1/**************************************************************************
2 *
3 * Copyright 2011 VMware, Inc.
4 * All Rights Reserved.
5 *
6 * Permission is hereby granted, free of charge, to any person obtaining a
7 * copy of this software and associated documentation files (the
8 * "Software"), to deal in the Software without restriction, including
9 * without limitation the rights to use, copy, modify, merge, publish,
10 * distribute, sub license, and/or sell copies of the Software, and to
11 * permit persons to whom the Software is furnished to do so, subject to
12 * the following conditions:
13 *
14 * The above copyright notice and this permission notice (including the
15 * next paragraph) shall be included in all copies or substantial portions
16 * of the Software.
17 *
18 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
19 * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
20 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT.
21 * IN NO EVENT SHALL VMWARE AND/OR ITS SUPPLIERS BE LIABLE FOR
22 * ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
23 * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
24 * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
25 *
26 **************************************************************************/
27
28
29#include "util/u_debug.h"
30#include "util/u_inlines.h"
31#include "util/u_math.h"
32#include "util/u_format.h"
33#include "util/u_draw.h"
34
35
36/**
37 * Returns the largest legal index value plus one for the current set
38 * of bound vertex buffers.  Regardless of any other consideration,
39 * all vertex lookups need to be clamped to 0..max_index-1 to prevent
40 * an out-of-bound access.
41 *
42 * Note that if zero is returned it means that one or more buffers is
43 * too small to contain any valid vertex data.
44 */
45unsigned
46util_draw_max_index(
47      const struct pipe_vertex_buffer *vertex_buffers,
48      const struct pipe_vertex_element *vertex_elements,
49      unsigned nr_vertex_elements,
50      const struct pipe_draw_info *info)
51{
52   unsigned max_index;
53   unsigned i;
54
55   max_index = ~0U - 1;
56   for (i = 0; i < nr_vertex_elements; i++) {
57      const struct pipe_vertex_element *element =
58         &vertex_elements[i];
59      const struct pipe_vertex_buffer *buffer =
60         &vertex_buffers[element->vertex_buffer_index];
61      unsigned buffer_size;
62      const struct util_format_description *format_desc;
63      unsigned format_size;
64
65      if (!buffer->buffer) {
66         continue;
67      }
68
69      assert(buffer->buffer->height0 == 1);
70      assert(buffer->buffer->depth0 == 1);
71      buffer_size = buffer->buffer->width0;
72
73      format_desc = util_format_description(element->src_format);
74      assert(format_desc->block.width == 1);
75      assert(format_desc->block.height == 1);
76      assert(format_desc->block.bits % 8 == 0);
77      format_size = format_desc->block.bits/8;
78
79      if (buffer->buffer_offset >= buffer_size) {
80         /* buffer is too small */
81         return 0;
82      }
83
84      buffer_size -= buffer->buffer_offset;
85
86      if (element->src_offset >= buffer_size) {
87         /* buffer is too small */
88         return 0;
89      }
90
91      buffer_size -= element->src_offset;
92
93      if (format_size > buffer_size) {
94         /* buffer is too small */
95         return 0;
96      }
97
98      buffer_size -= format_size;
99
100      if (buffer->stride != 0) {
101         unsigned buffer_max_index;
102
103         buffer_max_index = buffer_size / buffer->stride;
104
105         if (element->instance_divisor == 0) {
106            /* Per-vertex data */
107            max_index = MIN2(max_index, buffer_max_index);
108         }
109         else {
110            /* Per-instance data. Simply make sure the state tracker didn't
111             * request more instances than those that fit in the buffer */
112            if ((info->start_instance + info->instance_count)/element->instance_divisor
113                > (buffer_max_index + 1)) {
114               /* FIXME: We really should stop thinking in terms of maximum
115                * indices/instances and simply start clamping against buffer
116                * size. */
117               debug_printf("%s: too many instances for vertex buffer\n",
118                            __FUNCTION__);
119               return 0;
120            }
121         }
122      }
123   }
124
125   return max_index + 1;
126}
127
128
129/* This extracts the draw arguments from the info_in->indirect resource,
130 * puts them into a new instance of pipe_draw_info, and calls draw_vbo on it.
131 */
132void
133util_draw_indirect(struct pipe_context *pipe,
134                   const struct pipe_draw_info *info_in)
135{
136   struct pipe_draw_info info;
137   struct pipe_transfer *transfer;
138   uint32_t *params;
139   const unsigned num_params = info_in->indexed ? 5 : 4;
140
141   assert(info_in->indirect);
142   assert(!info_in->count_from_stream_output);
143
144   memcpy(&info, info_in, sizeof(info));
145
146   params = (uint32_t *)
147      pipe_buffer_map_range(pipe,
148                            info_in->indirect,
149                            info_in->indirect_offset,
150                            num_params * sizeof(uint32_t),
151                            PIPE_TRANSFER_READ,
152                            &transfer);
153   if (!transfer) {
154      debug_printf("%s: failed to map indirect buffer\n", __FUNCTION__);
155      return;
156   }
157
158   info.count = params[0];
159   info.instance_count = params[1];
160   info.start = params[2];
161   info.index_bias = info_in->indexed ? params[3] : 0;
162   info.start_instance = info_in->indexed ? params[4] : params[3];
163   info.indirect = NULL;
164
165   pipe_buffer_unmap(pipe, transfer);
166
167   pipe->draw_vbo(pipe, &info);
168}
169