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/**************************************************************************
*
* 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"
/* 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 (nr_attrs == 3 &&
0 /* some other tests */)
{
draw->vertex_fetch.pt_fetch = fetch_xyz_rgb_st;
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 (!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;
}
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