene_linear(ibuf->rect_colorspace));
  const bool mipmap = GPU_get_mipmap();

#ifndef WITH_DDS
  (void)ibuf;
  /* Fall back to uncompressed if DDS isn't enabled */
  GPU_create_gl_tex(bind, ibuf->rect, NULL, ibuf->x, ibuf->y, textarget, mipmap, use_srgb, ima);
#else
  glGenTextures(1, (GLuint *)bind);
  glBindTexture(textarget, *bind);

  if (textarget == GL_TEXTURE_2D && GPU_upload_dxt_texture(ibuf, use_srgb) == 0) {
    glDeleteTextures(1, (GLuint *)bind);
    GPU_create_gl_tex(bind, ibuf->rect, NULL, ibuf->x, ibuf->y, textarget, mipmap, use_srgb, ima);
  }

  glBindTexture(textarget, 0);
#endif
}

/* 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 GPU_paint_set_mipmap(Main *bmain, bool mipmap)
{
  if (!GTS.domipmap) {
    return;
  }

  GTS.texpaint = !mipmap;

  if (mipmap) {
    for (Image *ima = bmain->images.first; ima; ima = ima->id.next) {
      if (BKE_image_has_opengl_texture(ima)) {
        if (ima->gpuflag & IMA_GPU_MIPMAP_COMPLETE) {
          if (ima->gputexture[TEXTARGET_TEXTURE_2D]) {
            GPU_texture_bind(ima->gputexture[TEXTARGET_TEXTURE_2D], 0);
            glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, gpu_get_mipmap_filter(0));
            glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, gpu_get_mipmap_filter(1));
            GPU_texture_unbind(ima->gputexture[TEXTARGET_TEXTURE_2D]);
          }
        }
        else {
          GPU_free_image(ima);
        }
      }
      else {
        ima->gpuflag &= ~IMA_GPU_MIPMAP_COMPLETE;
      }
    }
  }
  else {
    for (Image *ima = bmain->images.first; ima; ima = ima->id.next) {
      if (BKE_image_has_opengl_texture(ima)) {
        if (ima->gputexture[TEXTARGET_TEXTURE_2D]) {
          GPU_texture_bind(ima->gputexture[TEXTARGET_TEXTURE_2D], 0);
          glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
          glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, gpu_get_mipmap_filter(1));
          GPU_texture_unbind(ima->gputexture[TEXTARGET_TEXTURE_2D]);
        }
      }
      else {
        ima->gpuflag &= ~IMA_GPU_MIPMAP_COMPLETE;
      }
    }
  }
}

void GPU_paint_update_image(Image *ima, ImageUser *iuser, int x, int y, int w, int h)
{
  ImBuf *ibuf = BKE_image_acquire_ibuf(ima, iuser, NULL);

  if ((ima->gputexture[TEXTARGET_TEXTURE_2D] == NULL) || (ibuf == NULL) || (w == 0) || (h == 0)) {
    /* Full reload of texture. */
    GPU_free_image(ima);
  }
  else {
    /* Partial update of texture. */
    GPU_texture_bind(ima->gputexture[TEXTARGET_TEXTURE_2D], 0);

    gpu_texture_update_from_ibuf(ima, ibuf, x, y, w, h);

    if (GPU_get_mipmap()) {
      glGenerateMipmap(GL_TEXTURE_2D);
    }
    else {
      ima->gpuflag &= ~IMA_GPU_MIPMAP_COMPLETE;
    }

    GPU_texture_unbind(ima->gputexture[TEXTARGET_TEXTURE_2D]);
  }

  BKE_image_release_ibuf(ima, ibuf, NULL);
}

/* *************************** Transfer functions *************************** */

enum {
  TFUNC_FLAME_SPECTRUM = 0,
  TFUNC_COLOR_RAMP = 1,
};

