/**
 * Handle primitive restart in software.
 *
 * This function breaks up calls into the driver so primitive restart
 * support is not required in the driver.
 */
void
vbo_sw_primitive_restart(struct gl_context *ctx,
                         const struct _mesa_prim *prims,
                         GLuint nr_prims,
                         const struct _mesa_index_buffer *ib,
                         struct gl_buffer_object *indirect)
{
   GLuint prim_num;
   struct _mesa_prim new_prim;
   struct _mesa_index_buffer new_ib;
   struct sub_primitive *sub_prims;
   struct sub_primitive *sub_prim;
   GLuint num_sub_prims;
   GLuint sub_prim_num;
   GLuint end_index;
   GLuint sub_end_index;
   GLuint restart_index = _mesa_primitive_restart_index(ctx, ib->index_size);
   struct _mesa_prim temp_prim;
   struct vbo_context *vbo = vbo_context(ctx);
   vbo_draw_func draw_prims_func = vbo->draw_prims;
   GLboolean map_ib = ib->obj->Name && !ib->obj->Mappings[MAP_INTERNAL].Pointer;
   void *ptr;

   /* If there is an indirect buffer, map it and extract the draw params */
   if (indirect && prims[0].is_indirect) {
      const uint32_t *indirect_params;
      if (!ctx->Driver.MapBufferRange(ctx, 0, indirect->Size, GL_MAP_READ_BIT,
                                      indirect, MAP_INTERNAL)) {

         /* something went wrong with mapping, give up */
         _mesa_error(ctx, GL_OUT_OF_MEMORY,
                     "failed to map indirect buffer for sw primitive restart");
         return;
      }

      assert(nr_prims == 1);
      new_prim = prims[0];
      indirect_params = (const uint32_t *)
                        ADD_POINTERS(indirect->Mappings[MAP_INTERNAL].Pointer,
                                     new_prim.indirect_offset);

      new_prim.is_indirect = 0;
      new_prim.count = indirect_params[0];
      new_prim.num_instances = indirect_params[1];
      new_prim.start = indirect_params[2];
      new_prim.basevertex = indirect_params[3];
      new_prim.base_instance = indirect_params[4];

      new_ib = *ib;
      new_ib.count = new_prim.count;

      prims = &new_prim;
      ib = &new_ib;

      ctx->Driver.UnmapBuffer(ctx, indirect, MAP_INTERNAL);
   }

   /* Find the sub-primitives. These are regions in the index buffer which
    * are split based on the primitive restart index value.
    */
   if (map_ib) {
      ctx->Driver.MapBufferRange(ctx, 0, ib->obj->Size, GL_MAP_READ_BIT,
                                 ib->obj, MAP_INTERNAL);
   }

   ptr = ADD_POINTERS(ib->obj->Mappings[MAP_INTERNAL].Pointer, ib->ptr);

   sub_prims = find_sub_primitives(ptr, ib->index_size,
                                   0, ib->count, restart_index,
                                   &num_sub_prims);

   if (map_ib) {
      ctx->Driver.UnmapBuffer(ctx, ib->obj, MAP_INTERNAL);
   }

   /* Loop over the primitives, and use the located sub-primitives to draw
    * each primitive with a break to implement each primitive restart.
    */
   for (prim_num = 0; prim_num < nr_prims; prim_num++) {
      end_index = prims[prim_num].start + prims[prim_num].count;
      memcpy(&temp_prim, &prims[prim_num], sizeof (temp_prim));
      /* Loop over the sub-primitives drawing sub-ranges of the primitive. */
      for (sub_prim_num = 0; sub_prim_num < num_sub_prims; sub_prim_num++) {
         sub_prim = &sub_prims[sub_prim_num];
         sub_end_index = sub_prim->start + sub_prim->count;
         if (prims[prim_num].start <= sub_prim->start) {
            temp_prim.start = MAX2(prims[prim_num].start, sub_prim->start);
            temp_prim.count = MIN2(sub_end_index, end_index) - temp_prim.start;
            if ((temp_prim.start == sub_prim->start) &&
                (temp_prim.count == sub_prim->count)) {
               draw_prims_func(ctx, &temp_prim, 1, ib,
                               GL_TRUE, sub_prim->min_index, sub_prim->max_index,
                               NULL, 0, NULL);
            } else {
               draw_prims_func(ctx, &temp_prim, 1, ib,
                               GL_FALSE, -1, -1,
                               NULL, 0, NULL);
            }
         }
         if (sub_end_index >= end_index) {
            break;
         }
      }
   }

   free(sub_prims);
}
/**
 * Handle primitive restart in software.
 *
 * This function breaks up calls into the driver so primitive restart
 * support is not required in the driver.
 */
void
vbo_sw_primitive_restart(struct gl_context *ctx,
                         const struct _mesa_prim *prims,
                         GLuint nr_prims,
                         const struct _mesa_index_buffer *ib)
{
   GLuint prim_num;
   struct sub_primitive *sub_prims;
   struct sub_primitive *sub_prim;
   GLuint num_sub_prims;
   GLuint sub_prim_num;
   GLuint end_index;
   GLuint sub_end_index;
   GLuint restart_index = ctx->Array.RestartIndex;
   struct _mesa_prim temp_prim;
   struct vbo_context *vbo = vbo_context(ctx);
   vbo_draw_func draw_prims_func = vbo->draw_prims;
   GLboolean map_ib = ib->obj->Name && !ib->obj->Pointer;
   void *ptr;

   /* Find the sub-primitives. These are regions in the index buffer which
    * are split based on the primitive restart index value.
    */
   if (map_ib) {
      ctx->Driver.MapBufferRange(ctx, 0, ib->obj->Size, GL_MAP_READ_BIT,
                                 ib->obj);
   }

   ptr = ADD_POINTERS(ib->obj->Pointer, ib->ptr);

   sub_prims = find_sub_primitives(ptr, vbo_sizeof_ib_type(ib->type),
                                   0, ib->count, restart_index,
                                   &num_sub_prims);

   if (map_ib) {
      ctx->Driver.UnmapBuffer(ctx, ib->obj);
   }

   /* Loop over the primitives, and use the located sub-primitives to draw
    * each primitive with a break to implement each primitive restart.
    */
   for (prim_num = 0; prim_num < nr_prims; prim_num++) {
      end_index = prims[prim_num].start + prims[prim_num].count;
      memcpy(&temp_prim, &prims[prim_num], sizeof (temp_prim));
      /* Loop over the sub-primitives drawing sub-ranges of the primitive. */
      for (sub_prim_num = 0; sub_prim_num < num_sub_prims; sub_prim_num++) {
         sub_prim = &sub_prims[sub_prim_num];
         sub_end_index = sub_prim->start + sub_prim->count;
         if (prims[prim_num].start <= sub_prim->start) {
            temp_prim.start = MAX2(prims[prim_num].start, sub_prim->start);
            temp_prim.count = MIN2(sub_end_index, end_index) - temp_prim.start;
            if ((temp_prim.start == sub_prim->start) &&
                (temp_prim.count == sub_prim->count)) {
               draw_prims_func(ctx, &temp_prim, 1, ib,
                               GL_TRUE, sub_prim->min_index, sub_prim->max_index,
                               NULL);
            } else {
               draw_prims_func(ctx, &temp_prim, 1, ib,
                               GL_FALSE, -1, -1,
                               NULL);
            }
         }
         if (sub_end_index >= end_index) {
            break;
         }
      }
   }

   free(sub_prims);
}