/**************************************************************************
 *
 * 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.
 *
 **************************************************************************/

/**
 * Post-transform vertex buffering.  This is an optional part of the
 * softpipe rendering pipeline.
 * Probably not desired in general, but useful for testing/debuggin.
 * Enabled/Disabled with SP_VBUF env var.
 *
 * Authors
 *  Brian Paul
 */


#include "sp_context.h"
#include "sp_state.h"
#include "sp_prim_vbuf.h"
#include "sp_prim_setup.h"
#include "sp_setup.h"
#include "draw/draw_context.h"
#include "draw/draw_vbuf.h"


#define SP_MAX_VBUF_INDEXES 1024
#define SP_MAX_VBUF_SIZE    4096

typedef const float (*cptrf4)[4];

/**
 * Subclass of vbuf_render.
 */
struct softpipe_vbuf_render
{
   struct vbuf_render base;
   struct softpipe_context *softpipe;
   uint prim;
   uint vertex_size;
   void *vertex_buffer;
};


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


static const struct vertex_info *
sp_vbuf_get_vertex_info(struct vbuf_render *vbr)
{
   struct softpipe_vbuf_render *cvbr = softpipe_vbuf_render(vbr);
   return softpipe_get_vbuf_vertex_info(cvbr->softpipe);
}


static void *
sp_vbuf_allocate_vertices(struct vbuf_render *vbr,
                            ushort vertex_size, ushort nr_vertices)
{
   struct softpipe_vbuf_render *cvbr = softpipe_vbuf_render(vbr);
   assert(!cvbr->vertex_buffer);
   cvbr->vertex_buffer = align_malloc(vertex_size * nr_vertices, 16);
   cvbr->vertex_size = vertex_size;
   return cvbr->vertex_buffer;
}


static void
sp_vbuf_release_vertices(struct vbuf_render *vbr, void *vertices,
                           unsigned vertex_size, unsigned vertices_used)
{
   struct softpipe_vbuf_render *cvbr = softpipe_vbuf_render(vbr);
   align_free(vertices);
   assert(vertices == cvbr->vertex_buffer);
   cvbr->vertex_buffer = NULL;
}


static boolean
sp_vbuf_set_primitive(struct vbuf_render *vbr, unsigned prim)
{
   struct softpipe_vbuf_render *cvbr = softpipe_vbuf_render(vbr);
   if (prim == PIPE_PRIM_TRIANGLES ||
       prim == PIPE_PRIM_LINES ||
       prim == PIPE_PRIM_POINTS) {
      cvbr->prim = prim;
      return TRUE;
   }
   else {
      return FALSE;
   }

}


/**
 * Recalculate prim's determinant.  This is needed as we don't have
 * get this information through the vbuf_render interface & we must
 * calculate it here.
 */
static float
calc_det( const float (*v0)[4],
          const float (*v1)[4],
          const float (*v2)[4] )
{
   /* edge vectors e = v0 - v2, f = v1 - v2 */
   const float ex = v0[0][0] - v2[0][0];
   const float ey = v0[0][1] - v2[0][1];
   const float fx = v1[0][0] - v2[0][0];
   const float fy = v1[0][1] - v2[0][1];

   /* det = cross(e,f).z */
   return ex * fy - ey * fx;
}


static void
sp_vbuf_draw(struct vbuf_render *vbr, const ushort *indices, uint nr_indices)
{
   struct softpipe_vbuf_render *cvbr = softpipe_vbuf_render(vbr);
   struct softpipe_context *softpipe = cvbr->softpipe;
   unsigned vertex_size = softpipe->vertex_info_vbuf.size * sizeof(float);
   unsigned i, j;
   void *vertex_buffer = cvbr->vertex_buffer;
   cptrf4 v[3];

   /* XXX: break this dependency - make setup_context live under
    * softpipe, rename the old "setup" draw stage to something else.
    */
   struct draw_stage *setup = softpipe->setup;
   struct setup_context *setup_ctx = sp_draw_setup_context(softpipe->setup);
   
