1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
|
Name
ANGLE_base_vertex_base_instance_shader_builtin
Name Strings
GL_ANGLE_base_vertex_base_instance_shader_builtin
Contributors
Shrek Shao, Google Inc.
Contributors to the ANGLE_base_vertex_base_instance specification
Contributors to the ARB_shader_draw_parameters specification
Contact
Shrek Shao (shrekshao 'at' google.com)
Status
Incomplete
Version
Last Modified Date: Nov 19, 2021
Author Revision: 1
Number
OpenGL ES Extension XX
Dependencies
The extension is based on ANGLE_base_vertex_base_instance, all limitations of which
apply to this extension.
Overview
This extension is based on ANGLE_base_vertex_base_instance. It should be enabled
only if ANGLE_base_vertex_base_instance is enabled.
Additional to the functionality exposed by ANGLE_base_vertex_base_instance,
<gl_BaseVertex> and <gl_BaseInstance> builtins are added to the shading language.
For any *BaseVertex* draw call variant, the <baseVertex> of the draw may be
read by the vertex shader as <gl_BaseVertex>. For non *BaseVertex* calls,
the value of <gl_BaseVertex> is 0.
For any *BaseInstance draw call variant, the baseInstance of the draw may
be read by the vertex shader as <gl_BaseInstance>. For non *BaseInstance
calls, the value of <gl_BaseInstance> is 0.
IP Status
No known IP claims.
New Procedures and Functions
None.
New Tokens
None.
Additions to Chapter 10 of the OpenGL ES 3.2 Specification
Section 10.5 Drawing Commands Using Vertex Arrays:
The base index of the instance may be read by a vertex shader as
<gl_BaseInstance>, for the commands
void DrawArraysInstancedBaseInstanceANGLE(
enum mode,
int first,
sizei count,
sizei instanceCount,
uint baseInstance);
and
void MultiDrawArraysInstancedBaseInstanceANGLE(
enum mode,
const int *firsts,
const sizei *counts,
const sizei *instanceCounts,
const uint *baseInstances,
sizei drawcount);
The base index of the vertex may be read by a vertex shader as
<gl_BaseVertex>. This value is also added to the <gl_VertexID>.
The base index of the instance may be read by a vertex shader as
<gl_BaseInstance>. Note that this value is not added to the
<gl_InstanceID>, for the commands
void DrawElementsInstancedBaseVertexBaseInstanceANGLE(
enum mode,
sizei count,
enum type,
const void *indices,
sizei instanceCount,
int baseVertex,
uint baseInstance);
and
void MultiDrawElementsInstancedBaseVertexBaseInstanceANGLE(
enum mode,
const sizei *counts,
enum type,
const void *const *indices,
const sizei *instanceCounts,
const int *baseVertices,
const uint *baseInstances,
sizei drawcount);
Errors
None.
Modifications to the OpenGL ES Shading Language Specification, Version 3.00
Including the following line in a shader controls the
language featured described in this extension:
#extension GL_ANGLE_base_vertex_base_instance_shader_builtin : <behavior>
where <behavior> is as specified in section 3.5.
A new preprocessor #define is added to the OpenGL ES Shading Language:
#define GL_ANGLE_base_vertex_base_instance_shader_builtin 1
Issues
None
Revision History
Rev. Date Author Changes
---- -------- ---------------- --------------------------------------------
1 11/19/21 Shrek Shao First revision.
2 06/21/22 Alexey Knyazev Fixed typos and type usage.
|
