/**************************************************************************
 * 
 * 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/draw/draw_context.h"
#include "pipe/draw/draw_vertex.h"

#include "sp_context.h"
#include "sp_state.h"

#include "pipe/tgsi/exec/tgsi_attribs.h"



static void
emit_vertex_attr(struct vertex_info *vinfo, uint vfAttr, uint format,
                 uint interp)
{
   const uint n = vinfo->num_attribs;
   vinfo->attr_mask |= (1 << vfAttr);
   vinfo->slot_to_attrib[n] = vfAttr;
   vinfo->interp_mode[n] = interp;
   vinfo->format[n] = format;
   vinfo->num_attribs++;
}



/**
 * Determine which post-transform / pre-rasterization vertex attributes
 * we need.
 * Derived from:  fs, setup states.
 */
static void calculate_vertex_layout( struct softpipe_context *softpipe )
{
   const unsigned inputsRead = softpipe->fs.inputs_read;
   const uint colorInterp
      = softpipe->setup.flatshade ? INTERP_CONSTANT : INTERP_LINEAR;
   struct vertex_info *vinfo = &softpipe->vertex_info;
   uint i;

   memset(vinfo, 0, sizeof(*vinfo));

   /* Need Z if depth test is enabled or the fragment program uses the
    * fragment position (XYZW).
    */
   if (softpipe->depth_test.enabled ||
       (inputsRead & (1 << TGSI_ATTRIB_POS)))
      softpipe->need_z = TRUE;
   else
      softpipe->need_z = FALSE;

   /* Need W if we do any perspective-corrected interpolation or the
    * fragment program uses the fragment position.
    */
   if (inputsRead & (1 << TGSI_ATTRIB_POS))
      softpipe->need_w = TRUE;
   else
      softpipe->need_w = FALSE;

   /* position */
   /* TODO - Figure out if we need to do perspective divide, etc. */
   emit_vertex_attr(vinfo, TGSI_ATTRIB_POS, FORMAT_4F, INTERP_LINEAR);
 
   /* color0 */
   if (inputsRead & (1 << TGSI_ATTRIB_COLOR0)) {
      emit_vertex_attr(vinfo, TGSI_ATTRIB_COLOR0, FORMAT_4F, colorInterp);
   }

   /* color1 */
   if (inputsRead & (1 << TGSI_ATTRIB_COLOR1)) {
      emit_vertex_attr(vinfo, TGSI_ATTRIB_COLOR1, FORMAT_4F, colorInterp);
   }

   /* fog */
   if (inputsRead & (1 << TGSI_ATTRIB_FOG)) {
      emit_vertex_attr(vinfo, TGSI_ATTRIB_FOG, FORMAT_1F, INTERP_PERSPECTIVE);
   }

   /* texcoords and varying vars */
   for (i = TGSI_ATTRIB_TEX0; i < TGSI_ATTRIB_VAR7; i++) {
      if (inputsRead & (1 << i)) {
         emit_vertex_attr(vinfo, i, FORMAT_4F, INTERP_PERSPECTIVE);
         softpipe->need_w = TRUE;
      }
   }

   softpipe->nr_frag_attrs = vinfo->num_attribs;

   /* Additional attributes required for setup: Just twosided
    * lighting.  Edgeflag is dealt with specially by setting bits in
    * the vertex header.
    */
   if (softpipe->setup.light_twoside) {
      if (inputsRead & (1 << TGSI_ATTRIB_COLOR0)) {
         emit_vertex_attr(vinfo, TGSI_ATTRIB_BFC0, FORMAT_OMIT, INTERP_LINEAR);
      }
	    
      if (inputsRead & (1 << TGSI_ATTRIB_COLOR1)) {
         emit_vertex_attr(vinfo, TGSI_ATTRIB_BFC1, FORMAT_OMIT, INTERP_LINEAR);
      }
   }

   /* If the attributes have changed, tell the draw module about
    * the new vertex layout.
    */
   if (vinfo->attr_mask != softpipe->attr_mask) {
      softpipe->attr_mask = vinfo->attr_mask;

      draw_set_vertex_attributes( softpipe->draw,
                                  vinfo->slot_to_attrib,
                                  vinfo->num_attribs);
   }
}


/**
 * 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->setup.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_SETUP | SP_NEW_FS))
      calculate_vertex_layout( softpipe );

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

   if (softpipe->dirty & (SP_NEW_BLEND |
                          SP_NEW_DEPTH_TEST |
                          SP_NEW_ALPHA_TEST |
                          SP_NEW_FRAMEBUFFER |
                          SP_NEW_STENCIL |
                          SP_NEW_SETUP |
                          SP_NEW_FS))
      sp_build_quad_pipeline(softpipe);

   softpipe->dirty = 0;
}