1 /*
2 * Copyright 2007 VMware, Inc.
3 * All Rights Reserved.
4 *
5 * Copyright © 2012 Intel Corporation
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 (including the next
15 * paragraph) shall be included in all copies or substantial portions of the
16 * Software.
17 *
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
24 * IN THE SOFTWARE.
25 *
26 * Authors:
27 * Jordan Justen <jordan.l.justen@intel.com>
28 *
29 */
30
31 #include "main/errors.h"
32
33 #include "main/macros.h"
34 #include "main/varray.h"
35
36 #include "vbo.h"
37
38
39 #define UPDATE_MIN2(a, b) (a) = MIN2((a), (b))
40 #define UPDATE_MAX2(a, b) (a) = MAX2((a), (b))
41
42 /*
43 * Notes on primitive restart:
44 * The code below is used when the driver does not fully support primitive
45 * restart (for example, if it only does restart index of ~0).
46 *
47 * We map the index buffer, find the restart indexes, unmap
48 * the index buffer then draw the sub-primitives delineated by the restarts.
49 *
50 * A couple possible optimizations:
51 * 1. Save the list of sub-primitive (start, count) values in a list attached
52 * to the index buffer for re-use in subsequent draws. The list would be
53 * invalidated when the contents of the buffer changed.
54 * 2. If drawing triangle strips or quad strips, create a new index buffer
55 * that uses duplicated vertices to render the disjoint strips as one
56 * long strip. We'd have to be careful to avoid using too much memory
57 * for this.
58 *
59 * Finally, some apps might perform better if they don't use primitive restart
60 * at all rather than this fallback path. Set MESA_EXTENSION_OVERRIDE to
61 * "-GL_NV_primitive_restart" to test that.
62 */
63
64
65 struct sub_primitive
66 {
67 GLuint start;
68 GLuint count;
69 GLuint min_index;
70 GLuint max_index;
71 };
72
73
74 /**
75 * Scan the elements array to find restart indexes. Return an array
76 * of struct sub_primitive to indicate how to draw the sub-primitives
77 * are delineated by the restart index.
78 */
79 static struct sub_primitive *
find_sub_primitives(const void * elements,unsigned element_size,unsigned start,unsigned end,unsigned restart_index,unsigned * num_sub_prims)80 find_sub_primitives(const void *elements, unsigned element_size,
81 unsigned start, unsigned end, unsigned restart_index,
82 unsigned *num_sub_prims)
83 {
84 const unsigned max_prims = end - start;
85 struct sub_primitive *sub_prims;
86 unsigned i, cur_start, cur_count;
87 GLuint scan_index;
88 unsigned scan_num;
89
90 sub_prims =
91 malloc(max_prims * sizeof(struct sub_primitive));
92
93 if (!sub_prims) {
94 *num_sub_prims = 0;
95 return NULL;
96 }
97
98 cur_start = start;
99 cur_count = 0;
100 scan_num = 0;
101
102 #define IB_INDEX_READ(TYPE, INDEX) (((const GL##TYPE *) elements)[INDEX])
103
104 #define SCAN_ELEMENTS(TYPE) \
105 sub_prims[scan_num].min_index = (GL##TYPE) 0xffffffff; \
106 sub_prims[scan_num].max_index = 0; \
107 for (i = start; i < end; i++) { \
108 scan_index = IB_INDEX_READ(TYPE, i); \
109 if (scan_index == restart_index) { \
110 if (cur_count > 0) { \
111 assert(scan_num < max_prims); \
112 sub_prims[scan_num].start = cur_start; \
113 sub_prims[scan_num].count = cur_count; \
114 scan_num++; \
115 sub_prims[scan_num].min_index = (GL##TYPE) 0xffffffff; \
116 sub_prims[scan_num].max_index = 0; \
117 } \
118 cur_start = i + 1; \
119 cur_count = 0; \
120 } \
121 else { \
122 UPDATE_MIN2(sub_prims[scan_num].min_index, scan_index); \
123 UPDATE_MAX2(sub_prims[scan_num].max_index, scan_index); \
124 cur_count++; \
125 } \
126 } \
127 if (cur_count > 0) { \
128 assert(scan_num < max_prims); \
129 sub_prims[scan_num].start = cur_start; \
130 sub_prims[scan_num].count = cur_count; \
131 scan_num++; \
132 }
133
134 switch (element_size) {
135 case 1:
136 SCAN_ELEMENTS(ubyte);
137 break;
138 case 2:
139 SCAN_ELEMENTS(ushort);
140 break;
141 case 4:
142 SCAN_ELEMENTS(uint);
143 break;
144 default:
145 assert(0 && "bad index_size in find_sub_primitives()");
146 }
147
148 #undef SCAN_ELEMENTS
149
150 *num_sub_prims = scan_num;
151
152 return sub_prims;
153 }
154
155
156 /**
157 * Handle primitive restart in software.
158 *
159 * This function breaks up calls into the driver so primitive restart
160 * support is not required in the driver.