#define TFUNC_WIDTH 256

#ifdef WITH_SMOKE
static void create_flame_spectrum_texture(float *data)
{
#  define FIRE_THRESH 7
#  define MAX_FIRE_ALPHA 0.06f
#  define FULL_ON_FIRE 100

  float *spec_pixels = MEM_mallocN(TFUNC_WIDTH * 4 * 16 * 16 * sizeof(float), "spec_pixels");

  blackbody_temperature_to_rgb_table(data, TFUNC_WIDTH, 1500, 3000);

  for (int i = 0; i < 16; i++) {
    for (int j = 0; j < 16; j++) {
      for (int k = 0; k < TFUNC_WIDTH; k++) {
        int index = (j * TFUNC_WIDTH * 16 + i * TFUNC_WIDTH + k) * 4;
        if (k >= FIRE_THRESH) {
          spec_pixels[index] = (data[k * 4]);
          spec_pixels[index + 1] = (data[k * 4 + 1]);
          spec_pixels[index + 2] = (data[k * 4 + 2]);
          spec_pixels[index + 3] = MAX_FIRE_ALPHA *
                                   ((k > FULL_ON_FIRE) ?
                                        1.0f :
                                        (k - FIRE_THRESH) / ((float)FULL_ON_FIRE - FIRE_THRESH));
        }
        else {
          zero_v4(&spec_pixels[index]);
        }
      }
    }
  }

  memcpy(data, spec_pixels, sizeof(float) * 4 * TFUNC_WIDTH);

  MEM_freeN(spec_pixels);

#  undef FIRE_THRESH
#  undef MAX_FIRE_ALPHA
#  undef FULL_ON_FIRE
}

static void create_color_ramp(const ColorBand *coba, float *data)
{
  for (int i = 0; i < TFUNC_WIDTH; i++) {
    BKE_colorband_evaluate(coba, (float)i / TFUNC_WIDTH, &data[i * 4]);
  }
}

static GPUTexture *create_transfer_function(int type, const ColorBand *coba)
{
  float *data = MEM_mallocN(sizeof(float) * 4 * TFUNC_WIDTH, __func__);

  switch (type) {
    case TFUNC_FLAME_SPECTRUM:
      create_flame_spectrum_texture(data);
      break;
    case TFUNC_COLOR_RAMP:
      create_color_ramp(coba, data);
      break;
  }

  GPUTexture *tex = GPU_texture_create_1d(TFUNC_WIDTH, GPU_RGBA8, data, NULL);

  MEM_freeN(data);

  return tex;
}

static void swizzle_texture_channel_rrrr(GPUTexture *tex)
{
  GPU_texture_bind(tex, 0);
  glTexParameteri(GL_TEXTURE_3D, GL_TEXTURE_SWIZZLE_R, GL_RED);
  glTexParameteri(GL_TEXTURE_3D, GL_TEXTURE_SWIZZLE_G, GL_RED);
  glTexParameteri(GL_TEXTURE_3D, GL_TEXTURE_SWIZZLE_B, GL_RED);
  glTexParameteri(GL_TEXTURE_3D, GL_TEXTURE_SWIZZLE_A, GL_RED);
  GPU_texture_unbind(tex);
}

static GPUTexture *create_field_texture(SmokeDomainSettings *sds)
{
  float *field = NULL;

  switch (sds->coba_field) {
    case FLUID_FIELD_DENSITY:
      field = smoke_get_density(sds->fluid);
      break;
    case FLUID_FIELD_HEAT:
      field = smoke_get_heat(sds->fluid);
      break;
    case FLUID_FIELD_FUEL:
      field = smoke_get_fuel(sds->fluid);
      break;
    case FLUID_FIELD_REACT:
      field = smoke_get_react(sds->fluid);
      break;
    case FLUID_FIELD_FLAME:
      field = smoke_get_flame(sds->fluid);
      break;
    case FLUID_FIELD_VELOCITY_X:
      field = smoke_get_velocity_x(sds->fluid);
      break;
    case FLUID_FIELD_VELOCITY_Y:
      field = smoke_get_velocity_y(sds->fluid);
      break;
    case FLUID_FIELD_VELOCITY_Z:
      field = smoke_get_velocity_z(sds->fluid);
      break;
    case FLUID_FIELD_COLOR_R:
      field = smoke_get_color_r(sds->fluid);
      break;
    case FLUID_FIELD_COLOR_G:
      field = smoke_get_color_g(sds->fluid);
      break;
    case FLUID_FIELD_COLOR_B:
      field = smoke_get_color_b(sds->fluid);
      break;
    case FLUID_FIELD_FORCE_X:
      field = smoke_get_force_x(sds->fluid);
      break;
    case FLUID_FIELD_FORCE_Y:
      field = smoke_get_force_y(sds->fluid);
      break;
    case FLUID_FIELD_FORCE_Z:
      field = smoke_get_force_z(sds->fluid);
      break;
    default:
      return NULL;
  }

