u_indices.c

/*
 * Copyright 2009 VMware, Inc.
 * 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
 * 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
 * VMWARE 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 "u_indices.h"
#include "u_indices_priv.h"

static void translate_memcpy_ushort( const void *in,
                                     unsigned start,
                                     unsigned in_nr,
                                     unsigned out_nr,
                                     unsigned restart_index,
                                     void *out )
{
   memcpy(out, &((short *)in)[start], out_nr*sizeof(short));
}
                              
static void translate_memcpy_uint( const void *in,
                                   unsigned start,
                                   unsigned in_nr,
                                   unsigned out_nr,
                                   unsigned restart_index,
                                   void *out )
{
   memcpy(out, &((int *)in)[start], out_nr*sizeof(int));
}

static void translate_byte_to_ushort( const void *in,
                                      unsigned start,
                                      UNUSED unsigned in_nr,
                                      unsigned out_nr,
                                      UNUSED unsigned restart_index,
                                      void *out )
{
   uint8_t *src = (uint8_t *)in + start;
   uint16_t *dst = out;
   while (out_nr--) {
      *dst++ = *src++;
   }
}

enum pipe_prim_type
u_index_prim_type_convert(unsigned hw_mask, enum pipe_prim_type prim, bool pv_matches)
{
   if ((hw_mask & (1<<prim)) && pv_matches)
      return prim;

   switch (prim) {
   case PIPE_PRIM_POINTS:
      return PIPE_PRIM_POINTS;
   case PIPE_PRIM_LINES:
   case PIPE_PRIM_LINE_STRIP:
   case PIPE_PRIM_LINE_LOOP:
      return PIPE_PRIM_LINES;
   case PIPE_PRIM_TRIANGLES:
   case PIPE_PRIM_TRIANGLE_STRIP:
   case PIPE_PRIM_TRIANGLE_FAN:
   case PIPE_PRIM_QUADS:
   case PIPE_PRIM_QUAD_STRIP:
   case PIPE_PRIM_POLYGON:
      return PIPE_PRIM_TRIANGLES;
   case PIPE_PRIM_LINES_ADJACENCY:
   case PIPE_PRIM_LINE_STRIP_ADJACENCY:
      return PIPE_PRIM_LINES_ADJACENCY;
   case PIPE_PRIM_TRIANGLES_ADJACENCY:
   case PIPE_PRIM_TRIANGLE_STRIP_ADJACENCY:
      return PIPE_PRIM_TRIANGLES_ADJACENCY;
   default:
      assert(0);
      break;
   }
   return PIPE_PRIM_POINTS;
}

/**
 * Translate indexes when a driver can't support certain types
 * of drawing.  Example include:
 * - Translate 1-byte indexes into 2-byte indexes
 * - Translate PIPE_PRIM_QUADS into PIPE_PRIM_TRIANGLES when the hardware
 *   doesn't support the former.
 * - Translate from first provoking vertex to last provoking vertex and
 *   vice versa.
 *
 * Note that this function is used for indexed primitives.
 *
 * \param hw_mask  mask of (1 << PIPE_PRIM_x) flags indicating which types
 *                 of primitives are supported by the hardware.
 * \param prim  incoming PIPE_PRIM_x
 * \param in_index_size  bytes per index value (1, 2 or 4)
 * \param nr  number of incoming vertices
 * \param in_pv  incoming provoking vertex convention (PV_FIRST or PV_LAST)
 * \param out_pv  desired provoking vertex convention (PV_FIRST or PV_LAST)
 * \param prim_restart  whether primitive restart is disable or enabled
 * \param out_prim  returns new PIPE_PRIM_x we'll translate to
 * \param out_index_size  returns bytes per new index value (2 or 4)
 * \param out_nr  returns number of new vertices
 * \param out_translate  returns the translation function to use by the caller
 */
enum indices_mode
u_index_translator(unsigned hw_mask,
                   enum pipe_prim_type prim,
                   unsigned in_index_size,
                   unsigned nr,
                   unsigned in_pv,
                   unsigned out_pv,
                   unsigned prim_restart,
                   enum pipe_prim_type *out_prim,
                   unsigned *out_index_size,
                   unsigned *out_nr,
                   u_translate_func *out_translate)
{
   unsigned in_idx;
   unsigned out_idx;
   enum indices_mode ret = U_TRANSLATE_NORMAL;

   assert(in_index_size == 1 ||
          in_index_size == 2 ||
          in_index_size == 4);

   u_index_init();

   in_idx = in_size_idx(in_index_size);
   *out_index_size = u_index_size_convert(in_index_size);
   out_idx = out_size_idx(*out_index_size);

   if ((hw_mask & (1<<prim)) &&
       in_pv == out_pv)
   {
      if (in_index_size == 4)
         *out_translate = translate_memcpy_uint;
      else if (in_index_size == 2)
         *out_translate = translate_memcpy_ushort;
      else
         *out_translate = translate_byte_to_ushort;

