/**************************************************************************
 *
 * Copyright 2007 Tungsten Graphics, Inc., Cedar Park, Texas.
 * All Rights Reserved.
 *
 * 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 TUNGSTEN GRAPHICS AND/OR ITS 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.
 *
 **************************************************************************/

/**
 * Interface between 'draw' module's output and the llvmpipe rasterizer/setup
 * code.  When the 'draw' module has finished filling a vertex buffer, the
 * draw_arrays() functions below will be called.  Loop over the vertices and
 * call the point/line/tri setup functions.
 *
 * Authors
 *  Brian Paul
 */


#include "lp_setup_context.h"
#include "draw/draw_vbuf.h"
#include "draw/draw_vertex.h"
#include "util/u_memory.h"


#define LP_MAX_VBUF_INDEXES 1024
#define LP_MAX_VBUF_SIZE    4096

  
/** cast wrapper */
static struct lp_setup_context *
lp_setup_context(struct vbuf_render *vbr)
{
   return (struct lp_setup_context *) vbr;
}


static const struct vertex_info *
lp_setup_get_vertex_info(struct vbuf_render *vbr)
{
   struct lp_setup_context *setup = lp_setup_context(vbr);

   /* Vertex size/info depends on the latest state.
    * The draw module may have issued additional state-change commands.
    */
   lp_setup_update_state(setup, FALSE);

   return setup->vertex_info;
}


static boolean
lp_setup_allocate_vertices(struct vbuf_render *vbr,
                          ushort vertex_size, ushort nr_vertices)
{
   struct lp_setup_context *setup = lp_setup_context(vbr);
   unsigned size = vertex_size * nr_vertices;

   if (setup->vertex_buffer_size < size) {
      align_free(setup->vertex_buffer);
      setup->vertex_buffer = align_malloc(size, 16);
      setup->vertex_buffer_size = size;
   }

   setup->vertex_size = vertex_size;
   setup->nr_vertices = nr_vertices;
   
   return setup->vertex_buffer != NULL;
}

static void
lp_setup_release_vertices(struct vbuf_render *vbr)
{
   /* keep the old allocation for next time */
}

static void *
lp_setup_map_vertices(struct vbuf_render *vbr)
{
   struct lp_setup_context *setup = lp_setup_context(vbr);
   return setup->vertex_buffer;
}

static void 
lp_setup_unmap_vertices(struct vbuf_render *vbr, 
                       ushort min_index,
                       ushort max_index )
{
   struct lp_setup_context *setup = lp_setup_context(vbr);
   assert( setup->vertex_buffer_size >= (max_index+1) * setup->vertex_size );
   /* do nothing */
}


static void
lp_setup_set_primitive(struct vbuf_render *vbr, unsigned prim)
{
   lp_setup_context(vbr)->prim = prim;
}

typedef const float (*const_float4_ptr)[4];

static INLINE const_float4_ptr get_vert( const void *vertex_buffer,
                                         int index,
                                         int stride )
{
   return (const_float4_ptr)((char *)vertex_buffer + index * stride);
}

/**
 * draw elements / indexed primitives
 */
static void
lp_setup_draw_elements(struct vbuf_render *vbr, const ushort *indices, uint nr)
{
   struct lp_setup_context *setup = lp_setup_context(vbr);
   const unsigned stride = setup->vertex_info->size * sizeof(float);
   const void *vertex_buffer = setup->vertex_buffer;
   const boolean flatshade_first = setup->flatshade_first;
   unsigned i;

   assert(setup->setup.variant);

   if (!lp_setup_update_state(setup, TRUE))
      return;

   switch (setup->prim) {
   case PIPE_PRIM_POINTS:
      for (i = 0; i < nr; i++) {
         setup->point( setup,
                       get_vert(vertex_buffer, indices[i-0], stride) );
      }
      break;

   case PIPE_PRIM_LINES:
      for (i = 1; i < nr; i += 2) {
         setup->line( setup,
                      get_vert(vertex_buffer, indices[i-1], stride),
                      get_vert(vertex_buffer, indices[i-0], stride) );
      }
      break;

   case PIPE_PRIM_LINE_STRIP:
      for (i = 1; i < nr; i ++) {
         setup->line( setup,
                      get_vert(vertex_buffer, indices[i-1], stride),
                      get_vert(vertex_buffer, indices[i-0], stride) );
      }
      break;

   case PIPE_PRIM_LINE_LOOP:
      for (i = 1; i < nr; i ++) {
         setup->line( setup,
                      get_vert(vertex_buffer, indices[i-1], stride),
                      get_vert(vertex_buffer, indices[i-0], stride) );
      }
      if (nr) {
         setup->line( setup,
                      get_vert(vertex_buffer, indices[nr-1], stride),
                      get_vert(vertex_buffer, indices[0], stride) );
      }
      break;

