path: root/src/gallium/auxiliary/draw/draw_passthrough.c

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

 /*
  * Authors:
  *   Keith Whitwell <keith@tungstengraphics.com>
  */


/* This code is a prototype of what a passhthrough vertex shader might
 * look like.
 *
 * Probably the best approach for us is to do:
 *    - vertex fetch
 *    - vertex shader
 *    - cliptest / viewport transform
 *
 * in one step, then examine the clipOrMask & choose between two paths:
 *
 * Either:
 *    - build primitive headers
 *    - clip and the primitive path
 *    - build clipped vertex buffers,
 *    - vertex-emit to vbuf buffers
 *
 * Or, if no clipping:
 *    - vertex-emit directly to vbuf buffers
 *
 * But when bypass clipping is enabled, we just take the latter
 * choice.  If (some new) passthrough-vertex-shader flag is also set,
 * the pipeline degenerates to:
 *
 *    - vertex fetch
 *    - vertex emit to vbuf buffers
 *
 * Which is what is prototyped here.
 */
#include "pipe/p_util.h"
#include "draw/draw_context.h"
#include "draw/draw_private.h"
#include "draw/draw_vbuf.h"
#include "draw/draw_vertex.h"


/**
 * General-purpose fetch from user's vertex arrays, emit to driver's
 * vertex buffer.
 *
 * XXX this is totally temporary.
 */
static void
fetch_store_general( struct draw_context *draw,
                     float *out,
                     unsigned start,
                     unsigned count )
{
   const struct vertex_info *vinfo = draw->render->get_vertex_info(draw->render);
   const unsigned nr_attrs = vinfo->num_attribs;
   uint i, j;

   const unsigned *pitch   = draw->vertex_fetch.pitch;
   const ubyte **src       = draw->vertex_fetch.src_ptr;

   for (i = start; i < count; i++) {
      for (j = 0; j < nr_attrs; j++) {
         const uint jj = vinfo->src_index[j];
         const enum pipe_format srcFormat  = draw->vertex_element[jj].src_format;
         const ubyte *from = src[jj] + i * pitch[jj];
         float attrib[4];

         switch (srcFormat) {
         case PIPE_FORMAT_R32G32B32A32_FLOAT:
            {
               float *f = (float *) from;
               attrib[0] = f[0];
               attrib[1] = f[1];
               attrib[2] = f[2];
               attrib[3] = f[3];
            }
            break;
         case PIPE_FORMAT_R32G32B32_FLOAT:
            {
               float *f = (float *) from;
               attrib[0] = f[0];
               attrib[1] = f[1];
               attrib[2] = f[2];
               attrib[3] = 1.0;
            }
            break;
         case PIPE_FORMAT_R32G32_FLOAT:
            {
               float *f = (float *) from;
               attrib[0] = f[0];
               attrib[1] = f[1];
               attrib[2] = 0.0;
               attrib[3] = 1.0;
            }
            break;
         case PIPE_FORMAT_R32_FLOAT:
            {
               float *f = (float *) from;
               attrib[0] = f[0];
               attrib[1] = 0.0;
               attrib[2] = 0.0;
               attrib[3] = 1.0;
            }
            break;
         default:
            abort();
         }

         /* XXX this will probably only work for softpipe */
         switch (vinfo->emit[j]) {
         case EMIT_HEADER:
            memset(out, 0, sizeof(struct vertex_header));
            out += sizeof(struct vertex_header) / 4;
            break;
         case EMIT_4F:
            out[0] = attrib[0];
            out[1] = attrib[1];
            out[2] = attrib[2];
            out[3] = attrib[3];
            out += 4;
            break;
         default:
            abort();
         }

      }
   }
}



/* Example of a fetch/emit passthrough shader which could be
 * generated when bypass_clipping is enabled on a passthrough vertex
 * shader.
 */
static void fetch_xyz_rgb_st( struct draw_context *draw,
			      float *out,
			      unsigned start,
			      unsigned count )
{
   const unsigned *pitch   = draw->vertex_fetch.pitch;
   const ubyte **src       = draw->vertex_fetch.src_ptr;
   unsigned i;

   const ubyte *xyzw = src[0] + start * pitch[0];
   const ubyte *rgba = src[1] + start * pitch[1];
   const ubyte *st = src[2] + start * pitch[2];