      *out_prim = prim;
      *out_nr = nr;

      return U_TRANSLATE_MEMCPY;
   }
   *out_translate = translate[in_idx][out_idx][in_pv][out_pv][prim_restart][prim];
   *out_prim = u_index_prim_type_convert(hw_mask, prim, in_pv == out_pv);
   *out_nr = u_index_count_converted_indices(hw_mask, in_pv == out_pv, prim, nr);

   return ret;
}

unsigned
u_index_count_converted_indices(unsigned hw_mask, bool pv_matches, enum pipe_prim_type prim, unsigned nr)
{
   if ((hw_mask & (1<<prim)) && pv_matches)
      return nr;

   switch (prim) {
   case PIPE_PRIM_POINTS:
      return nr;
   case PIPE_PRIM_LINES:
      return nr;
   case PIPE_PRIM_LINE_STRIP:
      return (nr - 1) * 2;
   case PIPE_PRIM_LINE_LOOP:
      return nr * 2;
   case PIPE_PRIM_TRIANGLES:
      return nr;
   case PIPE_PRIM_TRIANGLE_STRIP:
      return (nr - 2) * 3;
   case PIPE_PRIM_TRIANGLE_FAN:
      return (nr - 2) * 3;
   case PIPE_PRIM_QUADS:
      return (nr / 4) * 6;
   case PIPE_PRIM_QUAD_STRIP:
      return (nr - 2) * 3;
   case PIPE_PRIM_POLYGON:
      return (nr - 2) * 3;
   case PIPE_PRIM_LINES_ADJACENCY:
      return nr;
   case PIPE_PRIM_LINE_STRIP_ADJACENCY:
      return (nr - 3) * 4;
   case PIPE_PRIM_TRIANGLES_ADJACENCY:
      return nr;
   case PIPE_PRIM_TRIANGLE_STRIP_ADJACENCY:
      return ((nr - 4) / 2) * 6;
   default:
      assert(0);
      break;
   }
   return nr;
}


/**
 * If a driver does not support a particular gallium primitive type
 * (such as PIPE_PRIM_QUAD_STRIP) this function can be used to help
 * convert the primitive into a simpler type (like PIPE_PRIM_TRIANGLES).
 *
 * The generator functions generates a number of ushort or uint indexes
 * for drawing the new type of primitive.
 *
 * Note that this function is used for non-indexed primitives.
 *
 * \param hw_mask  a bitmask of (1 << PIPE_PRIM_x) values that indicates
 *                 kind of primitives are supported by the driver.
 * \param prim  the PIPE_PRIM_x that the user wants to draw
 * \param start  index of first vertex to draw
 * \param nr  number of vertices to draw
 * \param in_pv  user's provoking vertex (PV_FIRST/LAST)
 * \param out_pv  desired proking vertex for the hardware (PV_FIRST/LAST)
 * \param out_prim  returns the new primitive type for the driver
 * \param out_index_size  returns OUT_USHORT or OUT_UINT
 * \param out_nr  returns new number of vertices to draw
 * \param out_generate  returns pointer to the generator function
 */
enum indices_mode
u_index_generator(unsigned hw_mask,
                  enum pipe_prim_type prim,
                  unsigned start,
                  unsigned nr,
                  unsigned in_pv,
                  unsigned out_pv,
                  enum pipe_prim_type *out_prim,
                  unsigned *out_index_size,
                  unsigned *out_nr,
                  u_generate_func *out_generate)
{
   unsigned out_idx;

   u_index_init();

   *out_index_size = ((start + nr) > 0xfffe) ? 4 : 2;
   out_idx = out_size_idx(*out_index_size);
   *out_prim = u_index_prim_type_convert(hw_mask, prim, in_pv == out_pv);
   *out_nr = u_index_count_converted_indices(hw_mask, in_pv == out_pv, prim, nr);

   if ((hw_mask & (1<<prim)) && 
       (in_pv == out_pv)) {
       
      *out_generate = generate[out_idx][in_pv][out_pv][PIPE_PRIM_POINTS];
      return U_GENERATE_LINEAR;
   }
   *out_generate = generate[out_idx][in_pv][out_pv][prim];
   return prim == PIPE_PRIM_LINE_LOOP ? U_GENERATE_ONE_OFF : U_GENERATE_REUSABLE;
}