/*
 * Copyright (c) 2018-2024 Broadcom. All Rights Reserved.
 * The term “Broadcom” refers to Broadcom Inc.
 * and/or its subsidiaries.
 * SPDX-License-Identifier: MIT
 */

#include "util/u_inlines.h"
#include "util/u_memory.h"
#include "util/u_simple_shaders.h"

#include "svga_context.h"
#include "svga_cmd.h"
#include "svga_tgsi.h"
#include "svga_shader.h"


static void
make_tcs_key(struct svga_context *svga, struct svga_compile_key *key)
{
   struct svga_tcs_shader *tcs = svga->curr.tcs;

   memset(key, 0, sizeof *key);

   /*
    * SVGA_NEW_TEXTURE_BINDING | SVGA_NEW_SAMPLER
    */
   svga_init_shader_key_common(svga, PIPE_SHADER_TESS_CTRL, &tcs->base, key);

   /* SVGA_NEW_TCS_PARAM */
   key->tcs.vertices_per_patch = svga->curr.vertices_per_patch;

   /* The tessellator parameters come from the layout section in the
    * tessellation evaluation shader. Get these parameters from the
    * current tessellation evaluation shader variant.
    * Note: this requires the tessellation evaluation shader to be
    * compiled first.
    */
   struct svga_tes_variant *tes = svga_tes_variant(svga->state.hw_draw.tes);
   key->tcs.prim_mode = tes->prim_mode;
   key->tcs.spacing = tes->spacing;
   key->tcs.vertices_order_cw = tes->vertices_order_cw;
   key->tcs.point_mode = tes->point_mode;

   /* The number of control point output from tcs is determined by the
    * number of control point input expected in tes. If tes does not expect
    * any control point input, then vertices_per_patch in the tes key will
    * be 0, otherwise it will contain the number of vertices out as specified
    * in the tcs property.
    */
   key->tcs.vertices_out = tes->base.key.tes.vertices_per_patch;

   if (svga->tcs.passthrough)
      key->tcs.passthrough = 1;

   key->clip_plane_enable = svga->curr.rast->templ.clip_plane_enable;

   /* tcs is always followed by tes */
   key->last_vertex_stage = 0;
}


static enum pipe_error
emit_hw_tcs(struct svga_context *svga, uint64_t dirty)
{
   struct svga_shader_variant *variant;
   struct svga_tcs_shader *tcs = svga->curr.tcs;
   enum pipe_error ret = PIPE_OK;
   struct svga_compile_key key;

   assert(svga_have_sm5(svga));

   SVGA_STATS_TIME_PUSH(svga_sws(svga), SVGA_STATS_TIME_EMITTCS);

   if (!tcs) {
      /* If there is no active tcs, then there should not be
       * active tes either
       */
      assert(!svga->curr.tes);
      if (svga->state.hw_draw.tcs != NULL) {

         /** The previous tessellation control shader is made inactive.
          *  Needs to unbind the tessellation control shader.
          */
         ret = svga_set_shader(svga, SVGA3D_SHADERTYPE_HS, NULL);
         if (ret != PIPE_OK)
            goto done;
         svga->state.hw_draw.tcs = NULL;
      }
      goto done;
   }

   make_tcs_key(svga, &key);

   /* See if we already have a TCS variant that matches the key */
   variant = svga_search_shader_key(&tcs->base, &key);

   if (!variant) {
      ret = svga_compile_shader(svga, &tcs->base, &key, &variant);
      if (ret != PIPE_OK)
         goto done;
   }

   if (variant != svga->state.hw_draw.tcs) {
      /* Bind the new variant */
      ret = svga_set_shader(svga, SVGA3D_SHADERTYPE_HS, variant);
      if (ret != PIPE_OK)
         goto done;

      svga->rebind.flags.tcs = false;
      svga->dirty |= SVGA_NEW_TCS_VARIANT;
      svga->state.hw_draw.tcs = variant;
   }

done:
   SVGA_STATS_TIME_POP(svga_sws(svga));
   return ret;
}


struct svga_tracked_state svga_hw_tcs =
{
   "tessellation control shader (hwtnl)",
   (SVGA_NEW_VS |
    SVGA_NEW_TCS |
    SVGA_NEW_TES |
    SVGA_NEW_TEXTURE_BINDING |
    SVGA_NEW_SAMPLER |
    SVGA_NEW_RAST |
    SVGA_NEW_TCS_RAW_BUFFER),
   emit_hw_tcs
};


static void
make_tes_key(struct svga_context *svga, struct svga_compile_key *key)
{
   struct svga_tes_shader *tes = svga->curr.tes;

   memset(key, 0, sizeof *key);

   /*
    * SVGA_NEW_TEXTURE_BINDING | SVGA_NEW_SAMPLER
    */
   svga_init_shader_key_common(svga, PIPE_SHADER_TESS_EVAL, &tes->base, key);

   assert(svga->curr.tcs);

   key->tes.vertices_per_patch = tes->base.info.tes.reads_control_point ?
      svga->curr.tcs->base.info.tcs.vertices_out : 0;

   key->tes.need_prescale = svga->state.hw_clear.prescale[0].enabled &&
                            (svga->curr.gs == NULL);