   case PIPE_PRIM_TRIANGLES:
      for (i = 2; i < nr; i += 3) {
         setup->triangle( setup,
                          get_vert(vertex_buffer, indices[i-2], stride),
                          get_vert(vertex_buffer, indices[i-1], stride),
                          get_vert(vertex_buffer, indices[i-0], stride) );
      }
      break;

   case PIPE_PRIM_TRIANGLE_STRIP:
      if (flatshade_first) {
         for (i = 2; i < nr; i += 1) {
            /* emit first triangle vertex as first triangle vertex */
            setup->triangle( setup,
                             get_vert(vertex_buffer, indices[i-2], stride),
                             get_vert(vertex_buffer, indices[i+(i&1)-1], stride),
                             get_vert(vertex_buffer, indices[i-(i&1)], stride) );

         }
      }
      else {
         for (i = 2; i < nr; i += 1) {
            /* emit last triangle vertex as last triangle vertex */
            setup->triangle( setup,
                             get_vert(vertex_buffer, indices[i+(i&1)-2], stride),
                             get_vert(vertex_buffer, indices[i-(i&1)-1], stride),
                             get_vert(vertex_buffer, indices[i-0], stride) );
         }
      }
      break;

   case PIPE_PRIM_TRIANGLE_FAN:
      if (flatshade_first) {
         for (i = 2; i < nr; i += 1) {
            /* emit first non-spoke vertex as first vertex */
            setup->triangle( setup,
                             get_vert(vertex_buffer, indices[i-1], stride),
                             get_vert(vertex_buffer, indices[i-0], stride),
                             get_vert(vertex_buffer, indices[0], stride) );
         }
      }
      else {
         for (i = 2; i < nr; i += 1) {
            /* emit last non-spoke vertex as last vertex */
            setup->triangle( setup,
                             get_vert(vertex_buffer, indices[0], stride),
                             get_vert(vertex_buffer, indices[i-1], stride),
                             get_vert(vertex_buffer, indices[i-0], stride) );
         }
      }
      break;

   case PIPE_PRIM_QUADS:
      /* GL quads don't follow provoking vertex convention */
      if (flatshade_first) { 
         /* emit last quad vertex as first triangle vertex */
         for (i = 3; i < nr; i += 4) {
            setup->triangle( setup,
                             get_vert(vertex_buffer, indices[i-0], stride),
                             get_vert(vertex_buffer, indices[i-3], stride),
                             get_vert(vertex_buffer, indices[i-2], stride) );

            setup->triangle( setup,
                             get_vert(vertex_buffer, indices[i-0], stride),
                             get_vert(vertex_buffer, indices[i-2], stride),
                             get_vert(vertex_buffer, indices[i-1], stride) );
         }
      }
      else {
         /* emit last quad vertex as last triangle vertex */
         for (i = 3; i < nr; i += 4) {
            setup->triangle( setup,
                          get_vert(vertex_buffer, indices[i-3], stride),
                          get_vert(vertex_buffer, indices[i-2], stride),
                          get_vert(vertex_buffer, indices[i-0], stride) );

            setup->triangle( setup,
                             get_vert(vertex_buffer, indices[i-2], stride),
                             get_vert(vertex_buffer, indices[i-1], stride),
                             get_vert(vertex_buffer, indices[i-0], stride) );
         }
      }
      break;

   case PIPE_PRIM_QUAD_STRIP:
      /* GL quad strips don't follow provoking vertex convention */
      if (flatshade_first) { 
         /* emit last quad vertex as first triangle vertex */
         for (i = 3; i < nr; i += 2) {
            setup->triangle( setup,
                             get_vert(vertex_buffer, indices[i-0], stride),
                             get_vert(vertex_buffer, indices[i-3], stride),
                             get_vert(vertex_buffer, indices[i-2], stride) );
            setup->triangle( setup,
                             get_vert(vertex_buffer, indices[i-0], stride),
                             get_vert(vertex_buffer, indices[i-1], stride),
                             get_vert(vertex_buffer, indices[i-3], stride) );
         }
      }
      else {
         /* emit last quad vertex as last triangle vertex */
         for (i = 3; i < nr; i += 2) {
            setup->triangle( setup,
                             get_vert(vertex_buffer, indices[i-3], stride),
                             get_vert(vertex_buffer, indices[i-2], stride),
                             get_vert(vertex_buffer, indices[i-0], stride) );
            setup->triangle( setup,
                             get_vert(vertex_buffer, indices[i-1], stride),
                             get_vert(vertex_buffer, indices[i-3], stride),
                             get_vert(vertex_buffer, indices[i-0], stride) );
         }
      }
      break;

