u_draw.c revision 3733da31e8b4405b65e1b6ca3b6599ecc5af5fe7
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_math.h" 31#include "util/u_format.h" 32#include "util/u_draw.h" 33 34 35/** 36 * Returns the largest legal index value for the current set of bound vertex 37 * buffers. Regardless of any other consideration, all vertex lookups need to 38 * be clamped to 0..max_index to prevent an out-of-bound access. 39 */ 40unsigned 41util_draw_max_index( 42 const struct pipe_vertex_buffer *vertex_buffers, 43 unsigned nr_vertex_buffers, 44 const struct pipe_vertex_element *vertex_elements, 45 unsigned nr_vertex_elements, 46 const struct pipe_draw_info *info) 47{ 48 unsigned max_index; 49 unsigned i; 50 51 max_index = ~0; 52 for (i = 0; i < nr_vertex_elements; i++) { 53 const struct pipe_vertex_element *element = 54 &vertex_elements[i]; 55 const struct pipe_vertex_buffer *buffer = 56 &vertex_buffers[element->vertex_buffer_index]; 57 unsigned buffer_size; 58 const struct util_format_description *format_desc; 59 unsigned format_size; 60 61 assert(buffer->buffer->height0 == 1); 62 assert(buffer->buffer->depth0 == 1); 63 buffer_size = buffer->buffer->width0; 64 65 format_desc = util_format_description(element->src_format); 66 assert(format_desc->block.width == 1); 67 assert(format_desc->block.height == 1); 68 assert(format_desc->block.bits % 8 == 0); 69 format_size = format_desc->block.bits/8; 70 71 assert(buffer_size - buffer->buffer_offset <= buffer_size); 72 buffer_size -= buffer->buffer_offset; 73 74 assert(buffer_size - element->src_offset <= buffer_size); 75 buffer_size -= element->src_offset; 76 77 assert(buffer_size - format_size <= buffer_size); 78 buffer_size -= format_size; 79 80 if (buffer->stride != 0) { 81 unsigned buffer_max_index; 82 83 buffer_max_index = buffer_size / buffer->stride; 84 85 if (element->instance_divisor == 0) { 86 /* Per-vertex data */ 87 max_index = MIN2(max_index, buffer_max_index); 88 } 89 else { 90 /* Per-instance data. Simply make sure the state tracker didn't 91 * request more instances than those that fit in the buffer */ 92 assert((info->start_instance + info->instance_count)/element->instance_divisor 93 <= (buffer_max_index + 1)); 94 } 95 } 96 } 97 98 return max_index; 99} 100