2 * Copyright 2007 Tungsten Graphics, Inc., Cedar Park, Texas.
5 * Copyright © 2012 Intel Corporation
7 * Permission is hereby granted, free of charge, to any person obtaining a
8 * copy of this software and associated documentation files (the "Software"),
9 * to deal in the Software without restriction, including without limitation
10 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
11 * and/or sell copies of the Software, and to permit persons to whom the
12 * Software is furnished to do so, subject to the following conditions:
14 * The above copyright notice and this permission notice (including the next
15 * paragraph) shall be included in all copies or substantial portions of the
18 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
19 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
20 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
21 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
22 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
23 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
27 * Jordan Justen <jordan.l.justen@intel.com>
31 #include "main/imports.h"
32 #include "main/bufferobj.h"
33 #include "main/macros.h"
36 #include "vbo_context.h"
38 #define UPDATE_MIN2(a, b) (a) = MIN2((a), (b))
39 #define UPDATE_MAX2(a, b) (a) = MAX2((a), (b))
42 * Notes on primitive restart:
43 * The code below is used when the driver does not support primitive
44 * restart itself. (ctx->Const.PrimitiveRestartInSoftware == GL_TRUE)
46 * We map the index buffer, find the restart indexes, unmap
47 * the index buffer then draw the sub-primitives delineated by the restarts.
49 * A couple possible optimizations:
50 * 1. Save the list of sub-primitive (start, count) values in a list attached
51 * to the index buffer for re-use in subsequent draws. The list would be
52 * invalidated when the contents of the buffer changed.
53 * 2. If drawing triangle strips or quad strips, create a new index buffer
54 * that uses duplicated vertices to render the disjoint strips as one
55 * long strip. We'd have to be careful to avoid using too much memory
58 * Finally, some apps might perform better if they don't use primitive restart
59 * at all rather than this fallback path. Set MESA_EXTENSION_OVERRIDE to
60 * "-GL_NV_primitive_restart" to test that.
74 * Scan the elements array to find restart indexes. Return an array
75 * of struct sub_primitive to indicate how to draw the sub-primitives
76 * are delineated by the restart index.
78 static struct sub_primitive
*
79 find_sub_primitives(const void *elements
, unsigned element_size
,
80 unsigned start
, unsigned end
, unsigned restart_index
,
81 unsigned *num_sub_prims
)
83 const unsigned max_prims
= end
- start
;
84 struct sub_primitive
*sub_prims
;
85 unsigned i
, cur_start
, cur_count
;
89 sub_prims
= (struct sub_primitive
*)
90 malloc(max_prims
* sizeof(struct sub_primitive
));
101 #define IB_INDEX_READ(TYPE, INDEX) (((const GL##TYPE *) elements)[INDEX])
103 #define SCAN_ELEMENTS(TYPE) \
104 sub_prims[scan_num].min_index = (GL##TYPE) 0xffffffff; \
105 sub_prims[scan_num].max_index = 0; \
106 for (i = start; i < end; i++) { \
107 scan_index = IB_INDEX_READ(TYPE, i); \
108 if (scan_index == restart_index) { \
109 if (cur_count > 0) { \
110 assert(scan_num < max_prims); \
111 sub_prims[scan_num].start = cur_start; \
112 sub_prims[scan_num].count = cur_count; \
114 sub_prims[scan_num].min_index = (GL##TYPE) 0xffffffff; \
115 sub_prims[scan_num].max_index = 0; \
121 UPDATE_MIN2(sub_prims[scan_num].min_index, scan_index); \
122 UPDATE_MAX2(sub_prims[scan_num].max_index, scan_index); \
126 if (cur_count > 0) { \
127 assert(scan_num < max_prims); \
128 sub_prims[scan_num].start = cur_start; \
129 sub_prims[scan_num].count = cur_count; \
133 switch (element_size
) {
135 SCAN_ELEMENTS(ubyte
);
138 SCAN_ELEMENTS(ushort
);
144 assert(0 && "bad index_size in find_sub_primitives()");
149 *num_sub_prims
= scan_num
;
156 * Handle primitive restart in software.
158 * This function breaks up calls into the driver so primitive restart
159 * support is not required in the driver.
162 vbo_sw_primitive_restart(struct gl_context
*ctx
,
163 const struct _mesa_prim
*prims
,
165 const struct _mesa_index_buffer
*ib
)
168 struct sub_primitive
*sub_prims
;
169 struct sub_primitive
*sub_prim
;
170 GLuint num_sub_prims
;
173 GLuint sub_end_index
;
174 GLuint restart_index
= ctx
->Array
.RestartIndex
;
175 struct _mesa_prim temp_prim
;
176 struct vbo_context
*vbo
= vbo_context(ctx
);
177 vbo_draw_func draw_prims_func
= vbo
->draw_prims
;
178 GLboolean map_ib
= ib
->obj
->Name
&& !ib
->obj
->Pointer
;
181 /* Find the sub-primitives. These are regions in the index buffer which
182 * are split based on the primitive restart index value.
185 ctx
->Driver
.MapBufferRange(ctx
, 0, ib
->obj
->Size
, GL_MAP_READ_BIT
,
189 ptr
= ADD_POINTERS(ib
->obj
->Pointer
, ib
->ptr
);
191 sub_prims
= find_sub_primitives(ptr
, vbo_sizeof_ib_type(ib
->type
),
192 0, ib
->count
, restart_index
,
196 ctx
->Driver
.UnmapBuffer(ctx
, ib
->obj
);
199 /* Loop over the primitives, and use the located sub-primitives to draw
200 * each primitive with a break to implement each primitive restart.
202 for (prim_num
= 0; prim_num
< nr_prims
; prim_num
++) {
203 end_index
= prims
[prim_num
].start
+ prims
[prim_num
].count
;
204 memcpy(&temp_prim
, &prims
[prim_num
], sizeof (temp_prim
));
205 /* Loop over the sub-primitives drawing sub-ranges of the primitive. */
206 for (sub_prim_num
= 0; sub_prim_num
< num_sub_prims
; sub_prim_num
++) {
207 sub_prim
= &sub_prims
[sub_prim_num
];
208 sub_end_index
= sub_prim
->start
+ sub_prim
->count
;
209 if (prims
[prim_num
].start
<= sub_prim
->start
) {
210 temp_prim
.start
= MAX2(prims
[prim_num
].start
, sub_prim
->start
);
211 temp_prim
.count
= MIN2(sub_end_index
, end_index
) - temp_prim
.start
;
212 if ((temp_prim
.start
== sub_prim
->start
) &&
213 (temp_prim
.count
== sub_prim
->count
)) {
214 draw_prims_func(ctx
, &temp_prim
, 1, ib
,
215 GL_TRUE
, sub_prim
->min_index
, sub_prim
->max_index
,
218 draw_prims_func(ctx
, &temp_prim
, 1, ib
,
223 if (sub_end_index
>= end_index
) {