  GPUTexture *tex = GPU_texture_create_nD(
      sds->res[0], sds->res[1], sds->res[2], 3, field, GPU_R8, GPU_DATA_FLOAT, 0, true, NULL);

  swizzle_texture_channel_rrrr(tex);
  return tex;
}

static GPUTexture *create_density_texture(SmokeDomainSettings *sds, int highres)
{
  float *data = NULL, *source;
  int cell_count = (highres) ? smoke_turbulence_get_cells(sds->wt) : sds->total_cells;
  const bool has_color = (highres) ? smoke_turbulence_has_colors(sds->wt) :
                                     smoke_has_colors(sds->fluid);
  int *dim = (highres) ? sds->res_wt : sds->res;
  eGPUTextureFormat format = (has_color) ? GPU_RGBA8 : GPU_R8;

  if (has_color) {
    data = MEM_callocN(sizeof(float) * cell_count * 4, "smokeColorTexture");
  }

  if (highres) {
    if (has_color) {
      smoke_turbulence_get_rgba(sds->wt, data, 0);
    }
    else {
      source = smoke_turbulence_get_density(sds->wt);
    }
  }
  else {
    if (has_color) {
      smoke_get_rgba(sds->fluid, data, 0);
    }
    else {
      source = smoke_get_density(sds->fluid);
    }
  }

  GPUTexture *tex = GPU_texture_create_nD(dim[0],
                                          dim[1],
                                          dim[2],
                                          3,
                                          (has_color) ? data : source,
                                          format,
                                          GPU_DATA_FLOAT,
                                          0,
                                          true,
                                          NULL);
  if (data) {
    MEM_freeN(data);
  }

  if (format == GPU_R8) {
    /* Swizzle the RGBA components to read the Red channel so
     * that the shader stay the same for colored and non color
     * density textures. */
    swizzle_texture_channel_rrrr(tex);
  }
  return tex;
}

static GPUTexture *create_flame_texture(SmokeDomainSettings *sds, int highres)
{
  float *source = NULL;
  const bool has_fuel = (highres) ? smoke_turbulence_has_fuel(sds->wt) :
                                    smoke_has_fuel(sds->fluid);
  int *dim = (highres) ? sds->res_wt : sds->res;

  if (!has_fuel) {
    return NULL;
  }

  if (highres) {
    source = smoke_turbulence_get_flame(sds->wt);
  }
  else {
    source = smoke_get_flame(sds->fluid);
  }

  GPUTexture *tex = GPU_texture_create_nD(
      dim[0], dim[1], dim[2], 3, source, GPU_R8, GPU_DATA_FLOAT, 0, true, NULL);

  swizzle_texture_channel_rrrr(tex);

  return tex;
}
#endif /* WITH_SMOKE */

void GPU_free_smoke(SmokeModifierData *smd)
{
  if (smd->type & MOD_SMOKE_TYPE_DOMAIN && smd->domain) {
    if (smd->domain->tex) {
      GPU_texture_free(smd->domain->tex);
    }
    smd->domain->tex = NULL;

    if (smd->domain->tex_shadow) {
      GPU_texture_free(smd->domain->tex_shadow);
    }
    smd->domain->tex_shadow = NULL;

    if (smd->domain->tex_flame) {
      GPU_texture_free(smd->domain->tex_flame);
    }
    smd->domain->tex_flame = NULL;

