From 2b3d00f1d41d6fef101e638a0ca883fce3865c4d Mon Sep 17 00:00:00 2001 From: Hartmut Seichter Date: Tue, 6 Dec 2022 21:12:15 +0100 Subject: [PATCH] working version of the frustum based calculation for the perspective matrix --- src/main.rs | 3 +++ src/offaxis.rs | 65 +++++++++++++++++++++++++++++++++++++++++++++++++- src/scene.rs | 2 +- src/utils.rs | 21 ++++++++++++---- src/viewer.rs | 39 ++++++++++++++++++++++-------- 5 files changed, 113 insertions(+), 17 deletions(-) diff --git a/src/main.rs b/src/main.rs index 47e9b81..37813c3 100644 --- a/src/main.rs +++ b/src/main.rs @@ -7,6 +7,7 @@ use crate::scene::*; use crate::utils::*; +use crate::viewer::*; use bevy::{prelude::*, window::PresentMode, render::camera::CameraProjectionPlugin}; use offaxis::{offaxis_camera_setup, OffAxisProjection}; @@ -15,6 +16,7 @@ mod offaxis; mod scene; mod screeninfo; mod utils; +mod viewer; fn main() { App::new() @@ -38,6 +40,7 @@ fn main() { .add_startup_system(offaxis_camera_setup) .add_plugin(CameraProjectionPlugin::::default()) .add_system(update_offaxis) + .add_system(simulate_viewer) .run(); } diff --git a/src/offaxis.rs b/src/offaxis.rs index c50e156..a311057 100644 --- a/src/offaxis.rs +++ b/src/offaxis.rs @@ -3,8 +3,10 @@ use bevy::prelude::*; use bevy::render::camera::{Camera, CameraProjection}; use bevy::render::primitives::Frustum; use bevy::render::view::VisibleEntities; +use bevy::math::Mat4; use crate::screeninfo::ScreenInfo; +use crate::viewer::*; #[derive(Component, Debug, Clone, Reflect)] #[reflect(Component, Default)] @@ -19,6 +21,8 @@ impl CameraProjection for OffAxisProjection { println!("Here we go! {:?}",self); + //Mat4::perspective_rh_gl(fov_y_radians, aspect_ratio, z_near, z_far) + Mat4::orthographic_rh(-self.aspect, self.aspect, -1.0, 1.0, self.near, self.far) } @@ -42,6 +46,23 @@ impl Default for OffAxisProjection { } } + +pub fn make_projection_rh_from_frustum(left: f32, right: f32, bottom: f32, top: f32, near:f32, far:f32) -> Mat4 +{ + // based on OpenSceneGraph / glFrustum implementation + let a = (right + left) / (right - left); + let b: f32 = (top + bottom) / (top - bottom); + let c= if far.abs() > f32::MAX { -1.0 } else { -(far + near) / (far - near)}; + let d = if far.abs() > f32::MAX { -2.0 * near } else { -2.0 * far * near / (far - near) }; + + Mat4::from_cols( + Vec4::new(2.0 * near/(right-left),0.0,0.0,0.0), + Vec4::new(0.0,2.0*near/(top-bottom), 0.0,0.0), + Vec4::new(a, b, c, -1.0), + Vec4::new(0.0, 0.0, d, 0.0)) +} + + pub fn offaxis_camera_setup(mut commands: Commands) { let projection = OffAxisProjection::default(); @@ -68,6 +89,48 @@ pub fn offaxis_camera_setup(mut commands: Commands) { VisibleEntities::default(), Camera::default(), Camera3d::default(), - ScreenInfo::new("Test") + ScreenInfo::new("Test"), + Viewer::new(transform.translation) )); } + + + +#[cfg(test)] +mod tests { + use bevy::prelude::Mat4; + + use super::make_projection_rh_from_frustum; + + + #[test] + fn compare_projections() { + + // build an on-axis frustum + let fovy = 33.0_f32; + let aspect_ratio = 1.6666_f32; + let z_near = 1.0_f32; + let z_far = 500.0_f32; + + let tan_fovy = (fovy * 0.5).to_radians().tan(); // use half angle beta + let right = tan_fovy * aspect_ratio * z_near; + let left = -right; + let top = tan_fovy * z_near; + let bottom = -top; + + let mat_frust = make_projection_rh_from_frustum(left, right, bottom, top, z_near, z_far); + + println!