161 */
162 void
vbo_sw_primitive_restart(struct gl_context * ctx,const struct _mesa_prim * prims,GLuint nr_prims,const struct _mesa_index_buffer * ib,GLuint num_instances,GLuint base_instance,struct gl_buffer_object * indirect,GLsizeiptr indirect_offset)163 vbo_sw_primitive_restart(struct gl_context *ctx,
164 const struct _mesa_prim *prims,
165 GLuint nr_prims,
166 const struct _mesa_index_buffer *ib,
167 GLuint num_instances, GLuint base_instance,
168 struct gl_buffer_object *indirect,
169 GLsizeiptr indirect_offset)
170 {
171 GLuint prim_num;
172 struct _mesa_prim new_prim;
173 struct _mesa_index_buffer new_ib;
174 struct sub_primitive *sub_prims;
175 struct sub_primitive *sub_prim;
176 GLuint num_sub_prims;
177 GLuint sub_prim_num;
178 GLuint end_index;
179 GLuint sub_end_index;
180 GLuint restart_index = ctx->Array._RestartIndex[(1 << ib->index_size_shift) - 1];
181 struct _mesa_prim temp_prim;
182 GLboolean map_ib = ib->obj && !ib->obj->Mappings[MAP_INTERNAL].Pointer;
183 const void *ptr;
184
185 /* If there is an indirect buffer, map it and extract the draw params */
186 if (indirect) {
187 const uint32_t *indirect_params;
188 if (!ctx->Driver.MapBufferRange(ctx, 0, indirect->Size, GL_MAP_READ_BIT,
189 indirect, MAP_INTERNAL)) {
190
191 /* something went wrong with mapping, give up */
192 _mesa_error(ctx, GL_OUT_OF_MEMORY,
193 "failed to map indirect buffer for sw primitive restart");
194 return;
195 }
196
197 assert(nr_prims == 1);
198 new_prim = prims[0];
199 indirect_params = (const uint32_t *)
200 ADD_POINTERS(indirect->Mappings[MAP_INTERNAL].Pointer,
201 indirect_offset);
202
203 new_prim.count = indirect_params[0];
204 new_prim.start = indirect_params[2];
205 new_prim.basevertex = indirect_params[3];
206
207 num_instances = indirect_params[1];
208 base_instance = indirect_params[4];
209
210 new_ib = *ib;
211 new_ib.count = new_prim.count;
212
213 prims = &new_prim;
214 ib = &new_ib;
215
216 ctx->Driver.UnmapBuffer(ctx, indirect, MAP_INTERNAL);
217 }
218
219 /* Find the sub-primitives. These are regions in the index buffer which
220 * are split based on the primitive restart index value.
221 */
222 if (map_ib) {
223 ctx->Driver.MapBufferRange(ctx, 0, ib->obj->Size, GL_MAP_READ_BIT,
224 ib->obj, MAP_INTERNAL);
225 }
226
227 if (ib->obj)
228 ptr = ADD_POINTERS(ib->obj->Mappings[MAP_INTERNAL].Pointer, ib->ptr);
229 else
230 ptr = ib->ptr;
231
232 sub_prims = find_sub_primitives(ptr, 1 << ib->index_size_shift,
233 0, ib->count, restart_index,
234 &num_sub_prims);
235
236 if (map_ib) {
237 ctx->Driver.UnmapBuffer(ctx, ib->obj, MAP_INTERNAL);
238 }
239
240 /* Loop over the primitives, and use the located sub-primitives to draw
241 * each primitive with a break to implement each primitive restart.
242 */
243 for (prim_num = 0; prim_num < nr_prims; prim_num++) {
244 end_index = prims[prim_num].start + prims[prim_num].count;
245 memcpy(&temp_prim, &prims[prim_num], sizeof (temp_prim));
246 /* Loop over the sub-primitives drawing sub-ranges of the primitive. */
247 for (sub_prim_num = 0; sub_prim_num < num_sub_prims; sub_prim_num++) {
248 sub_prim = &sub_prims[sub_prim_num];
249 sub_end_index = sub_prim->start + sub_prim->count;
250 if (prims[prim_num].start <= sub_prim->start) {
251 temp_prim.start = MAX2(prims[prim_num].start, sub_prim->start);
252 temp_prim.count = MIN2(sub_end_index, end_index) - temp_prim.start;
253 if ((temp_prim.start == sub_prim->start) &&
254 (temp_prim.count == sub_prim->count)) {
255 ctx->Driver.Draw(ctx, &temp_prim, 1, ib, GL_TRUE,
256 sub_prim->min_index, sub_prim->max_index,
257 num_instances, base_instance,
258 NULL, 0);
259 } else {
260 ctx->Driver.Draw(ctx, &temp_prim, 1, ib,
261 GL_FALSE, -1, -1,
262 num_instances, base_instance,
263 NULL, 0);
264 }
265 }
266 if (sub_end_index >= end_index) {
267 break;
268 }
269 }
270 }
271
272 free(sub_prims);
273 }
274
275