   case PIPE_PRIM_POLYGON:
      /* Almost same as tri fan but the _first_ vertex specifies the flat
       * shading color.
       */
      if (flatshade_first) { 
         /* emit first polygon  vertex as first triangle vertex */
         for (i = 2; i < nr; i += 1) {
            setup->triangle( setup,
                             get_vert(vertex_buffer, indices[0], stride),
                             get_vert(vertex_buffer, indices[i-1], stride),
                             get_vert(vertex_buffer, indices[i-0], stride) );
         }
      }
      else {
         /* emit first polygon  vertex as last triangle vertex */
         for (i = 2; i < nr; i += 1) {
            setup->triangle( setup,
                             get_vert(vertex_buffer, indices[i-1], stride),
                             get_vert(vertex_buffer, indices[i-0], stride),
                             get_vert(vertex_buffer, indices[0], stride) );
         }
      }
      break;

   default:
      assert(0);
   }
}


/**
 * This function is hit when the draw module is working in pass-through mode.
 * It's up to us to convert the vertex array into point/line/tri prims.
 */
static void
lp_setup_draw_arrays(struct vbuf_render *vbr, uint start, uint nr)
{
   struct lp_setup_context *setup = lp_setup_context(vbr);
   const unsigned stride = setup->vertex_info->size * sizeof(float);
   const void *vertex_buffer =
      (void *) get_vert(setup->vertex_buffer, start, stride);
   const boolean flatshade_first = setup->flatshade_first;
   unsigned i;

   if (!lp_setup_update_state(setup, TRUE))
      return;

   switch (setup->prim) {
   case PIPE_PRIM_POINTS:
      for (i = 0; i < nr; i++) {
         setup->point( setup,
                       get_vert(vertex_buffer, i-0, stride) );
      }
      break;

   case PIPE_PRIM_LINES:
      for (i = 1; i < nr; i += 2) {
         setup->line( setup,
                      get_vert(vertex_buffer, i-1, stride),
                      get_vert(vertex_buffer, i-0, stride) );
      }
      break;

   case PIPE_PRIM_LINE_STRIP:
      for (i = 1; i < nr; i ++) {
         setup->line( setup,
                      get_vert(vertex_buffer, i-1, stride),
                      get_vert(vertex_buffer, i-0, stride) );
      }
      break;

   case PIPE_PRIM_LINE_LOOP:
      for (i = 1; i < nr; i ++) {
         setup->line( setup,
                      get_vert(vertex_buffer, i-1, stride),
                      get_vert(vertex_buffer, i-0, stride) );
      }
      if (nr) {
         setup->line( setup,
                      get_vert(vertex_buffer, nr-1, stride),
                      get_vert(vertex_buffer, 0, stride) );
      }
      break;

   case PIPE_PRIM_TRIANGLES:
      for (i = 2; i < nr; i += 3) {
         setup->triangle( setup,
                          get_vert(vertex_buffer, i-2, stride),
                          get_vert(vertex_buffer, i-1, stride),
                          get_vert(vertex_buffer, i-0, stride) );
      }
      break;

   case PIPE_PRIM_TRIANGLE_STRIP:
      if (flatshade_first) {
         for (i = 2; i < nr; i++) {
            /* emit first triangle vertex as first triangle vertex */
            setup->triangle( setup,
                             get_vert(vertex_buffer, i-2, stride),
                             get_vert(vertex_buffer, i+(i&1)-1, stride),
                             get_vert(vertex_buffer, i-(i&1), stride) );
         }
      }
      else {
         for (i = 2; i < nr; i++) {
            /* emit last triangle vertex as last triangle vertex */
            setup->triangle( setup,
                             get_vert(vertex_buffer, i+(i&1)-2, stride),
                             get_vert(vertex_buffer, i-(i&1)-1, stride),
                             get_vert(vertex_buffer, i-0, stride) );
         }
      }
      break;

   case PIPE_PRIM_TRIANGLE_FAN:
      if (flatshade_first) {
         for (i = 2; i < nr; i += 1) {
            /* emit first non-spoke vertex as first vertex */
            setup->triangle( setup,
                             get_vert(vertex_buffer, i-1, stride),
                             get_vert(vertex_buffer, i-0, stride),
                             get_vert(vertex_buffer, 0, stride)  );
         }
      }
      else {
         for (i = 2; i < nr; i += 1) {
            /* emit last non-spoke vertex as last vertex */
            setup->triangle( setup,
                             get_vert(vertex_buffer, 0, stride),
                             get_vert(vertex_buffer, i-1, stride),
                             get_vert(vertex_buffer, i-0, stride) );
         }
      }
      break;