("mat 1 {:?}",mat_frust); + + let mat_pers = Mat4::perspective_rh_gl(fovy.to_radians(),aspect_ratio,z_near,z_far); + + println!("mat 2 {:?}",mat_pers); + + assert!(mat_frust.abs_diff_eq(mat_pers, f32::EPSILON)); + + } + + + + +} \ No newline at end of file diff --git a/src/scene.rs b/src/scene.rs index d9444c1..8b7fc07 100644 --- a/src/scene.rs +++ b/src/scene.rs @@ -2,7 +2,6 @@ use bevy::{prelude::*, math::bool, render::primitives::Frustum}; use rand::prelude::*; use bevy::render::primitives::Plane; - // pub struct BuildScenePlugin; // impl Plugin for BuildScenePlugin { @@ -69,6 +68,7 @@ fn generalized_projection ( _ = 33; // camera.frustum.planes[4]. // should be near } + } pub fn build_scene( diff --git a/src/utils.rs b/src/utils.rs index fa16c1b..2480282 100644 --- a/src/utils.rs +++ b/src/utils.rs @@ -2,6 +2,8 @@ use crate::scene::*; use crate::offaxis::*; use crate::screeninfo; use crate::screeninfo::ScreenInfo; +use crate::viewer::Viewer; + use bevy::{prelude::*, window::PresentMode, render::camera::CameraProjectionPlugin}; @@ -19,16 +21,25 @@ pub fn cycle_msaa(input: Res>, mut msaa: ResMut) { pub fn update_offaxis(mut query : Query<( &mut OffAxisProjection, - &ScreenInfo + &mut Transform, + &ScreenInfo, + &Viewer )> ) { - for (mut q,si) in query.iter_mut() { + for (mut projection,mut transform,screen_info,viewer) in query.iter_mut() { // we fake access to far for updating the matrix - (*q).far *= 1.0; + (*projection).far *= 1.0; - println!("Update {:?}",q); + println!("Projection {:?}",*projection); - println!("Screeninfo {}",si.name); + println!("Screen Info {:?}",screen_info.name); + + println!("Viewer {:?}",viewer.position); + + *transform = Transform::from_translation(viewer.position).with_rotation(transform.rotation); + + + } } \ No newline at end of file diff --git a/src/viewer.rs b/src/viewer.rs index 635d167..6066fbf 100644 --- a/src/viewer.rs +++ b/src/viewer.rs @@ -1,22 +1,41 @@ use bevy::{prelude::*, window::PresentMode, render::camera::CameraProjectionPlugin}; -use offaxis::{offaxis_camera_setup, OffAxisProjection}; +// use offaxis::{offaxis_camera_setup, OffAxisProjection}; -#[derive(Component)] -struct Viewer; - -#[derive(Component)] +#[derive(Component,Default)] pub struct Viewer { - position: Vec3, - orientation: Quat, -} + pub position: Vec3, + pub orientation: Quat, + pub alpha: f32, +} impl Viewer { - fn default() -> Self { + pub fn new(position: Vec3) ->Self { Self { - position: Vec3::ZERO, + position, + orientation: Quat::IDENTITY, + alpha: 0.0, + } } + + pub fn default() -> Self { + Self { + position: Vec3::ZERO, + orientation: Quat::IDENTITY, + alpha: 0.0 + } + } +} + +pub fn simulate_viewer(mut query: Query<&mut Viewer>) +{ + for mut v in query.iter_mut() { + //v.position += Vec3::Y * 0.005; + v.alpha += 0.01; + let radius = 0.5; + v.position = Vec3::new(v.alpha.sin()*radius,v.alpha.cos()*radius,5.0); + } } \ No newline at end of file