/* SPDX-FileCopyrightText: 2019 Blender Authors
 *
 * SPDX-License-Identifier: GPL-2.0-or-later */

/** \file
 * \ingroup draw_engine
 */

#include "BKE_paint.hh"
#include "DRW_render.hh"

#include "overlay_private.hh"

void OVERLAY_facing_init(OVERLAY_Data * /*vedata*/) {}

void OVERLAY_facing_cache_init(OVERLAY_Data *vedata)
{
  const DRWContextState *draw_ctx = DRW_context_state_get();
  OVERLAY_PassList *psl = vedata->psl;
  OVERLAY_PrivateData *pd = vedata->stl->pd;
  const bool is_solid_viewport = draw_ctx->v3d && draw_ctx->v3d->shading.type == OB_SOLID;

  for (int i = 0; i < 2; i++) {
    /* Non Meshes Pass (Camera, empties, lights ...) */
    DRWState state = DRW_STATE_WRITE_COLOR | DRW_STATE_WRITE_DEPTH;
    /* Use the Depth Equal test in solid mode to ensure transparent textures display correctly.
     * (See #128113). And the Depth-Less test in other modes (E.g. EEVEE) to ensure the overlay
     * displays correctly (See # 114000). */
    state |= is_solid_viewport ? DRW_STATE_DEPTH_EQUAL : DRW_STATE_DEPTH_LESS_EQUAL;

    if (is_solid_viewport && (draw_ctx->v3d->shading.flag & V3D_SHADING_BACKFACE_CULLING)) {
      state |= DRW_STATE_CULL_BACK;
    }

    DRW_PASS_CREATE(psl->facing_ps[i], state | pd->clipping_state);

    GPUShader *sh = OVERLAY_shader_facing();
    pd->facing_grp[i] = DRW_shgroup_create(sh, psl->facing_ps[i]);
    DRW_shgroup_uniform_block(pd->facing_grp[i], "globalsBlock", G_draw.block_ubo);
  }

  if (!pd->use_in_front) {
    pd->facing_grp[IN_FRONT] = pd->facing_grp[NOT_IN_FRONT];
  }
}

void OVERLAY_facing_cache_populate(OVERLAY_Data *vedata, Object *ob)
{
  OVERLAY_PrivateData *pd = vedata->stl->pd;

  if (pd->xray_enabled) {
    return;
  }

  const DRWContextState *draw_ctx = DRW_context_state_get();
  const bool use_sculpt_pbvh = BKE_sculptsession_use_pbvh_draw(ob, draw_ctx->rv3d) &&
                               !DRW_state_is_image_render();
  const bool is_xray = (ob->dtx & OB_DRAW_IN_FRONT) != 0;

  if (use_sculpt_pbvh) {
    DRW_shgroup_call_sculpt(pd->facing_grp[is_xray], ob, false, false, false, false, false);
  }
  else {
    blender::gpu::Batch *geom = DRW_cache_object_surface_get(ob);
    if (geom) {
      DRW_shgroup_call(pd->facing_grp[is_xray], geom, ob);
    }
  }
}

void OVERLAY_facing_draw(OVERLAY_Data *vedata)
{
  OVERLAY_PassList *psl = vedata->psl;

  DRW_draw_pass(psl->facing_ps[NOT_IN_FRONT]);
}

void OVERLAY_facing_infront_draw(OVERLAY_Data *vedata)
{
  OVERLAY_PassList *psl = vedata->psl;

  DRW_draw_pass(psl->facing_ps[IN_FRONT]);
}