   /* loop over vertex attributes (vertex shader inputs)
    */
   for (i = 0; i < count; i++) {
      {
	 const float *in = (const float *)xyzw; xyzw += pitch[0];
         /* decode input, encode output.  Assume both are float[4] */
	 out[0] = in[0];
	 out[1] = in[1];
	 out[2] = in[2];
	 out[3] = in[3];
      }

      {
	 const float *in = (const float *)rgba; rgba += pitch[1];
         /* decode input, encode output.  Assume both are float[4] */
	 out[4] = in[0];
	 out[5] = in[1];
	 out[6] = in[2];
 	 out[7] = in[3];
      }

      {
	 const float *in = (const float *)st; st += pitch[2];
         /* decode input, encode output.  Assume both are float[2] */
	 out[8] = in[0];
	 out[9] = in[1];
      }

      out += 10;
   }
}

static boolean update_shader( struct draw_context *draw )
{
   const struct vertex_info *vinfo = draw->render->get_vertex_info(draw->render);

   unsigned nr_attrs = vinfo->num_attribs;
   unsigned i;

   for (i = 0; i < nr_attrs; i++) {
      unsigned buf = draw->vertex_element[i].vertex_buffer_index;

      draw->vertex_fetch.src_ptr[i] = (const ubyte *) draw->user.vbuffer[buf] + 
						       draw->vertex_buffer[buf].buffer_offset + 
						       draw->vertex_element[i].src_offset;

      draw->vertex_fetch.pitch[i] = draw->vertex_buffer[buf].pitch;
      draw->vertex_fetch.fetch[i] = NULL;
   }

   draw->vertex_fetch.nr_attrs = nr_attrs;
   draw->vertex_fetch.fetch_func = NULL;
   draw->vertex_fetch.pt_fetch = NULL;

   draw->pt.hw_vertex_size = vinfo->size * 4;

   /* Just trying to figure out how this would work:
    */
   if (draw->rasterizer->bypass_vs ||
       (nr_attrs == 3 && 0 /* some other tests */))
   {
#if 0
      draw->vertex_fetch.pt_fetch = fetch_xyz_rgb_st;
#else
      draw->vertex_fetch.pt_fetch = fetch_store_general;
#endif
      /*assert(vinfo->size == 10);*/
      return TRUE;
   }
   
   return FALSE;
}



static boolean set_prim( struct draw_context *draw,
		      unsigned prim )
{
   assert(!draw->user.elts);   

   draw->pt.prim = prim;

   switch (prim) { 
   case PIPE_PRIM_LINE_LOOP:
   case PIPE_PRIM_QUADS:
   case PIPE_PRIM_QUAD_STRIP:
      return FALSE;
   default:
      draw->render->set_primitive( draw->render, prim );
      return TRUE;
   }
}


boolean
draw_passthrough_arrays(struct draw_context *draw, 
                        unsigned prim,
                        unsigned start, 
                        unsigned count)
{
   float *hw_verts;

   if (draw_need_pipeline(draw))
      return FALSE;

   if (!set_prim(draw, prim))
      return FALSE;

   if (!update_shader(draw))
      return FALSE;

   hw_verts = draw->render->allocate_vertices( draw->render,
                                               draw->pt.hw_vertex_size,
                                               count );

   if (!hw_verts)
      return FALSE;
					
   /* Single routine to fetch vertices, run shader and emit HW verts.
    * Clipping and viewport transformation are done on hardware.
    */
   draw->vertex_fetch.pt_fetch( draw, 
				hw_verts,
				start, count );

   /* Draw arrays path to avoid re-emitting index list again and
    * again.
    */
   draw->render->draw_arrays( draw->render,
                              start,
                              count );
   

   draw->render->release_vertices( draw->render, 
				   hw_verts, 
				   draw->pt.hw_vertex_size, 
				   count );

   return TRUE;
}