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.
   *
   * The Original Code is Copyright (C) 2016 by Mike Erwin.
   * All rights reserved.
   */
  
  /** \file
   * \ingroup gpu
   *
   * GPU element list (AKA index buffer)
   */
  
  #ifndef __GPU_ELEMENT_H__
  #define __GPU_ELEMENT_H__
  
  #include "GPU_primitive.h"
  
  #define GPU_TRACK_INDEX_RANGE 1
  
  #define GPU_PRIM_RESTART 0xFFFFFFFF
  
  typedef enum {
    GPU_INDEX_U8, /* GL has this, Vulkan does not */
    GPU_INDEX_U16,
    GPU_INDEX_U32,
  } GPUIndexBufType;
  
  typedef struct GPUIndexBuf {
    uint index_len;
  #if GPU_TRACK_INDEX_RANGE
    GPUIndexBufType index_type;
    uint32_t gl_index_type;
    uint min_index;
    uint max_index;
    uint base_index;
  #endif
    uint32_t ibo_id; /* 0 indicates not yet sent to VRAM */
    void *data;      /* non-NULL indicates not yet sent to VRAM */
    bool use_prim_restart;
  } GPUIndexBuf;
  
  void GPU_indexbuf_use(GPUIndexBuf *);
  uint GPU_indexbuf_size_get(const GPUIndexBuf *);
  
  typedef struct GPUIndexBufBuilder {
    uint max_allowed_index;
    uint max_index_len;
    uint index_len;
    GPUPrimType prim_type;
    uint *data;
    bool use_prim_restart;
  } GPUIndexBufBuilder;
  
  /* supports all primitive types. */
  void GPU_indexbuf_init_ex(
      GPUIndexBufBuilder *, GPUPrimType, uint index_len, uint vertex_len, bool use_prim_restart);
  
  /* supports only GPU_PRIM_POINTS, GPU_PRIM_LINES and GPU_PRIM_TRIS. */
  void GPU_indexbuf_init(GPUIndexBufBuilder *, GPUPrimType, uint prim_len, uint vertex_len);
  
  void GPU_indexbuf_add_generic_vert(GPUIndexBufBuilder *, uint v);
  void GPU_indexbuf_add_primitive_restart(GPUIndexBufBuilder *);
  
  void GPU_indexbuf_add_point_vert(GPUIndexBufBuilder *, uint v);
  void GPU_indexbuf_add_line_verts(GPUIndexBufBuilder *, uint v1, uint v2);
  void GPU_indexbuf_add_tri_verts(GPUIndexBufBuilder *, uint v1, uint v2, uint v3);
  void GPU_indexbuf_add_line_adj_verts(GPUIndexBufBuilder *, uint v1, uint v2, uint v3, uint v4);
  
  GPUIndexBuf *GPU_indexbuf_build(GPUIndexBufBuilder *);
  void GPU_indexbuf_build_in_place(GPUIndexBufBuilder *, GPUIndexBuf *);
  
  void GPU_indexbuf_discard(GPUIndexBuf *);
  
  int GPU_indexbuf_primitive_len(GPUPrimType prim_type);
  
  /* Macros */
  
  #define GPU_INDEXBUF_DISCARD_SAFE(elem) \
    do { \
      if (elem != NULL) { \
        GPU_indexbuf_discard(elem); \
        elem = NULL; \
      } \
    } while (0)
  
  #endif /* __GPU_ELEMENT_H__ */
  