/*
 * Copyright (c) 2008-2024 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 "pipe/p_defines.h"
#include "util/u_math.h"
#include "util/u_memory.h"
#include "util/u_bitmask.h"
#include "translate/translate.h"
#include "tgsi/tgsi_ureg.h"

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

#include "svga_hw_reg.h"


/**
 * If we fail to compile a vertex shader we'll use a dummy/fallback shader
 * that simply emits a (0,0,0,1) vertex position.
 */
static const struct tgsi_token *
get_dummy_vertex_shader(void)
{
   static const float zero[4] = { 0.0, 0.0, 0.0, 1.0 };
   struct ureg_program *ureg;
   const struct tgsi_token *tokens;
   struct ureg_src src;
   struct ureg_dst dst;

   ureg = ureg_create(PIPE_SHADER_VERTEX);
   if (!ureg)
      return NULL;

   dst = ureg_DECL_output(ureg, TGSI_SEMANTIC_POSITION, 0);
   src = ureg_DECL_immediate(ureg, zero, 4);
   ureg_MOV(ureg, dst, src);
   ureg_END(ureg);

   tokens = ureg_get_tokens(ureg, NULL);

   ureg_destroy(ureg);

   return tokens;
}


/**
 * Replace the given shader's instruction with a simple / dummy shader.
 * We use this when normal shader translation fails.
 */
struct svga_shader_variant *
svga_get_compiled_dummy_vertex_shader(struct svga_context *svga,
                                      struct svga_shader *shader,
                                      const struct svga_compile_key *key)
{
   struct svga_vertex_shader *vs = (struct svga_vertex_shader *)shader;
   const struct tgsi_token *dummy = get_dummy_vertex_shader();
   struct svga_shader_variant *variant;

   if (!dummy) {
      return NULL;
   }

   FREE((void *) vs->base.tokens);
   vs->base.tokens = dummy;

   svga_tgsi_scan_shader(&vs->base);

   variant = svga_tgsi_compile_shader(svga, shader, key);
   return variant;
}


/* SVGA_NEW_PRESCALE, SVGA_NEW_RAST, SVGA_NEW_FS
 */
static void
make_vs_key(struct svga_context *svga, struct svga_compile_key *key)
{
   struct svga_vertex_shader *vs = svga->curr.vs;

   memset(key, 0, sizeof *key);

   if (svga->state.sw.need_swtnl && svga_have_vgpu10(svga)) {
      /* Set both of these flags, to match compile_passthrough_vs() */
      key->vs.passthrough = 1;
      key->vs.undo_viewport = 1;
      return;
   }

   if (svga_have_vgpu10(svga)) {
      key->vs.need_vertex_id_bias = 1;
   }

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

   /* SVGA_NEW_RAST */
   key->vs.allow_psiz = svga->curr.rast->templ.point_size_per_vertex;

   /* SVGA_NEW_FS */
   key->vs.fs_generic_inputs = svga->curr.fs->base.info.generic_inputs_mask;

   svga_remap_generics(key->vs.fs_generic_inputs, key->generic_remap_table);

   /* SVGA_NEW_VELEMENT */
   key->vs.adjust_attrib_range = svga->curr.velems->adjust_attrib_range;
   key->vs.adjust_attrib_w_1 = svga->curr.velems->adjust_attrib_w_1;
   key->vs.attrib_is_pure_int = svga->curr.velems->attrib_is_pure_int;
   key->vs.adjust_attrib_itof = svga->curr.velems->adjust_attrib_itof;
   key->vs.adjust_attrib_utof = svga->curr.velems->adjust_attrib_utof;
   key->vs.attrib_is_bgra = svga->curr.velems->attrib_is_bgra;
   key->vs.attrib_puint_to_snorm = svga->curr.velems->attrib_puint_to_snorm;
   key->vs.attrib_puint_to_uscaled = svga->curr.velems->attrib_puint_to_uscaled;
   key->vs.attrib_puint_to_sscaled = svga->curr.velems->attrib_puint_to_sscaled;

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

   /* SVGA_NEW_RAST */
   key->clip_plane_enable = svga->curr.rast->templ.clip_plane_enable;

   /* Determine if this shader is the last shader in the vertex
    * processing stage.
    */
   key->last_vertex_stage = !(svga->curr.gs ||
                              svga->curr.tcs || svga->curr.tes);
}


/**
 * svga_reemit_vs_bindings - Reemit the vertex shader bindings
 */
enum pipe_error
svga_reemit_vs_bindings(struct svga_context *svga)
{
   enum pipe_error ret;
   struct svga_winsys_gb_shader *gbshader = NULL;
   SVGA3dShaderId shaderId = SVGA3D_INVALID_ID;

   assert(svga->rebind.flags.vs);
   assert(svga_have_gb_objects(svga));

   if (svga->state.hw_draw.vs) {
      gbshader = svga->state.hw_draw.vs->gb_shader;
      shaderId = svga->state.hw_draw.vs->id;
   }

   if (!svga_need_to_rebind_resources(svga)) {
      ret =  svga->swc->resource_rebind(svga->swc, NULL, gbshader,
                                        SVGA_RELOC_READ);
   }
   else {
      if (svga_have_vgpu10(svga))
         ret = SVGA3D_vgpu10_SetShader(svga->swc, SVGA3D_SHADERTYPE_VS,
                                       gbshader, shaderId);
      else
         ret = SVGA3D_SetGBShader(svga->swc, SVGA3D_SHADERTYPE_VS, gbshader);
   }

   if (ret != PIPE_OK)
      return ret;

