/*
 * Copyright (c) 2008-2024 Broadcom. All Rights Reserved.
 * The term “Broadcom” refers to Broadcom Inc.
 * and/or its subsidiaries.
 * SPDX-License-Identifier: MIT
 */

#include "indices/u_indices.h"
#include "util/u_inlines.h"
#include "util/u_prim.h"
#include "util/u_upload_mgr.h"

#include "svga_cmd.h"
#include "svga_draw.h"
#include "svga_draw_private.h"
#include "svga_resource_buffer.h"
#include "svga_winsys.h"
#include "svga_context.h"
#include "svga_hw_reg.h"


/**
 * Return a new index buffer which contains a translation of the original
 * index buffer.  An example of a translation is converting from QUAD
 * primitives to TRIANGLE primitives.  Each set of four indexes for a quad
 * will be converted to six indices for two triangles.
 *
 * Before generating the new index buffer we'll check if the incoming
 * buffer already has a translated buffer that can be re-used.
 * This benefits demos like Cinebench R15 which has many
 * glDrawElements(GL_QUADS) commands (we can't draw quads natively).
 *
 * \param offset  offset in bytes to first index to translate in src buffer
 * \param orig_prim  original primitive type (like MESA_PRIM_QUADS)
 * \param gen_prim  new/generated primitive type (like MESA_PRIM_TRIANGLES)
 * \param orig_nr  number of indexes to translate in source buffer
 * \param gen_nr  number of indexes to write into new/dest buffer
 * \param index_size  bytes per index (2 or 4)
 * \param translate  the translation function from the u_translate module
 * \param out_buf  returns the new/translated index buffer
 * \return error code to indicate success failure
 */
static enum pipe_error
translate_indices(struct svga_hwtnl *hwtnl,
                  const struct pipe_draw_info *info,
                  const struct pipe_draw_start_count_bias *draw,
                  enum mesa_prim gen_prim,
                  unsigned orig_nr, unsigned gen_nr,
                  unsigned gen_size,
                  u_translate_func translate,
                  struct pipe_resource **out_buf,
                  unsigned *out_offset)
{
   struct pipe_context *pipe = &hwtnl->svga->pipe;
   struct svga_screen *screen = svga_screen(pipe->screen);
   struct svga_buffer *src_sbuf = NULL;
   struct pipe_transfer *src_transfer = NULL;
   struct pipe_transfer *dst_transfer = NULL;
   const unsigned size = gen_size * gen_nr;
   const unsigned offset = draw->start * info->index_size;
   const void *src_map = NULL;
   struct pipe_resource *dst = NULL;
   void *dst_map = NULL;

   assert(gen_size == 2 || gen_size == 4);
   if (!info->has_user_indices)
      src_sbuf = svga_buffer(info->index.resource);

   /* If the draw_info provides us with a buffer rather than a
    * user pointer, Check to see if we've already translated that buffer
    */
   if (src_sbuf && !screen->debug.no_cache_index_buffers) {
      /* Check if we already have a translated index buffer */
      if (src_sbuf->translated_indices.buffer &&
          src_sbuf->translated_indices.orig_prim == info->mode &&
          src_sbuf->translated_indices.new_prim == gen_prim &&
          src_sbuf->translated_indices.offset == offset &&
          src_sbuf->translated_indices.count == orig_nr &&
          src_sbuf->translated_indices.index_size == gen_size) {
         pipe_resource_reference(out_buf, src_sbuf->translated_indices.buffer);
         return PIPE_OK;
      }
   }

   /* Need to trim vertex count to make sure we don't write too much data
    * to the dst buffer in the translate() call.
    */
   u_trim_pipe_prim(gen_prim, &gen_nr);

   if (src_sbuf) {
      /* If we have a source buffer, create a destination buffer in the
       * hope that we can reuse the translated data later. If not,
       * we'd probably be better off using the upload buffer.
       */
      dst = pipe_buffer_create(pipe->screen,
                               PIPE_BIND_INDEX_BUFFER, PIPE_USAGE_IMMUTABLE,
                               size);
      if (!dst)
         goto fail;

      dst_map = pipe_buffer_map(pipe, dst, PIPE_MAP_WRITE, &dst_transfer);
      if (!dst_map)
         goto fail;

      *out_offset = 0;
      src_map = pipe_buffer_map(pipe, info->index.resource,
                                PIPE_MAP_READ |
                                PIPE_MAP_UNSYNCHRONIZED,
                                &src_transfer);
      if (!src_map)
         goto fail;
   } else {
      /* Allocate upload buffer space. Align to the index size. */
      u_upload_alloc(pipe->stream_uploader, 0, size, gen_size,
                     out_offset, &dst, &dst_map);
      if (!dst)
         goto fail;

      src_map = info->index.user;
   }

   translate((const char *) src_map + offset, 0, 0, gen_nr, 0, dst_map);

   if (src_transfer)
      pipe_buffer_unmap(pipe, src_transfer);

   if (dst_transfer)
      pipe_buffer_unmap(pipe, dst_transfer);
   else
      u_upload_unmap(pipe->stream_uploader);