   /* XXX: call this from allocate_vertices: 
    */
   setup_prepare( setup_ctx );


   switch (cvbr->prim) {
   case PIPE_PRIM_TRIANGLES:
      for (i = 0; i < nr_indices; i += 3) {
         for (j = 0; j < 3; j++)
            v[j] = (cptrf4)((char *)vertex_buffer +
                             indices[i+j] * vertex_size);

         setup_tri( setup_ctx,
                    calc_det(v[0], v[1], v[2]),
                    v[0],
                    v[1],
                    v[2]);
      }
      break;

   case PIPE_PRIM_LINES:
      for (i = 0; i < nr_indices; i += 2) {
         for (j = 0; j < 2; j++)
            v[j] = (cptrf4)((char *)vertex_buffer +
                            indices[i+j] * vertex_size);

         setup_line( setup_ctx,
                     v[0],
                     v[1] );
      }
      break;

   case PIPE_PRIM_POINTS:
      for (i = 0; i < nr_indices; i++) {
         v[0] = (cptrf4)((char *)vertex_buffer +
                         indices[i] * vertex_size);

         setup_point( setup_ctx,
                      v[0] );
      }
      break;
   }

   /* XXX: why are we calling this???  If we had to call something, it
    * would be a function in sp_setup.c:
    */
   sp_draw_flush( setup );
}


/**
 * 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
sp_vbuf_draw_arrays(struct vbuf_render *vbr, uint start, uint nr)
{
   struct softpipe_vbuf_render *cvbr = softpipe_vbuf_render(vbr);
   struct softpipe_context *softpipe = cvbr->softpipe;
   struct draw_stage *setup = softpipe->setup;
   const void *vertex_buffer = cvbr->vertex_buffer;
   const unsigned vertex_size = softpipe->vertex_info_vbuf.size * sizeof(float);
   unsigned i;
   struct setup_context *setup_ctx = sp_draw_setup_context(setup);
   cptrf4 v[3];

#define VERTEX(I) \
   (cptrf4) ((char *) vertex_buffer + (I) * vertex_size)

   switch (cvbr->prim) {
   case PIPE_PRIM_POINTS:
      for (i = 0; i < nr; i++) {
         v[0] = VERTEX(i);
         setup_point( setup_ctx, v[0] );
      }
      break;
   case PIPE_PRIM_LINES:
      assert(nr % 2 == 0);
      for (i = 0; i < nr; i += 2) {
         v[0] = VERTEX(i);
         v[1] = VERTEX(i + 1);
         setup_line( setup_ctx, v[0], v[1] );
      }
      break;
   case PIPE_PRIM_LINE_STRIP:
      for (i = 1; i < nr; i++) {
         v[0] = VERTEX(i - 1);
         v[1] = VERTEX(i);
         setup_line( setup_ctx, v[0], v[1] );
      }
      break;
   case PIPE_PRIM_TRIANGLES:
      assert(nr % 3 == 0);
      for (i = 0; i < nr; i += 3) {
         v[0] = VERTEX(i + 0);
         v[1] = VERTEX(i + 1);
         v[2] = VERTEX(i + 2);
         setup_tri( setup_ctx,
                    calc_det(v[0], v[1], v[2]),
                    v[0],
                    v[1],
                    v[2] );
      }
      break;
   case PIPE_PRIM_TRIANGLE_STRIP:
      assert(nr >= 3);
      for (i = 2; i < nr; i++) {
         v[0] = VERTEX(i - 2);
         v[1] = VERTEX(i - 1);
         v[2] = VERTEX(i);
         setup_tri( setup_ctx,
                    calc_det(v[0], v[1], v[2]),
                    v[0],
                    v[1],
                    v[2] );
      }
      break;
   case PIPE_PRIM_TRIANGLE_FAN:
      assert(nr >= 3);
      for (i = 2; i < nr; i++) {
         v[0] = VERTEX(0);
         v[1] = VERTEX(i - 1);
         v[2] = VERTEX(i);
         setup_tri( setup_ctx,
                    calc_det(v[0], v[1], v[2]),
                    v[0],
                    v[1],
                    v[2] );
      }
      break;
   case PIPE_PRIM_QUADS:
      assert(nr % 4 == 0);
      for (i = 0; i < nr; i += 4) {
         v[0] = VERTEX(i + 0);
         v[1] = VERTEX(i + 1);
         v[2] = VERTEX(i + 2);
         setup_tri( setup_ctx,
                    calc_det(v[0], v[1], v[2]),
                    v[0],
                    v[1],
                    v[2] );

