matrixfurry.com
The open source OpenXR runtime
1// Copyright 2020-2023, Collabora Ltd.
2//
3// Author: Jakob Bornecrantz <jakob@collabora.com>
4// Author: Lubosz Sarnecki <lubosz.sarnecki@collabora.com>
5//
6// SPDX-License-Identifier: BSL-1.0
7
8#version 460
9
10
11layout (binding = 0, std140) uniform Config
12{
13 vec4 post_transform;
14 vec4 to_tanget;
15 mat4 mvp;
16} ubo;
17
18layout (location = 0) out vec2 out_uv;
19
20out gl_PerVertex
21{
22 vec4 gl_Position;
23};
24
25vec2 pos[4] = {
26 vec2(0, 0),
27 vec2(0, 1),
28 vec2(1, 0),
29 vec2(1, 1),
30};
31
32void main()
33{
34 // We now get a unmodified UV position.
35 vec2 in_uv = pos[gl_VertexIndex % 4];
36
37 // Turn the UV into tanget angle space.
38 vec2 pos = fma(in_uv, ubo.to_tanget.zw, ubo.to_tanget.xy);
39
40 // Flip to OpenXR coordinate system.
41 pos.y = -pos.y;
42
43 // Do timewarp by moving from a plane that is 1m in front of the
44 // origin of the projection layer into the view of the new position.
45 vec4 position = ubo.mvp * vec4(pos, -1.0f, 1.0f);
46
47 // To deal with OpenGL flip and sub image view.
48 vec2 uv = fma(in_uv, ubo.post_transform.zw, ubo.post_transform.xy);
49
50 gl_Position = position;
51 out_uv = uv;
52}