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1 /*
2  * Copyright © 2021 Bas Nieuwenhuizen
3  * Copyright © 2024 Valve Corporation
4  *
5  * Permission is hereby granted, free of charge, to any person obtaining a
6  * copy of this software and associated documentation files (the "Software"),
7  * to deal in the Software without restriction, including without limitation
8  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
9  * and/or sell copies of the Software, and to permit persons to whom the
10  * Software is furnished to do so, subject to the following conditions:
11  *
12  * The above copyright notice and this permission notice (including the next
13  * paragraph) shall be included in all copies or substantial portions of the
14  * Software.
15  *
16  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
17  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
18  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
19  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
20  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
21  * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
22  * IN THE SOFTWARE.
23  */
24 
25 #ifndef TU_BVH_H
26 #define TU_BVH_H
27 
28 #ifdef VULKAN
29 #define VK_UUID_SIZE 16
30 #else
31 #include <vulkan/vulkan.h>
32 #endif
33 
34 #include "vk_bvh.h"
35 
36 /* The size in bytes of each record in the D3D-style UAV descriptor for
37  * acceleration structures. The first record is the acceleration struct header
38  * and the rest are the instances.
39  */
40 #define AS_RECORD_SIZE 128
41 
42 /* The size of a BVH node as defined by the HW. */
43 #define AS_NODE_SIZE 64
44 
45 struct tu_accel_struct_header {
46    vk_aabb aabb;
47 
48    uint64_t bvh_ptr;
49 
50    /* This word contains flags that should be set in the leaf nodes for
51     * instances pointing to this BLAS. ALL_NODES_{OPAQUE_NONOPAQUE} may be
52     * modified by the FORCE_OPAQUE and FORCE_NON_OPAQUE instance flags.
53     */
54    uint32_t instance_flags;
55 
56    /* Everything after this gets either updated/copied from the CPU or written by header.comp. */
57    uint32_t copy_dispatch_size[3];
58 
59    uint64_t compacted_size;
60    uint64_t serialization_size;
61    uint64_t size;
62 
63    /* Everything after this gets updated/copied from the CPU. */
64    uint64_t instance_count;
65 
66    uint64_t self_ptr;
67 
68    uint32_t padding[10];
69 };
70 
71 /* See
72  * https://gitlab.freedesktop.org/freedreno/freedreno/-/wikis/a7xx-ray-tracing
73  * for details of the encoding.
74  */
75 
76 #define TU_NODE_TYPE_TLAS      (1u << 24)
77 #define TU_NODE_TYPE_LEAF      (1u << 25)
78 #define TU_NODE_TYPE_NONOPAQUE (1u << 26)
79 #define TU_NODE_TYPE_AABB      (1u << 27)
80 
81 #define TU_INTERSECTION_TYPE_TLAS      (1u << 8)
82 #define TU_INTERSECTION_TYPE_LEAF      (1u << 9)
83 #define TU_INTERSECTION_TYPE_NONOPAQUE (1u << 10)
84 #define TU_INTERSECTION_TYPE_AABB      (1u << 11)
85 #define TU_INTERSECTION_BACK_FACE      (1u << 12)
86 
87 #define TU_INSTANCE_ALL_OPAQUE    (1u << 2)
88 #define TU_INSTANCE_ALL_NONOPAQUE (1u << 3)
89 #define TU_INSTANCE_ALL_AABB      (1u << 6)
90 
91 struct tu_leaf_node {
92    uint32_t id;
93    float coords[3][3];
94    uint32_t geometry_id; /* Ignored by HW, we use it to stash the geometry ID */
95    uint32_t padding[4];
96    uint32_t type_flags;
97 };
98 
99 struct tu_internal_node {
100    uint32_t id;
101    uint16_t bases[3];
102    uint8_t mantissas[8][2][3];
103    uint8_t exponents[3];
104    uint8_t child_count;
105    uint16_t type_flags;
106 };
107 
108 struct tu_compressed_node {
109    uint32_t id;
110    uint32_t bases[3];
111    uint32_t data[12];
112 };
113 
114 struct tu_instance_descriptor {
115    uint64_t bvh_ptr;
116 
117    uint32_t custom_instance_index;
118 
119    /* lower 24 bits are the sbt offset, upper 8 bits are the
120     * VkGeometryInstanceFlagsKHR
121     */
122    uint32_t sbt_offset_and_flags;
123 
124    mat3x4 wto_matrix;
125 
126    uint32_t bvh_offset;
127 
128    /* Pad to make the size a power of 2 so that addressing math is
129     * simplified.
130     */
131    uint32_t reserved[3];
132 
133    /* Object to world matrix inverted from the initial transform. */
134    mat3x4 otw_matrix;
135 };
136 
137 #endif
138 
139