    if (smd->domain->tex_flame_coba) {
      GPU_texture_free(smd->domain->tex_flame_coba);
    }
    smd->domain->tex_flame_coba = NULL;

    if (smd->domain->tex_coba) {
      GPU_texture_free(smd->domain->tex_coba);
    }
    smd->domain->tex_coba = NULL;

    if (smd->domain->tex_field) {
      GPU_texture_free(smd->domain->tex_field);
    }
    smd->domain->tex_field = NULL;
  }
}

void GPU_create_smoke_coba_field(SmokeModifierData *smd)
{
#ifdef WITH_SMOKE
  if (smd->type & MOD_SMOKE_TYPE_DOMAIN) {
    SmokeDomainSettings *sds = smd->domain;

    if (!sds->tex_field) {
      sds->tex_field = create_field_texture(sds);
    }
    if (!sds->tex_coba) {
      sds->tex_coba = create_transfer_function(TFUNC_COLOR_RAMP, sds->coba);
    }
  }
#else   // WITH_SMOKE
  smd->domain->tex_field = NULL;
#endif  // WITH_SMOKE
}

void GPU_create_smoke(SmokeModifierData *smd, int highres)
{
#ifdef WITH_SMOKE
  if (smd->type & MOD_SMOKE_TYPE_DOMAIN) {
    SmokeDomainSettings *sds = smd->domain;

    if (!sds->tex) {
      sds->tex = create_density_texture(sds, highres);
    }
    if (!sds->tex_flame) {
      sds->tex_flame = create_flame_texture(sds, highres);
    }
    if (!sds->tex_flame_coba && sds->tex_flame) {
      sds->tex_flame_coba = create_transfer_function(TFUNC_FLAME_SPECTRUM, NULL);
    }
    if (!sds->tex_shadow) {
      sds->tex_shadow = GPU_texture_create_nD(sds->res[0],
                                              sds->res[1],
                                              sds->res[2],
                                              3,
                                              sds->shadow,
                                              GPU_R8,
                                              GPU_DATA_FLOAT,
                                              0,
                                              true,
                                              NULL);
    }
  }
#else   // WITH_SMOKE
  (void)highres;
  smd->domain->tex = NULL;
  smd->domain->tex_flame = NULL;
  smd->domain->tex_flame_coba = NULL;
  smd->domain->tex_shadow = NULL;
#endif  // WITH_SMOKE
}

void GPU_create_smoke_velocity(SmokeModifierData *smd)
{
#ifdef WITH_SMOKE
  if (smd->type & MOD_SMOKE_TYPE_DOMAIN) {
    SmokeDomainSettings *sds = smd->domain;

    const float *vel_x = smoke_get_velocity_x(sds->fluid);
    const float *vel_y = smoke_get_velocity_y(sds->fluid);
    const float *vel_z = smoke_get_velocity_z(sds->fluid);

    if (ELEM(NULL, vel_x, vel_y, vel_z)) {
      return;
    }

    if (!sds->tex_velocity_x) {
      sds->tex_velocity_x = GPU_texture_create_3d(
          sds->res[0], sds->res[1], sds->res[2], GPU_R16F, vel_x, NULL);
      sds->tex_velocity_y = GPU_texture_create_3d(
          sds->res[0], sds->res[1], sds->res[2], GPU_R16F, vel_y, NULL);
      sds->tex_velocity_z = GPU_texture_create_3d(
          sds->res[0], sds->res[1], sds->res[2], GPU_R16F, vel_z, NULL);
    }
  }
#else   // WITH_SMOKE
  smd->domain->tex_velocity_x = NULL;
  smd->domain->tex_velocity_y = NULL;
  smd->domain->tex_velocity_z = NULL;
#endif  // WITH_SMOKE
}