   svga->rebind.flags.vs = false;
   return PIPE_OK;
}


/**
 * The current vertex shader is already executed by the 'draw'
 * module, so we just need to generate a simple vertex shader
 * to pass through all those VS outputs that will
 * be consumed by the fragment shader.
 * Used when we employ the 'draw' module.
 */
static enum pipe_error
compile_passthrough_vs(struct svga_context *svga,
                       struct svga_vertex_shader *vs,
                       struct svga_fragment_shader *fs,
                       struct svga_shader_variant **out_variant)
{
   struct svga_shader_variant *variant = NULL;
   unsigned num_inputs;
   unsigned i;
   unsigned num_elements;
   struct svga_vertex_shader new_vs;
   struct ureg_src src[PIPE_MAX_SHADER_INPUTS];
   struct ureg_dst dst[PIPE_MAX_SHADER_OUTPUTS];
   struct ureg_program *ureg;
   struct svga_compile_key key;
   enum pipe_error ret;

   assert(svga_have_vgpu10(svga));
   assert(fs);

   num_inputs = fs->base.tgsi_info.num_inputs;

   ureg = ureg_create(PIPE_SHADER_VERTEX);
   if (!ureg)
      return PIPE_ERROR_OUT_OF_MEMORY;

   /* draw will always add position */
   dst[0] = ureg_DECL_output(ureg, TGSI_SEMANTIC_POSITION, 0);
   src[0] = ureg_DECL_vs_input(ureg, 0);
   num_elements = 1;

   /**
    * swtnl backend redefines the input layout based on the
    * fragment shader's inputs. So we only need to passthrough
    * those inputs that will be consumed by the fragment shader.
    * Note: DX10 requires the number of vertex elements
    * specified in the input layout to be no less than the
    * number of inputs to the vertex shader.
    */
   for (i = 0; i < num_inputs; i++) {
      switch (fs->base.tgsi_info.input_semantic_name[i]) {
      case TGSI_SEMANTIC_COLOR:
      case TGSI_SEMANTIC_GENERIC:
      case TGSI_SEMANTIC_FOG:
         dst[num_elements] = ureg_DECL_output(ureg,
                                fs->base.tgsi_info.input_semantic_name[i],
                                fs->base.tgsi_info.input_semantic_index[i]);
         src[num_elements] = ureg_DECL_vs_input(ureg, num_elements);
         num_elements++;
         break;
      default:
         break;
      }
   }

   for (i = 0; i < num_elements; i++) {
      ureg_MOV(ureg, dst[i], src[i]);
   }

   ureg_END(ureg);

   memset(&new_vs, 0, sizeof(new_vs));
   new_vs.base.tokens = ureg_get_tokens(ureg, NULL);
   svga_tgsi_scan_shader(&new_vs.base);

   memset(&key, 0, sizeof(key));
   key.vs.undo_viewport = 1;

   ret = svga_compile_shader(svga, &new_vs.base, &key, &variant);
   if (ret != PIPE_OK)
      return ret;

   ureg_free_tokens(new_vs.base.tokens);
   ureg_destroy(ureg);

   /* Overwrite the variant key to indicate it's a pass-through VS */
   memset(&variant->key, 0, sizeof(variant->key));
   variant->key.vs.passthrough = 1;
   variant->key.vs.undo_viewport = 1;

   *out_variant = variant;

   return PIPE_OK;
}


static enum pipe_error
emit_hw_vs(struct svga_context *svga, uint64_t dirty)
{
   struct svga_shader_variant *variant;
   struct svga_vertex_shader *vs = svga->curr.vs;
   struct svga_fragment_shader *fs = svga->curr.fs;
   enum pipe_error ret = PIPE_OK;
   struct svga_compile_key key;

   SVGA_STATS_TIME_PUSH(svga_sws(svga), SVGA_STATS_TIME_EMITVS);

   /* If there is an active geometry shader, and it has stream output
    * defined, then we will skip the stream output from the vertex shader
    */
   if (!svga_have_gs_streamout(svga)) {
      /* No GS stream out */
      if (svga_have_vs_streamout(svga)) {
         /* Set VS stream out */
         ret = svga_set_stream_output(svga, vs->base.stream_output);
      }
      else {
         /* turn off stream out */
         ret = svga_set_stream_output(svga, NULL);
      }
      if (ret != PIPE_OK) {
         goto done;
      }
   }

   /* SVGA_NEW_NEED_SWTNL */
   if (svga->state.sw.need_swtnl && !svga_have_vgpu10(svga)) {
      /* No vertex shader is needed */
      variant = NULL;
   }
   else {
      make_vs_key(svga, &key);

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

      if (!variant) {
         /* Create VS variant now */
         if (key.vs.passthrough) {
            ret = compile_passthrough_vs(svga, vs, fs, &variant);
         }
         else {
            ret = svga_compile_shader(svga, &vs->base, &key, &variant);
         }
         if (ret != PIPE_OK)
            goto done;
      }
   }

   if (variant != svga->state.hw_draw.vs) {
      /* Bind the new variant */
      if (variant) {
         ret = svga_set_shader(svga, SVGA3D_SHADERTYPE_VS, variant);
         if (ret != PIPE_OK)
            goto done;
         svga->rebind.flags.vs = false;
      }

      svga->dirty |= SVGA_NEW_VS_VARIANT;
      svga->state.hw_draw.vs = variant;
   }

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

struct svga_tracked_state svga_hw_vs = 
{
   "vertex shader (hwtnl)",
   (SVGA_NEW_VS |
    SVGA_NEW_FS |
    SVGA_NEW_TEXTURE_BINDING |
    SVGA_NEW_SAMPLER |
    SVGA_NEW_RAST |
    SVGA_NEW_PRESCALE |
    SVGA_NEW_VELEMENT |
    SVGA_NEW_NEED_SWTNL |
    SVGA_NEW_VS_RAW_BUFFER),
   emit_hw_vs
};