text: /*
   * 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.
   *
   * Copyright 2016, Blender Foundation.
   */
  
  /** \file
   * \ingroup draw
   */
  
  #pragma once
  
  #include "GPU_batch.h"
  #include "MEM_guardedalloc.h"
  
  /* Common */
  // #define DRW_DEBUG_MESH_CACHE_REQUEST
  
  #ifdef DRW_DEBUG_MESH_CACHE_REQUEST
  #  define DRW_ADD_FLAG_FROM_VBO_REQUEST(flag, vbo, value) \
      (flag |= DRW_vbo_requested(vbo) ? (printf("  VBO requested " #vbo "\n") ? value : value) : 0)
  #  define DRW_ADD_FLAG_FROM_IBO_REQUEST(flag, ibo, value) \
      (flag |= DRW_ibo_requested(ibo) ? (printf("  IBO requested " #ibo "\n") ? value : value) : 0)
  #else
  #  define DRW_ADD_FLAG_FROM_VBO_REQUEST(flag, vbo, value) \
      (flag |= DRW_vbo_requested(vbo) ? (value) : 0)
  #  define DRW_ADD_FLAG_FROM_IBO_REQUEST(flag, ibo, value) \
      (flag |= DRW_ibo_requested(ibo) ? (value) : 0)
  #endif
  
  /* Test and assign NULL if test fails */
  #define DRW_TEST_ASSIGN_VBO(v) (v = (DRW_vbo_requested(v) ? (v) : NULL))
  #define DRW_TEST_ASSIGN_IBO(v) (v = (DRW_ibo_requested(v) ? (v) : NULL))
  
  BLI_INLINE GPUBatch *DRW_batch_request(GPUBatch **batch)
  {
    /* XXX TODO(fclem): We are writing to batch cache here. Need to make this thread safe. */
    if (*batch == NULL) {
      *batch = GPU_batch_calloc();
    }
    return *batch;
  }
  
  BLI_INLINE bool DRW_batch_requested(GPUBatch *batch, int prim_type)
  {
    /* Batch has been requested if it has been created but not initialized. */
    if (batch != NULL && batch->verts[0] == NULL) {
      /* HACK. We init without a valid VBO and let the first vbo binding
       * fill verts[0]. */
      GPU_batch_init_ex(batch, prim_type, (GPUVertBuf *)1, NULL, 0);
      batch->verts[0] = NULL;
      return true;
    }
    return false;
  }
  
  BLI_INLINE void DRW_ibo_request(GPUBatch *batch, GPUIndexBuf **ibo)
  {
    if (*ibo == NULL) {
      *ibo = GPU_indexbuf_calloc();
    }
    if (batch != NULL) {
      GPU_batch_elembuf_set(batch, *ibo, false);
    }
  }
  
  BLI_INLINE bool DRW_ibo_requested(GPUIndexBuf *ibo)
  {
    /* TODO do not rely on data uploaded. This prevents multithreading.
     * (need access to a gl context) */
    return (ibo != NULL && ibo->ibo_id == 0 && ibo->data == NULL);
  }
  
  BLI_INLINE void DRW_vbo_request(GPUBatch *batch, GPUVertBuf **vbo)
  {
    if (*vbo == NULL) {
      *vbo = GPU_vertbuf_create(GPU_USAGE_STATIC);
    }
    if (batch != NULL) {
      /* HACK set first vbo if not init. */
      if (batch->verts[0] == NULL) {
        GPU_batch_vertbuf_add(batch, *vbo);
      }
      else {
        /* HACK: bypass assert */
        int vbo_vert_len = (*vbo)->vertex_len;
        (*vbo)->vertex_len = batch->verts[0]->vertex_len;
        GPU_batch_vertbuf_add(batch, *vbo);
        (*vbo)->vertex_len = vbo_vert_len;
      }
    }
  }
  
  BLI_INLINE bool DRW_vbo_requested(GPUVertBuf *vbo)
  {
    return (vbo != NULL && vbo->format.attr_len == 0);
  }
  