/**************************************************************************
 *
 * Copyright 2023 Red Hat.
 * All Rights Reserved.
 *
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the "Software"),
 * to deal in the Software without restriction, including without limitation
 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
 * and/or sell copies of the Software, and to permit persons to whom the
 * Software is furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included
 * in all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
 * DEALINGS IN THE SOFTWARE.
 *
 **************************************************************************/

/*
 * Mesh primitive assembler
 *
 * This takes vertex and per-primitive data, and assembles a linear set
 * of draw compatible vertices.
 */
#include "draw_mesh_prim.h"

#include "draw/draw_context.h"
#include "draw/draw_private.h"
#include "util/u_debug.h"
#include "util/u_memory.h"
#include "util/u_prim.h"

#include "pipe/p_defines.h"

struct draw_mesh_prim
{
   struct draw_context *draw;

   struct draw_prim_info *output_prims;
   struct draw_vertex_info *output_verts;

   const struct draw_prim_info *input_prims;
   const struct draw_vertex_info *input_verts;

   unsigned num_prims;
   const char *per_prim;
   uint32_t num_per_prim;
   uint32_t added_prim_size;
   int cull_prim_idx;
};

static void
add_prim(struct draw_mesh_prim *asmblr, unsigned length)
{
   struct draw_prim_info *output_prims = asmblr->output_prims;

   output_prims->primitive_lengths = realloc(output_prims->primitive_lengths, sizeof(unsigned) * (output_prims->primitive_count + 1));
   output_prims->primitive_lengths[output_prims->primitive_count] = length;
   output_prims->primitive_count++;
}


/*
 * Copy the vertex header along with its data from the current
 * vertex buffer into a buffer holding vertices arranged
 * into decomposed primitives (i.e. buffer without the
 * adjacency vertices)
 */
static void
copy_verts(struct draw_mesh_prim *asmblr,
           unsigned *indices, unsigned num_indices)
{
   char *output = (char*)asmblr->output_verts->verts;
   const char *input = (const char*)asmblr->input_verts->verts;

   for (unsigned i = 0; i < num_indices; ++i) {
      unsigned idx = indices[i];
      unsigned output_offset =
         asmblr->output_verts->count * asmblr->output_verts->stride;
      unsigned input_offset = asmblr->input_verts->stride * idx;
      memcpy(output + output_offset, input + input_offset,
             asmblr->input_verts->vertex_size);

      memcpy(output + output_offset + asmblr->input_verts->vertex_size,
             asmblr->per_prim + (asmblr->num_prims * asmblr->added_prim_size * 8),
             asmblr->added_prim_size);
      asmblr->output_verts->count += 1;
   }
   ++asmblr->num_prims;
}

static bool
cull_prim(struct draw_mesh_prim *asmblr)
{
   if (asmblr->cull_prim_idx == -1)
      return false;

   const uint32_t *cull_prim_ptr = (uint32_t *)(asmblr->per_prim + (asmblr->num_prims * asmblr->added_prim_size * 8));
   cull_prim_ptr += (asmblr->cull_prim_idx * 4);

   return (*cull_prim_ptr) ? true : false;
}


static void
prim_point(struct draw_mesh_prim *asmblr,
           unsigned idx)
{
   unsigned indices[1];

   indices[0] = idx;

   if (cull_prim(asmblr)) {
      ++asmblr->num_prims;
      return;
   }
   add_prim(asmblr, 1);
   copy_verts(asmblr, indices, 1);
}


static void
prim_line(struct draw_mesh_prim *asmblr,
          unsigned i0, unsigned i1)
{
   unsigned indices[2];

   indices[0] = i0;
   indices[1] = i1;

   if (cull_prim(asmblr)) {
      ++asmblr->num_prims;
      return;
   }
   add_prim(asmblr, 2);
   copy_verts(asmblr, indices, 2);
}


static void
prim_tri(struct draw_mesh_prim *asmblr,
         unsigned i0, unsigned i1, unsigned i2)
{
   unsigned indices[3];

   indices[0] = i0;
   indices[1] = i1;
   indices[2] = i2;

   if (cull_prim(asmblr)) {
      ++asmblr->num_prims;
      return;
   }
   add_prim(asmblr, 3);
   copy_verts(asmblr, indices, 3);
}


#define FUNC assembler_run_linear
#define GET_ELT(idx) (start + (idx))
#include "draw_mesh_prim_tmp.h"

#define FUNC assembler_run_elts
#define LOCAL_VARS   const uint16_t *elts = input_prims->elts;
#define GET_ELT(idx) (elts[start + (idx)])
#include "draw_mesh_prim_tmp.h"


void
draw_mesh_prim_run(struct draw_context *draw,
                   unsigned num_per_prim_inputs,
                   void *per_prim_inputs,
                   int cull_prim_idx,
                   const struct draw_prim_info *input_prims,
                   const struct draw_vertex_info *input_verts,
                   struct draw_prim_info *output_prims,
                   struct draw_vertex_info *output_verts)
{
   struct draw_mesh_prim asmblr_mesh;
   struct draw_mesh_prim *asmblr = &asmblr_mesh;
   unsigned start, i;
   unsigned max_primitives = input_prims->primitive_count;
   unsigned max_verts = u_vertices_per_prim(input_prims->prim) * max_primitives;

   asmblr->output_prims = output_prims;
   asmblr->output_verts = output_verts;
   asmblr->input_prims = input_prims;
   asmblr->input_verts = input_verts;
   asmblr->num_prims = 0;
   asmblr->num_per_prim = num_per_prim_inputs;
   asmblr->per_prim = per_prim_inputs;
   asmblr->cull_prim_idx = cull_prim_idx;

   output_prims->linear = true;
   output_prims->elts = NULL;
   output_prims->start = 0;
   output_prims->prim = input_prims->prim;
   output_prims->flags = 0x0;
   output_prims->primitive_lengths = MALLOC(sizeof(unsigned));
   output_prims->primitive_lengths[0] = 0;
   output_prims->primitive_count = 0;

   asmblr->added_prim_size = asmblr->num_per_prim * (4 * sizeof(float));
   output_verts->vertex_size = input_verts->vertex_size + asmblr->added_prim_size;
   output_verts->stride = output_verts->vertex_size;
   output_verts->verts = (struct vertex_header*)MALLOC(
      output_verts->vertex_size * max_verts);
   output_verts->count = 0;

   for (start = i = 0; i < input_prims->primitive_count;
        start += input_prims->primitive_lengths[i], i++) {
      unsigned count = input_prims->primitive_lengths[i];
      if (input_prims->linear) {
         assembler_run_linear(asmblr, input_prims, input_verts,
                              start, count);
      } else {
         assembler_run_elts(asmblr, input_prims, input_verts,
                            start, count);
      }
   }

   output_prims->count = output_verts->count;
}