/* TODO Unify with the other GPU_free_smoke. */
void GPU_free_smoke_velocity(SmokeModifierData *smd)
{
  if (smd->type & MOD_SMOKE_TYPE_DOMAIN && smd->domain) {
    if (smd->domain->tex_velocity_x) {
      GPU_texture_free(smd->domain->tex_velocity_x);
    }

    if (smd->domain->tex_velocity_y) {
      GPU_texture_free(smd->domain->tex_velocity_y);
    }

    if (smd->domain->tex_velocity_z) {
      GPU_texture_free(smd->domain->tex_velocity_z);
    }

    smd->domain->tex_velocity_x = NULL;
    smd->domain->tex_velocity_y = NULL;
    smd->domain->tex_velocity_z = NULL;
  }
}

static LinkNode *image_free_queue = NULL;
static ThreadMutex img_queue_mutex = BLI_MUTEX_INITIALIZER;

static void gpu_queue_image_for_free(Image *ima)
{
  BLI_mutex_lock(&img_queue_mutex);
  BLI_linklist_prepend(&image_free_queue, ima);
  BLI_mutex_unlock(&img_queue_mutex);
}

void GPU_free_unused_buffers(Main *bmain)
{
  if (!BLI_thread_is_main()) {
    return;
  }

  BLI_mutex_lock(&img_queue_mutex);

  /* images */
  for (LinkNode *node = image_free_queue; node; node = node->next) {
    Image *ima = node->link;

    /* check in case it was freed in the meantime */
    if (bmain && BLI_findindex(&bmain->images, ima) != -1) {
      GPU_free_image(ima);
    }
  }

  BLI_linklist_free(image_free_queue, NULL);
  image_free_queue = NULL;

  BLI_mutex_unlock(&img_queue_mutex);
}

static void gpu_free_image_immediate(Image *ima)
{
  for (int i = 0; i < TEXTARGET_COUNT; i++) {
    /* free glsl image binding */
    if (ima->gputexture[i]) {
      GPU_texture_free(ima->gputexture[i]);
      ima->gputexture[i] = NULL;
    }
  }

  ima->gpuflag &= ~(IMA_GPU_MIPMAP_COMPLETE);
}

void GPU_free_image(Image *ima)
{
  if (!BLI_thread_is_main()) {
    gpu_queue_image_for_free(ima);
    return;
  }

  gpu_free_image_immediate(ima);
}

void GPU_free_images(Main *bmain)
{
  if (bmain) {
    for (Image *ima = bmain->images.first; ima; ima = ima->id.next) {
      GPU_free_image(ima);
    }
  }
}

/* same as above but only free animated images */
void GPU_free_images_anim(Main *bmain)
{
  if (bmain) {
    for (Image *ima = bmain->images.first; ima; ima = ima->id.next) {
      if (BKE_image_is_animated(ima)) {
        GPU_free_image(ima);
      }
    }
  }
}

void GPU_free_images_old(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;

  Image *ima = bmain->images.first;
  while (ima) {
    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)) {
        GPU_free_image(ima);
        ima->lastused = ctime;
      }
      /* Otherwise, just kill the buffers */
      else {
        BKE_image_free_buffers(ima);
      }
    }
    ima = ima->id.next;
  }
}

static void gpu_disable_multisample(void)
{
#ifdef __linux__
  /* changing multisample from the default (enabled) causes problems on some
   * systems (NVIDIA/Linux) when the pixel format doesn't have a multisample buffer */
  bool toggle_ok = true;

  if (GPU_type_matches(GPU_DEVICE_NVIDIA, GPU_OS_UNIX, GPU_DRIVER_ANY)) {
    int samples = 0;
    glGetIntegerv(GL_SAMPLES, &samples);

    if (samples == 0) {
      toggle_ok = false;
    }
  }

  if (toggle_ok) {
    glDisable(GL_MULTISAMPLE);
  }
#else
  glDisable(GL_MULTISAMPLE);
#endif
}

/* Default OpenGL State
 *
 * This is called on startup, for opengl offscreen render.
 * Generally we should always return to this state when
 * temporarily modifying the state for drawing, though that are (undocumented)
 * exceptions that we should try to get rid of. */

void GPU_state_init(void)
{
  GPU_program_point_size(false);

  glEnable(GL_TEXTURE_CUBE_MAP_SEAMLESS);

  glDepthFunc(GL_LEQUAL);

  glDisable(GL_BLEND);
  glDisable(GL_DEPTH_TEST);
  glDisable(GL_COLOR_LOGIC_OP);
  glDisable(GL_STENCIL_TEST);

  glDepthRange(0.0, 1.0);

  glFrontFace(GL_CCW);
  glCullFace(GL_BACK);
  glDisable(GL_CULL_FACE);

  gpu_disable_multisample();

