1 /*
2 * Mesa 3-D graphics library
3 *
4 * Copyright 2008 VMware, Inc.
5 * Copyright (C) 2010 LunarG Inc.
6 *
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:
13 *
14 * The above copyright notice and this permission notice shall be included
15 * in all copies or substantial portions of the Software.
16 *
17 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
18 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
19 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
20 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
21 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
22 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
23 * DEALINGS IN THE SOFTWARE.
24 */
25
26 static void
FUNC(FUNC_VARS)27 FUNC(FUNC_VARS)
28 {
29 unsigned first, incr;
30 LOCAL_VARS
31
32 /*
33 * prim, start, count, and max_count_{simple,loop,fan} should have been
34 * defined
35 */
36 if (0) {
37 debug_printf("%s: prim 0x%x, start %d, count %d, max_count_simple %d, "
38 "max_count_loop %d, max_count_fan %d\n",
39 __FUNCTION__, prim, start, count, max_count_simple,
40 max_count_loop, max_count_fan);
41 }
42
43 draw_pt_split_prim(prim, &first, &incr);
44 /* sanitize primitive length */
45 count = draw_pt_trim_count(count, first, incr);
46 if (count < first)
47 return;
48
49 /* try flushing the entire primitive */
50 if (PRIMITIVE(start, count))
51 return;
52
53 /* must be able to at least flush two complete primitives */
54 assert(max_count_simple >= first + incr &&
55 max_count_loop >= first + incr &&
56 max_count_fan >= first + incr);
57
58 /* no splitting required */
59 if (count <= max_count_simple) {
60 SEGMENT_SIMPLE(0x0, start, count);
61 }
62 else {
63 const unsigned rollback = first - incr;
64 unsigned flags = DRAW_SPLIT_AFTER, seg_start = 0, seg_max;
65
66 /*
67 * Both count and seg_max below are explicitly trimmed. Because
68 *
69 * seg_start = N * (seg_max - rollback) = N' * incr,
70 *
71 * we have
72 *
73 * remaining = count - seg_start = first + N'' * incr.
74 *
75 * That is, remaining is implicitly trimmed.
76 */
77 switch (prim) {
78 case PIPE_PRIM_POINTS:
79 case PIPE_PRIM_LINES:
80 case PIPE_PRIM_LINE_STRIP:
81 case PIPE_PRIM_TRIANGLES:
82 case PIPE_PRIM_TRIANGLE_STRIP:
83 case PIPE_PRIM_QUADS:
84 case PIPE_PRIM_QUAD_STRIP:
85 case PIPE_PRIM_LINES_ADJACENCY:
86 case PIPE_PRIM_LINE_STRIP_ADJACENCY:
87 case PIPE_PRIM_TRIANGLES_ADJACENCY:
88 case PIPE_PRIM_TRIANGLE_STRIP_ADJACENCY:
89 seg_max =
90 draw_pt_trim_count(MIN2(max_count_simple, count), first, incr);
91 if (prim == PIPE_PRIM_TRIANGLE_STRIP ||
92 prim == PIPE_PRIM_TRIANGLE_STRIP_ADJACENCY) {
93 /* make sure we flush even number of triangles at a time */
94 if (seg_max < count && !(((seg_max - first) / incr) & 1))
95 seg_max -= incr;
96 }
97
98 do {
99 const unsigned remaining = count - seg_start;
100
101 if (remaining > seg_max) {
102 SEGMENT_SIMPLE(flags, start + seg_start, seg_max);
103 seg_start += seg_max - rollback;
104
105 flags |= DRAW_SPLIT_BEFORE;
106 }
107 else {
108 flags &= ~DRAW_SPLIT_AFTER;
109
110 SEGMENT_SIMPLE(flags, start + seg_start, remaining);
111 seg_start += remaining;
112 }
113 } while (seg_start < count);
114 break;
115
116 case PIPE_PRIM_LINE_LOOP:
117 seg_max =
118 draw_pt_trim_count(MIN2(max_count_loop, count), first, incr);
119
120 do {
121 const unsigned remaining = count - seg_start;
122
123 if (remaining > seg_max) {
124 SEGMENT_LOOP(flags, start + seg_start, seg_max, start);
125 seg_start += seg_max - rollback;
126
127 flags |= DRAW_SPLIT_BEFORE;
128 }
129 else {
130 flags &= ~DRAW_SPLIT_AFTER;
131
132 SEGMENT_LOOP(flags, start + seg_start, remaining, start);
133 seg_start += remaining;
134 }
135 } while (seg_start < count);
136 break;
137
138 case PIPE_PRIM_TRIANGLE_FAN:
139 case PIPE_PRIM_POLYGON:
140 seg_max =
141 draw_pt_trim_count(MIN2(max_count_fan, count), first, incr);
142
143 do {
144 const unsigned remaining = count - seg_start;
145
146 if (remaining > seg_max) {
147 SEGMENT_FAN(flags, start + seg_start, seg_max, start);
148 seg_start += seg_max - rollback;
149
150 flags |= DRAW_SPLIT_BEFORE;
151 }
152 else {
153 flags &= ~DRAW_SPLIT_AFTER;
154
155 SEGMENT_FAN(flags, start + seg_start, remaining, start);
156 seg_start += remaining;
157 }
158 } while (seg_start < count);
159 break;
160
161 default:
162 assert(0);
163 break;
164 }
165 }
166 }
167
168 #undef FUNC
169 #undef FUNC_VARS
170 #undef LOCAL_VARS
171
172 #undef PRIMITIVE
173 #undef SEGMENT_SIMPLE
174 #undef SEGMENT_LOOP
175 #undef SEGMENT_FAN
176