/*
 * Copyright (c) 2012-2015 Etnaviv Project
 *
 * 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, 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 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.
 *
 * Authors:
 *    Wladimir J. van der Laan <laanwj@gmail.com>
 */

#include "etnaviv_zsa.h"

#include "etnaviv_context.h"
#include "etnaviv_screen.h"
#include "etnaviv_translate.h"
#include "util/u_half.h"
#include "util/u_memory.h"

#include "hw/common.xml.h"

void *
etna_zsa_state_create(struct pipe_context *pctx,
                      const struct pipe_depth_stencil_alpha_state *so)
{
   struct etna_context *ctx = etna_context(pctx);
   struct etna_screen *screen = ctx->screen;
   struct etna_zsa_state *cs = CALLOC_STRUCT(etna_zsa_state);

   if (!cs)
      return NULL;

   cs->base = *so;

   /* XXX does stencil[0] / stencil[1] order depend on rs->front_ccw? */
   bool early_z = !VIV_FEATURE(ctx->screen, chipFeatures, NO_EARLY_Z);
   bool disable_zs =
      (!so->depth.enabled || so->depth.func == PIPE_FUNC_ALWAYS) &&
      !so->depth.writemask;

/* Set operations to KEEP if write mask is 0.
 * When we don't do this, the depth buffer is written for the entire primitive
 * instead of just where the stencil condition holds (GC600 rev 0x0019, without
 * feature CORRECT_STENCIL).
 * Not sure if this is a hardware bug or just a strange edge case. */
#if 0 /* TODO: It looks like a hardware bug */
    for(int i=0; i<2; ++i)
    {
        if(so->stencil[i].writemask == 0)
        {
            so->stencil[i].fail_op = so->stencil[i].zfail_op = so->stencil[i].zpass_op = PIPE_STENCIL_OP_KEEP;
        }
    }
#endif

   /* Determine whether to enable early z reject. Don't enable it when any of
    * the stencil-modifying functions is used. */
   if (so->stencil[0].enabled) {
      if (so->stencil[0].func != PIPE_FUNC_ALWAYS ||
          (so->stencil[1].enabled && so->stencil[1].func != PIPE_FUNC_ALWAYS))
         disable_zs = false;

      if (so->stencil[0].fail_op != PIPE_STENCIL_OP_KEEP ||
          so->stencil[0].zfail_op != PIPE_STENCIL_OP_KEEP ||
          so->stencil[0].zpass_op != PIPE_STENCIL_OP_KEEP) {
         disable_zs = early_z = false;
      } else if (so->stencil[1].enabled) {
         if (so->stencil[1].fail_op != PIPE_STENCIL_OP_KEEP ||
             so->stencil[1].zfail_op != PIPE_STENCIL_OP_KEEP ||
             so->stencil[1].zpass_op != PIPE_STENCIL_OP_KEEP) {
            disable_zs = early_z = false;
         }
      }
   }

   /* Disable early z reject when no depth test is enabled.
    * This avoids having to sample depth even though we know it's going to
    * succeed. */
   if (so->depth.enabled == false || so->depth.func == PIPE_FUNC_ALWAYS)
      early_z = false;

   /* calculate extra_reference value */
   uint32_t extra_reference = 0;

   if (VIV_FEATURE(screen, chipMinorFeatures1, HALF_FLOAT))
      extra_reference = util_float_to_half(CLAMP(so->alpha.ref_value, 0.0f, 1.0f));

   cs->PE_STENCIL_CONFIG_EXT =
      VIVS_PE_STENCIL_CONFIG_EXT_EXTRA_ALPHA_REF(extra_reference);

   /* compare funcs have 1 to 1 mapping */
   cs->PE_DEPTH_CONFIG =
      VIVS_PE_DEPTH_CONFIG_DEPTH_FUNC(so->depth.enabled ? so->depth.func
                                                        : PIPE_FUNC_ALWAYS) |
      COND(so->depth.writemask, VIVS_PE_DEPTH_CONFIG_WRITE_ENABLE) |
      COND(early_z, VIVS_PE_DEPTH_CONFIG_EARLY_Z) |
      /* this bit changed meaning with HALTI5: */
      COND(disable_zs && screen->specs.halti < 5, VIVS_PE_DEPTH_CONFIG_DISABLE_ZS);
   cs->PE_ALPHA_OP =
      COND(so->alpha.enabled, VIVS_PE_ALPHA_OP_ALPHA_TEST) |
      VIVS_PE_ALPHA_OP_ALPHA_FUNC(so->alpha.func) |
      VIVS_PE_ALPHA_OP_ALPHA_REF(etna_cfloat_to_uint8(so->alpha.ref_value));

   for (unsigned i = 0; i < 2; i++) {
      const struct pipe_stencil_state *stencil_front = (so->stencil[1].enabled && so->stencil[1].valuemask) ? &so->stencil[i] : &so->stencil[0];
      const struct pipe_stencil_state *stencil_back = (so->stencil[1].enabled && so->stencil[1].valuemask) ? &so->stencil[!i] : &so->stencil[0];
      cs->PE_STENCIL_OP[i] =
         VIVS_PE_STENCIL_OP_FUNC_FRONT(stencil_front->func) |
         VIVS_PE_STENCIL_OP_FUNC_BACK(stencil_back->func) |
         VIVS_PE_STENCIL_OP_FAIL_FRONT(translate_stencil_op(stencil_front->fail_op)) |
         VIVS_PE_STENCIL_OP_FAIL_BACK(translate_stencil_op(stencil_back->fail_op)) |
         VIVS_PE_STENCIL_OP_DEPTH_FAIL_FRONT(translate_stencil_op(stencil_front->zfail_op)) |
         VIVS_PE_STENCIL_OP_DEPTH_FAIL_BACK(translate_stencil_op(stencil_back->zfail_op)) |
         VIVS_PE_STENCIL_OP_PASS_FRONT(translate_stencil_op(stencil_front->zpass_op)) |
         VIVS_PE_STENCIL_OP_PASS_BACK(translate_stencil_op(stencil_back->zpass_op));
      cs->PE_STENCIL_CONFIG[i] =
         translate_stencil_mode(so->stencil[0].enabled, so->stencil[0].enabled) |
         VIVS_PE_STENCIL_CONFIG_MASK_FRONT(stencil_front->valuemask) |
         VIVS_PE_STENCIL_CONFIG_WRITE_MASK_FRONT(stencil_front->writemask);
      cs->PE_STENCIL_CONFIG_EXT2[i] =
         VIVS_PE_STENCIL_CONFIG_EXT2_MASK_BACK(stencil_back->valuemask) |
         VIVS_PE_STENCIL_CONFIG_EXT2_WRITE_MASK_BACK(stencil_back->writemask);
   }

   /* XXX does alpha/stencil test affect PE_COLOR_FORMAT_OVERWRITE? */
   return cs;
}
