input refactor

src/xr_input/xr_camera.rs

@@ -0,0 +1,239 @@
+use crate::xr_input::{QuatConv, Vec3Conv};
+use crate::{LEFT_XR_TEXTURE_HANDLE, RIGHT_XR_TEXTURE_HANDLE};
+use bevy::core_pipeline::tonemapping::{DebandDither, Tonemapping};
+use bevy::prelude::*;
+use bevy::render::camera::{CameraProjection, CameraRenderGraph, RenderTarget};
+use bevy::render::primitives::Frustum;
+use bevy::render::view::{ColorGrading, VisibleEntities};
+use openxr::Fovf;
+
+#[derive(Bundle)]
+pub struct XrCamerasBundle {
+    pub left: XrCameraBundle,
+    pub right: XrCameraBundle,
+}
+impl XrCamerasBundle {
+    pub fn new() -> Self {
+        Self::default()
+    }
+}
+impl Default for XrCamerasBundle {
+    fn default() -> Self {
+        Self {
+            left: XrCameraBundle::new(Eye::Left),
+            right: XrCameraBundle::new(Eye::Right),
+        }
+    }
+}
+
+#[derive(Bundle)]
+pub struct XrCameraBundle {
+    pub camera: Camera,
+    pub camera_render_graph: CameraRenderGraph,
+    pub xr_projection: XRProjection,
+    pub visible_entities: VisibleEntities,
+    pub frustum: Frustum,
+    pub transform: Transform,
+    pub global_transform: GlobalTransform,
+    pub camera_3d: Camera3d,
+    pub tonemapping: Tonemapping,
+    pub dither: DebandDither,
+    pub color_grading: ColorGrading,
+    pub xr_camera_type: XrCameraType,
+}
+#[derive(Copy, Clone, Debug, Eq, PartialEq, Hash, Ord, PartialOrd, Component)]
+pub enum XrCameraType {
+    Xr(Eye),
+    Flatscreen,
+}
+#[derive(Copy, Clone, Debug, Eq, PartialEq, Hash, Ord, PartialOrd)]
+pub enum Eye {
+    Left = 0,
+    Right = 1,
+}
+
+impl XrCameraBundle {
+    pub fn new(eye: Eye) -> Self {
+        Self {
+            camera: Camera {
+                order: -1,
+                target: RenderTarget::TextureView(match eye {
+                    Eye::Left => LEFT_XR_TEXTURE_HANDLE,
+                    Eye::Right => RIGHT_XR_TEXTURE_HANDLE,
+                }),
+                viewport: None,
+                ..default()
+            },
+            camera_render_graph: CameraRenderGraph::new(bevy::core_pipeline::core_3d::graph::NAME),
+            xr_projection: Default::default(),
+            visible_entities: Default::default(),
+            frustum: Default::default(),
+            transform: Default::default(),
+            global_transform: Default::default(),
+            camera_3d: Default::default(),
+            tonemapping: Default::default(),
+            dither: DebandDither::Enabled,
+            color_grading: Default::default(),
+            xr_camera_type: XrCameraType::Xr(eye),
+        }
+    }
+}
+
+#[derive(Debug, Clone, Component, Reflect)]
+#[reflect(Component, Default)]
+pub struct XRProjection {
+    pub near: f32,
+    pub far: f32,
+    #[reflect(ignore)]
+    pub fov: Fovf,
+}
+
+impl Default for XRProjection {
+    fn default() -> Self {
+        Self {
+            near: 0.1,
+            far: 1000.,
+            fov: Default::default(),
+        }
+    }
+}
+
+impl XRProjection {
+    pub fn new(near: f32, far: f32, fov: Fovf) -> Self {
+        XRProjection { near, far, fov }
+    }
+}
+
+impl CameraProjection for XRProjection {
+    // =============================================================================
+    // math code adapted from
+    // https://github.com/KhronosGroup/OpenXR-SDK-Source/blob/master/src/common/xr_linear.h
+    // Copyright (c) 2017 The Khronos Group Inc.
+    // Copyright (c) 2016 Oculus VR, LLC.