   case PIPE_PRIM_QUADS:
      /* GL quads don't follow provoking vertex convention */
      if (flatshade_first) { 
         /* emit last quad vertex as first triangle vertex */
         for (i = 3; i < nr; i += 4) {
            setup->triangle( setup,
                             get_vert(vertex_buffer, i-0, stride),
                             get_vert(vertex_buffer, i-3, stride),
                             get_vert(vertex_buffer, i-2, stride) );
            setup->triangle( setup,
                             get_vert(vertex_buffer, i-0, stride),
                             get_vert(vertex_buffer, i-2, stride),
                             get_vert(vertex_buffer, i-1, stride) );
         }
      }
      else {
         /* emit last quad vertex as last triangle vertex */
         for (i = 3; i < nr; i += 4) {
            setup->triangle( setup,
                             get_vert(vertex_buffer, i-3, stride),
                             get_vert(vertex_buffer, i-2, stride),
                             get_vert(vertex_buffer, i-0, stride) );
            setup->triangle( setup,
                             get_vert(vertex_buffer, i-2, stride),
                             get_vert(vertex_buffer, i-1, stride),
                             get_vert(vertex_buffer, i-0, stride) );
         }
      }
      break;

   case PIPE_PRIM_QUAD_STRIP:
      /* GL quad strips don't follow provoking vertex convention */
      if (flatshade_first) { 
         /* emit last quad vertex as first triangle vertex */
         for (i = 3; i < nr; i += 2) {
            setup->triangle( setup,
                             get_vert(vertex_buffer, i-0, stride),
                             get_vert(vertex_buffer, i-3, stride),
                             get_vert(vertex_buffer, i-2, stride) );
            setup->triangle( setup,
                             get_vert(vertex_buffer, i-0, stride),
                             get_vert(vertex_buffer, i-1, stride),
                             get_vert(vertex_buffer, i-3, stride) );
         }
      }
      else {
         /* emit last quad vertex as last triangle vertex */
         for (i = 3; i < nr; i += 2) {
            setup->triangle( setup,
                             get_vert(vertex_buffer, i-3, stride),
                             get_vert(vertex_buffer, i-2, stride),
                             get_vert(vertex_buffer, i-0, stride) );
            setup->triangle( setup,
                             get_vert(vertex_buffer, i-1, stride),
                             get_vert(vertex_buffer, i-3, stride),
                             get_vert(vertex_buffer, i-0, stride) );
         }
      }
      break;

   case PIPE_PRIM_POLYGON:
      /* Almost same as tri fan but the _first_ vertex specifies the flat
       * shading color.
       */
      if (flatshade_first) { 
         /* emit first polygon  vertex as first triangle vertex */
         for (i = 2; i < nr; i += 1) {
            setup->triangle( setup,
                             get_vert(vertex_buffer, 0, stride),
                             get_vert(vertex_buffer, i-1, stride),
                             get_vert(vertex_buffer, i-0, stride) );
         }
      }
      else {
         /* emit first polygon  vertex as last triangle vertex */
         for (i = 2; i < nr; i += 1) {
            setup->triangle( setup,
                             get_vert(vertex_buffer, i-1, stride),
                             get_vert(vertex_buffer, i-0, stride),
                             get_vert(vertex_buffer, 0, stride) );
         }
      }
      break;

   default:
      assert(0);
   }
}


static void
lp_setup_vbuf_destroy(struct vbuf_render *vbr)
{
   struct lp_setup_context *setup = lp_setup_context(vbr);
   if (setup->vertex_buffer) {
      align_free(setup->vertex_buffer);
      setup->vertex_buffer = NULL;
   }
   lp_setup_destroy(setup);
}


/**
 * Create the post-transform vertex handler for the given context.
 */
void
lp_setup_init_vbuf(struct lp_setup_context *setup)
{
   setup->base.max_indices = LP_MAX_VBUF_INDEXES;
   setup->base.max_vertex_buffer_bytes = LP_MAX_VBUF_SIZE;

   setup->base.get_vertex_info = lp_setup_get_vertex_info;
   setup->base.allocate_vertices = lp_setup_allocate_vertices;
   setup->base.map_vertices = lp_setup_map_vertices;
   setup->base.unmap_vertices = lp_setup_unmap_vertices;
   setup->base.set_primitive = lp_setup_set_primitive;
   setup->base.draw_elements = lp_setup_draw_elements;
   setup->base.draw_arrays = lp_setup_draw_arrays;
   setup->base.release_vertices = lp_setup_release_vertices;
   setup->base.destroy = lp_setup_vbuf_destroy;
}