/**************************************************************************
 * 
 * Copyright 2003 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.
 * 
 **************************************************************************/

#include "pipe/p_util.h"
#include "pipe/p_shader_tokens.h"
#include "pipe/draw/draw_context.h"
#include "pipe/draw/draw_vertex.h"
#include "pipe/draw/draw_private.h"
#include "sp_context.h"
#include "sp_state.h"


static int
find_vs_output(const struct pipe_shader_state *vs,
               uint semantic_name,
               uint semantic_index)
{
   uint i;
   for (i = 0; i < vs->num_outputs; i++) {
      if (vs->output_semantic_name[i] == semantic_name &&
          vs->output_semantic_index[i] == semantic_index)
         return i;
   }
   return -1;
}



/**
 * Determine how to map vertex program outputs to fragment program inputs.
 * Basically, this will be used when computing the triangle interpolation
 * coefficients from the post-transform vertex attributes.
 */
static void calculate_vertex_layout( struct softpipe_context *softpipe )
{
   const struct pipe_shader_state *vs = &softpipe->vs->shader;
   const struct pipe_shader_state *fs = &softpipe->fs->shader;
   const enum interp_mode colorInterp
      = softpipe->rasterizer->flatshade ? INTERP_CONSTANT : INTERP_LINEAR;
   struct vertex_info *vinfo = &softpipe->vertex_info;
   uint i;

   if (softpipe->vbuf) {
      /* if using the post-transform vertex buffer, tell draw_vbuf to
       * simply emit the whole post-xform vertex as-is:
       */
      struct vertex_info *vinfo_vbuf = &softpipe->vertex_info_vbuf;
      vinfo_vbuf->num_attribs = 0;
      draw_emit_vertex_attr(vinfo_vbuf, EMIT_ALL, INTERP_NONE, 0);
      vinfo_vbuf->size = 4 * vs->num_outputs + sizeof(struct vertex_header)/4;
   }

   /*
    * Loop over fragment shader inputs, searching for the matching output
    * from the vertex shader.
    */
   vinfo->num_attribs = 0;
   for (i = 0; i < fs->num_inputs; i++) {
      int src;
      switch (fs->input_semantic_name[i]) {
      case TGSI_SEMANTIC_POSITION:
         src = find_vs_output(vs, TGSI_SEMANTIC_POSITION, 0);
         assert(src >= 0);
         draw_emit_vertex_attr(vinfo, EMIT_4F, INTERP_POS, src);
         break;

      case TGSI_SEMANTIC_COLOR:
         src = find_vs_output(vs, TGSI_SEMANTIC_COLOR, 
                              fs->input_semantic_index[i]);
         assert(src >= 0);
         draw_emit_vertex_attr(vinfo, EMIT_4F, colorInterp, src);
         break;

      case TGSI_SEMANTIC_FOG:
         src = find_vs_output(vs, TGSI_SEMANTIC_FOG, 0);
#if 1
         if (src < 0) /* XXX temp hack, try demos/fogcoord.c with this */
            src = 0;
#endif
         assert(src >= 0);
         draw_emit_vertex_attr(vinfo, EMIT_4F, INTERP_PERSPECTIVE, src);
         break;

      case TGSI_SEMANTIC_GENERIC:
         /* this includes texcoords and varying vars */
         src = find_vs_output(vs, TGSI_SEMANTIC_GENERIC,
                              fs->input_semantic_index[i]);
         assert(src >= 0);
         draw_emit_vertex_attr(vinfo, EMIT_4F, INTERP_PERSPECTIVE, src);
         break;

      default:
         assert(0);
      }
   }

   softpipe->psize_slot = find_vs_output(vs, TGSI_SEMANTIC_PSIZE, 0);
   if (softpipe->psize_slot >= 0) {
      draw_emit_vertex_attr(vinfo, EMIT_4F, INTERP_CONSTANT,
                            softpipe->psize_slot);
   }

   draw_compute_vertex_size(vinfo);
}


/**
 * Recompute cliprect from scissor bounds, scissor enable and surface size.
 */
static void
compute_cliprect(struct softpipe_context *sp)
{
   unsigned surfWidth, surfHeight;

   if (sp->framebuffer.num_cbufs > 0) {
      surfWidth = sp->framebuffer.cbufs[0]->width;
      surfHeight = sp->framebuffer.cbufs[0]->height;
   }
   else {
      /* no surface? */
      surfWidth = sp->scissor.maxx;
      surfHeight = sp->scissor.maxy;
   }

   if (sp->rasterizer->scissor) {
      /* clip to scissor rect */
      sp->cliprect.minx = MAX2(sp->scissor.minx, 0);
      sp->cliprect.miny = MAX2(sp->scissor.miny, 0);
      sp->cliprect.maxx = MIN2(sp->scissor.maxx, surfWidth);
      sp->cliprect.maxy = MIN2(sp->scissor.maxy, surfHeight);
   }
   else {
      /* clip to surface bounds */
      sp->cliprect.minx = 0;
      sp->cliprect.miny = 0;
      sp->cliprect.maxx = surfWidth;
      sp->cliprect.maxy = surfHeight;
   }
}


/* Hopefully this will remain quite simple, otherwise need to pull in
 * something like the state tracker mechanism.
 */
void softpipe_update_derived( struct softpipe_context *softpipe )
{
   if (softpipe->dirty & (SP_NEW_RASTERIZER |
                          SP_NEW_FS |
                          SP_NEW_VS))
      calculate_vertex_layout( softpipe );

   if (softpipe->dirty & (SP_NEW_SCISSOR |
                          SP_NEW_DEPTH_STENCIL_ALPHA |
                          SP_NEW_FRAMEBUFFER))
      compute_cliprect(softpipe);

   if (softpipe->dirty & (SP_NEW_BLEND |
                          SP_NEW_DEPTH_STENCIL_ALPHA |
                          SP_NEW_FRAMEBUFFER |
                          SP_NEW_RASTERIZER |
                          SP_NEW_FS | 
			  SP_NEW_QUERY))
      sp_build_quad_pipeline(softpipe);

   softpipe->dirty = 0;
}