/*
 * 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
 */

#ifndef __DRAW_CACHE_INLINE_H__
#define __DRAW_CACHE_INLINE_H__

#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 = MEM_callocN(sizeof(GPUBatch), "GPUBatch");
  }
  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 = MEM_callocN(sizeof(GPUIndexBuf), "GPUIndexBuf");
  }
  if (batch != NULL) {
    GPU_batch_vao_cache_clear(batch);
    batch->elem = *ibo;
  }
}

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 = MEM_callocN(sizeof(GPUVertBuf), "GPUVertBuf");
  }
  /* HACK set first vbo if not init. */
  if (batch->verts[0] == NULL) {
    GPU_batch_vao_cache_clear(batch);
    batch->verts[0] = *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);
}

#endif /* __DRAW_CACHE_INLINE_H__ */