/*
 * Copyright 2017 Advanced Micro Devices, Inc.
 *
 * 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
 * on the rights to use, copy, modify, merge, publish, distribute, sub
 * license, 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 (including the next
 * paragraph) 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 NON-INFRINGEMENT. IN NO EVENT SHALL
 * THE AUTHOR(S) AND/OR THEIR SUPPLIERS 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.
 */

#include "tgsi/tgsi_from_mesa.h"

#include "pipe/p_compiler.h"

/**
 * Determine the semantic index that is used when the given varying is mapped
 * to TGSI_SEMANTIC_GENERIC.
 */
unsigned
tgsi_get_generic_gl_varying_index(gl_varying_slot attr,
                                  bool needs_texcoord_semantic)
{
   if (attr >= VARYING_SLOT_VAR0) {
      if (needs_texcoord_semantic)
         return attr - VARYING_SLOT_VAR0;
      else
         return 9 + (attr - VARYING_SLOT_VAR0);
   }
   if (attr == VARYING_SLOT_PNTC) {
      assert(!needs_texcoord_semantic);
      return 8;
   }
   if (attr >= VARYING_SLOT_TEX0 && attr <= VARYING_SLOT_TEX7) {
      assert(!needs_texcoord_semantic);
      return attr - VARYING_SLOT_TEX0;
   }

   assert(0);
   return 0;
}

/**
 * Determine the semantic name and index used for the given varying.
 */
void
tgsi_get_gl_varying_semantic(gl_varying_slot attr,
                             bool needs_texcoord_semantic,
                             unsigned *semantic_name,
                             unsigned *semantic_index)
{
   switch (attr) {
   case VARYING_SLOT_POS:
      *semantic_name = TGSI_SEMANTIC_POSITION;
      *semantic_index = 0;
      break;
   case VARYING_SLOT_COL0:
      *semantic_name = TGSI_SEMANTIC_COLOR;
      *semantic_index = 0;
      break;
   case VARYING_SLOT_COL1:
      *semantic_name = TGSI_SEMANTIC_COLOR;
      *semantic_index = 1;
      break;
   case VARYING_SLOT_BFC0:
      *semantic_name = TGSI_SEMANTIC_BCOLOR;
      *semantic_index = 0;
      break;
   case VARYING_SLOT_BFC1:
      *semantic_name = TGSI_SEMANTIC_BCOLOR;
      *semantic_index = 1;
      break;
   case VARYING_SLOT_FOGC:
      *semantic_name = TGSI_SEMANTIC_FOG;
      *semantic_index = 0;
      break;
   case VARYING_SLOT_PSIZ:
      *semantic_name = TGSI_SEMANTIC_PSIZE;
      *semantic_index = 0;
      break;
   case VARYING_SLOT_CLIP_DIST0:
      *semantic_name = TGSI_SEMANTIC_CLIPDIST;
      *semantic_index = 0;
      break;
   case VARYING_SLOT_CLIP_DIST1:
      *semantic_name = TGSI_SEMANTIC_CLIPDIST;
      *semantic_index = 1;
      break;
   case VARYING_SLOT_CULL_DIST0:
   case VARYING_SLOT_CULL_DIST1:
      /* these should have been lowered by GLSL */
      assert(0);
      break;
   case VARYING_SLOT_EDGE:
      *semantic_name = TGSI_SEMANTIC_EDGEFLAG;
      *semantic_index = 0;
      break;
   case VARYING_SLOT_CLIP_VERTEX:
      *semantic_name = TGSI_SEMANTIC_CLIPVERTEX;
      *semantic_index = 0;
      break;
   case VARYING_SLOT_LAYER:
      *semantic_name = TGSI_SEMANTIC_LAYER;
      *semantic_index = 0;
      break;
   case VARYING_SLOT_VIEWPORT:
      *semantic_name = TGSI_SEMANTIC_VIEWPORT_INDEX;
      *semantic_index = 0;
      break;
   case VARYING_SLOT_PNTC:
      *semantic_name = TGSI_SEMANTIC_PCOORD;
      *semantic_index = 0;
      break;

   case VARYING_SLOT_TEX0:
   case VARYING_SLOT_TEX1:
   case VARYING_SLOT_TEX2:
   case VARYING_SLOT_TEX3:
   case VARYING_SLOT_TEX4:
   case VARYING_SLOT_TEX5:
   case VARYING_SLOT_TEX6:
   case VARYING_SLOT_TEX7:
      if (needs_texcoord_semantic) {
         *semantic_name = TGSI_SEMANTIC_TEXCOORD;
         *semantic_index = attr - VARYING_SLOT_TEX0;
         break;
      }
      /* fall through */
   case VARYING_SLOT_VAR0:
   default:
      assert(attr >= VARYING_SLOT_VAR0 ||
             (attr >= VARYING_SLOT_TEX0 && attr <= VARYING_SLOT_TEX7));
      *semantic_name = TGSI_SEMANTIC_GENERIC;
      *semantic_index =
         tgsi_get_generic_gl_varying_index(attr, needs_texcoord_semantic);
      break;
   }
}

/**
 * Determine the semantic name and index used for the given fragment shader
 * result.
 */
void
tgsi_get_gl_frag_result_semantic(gl_frag_result frag_result,
                                 unsigned *semantic_name,
                                 unsigned *semantic_index)
{
   if (frag_result >= FRAG_RESULT_DATA0) {
      *semantic_name = TGSI_SEMANTIC_COLOR;
      *semantic_index = frag_result - FRAG_RESULT_DATA0;
      return;
   }

   *semantic_index = 0;

   switch (frag_result) {
   case FRAG_RESULT_DEPTH:
      *semantic_name = TGSI_SEMANTIC_POSITION;
      break;
   case FRAG_RESULT_STENCIL:
      *semantic_name = TGSI_SEMANTIC_STENCIL;
      break;
   case FRAG_RESULT_COLOR:
      *semantic_name = TGSI_SEMANTIC_COLOR;
      break;
   case FRAG_RESULT_SAMPLE_MASK:
      *semantic_name = TGSI_SEMANTIC_SAMPLEMASK;
      break;
   default:
      assert(false);
   }
}