--- /dev/null
+/**************************************************************************
+ *
+ * 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;
+ int 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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