+    // SPDX-License-Identifier: Apache-2.0
+    // =============================================================================
+    fn get_projection_matrix(&self) -> Mat4 {
+        //  symmetric perspective for debugging
+        // let x_fov = (self.fov.angle_left.abs() + self.fov.angle_right.abs());
+        // let y_fov = (self.fov.angle_up.abs() + self.fov.angle_down.abs());
+        // return Mat4::perspective_infinite_reverse_rh(y_fov, x_fov / y_fov, self.near);
+
+        let fov = self.fov;
+        let is_vulkan_api = false; // FIXME wgpu probably abstracts this
+        let near_z = self.near;
+        let far_z = -1.; //   use infinite proj
+                         // let far_z = self.far;
+
+        let tan_angle_left = fov.angle_left.tan();
+        let tan_angle_right = fov.angle_right.tan();
+
+        let tan_angle_down = fov.angle_down.tan();
+        let tan_angle_up = fov.angle_up.tan();
+
+        let tan_angle_width = tan_angle_right - tan_angle_left;
+
+        // Set to tanAngleDown - tanAngleUp for a clip space with positive Y
+        // down (Vulkan). Set to tanAngleUp - tanAngleDown for a clip space with
+        // positive Y up (OpenGL / D3D / Metal).
+        // const float tanAngleHeight =
+        //     graphicsApi == GRAPHICS_VULKAN ? (tanAngleDown - tanAngleUp) : (tanAngleUp - tanAngleDown);
+        let tan_angle_height = if is_vulkan_api {
+            tan_angle_down - tan_angle_up
+        } else {
+            tan_angle_up - tan_angle_down
+        };
+
+        // Set to nearZ for a [-1,1] Z clip space (OpenGL / OpenGL ES).
+        // Set to zero for a [0,1] Z clip space (Vulkan / D3D / Metal).
+        // const float offsetZ =
+        //     (graphicsApi == GRAPHICS_OPENGL || graphicsApi == GRAPHICS_OPENGL_ES) ? nearZ : 0;
+        // FIXME handle enum of graphics apis
+        let offset_z = 0.;
+
+        let mut cols: [f32; 16] = [0.0; 16];
+
+        if far_z <= near_z {
+            // place the far plane at infinity
+            cols[0] = 2. / tan_angle_width;
+            cols[4] = 0.;
+            cols[8] = (tan_angle_right + tan_angle_left) / tan_angle_width;
+            cols[12] = 0.;
+
+            cols[1] = 0.;
+            cols[5] = 2. / tan_angle_height;
+            cols[9] = (tan_angle_up + tan_angle_down) / tan_angle_height;
+            cols[13] = 0.;
+
+            cols[2] = 0.;
+            cols[6] = 0.;
+            cols[10] = -1.;
+            cols[14] = -(near_z + offset_z);
+
+            cols[3] = 0.;
+            cols[7] = 0.;
+            cols[11] = -1.;
+            cols[15] = 0.;
+
+            //  bevy uses the _reverse_ infinite projection
+            //  https://dev.theomader.com/depth-precision/
+            let z_reversal = Mat4::from_cols_array_2d(&[
+                [1f32, 0., 0., 0.],
+                [0., 1., 0., 0.],
+                [0., 0., -1., 0.],
+                [0., 0., 1., 1.],
+            ]);
+
+            return z_reversal * Mat4::from_cols_array(&cols);
+        } else {
+            // normal projection
+            cols[0] = 2. / tan_angle_width;
+            cols[4] = 0.;
+            cols[8] = (tan_angle_right + tan_angle_left) / tan_angle_width;
+            cols[12] = 0.;
+
+            cols[1] = 0.;
+            cols[5] = 2. / tan_angle_height;
+            cols[9] = (tan_angle_up + tan_angle_down) / tan_angle_height;
+            cols[13] = 0.;
+
+            cols[2] = 0.;
+            cols[6] = 0.;
+            cols[10] = -(far_z + offset_z) / (far_z - near_z);
+            cols[14] = -(far_z * (near_z + offset_z)) / (far_z - near_z);
+
+            cols[3] = 0.;
+            cols[7] = 0.;
+            cols[11] = -1.;
+            cols[15] = 0.;
+        }
+
+        Mat4::from_cols_array(&cols)
+    }
+
+    fn update(&mut self, _width: f32, _height: f32) {}
+
+    fn far(&self) -> f32 {
+        self.far
+    }
+}
+
+pub fn xr_camera_head_sync(
+    views: ResMut<crate::resources::XrViews>,
+    mut query: Query<(&mut Transform, &XrCameraType, &mut XRProjection)>,
+) {
+    let mut f = || -> Option<()> {
+        for (mut transform, camera_type, mut xr_projection) in query.iter_mut() {
+            let view_idx = match camera_type {
+                XrCameraType::Xr(eye) => *eye as usize,
+                XrCameraType::Flatscreen => return None,
+            };
+            let v = views.lock().unwrap();
+            let view = v.get(view_idx)?;
+            xr_projection.fov = view.fov;
+            transform.rotation = view.pose.orientation.to_quat();
+            transform.translation = view.pose.position.to_vec3();
+        }
+        Some(())
+    };
+    let _ = f();
+}