         v[0] = VERTEX(i + 0);
         v[1] = VERTEX(i + 2);
         v[2] = VERTEX(i + 3);
         setup_tri( setup_ctx,
                    calc_det(v[0], v[1], v[2]),
                    v[0],
                    v[1],
                    v[2] );
      }
      break;
   case PIPE_PRIM_QUAD_STRIP:
      assert(nr >= 4);
      for (i = 2; i < nr; i += 2) {
         v[0] = VERTEX(i - 2);
         v[1] = VERTEX(i);
         v[2] = VERTEX(i + 1);
         setup_tri( setup_ctx,
                    calc_det(v[0], v[1], v[2]),
                    v[0],
                    v[1],
                    v[2] );

         v[0] = VERTEX(i - 2);
         v[1] = VERTEX(i + 1);
         v[2] = VERTEX(i - 1);
         setup_tri( setup_ctx,
                    calc_det(v[0], v[1], v[2]),
                    v[0],
                    v[1],
                    v[2] );
      }
      break;
   case PIPE_PRIM_POLYGON:
      /* draw as tri fan */
      for (i = 2; i < nr; i++) {
         v[0] = VERTEX(0);
         v[1] = VERTEX(i - 1);
         v[2] = VERTEX(i);
         setup_tri( setup_ctx,
                    calc_det(v[0], v[1], v[2]),
                    v[0],
                    v[1],
                    v[2] );
      }
      break;
   default:
      /* XXX finish remaining prim types */
      assert(0);
   }

#undef VERTEX
}



static void
sp_vbuf_destroy(struct vbuf_render *vbr)
{
   struct softpipe_vbuf_render *cvbr = softpipe_vbuf_render(vbr);
   cvbr->softpipe->vbuf_render = NULL;
   FREE(cvbr);
}


/**
 * Initialize the post-transform vertex buffer information for the given
 * context.
 */
void
sp_init_vbuf(struct softpipe_context *sp)
{
   assert(sp->draw);

   sp->vbuf_render = CALLOC_STRUCT(softpipe_vbuf_render);

   sp->vbuf_render->base.max_indices = SP_MAX_VBUF_INDEXES;
   sp->vbuf_render->base.max_vertex_buffer_bytes = SP_MAX_VBUF_SIZE;

   sp->vbuf_render->base.get_vertex_info = sp_vbuf_get_vertex_info;
   sp->vbuf_render->base.allocate_vertices = sp_vbuf_allocate_vertices;
   sp->vbuf_render->base.set_primitive = sp_vbuf_set_primitive;
   sp->vbuf_render->base.draw = sp_vbuf_draw;
   sp->vbuf_render->base.draw_arrays = sp_vbuf_draw_arrays;
   sp->vbuf_render->base.release_vertices = sp_vbuf_release_vertices;
   sp->vbuf_render->base.destroy = sp_vbuf_destroy;

   sp->vbuf_render->softpipe = sp;

   sp->vbuf = draw_vbuf_stage(sp->draw, &sp->vbuf_render->base);

   draw_set_rasterize_stage(sp->draw, sp->vbuf);

   draw_set_render(sp->draw, &sp->vbuf_render->base);
}