  /* This is a bit dangerous since addons could change this. */
  glEnable(GL_PRIMITIVE_RESTART);
  glPrimitiveRestartIndex((GLuint)0xFFFFFFFF);

  /* TODO: Should become default. But needs at least GL 4.3 */
  if (GLEW_ARB_ES3_compatibility) {
    /* Takes predecence over GL_PRIMITIVE_RESTART */
    glEnable(GL_PRIMITIVE_RESTART_FIXED_INDEX);
  }
}

/** \name Framebuffer color depth, for selection codes
 * \{ */

#define STATE_STACK_DEPTH 16

typedef struct {
  eGPUAttrMask mask;

  /* GL_ENABLE_BIT */
  uint is_blend : 1;
  uint is_cull_face : 1;
  uint is_depth_test : 1;
  uint is_dither : 1;
  uint is_lighting : 1;
  uint is_line_smooth : 1;
  uint is_color_logic_op : 1;
  uint is_multisample : 1;
  uint is_polygon_offset_line : 1;
  uint is_polygon_offset_fill : 1;
  uint is_polygon_smooth : 1;
  uint is_sample_alpha_to_coverage : 1;
  uint is_scissor_test : 1;
  uint is_stencil_test : 1;

  bool is_clip_plane[6];

  /* GL_DEPTH_BUFFER_BIT */
  /* uint is_depth_test : 1; */
  int depth_func;
  double depth_clear_value;
  bool depth_write_mask;

  /* GL_SCISSOR_BIT */
  int scissor_box[4];
  /* uint is_scissor_test : 1; */

  /* GL_VIEWPORT_BIT */
  int viewport[4];
  double near_far[2];
} GPUAttrValues;

typedef struct {
  GPUAttrValues attr_stack[STATE_STACK_DEPTH];
  uint top;
} GPUAttrStack;

static GPUAttrStack state = {
    .top = 0,
};

#define AttrStack state
#define Attr state.attr_stack[state.top]

/**
 * Replacement for glPush/PopAttributes
 *
 * We don't need to cover all the options of legacy OpenGL
 * but simply the ones used by Blender.
 */
void gpuPushAttr(eGPUAttrMask mask)
{
  Attr.mask = mask;

  if ((mask & GPU_DEPTH_BUFFER_BIT) != 0) {
    Attr.is_depth_test = glIsEnabled(GL_DEPTH_TEST);
    glGetIntegerv(GL_DEPTH_FUNC, &Attr.depth_func);
    glGetDoublev(GL_DEPTH_CLEAR_VALUE, &Attr.depth_clear_value);
    glGetBooleanv(GL_DEPTH_WRITEMASK, (GLboolean *)&Attr.depth_write_mask);
  }

  if ((mask & GPU_ENABLE_BIT) != 0) {
    Attr.is_blend = glIsEnabled(GL_BLEND);

    for (int i = 0; i < 6; i++) {
      Attr.is_clip_plane[i] = glIsEnabled(GL_CLIP_PLANE0 + i);
    }

    Attr.is_cull_face = glIsEnabled(GL_CULL_FACE);
    Attr.is_depth_test = glIsEnabled(GL_DEPTH_TEST);
    Attr.is_dither = glIsEnabled(GL_DITHER);
    Attr.is_line_smooth = glIsEnabled(GL_LINE_SMOOTH);
    Attr.is_color_logic_op = glIsEnabled(GL_COLOR_LOGIC_OP);
    Attr.is_multisample = glIsEnabled(GL_MULTISAMPLE);
    Attr.is_polygon_offset_line = glIsEnabled(GL_POLYGON_OFFSET_LINE);
    Attr.is_polygon_offset_fill = glIsEnabled(GL_POLYGON_OFFSET_FILL);
    Attr.is_polygon_smooth = glIsEnabled(GL_POLYGON_SMOOTH);
    Attr.is_sample_alpha_to_coverage = glIsEnabled(GL_SAMPLE_ALPHA_TO_COVERAGE);
    Attr.is_scissor_test = glIsEnabled(GL_SCISSOR_TEST);
    Attr.is_stencil_test = glIsEnabled(GL_STENCIL_TEST);
  }

