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      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  */
     45 unsigned
     46 util_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  */
    132 void
    133 util_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