   *out_buf = dst;

   if (src_sbuf && !screen->debug.no_cache_index_buffers) {
      /* Save the new, translated index buffer in the hope we can use it
       * again in the future.
       */
      pipe_resource_reference(&src_sbuf->translated_indices.buffer, dst);
      src_sbuf->translated_indices.orig_prim = info->mode;
      src_sbuf->translated_indices.new_prim = gen_prim;
      src_sbuf->translated_indices.offset = offset;
      src_sbuf->translated_indices.count = orig_nr;
      src_sbuf->translated_indices.index_size = gen_size;
   }

   return PIPE_OK;

 fail:
   if (src_transfer)
      pipe_buffer_unmap(pipe, src_transfer);

   if (dst_transfer)
      pipe_buffer_unmap(pipe, dst_transfer);
   else if (dst_map)
      u_upload_unmap(pipe->stream_uploader);

   if (dst)
      pipe_resource_reference(&dst, NULL);

   return PIPE_ERROR_OUT_OF_MEMORY;
}


enum pipe_error
svga_hwtnl_simple_draw_range_elements(struct svga_hwtnl *hwtnl,
                                      struct pipe_resource *index_buffer,
                                      unsigned index_size, int index_bias,
                                      unsigned min_index, unsigned max_index,
                                      enum mesa_prim prim, unsigned start,
                                      unsigned count,
                                      unsigned start_instance,
                                      unsigned instance_count,
                                      uint8_t vertices_per_patch)
{
   SVGA3dPrimitiveRange range;
   unsigned hw_prim;
   unsigned hw_count;
   unsigned index_offset = start * index_size;

   hw_prim = svga_translate_prim(prim, count, &hw_count, vertices_per_patch);
   if (hw_count == 0)
      return PIPE_OK; /* nothing to draw */

   range.primType = hw_prim;
   range.primitiveCount = hw_count;
   range.indexArray.offset = index_offset;
   range.indexArray.stride = index_size;
   range.indexWidth = index_size;
   range.indexBias = index_bias;

   return svga_hwtnl_prim(hwtnl, &range, count,
                          min_index, max_index, index_buffer,
                          start_instance, instance_count,
                          NULL, NULL);
}


enum pipe_error
svga_hwtnl_draw_range_elements(struct svga_hwtnl *hwtnl,
                               const struct pipe_draw_info *info,
                               const struct pipe_draw_start_count_bias *draw,
                               unsigned count)
{
   struct pipe_context *pipe = &hwtnl->svga->pipe;
   enum mesa_prim gen_prim;
   unsigned gen_size, gen_nr;
   enum indices_mode gen_type;
   u_translate_func gen_func;
   enum pipe_error ret = PIPE_OK;

   SVGA_STATS_TIME_PUSH(svga_sws(hwtnl->svga),
                        SVGA_STATS_TIME_HWTNLDRAWELEMENTS);

   if (svga_need_unfilled_fallback(hwtnl, info->mode)) {
      gen_type = u_unfilled_translator(info->mode,
                                       info->index_size,
                                       count,
                                       hwtnl->api_fillmode,
                                       &gen_prim,
                                       &gen_size, &gen_nr, &gen_func);
   }
   else {
      unsigned hw_pv;

      /* There is no geometry ordering with PATCH, so no need to
       * consider provoking vertex mode for the translation.
       * So use the same api_pv as the hw_pv.
       */
      hw_pv = info->mode == MESA_PRIM_PATCHES ? hwtnl->api_pv :
                                                hwtnl->hw_pv;
      gen_type = u_index_translator(svga_hw_prims,
                                    info->mode,
                                    info->index_size,
                                    count,
                                    hwtnl->api_pv,
                                    hw_pv,
                                    PR_DISABLE,
                                    &gen_prim, &gen_size, &gen_nr, &gen_func);
   }

   if ((gen_type == U_TRANSLATE_MEMCPY) && (info->index_size == gen_size)) {
      /* No need for translation, just pass through to hardware:
       */
      unsigned start_offset = draw->start * info->index_size;
      struct pipe_resource *index_buffer = NULL;
      unsigned index_offset;

      if (info->has_user_indices) {
         u_upload_data(pipe->stream_uploader, 0, count * info->index_size,
                       info->index_size, (char *) info->index.user + start_offset,
                       &index_offset, &index_buffer);
         u_upload_unmap(pipe->stream_uploader);
         index_offset /= info->index_size;
      } else {
         pipe_resource_reference(&index_buffer, info->index.resource);
         index_offset = draw->start;
      }

      assert(index_buffer != NULL);

      ret = svga_hwtnl_simple_draw_range_elements(hwtnl, index_buffer,
                                                  info->index_size,
                                                  draw->index_bias,
                                                  info->index_bounds_valid ? info->min_index : 0,
                                                  info->index_bounds_valid ? info->max_index : ~0,
                                                  gen_prim, index_offset, count,
                                                  info->start_instance,
                                                  info->instance_count,
                                                  hwtnl->svga->patch_vertices);
      pipe_resource_reference(&index_buffer, NULL);
   }
   else {
      struct pipe_resource *gen_buf = NULL;
      unsigned gen_offset = 0;

      /* Need to allocate a new index buffer and run the translate
       * func to populate it.  Could potentially cache this translated
       * index buffer with the original to avoid future
       * re-translations.  Not much point if we're just accelerating
       * GL though, as index buffers are typically used only once
       * there.
       */
      ret = translate_indices(hwtnl, info, draw, gen_prim,
                              count, gen_nr, gen_size,
                              gen_func, &gen_buf, &gen_offset);
      if (ret == PIPE_OK) {
         gen_offset /= gen_size;
         ret = svga_hwtnl_simple_draw_range_elements(hwtnl,
                                                     gen_buf,
                                                     gen_size,
                                                     draw->index_bias,
                                                     info->index_bounds_valid ? info->min_index : 0,
                                                     info->index_bounds_valid ? info->max_index : ~0,
                                                     gen_prim, gen_offset,
                                                     gen_nr,
                                                     info->start_instance,
                                                     info->instance_count,
                                                     hwtnl->svga->patch_vertices);
      }

      if (gen_buf) {
         pipe_resource_reference(&gen_buf, NULL);
      }
   }

   SVGA_STATS_TIME_POP(svga_sws(hwtnl->svga));
   return ret;
}