  if ((mask & GPU_SCISSOR_BIT) != 0) {
    Attr.is_scissor_test = glIsEnabled(GL_SCISSOR_TEST);
    glGetIntegerv(GL_SCISSOR_BOX, (GLint *)&Attr.scissor_box);
  }

  if ((mask & GPU_VIEWPORT_BIT) != 0) {
    glGetDoublev(GL_DEPTH_RANGE, (GLdouble *)&Attr.near_far);
    glGetIntegerv(GL_VIEWPORT, (GLint *)&Attr.viewport);
  }

  if ((mask & GPU_BLEND_BIT) != 0) {
    Attr.is_blend = glIsEnabled(GL_BLEND);
  }

  BLI_assert(AttrStack.top < STATE_STACK_DEPTH);
  AttrStack.top++;
}

static void restore_mask(GLenum cap, const bool value)
{
  if (value) {
    glEnable(cap);
  }
  else {
    glDisable(cap);
  }
}

void gpuPopAttr(void)
{
  BLI_assert(AttrStack.top > 0);
  AttrStack.top--;

  GLint mask = Attr.mask;

  if ((mask & GPU_DEPTH_BUFFER_BIT) != 0) {
    restore_mask(GL_DEPTH_TEST, Attr.is_depth_test);
    glDepthFunc(Attr.depth_func);
    glClearDepth(Attr.depth_clear_value);
    glDepthMask(Attr.depth_write_mask);
  }

  if ((mask & GPU_ENABLE_BIT) != 0) {
    restore_mask(GL_BLEND, Attr.is_blend);

    for (int i = 0; i < 6; i++) {
      restore_mask(GL_CLIP_PLANE0 + i, Attr.is_clip_plane[i]);
    }

    restore_mask(GL_CULL_FACE, Attr.is_cull_face);
    restore_mask(GL_DEPTH_TEST, Attr.is_depth_test);
    restore_mask(GL_DITHER, Attr.is_dither);
    restore_mask(GL_LINE_SMOOTH, Attr.is_line_smooth);
    restore_mask(GL_COLOR_LOGIC_OP, Attr.is_color_logic_op);
    restore_mask(GL_MULTISAMPLE, Attr.is_multisample);
    restore_mask(GL_POLYGON_OFFSET_LINE, Attr.is_polygon_offset_line);
    restore_mask(GL_POLYGON_OFFSET_FILL, Attr.is_polygon_offset_fill);
    restore_mask(GL_POLYGON_SMOOTH, Attr.is_polygon_smooth);
    restore_mask(GL_SAMPLE_ALPHA_TO_COVERAGE, Attr.is_sample_alpha_to_coverage);
    restore_mask(GL_SCISSOR_TEST, Attr.is_scissor_test);
    restore_mask(GL_STENCIL_TEST, Attr.is_stencil_test);
  }

  if ((mask & GPU_VIEWPORT_BIT) != 0) {
    glViewport(Attr.viewport[0], Attr.viewport[1], Attr.viewport[2], Attr.viewport[3]);
    glDepthRange(Attr.near_far[0], Attr.near_far[1]);
  }

  if ((mask & GPU_SCISSOR_BIT) != 0) {
    restore_mask(GL_SCISSOR_TEST, Attr.is_scissor_test);
    glScissor(Attr.scissor_box[0], Attr.scissor_box[1], Attr.scissor_box[2], Attr.scissor_box[3]);
  }

  if ((mask & GPU_BLEND_BIT) != 0) {
    restore_mask(GL_BLEND, Attr.is_blend);
  }
}

#undef Attr
#undef AttrStack

/** \} */