projecting clip to ui is hard

1 files changed, 45 insertions, 25 deletions

diff --git a/client/src/ui.rs b/client/src/ui.rs
index ffd840d..be206b5 100644
--- a/client/src/ui.rs
+++ b/client/src/ui.rs
@@ -19,7 +19,7 @@ use egui::{
     Context, Event, ImageData, TextureId, ViewportId, ViewportInfo,
     epaint::{ImageDelta, Primitive, Vertex},
 };
-use glam::{Affine3A, Mat2, Mat3, Mat4, Vec2, vec2};
+use glam::{Affine3A, Mat2, Mat3, Mat4, Vec2, Vec3Swizzles, Vec4Swizzles, vec2, vec4};
 use log::info;
 use rand::random;
 use std::{
@@ -309,23 +309,7 @@ impl UiRenderer {
 
         rpass.set_pipeline(&self.pipeline);
 
-        let _screen_size = vec2(
-            surface_configuration.width as f32,
-            surface_configuration.height as f32,
-        );
-
         let mut raw_input = egui::RawInput::default();
-        if input_state.cursor_pos != self.last_pointer {
-            raw_input.events.push(Event::PointerMoved(egui::Pos2::new(
-                input_state.cursor_pos.x,
-                input_state.cursor_pos.y,
-            )));
-            self.last_pointer = input_state.cursor_pos;
-        }
-        raw_input
-            .events
-            .extend(input_state.egui_events.iter().cloned());
-
         raw_input.viewport_id = surfaces.keys().next().copied().unwrap();
         raw_input.viewports = surfaces
             .keys()
@@ -339,6 +323,50 @@ impl UiRenderer {
 
         let mut surfaces_closed = Vec::new();
         for (viewport_id, surf) in surfaces.iter_mut() {
+            let scale = 0.03;
+            let projection = projection
+                * Mat4::from_translation(surf.transform.translation.into())
+                * Mat4::from_mat3a(surf.transform.matrix3)
+                * Mat4::from_mat3(Mat3::from_mat2(Mat2::from_cols_array(&[
+                    scale, 0., 0., -scale,
+                ])));
+
+            let screen_size = vec2(
+                surface_configuration.width as f32,
+                surface_configuration.height as f32,
+            );
+
+            let mouse_xy_clip = (input_state.cursor_pos / screen_size) * 2. - 1.;
+
+            let iproject = projection.inverse();
+
+            let mut mouse_world_1 = iproject * vec4(mouse_xy_clip.x, mouse_xy_clip.y, 0.0, 1.0);
+            let mut mouse_world_2 = iproject * vec4(mouse_xy_clip.x, mouse_xy_clip.y, 1.0, 1.0);
+
+            mouse_world_1 /= mouse_world_1.w;
+            mouse_world_2 /= mouse_world_2.w;
+
+            let mouse_world_1 = mouse_world_1.xyz();
+            let mouse_world_2 = mouse_world_2.xyz();
+
+            let ray_norm = (mouse_world_2 - mouse_world_1).normalize();
+            let ray_t = mouse_world_1.z / ray_norm.z;
+            let ray_hit = mouse_world_1 + ray_norm * ray_t;
+
+            let cursor_pos = ray_hit.xy();
+
+            let mut raw_input = raw_input.clone();
+            if cursor_pos != self.last_pointer {
+                raw_input.events.push(Event::PointerMoved(egui::Pos2::new(
+                    cursor_pos.x,
+                    cursor_pos.y,
+                )));
+                self.last_pointer = cursor_pos;
+            }
+            raw_input
+                .events
+                .extend(input_state.egui_events.iter().cloned());
+
             let mut close = false;
             let full_output = self.ctx.run(raw_input.clone(), |ctx| {
                 close = !(surf.content)(ctx);
@@ -439,14 +467,6 @@ impl UiRenderer {
             assert_eq!(index_count, index_offset);
             assert_eq!(vertex_count, vertex_offset);
 
-            let scale = 0.03;
-            let projection = projection
-                * Mat4::from_translation(surf.transform.translation.into())
-                * Mat4::from_mat3a(surf.transform.matrix3)
-                * Mat4::from_mat3(Mat3::from_mat2(Mat2::from_cols_array(&[
-                    scale, 0., 0., -scale,
-                ])));
-
             let projection = projection.to_cols_array().map(|v| v.to_le_bytes());
 
             rpass.set_push_constants(ShaderStages::VERTEX, 0, projection.as_flattened());