   /* tcs emits tessellation factors as extra outputs.
    * Since tes depends on them, save the tessFactor output index
    * from tcs in the tes compile key, so that if a different
    * tcs is bound and if the tessFactor index is different,
    * a different tes variant will be generated.
    */
   key->tes.tessfactor_index = svga->curr.tcs->base.info.num_outputs;

   key->clip_plane_enable = svga->curr.rast->templ.clip_plane_enable;

   /* This is the last vertex stage if there is no geometry shader. */
   key->last_vertex_stage = !svga->curr.gs;

   key->tes.need_tessinner = svga->curr.tcs->base.info.tcs.writes_tess_factor;
   key->tes.need_tessouter = svga->curr.tcs->base.info.tcs.writes_tess_factor;
}


static void
get_passthrough_tcs(struct svga_context *svga)
{
   if (svga->tcs.passthrough_tcs &&
       svga->tcs.vs == svga->curr.vs &&
       svga->tcs.tes == svga->curr.tes &&
       svga->tcs.vertices_per_patch == svga->curr.vertices_per_patch) {
      svga->pipe.bind_tcs_state(&svga->pipe,
                                svga->tcs.passthrough_tcs);
   }
   else {
      struct svga_tcs_shader *new_tcs;

      /* delete older passthrough shader*/
      if (svga->tcs.passthrough_tcs) {
         svga->pipe.delete_tcs_state(&svga->pipe,
                                     svga->tcs.passthrough_tcs);
      }

      new_tcs = (struct svga_tcs_shader *)
         util_make_tess_ctrl_passthrough_shader(&svga->pipe,
            svga->curr.vs->base.tgsi_info.num_outputs,
            svga->curr.tes->base.tgsi_info.num_inputs,
            svga->curr.vs->base.tgsi_info.output_semantic_name,
            svga->curr.vs->base.tgsi_info.output_semantic_index,
            svga->curr.tes->base.tgsi_info.input_semantic_name,
            svga->curr.tes->base.tgsi_info.input_semantic_index,
            svga->curr.vertices_per_patch);
      svga->pipe.bind_tcs_state(&svga->pipe, new_tcs);
      svga->tcs.passthrough_tcs = new_tcs;
      svga->tcs.vs = svga->curr.vs;
      svga->tcs.tes = svga->curr.tes;
      svga->tcs.vertices_per_patch = svga->curr.vertices_per_patch;
   }

   struct pipe_constant_buffer cb;

   cb.buffer = NULL;
   cb.user_buffer = (void *) svga->curr.default_tesslevels;
   cb.buffer_offset = 0;
   cb.buffer_size = 2 * 4 * sizeof(float);
   svga->pipe.set_constant_buffer(&svga->pipe, PIPE_SHADER_TESS_CTRL, 0, false, &cb);
}


static enum pipe_error
emit_hw_tes(struct svga_context *svga, uint64_t dirty)
{
   struct svga_shader_variant *variant;
   struct svga_tes_shader *tes = svga->curr.tes;
   enum pipe_error ret = PIPE_OK;
   struct svga_compile_key key;

   assert(svga_have_sm5(svga));

   SVGA_STATS_TIME_PUSH(svga_sws(svga), SVGA_STATS_TIME_EMITTES);

   if (!tes) {
      /* The GL spec implies that TES is optional when there's a TCS,
       * but that's apparently a spec error. Assert if we have a TCS
       * but no TES.
       */
      assert(!svga->curr.tcs);
      if (svga->state.hw_draw.tes != NULL) {

         /** The previous tessellation evaluation shader is made inactive.
          *  Needs to unbind the tessellation evaluation shader.
          */
         ret = svga_set_shader(svga, SVGA3D_SHADERTYPE_DS, NULL);
         if (ret != PIPE_OK)
            goto done;
         svga->state.hw_draw.tes = NULL;
      }
      goto done;
   }

   if (!svga->curr.tcs) {
      /* TES state is processed before the TCS
       * shader and that's why we're checking for and creating the
       * passthough TCS in the emit_hw_tes() function.
       */
      get_passthrough_tcs(svga);
      svga->tcs.passthrough = true;
   }
   else {
      svga->tcs.passthrough = false;
   }

   make_tes_key(svga, &key);

   /* See if we already have a TES variant that matches the key */
   variant = svga_search_shader_key(&tes->base, &key);

   if (!variant) {
      ret = svga_compile_shader(svga, &tes->base, &key, &variant);
      if (ret != PIPE_OK)
         goto done;
   }

   if (variant != svga->state.hw_draw.tes) {
      /* Bind the new variant */
      ret = svga_set_shader(svga, SVGA3D_SHADERTYPE_DS, variant);
      if (ret != PIPE_OK)
         goto done;

      svga->rebind.flags.tes = false;
      svga->dirty |= SVGA_NEW_TES_VARIANT;
      svga->state.hw_draw.tes = variant;
   }

done:
   SVGA_STATS_TIME_POP(svga_sws(svga));
   return ret;
}


struct svga_tracked_state svga_hw_tes =
{
   "tessellation evaluation shader (hwtnl)",
   /* TBD SVGA_NEW_VS/SVGA_NEW_FS/SVGA_NEW_GS are required or not*/
   (SVGA_NEW_VS |
    SVGA_NEW_FS |
    SVGA_NEW_GS |
    SVGA_NEW_TCS |
    SVGA_NEW_TES |
    SVGA_NEW_TEXTURE_BINDING |
    SVGA_NEW_SAMPLER |
    SVGA_NEW_RAST |
    SVGA_NEW_TES_RAW_BUFFER),
   emit_hw_tes
};