fix egui tab offset for single pass raymarching distortion

src/apps/ray_marching_renderer.rs

@@ -18,6 +18,7 @@ struct RayMarchingRendererResources {
     uniform_buffer_focal_length: wgpu::Buffer,
     uniform_buffer_aspect_ratio: wgpu::Buffer,
     uniform_buffer_viewport_size: wgpu::Buffer,
+    uniform_buffer_viewport_position: wgpu::Buffer,
     uniform_buffer_ray_origin: wgpu::Buffer,
     uniform_buffer_top_aabb: wgpu::Buffer,
     uniform_buffer_bottom_aabb: wgpu::Buffer,
@@ -39,6 +40,7 @@ impl RayMarchingRendererResources {
         focal_length: f32,
         aspect_ratio: f32,
         viewport_size: glam::Vec2,
+        viewport_position: glam::Vec2,
         ray_origin: glam::Vec3,
         top_aabb: glam::Vec3,
         bottom_aabb: glam::Vec3,
@@ -81,6 +83,11 @@ impl RayMarchingRendererResources {
             0,
             bytemuck::cast_slice(&[viewport_size]),
         );
+        queue.write_buffer(
+            &self.uniform_buffer_viewport_position,
+            0,
+            bytemuck::cast_slice(&[viewport_position]),
+        );
         queue.write_buffer(
             &self.uniform_buffer_ray_origin,
             0,
@@ -128,6 +135,7 @@ pub struct RayMarchingRenderer {
     focal_length: f32,
     aspect_ratio: f32,
     viewport_size: glam::Vec2,
+    viewport_position: glam::Vec2,
     ray_origin: glam::Vec3,
     top_aabb: glam::Vec3,
     bottom_aabb: glam::Vec3,
@@ -286,6 +294,15 @@ impl RayMarchingRenderer {
                 usage: wgpu::BufferUsages::COPY_DST | wgpu::BufferUsages::UNIFORM,
             });
 
+        let viewport_position = glam::Vec2::default();
+
+        let uniform_buffer_viewport_position =
+            device.create_buffer_init(&wgpu::util::BufferInitDescriptor {
+                label: Some("viewport size"),
+                contents: bytemuck::cast_slice(&[viewport_position]),
+                usage: wgpu::BufferUsages::COPY_DST | wgpu::BufferUsages::UNIFORM,
+            });
+
         let ray_origin = glam::Vec3::default();
 
         let uniform_buffer_ray_origin =
@@ -426,6 +443,16 @@ impl RayMarchingRenderer {
                         },
                         count: None,
                     },
+                    wgpu::BindGroupLayoutEntry {
+                        binding: 10,
+                        visibility: wgpu::ShaderStages::FRAGMENT,
+                        ty: wgpu::BindingType::Buffer {
+                            ty: wgpu::BufferBindingType::Uniform,
+                            has_dynamic_offset: false,
+                            min_binding_size: None,
+                        },
+                        count: None,
+                    },
                 ],
             });
 
@@ -461,18 +488,22 @@ impl RayMarchingRenderer {
                     },
                     wgpu::BindGroupEntry {
                         binding: 6,
-                        resource: uniform_buffer_ray_origin.as_entire_binding(),
+                        resource: uniform_buffer_viewport_position.as_entire_binding(),
                     },
                     wgpu::BindGroupEntry {
                         binding: 7,
-                        resource: uniform_buffer_top_aabb.as_entire_binding(),
+                        resource: uniform_buffer_ray_origin.as_entire_binding(),
                     },
                     wgpu::BindGroupEntry {
                         binding: 8,
-                        resource: uniform_buffer_bottom_aabb.as_entire_binding(),
+                        resource: uniform_buffer_top_aabb.as_entire_binding(),
                     },
                     wgpu::BindGroupEntry {
                         binding: 9,
+                        resource: uniform_buffer_bottom_aabb.as_entire_binding(),
+                    },
+                    wgpu::BindGroupEntry {
+                        binding: 10,
                         resource: uniform_buffer_camera_position.as_entire_binding(),
                     },
                 ],
@@ -552,6 +583,7 @@ impl RayMarchingRenderer {
             uniform_buffer_focal_length,
             uniform_buffer_aspect_ratio,
             uniform_buffer_viewport_size,
+            uniform_buffer_viewport_position,
             uniform_buffer_ray_origin,
             uniform_buffer_top_aabb,
             uniform_buffer_bottom_aabb,
@@ -590,6 +622,7 @@ impl RayMarchingRenderer {
             focal_length,
             aspect_ratio,
             viewport_size,
+            viewport_position,
             ray_origin,
             top_aabb,
             bottom_aabb,
@@ -643,6 +676,10 @@ impl RayMarchingRenderer {
             x: rect.width(),
             y: rect.height(),
         };
+        let viewport_position = Vec2 {
+            x: rect.left_top().x,
+            y: rect.left_top().y,
+        };
 
         let z_near = 0.0001;
         let z_far = 10.0;
@@ -709,6 +746,7 @@ impl RayMarchingRenderer {
                     focal_length,
                     aspect_ratio,
                     viewport_size,
+                    viewport_position,
                     ray_origin,
                     top_aabb,
                     bottom_aabb,

src/apps/ray_marching_shader.wgsl

@@ -39,12 +39,14 @@ var<uniform> aspect_ratio: f32;
 @group(2) @binding(5)
 var<uniform> viewport_size: vec2<f32>;
 @group(2) @binding(6)
-var<uniform> ray_origin: vec3<f32>;
+var<uniform> viewport_position: vec2<f32>;
 @group(2) @binding(7)
-var<uniform> top_aabb: vec3<f32>;
+var<uniform> ray_origin: vec3<f32>;
 @group(2) @binding(8)
-var<uniform> bottom_aabb: vec3<f32>;
+var<uniform> top_aabb: vec3<f32>;
 @group(2) @binding(9)
+var<uniform> bottom_aabb: vec3<f32>;
+@group(2) @binding(10)
 var<uniform> camera_position: vec3<f32>;
 
 fn intersectAABB(ray_origin: vec3<f32>, rayDir: vec3<f32>, boxMin: vec3<f32>, boxMax: vec3<f32>) -> vec2<f32> {
@@ -109,8 +111,10 @@ fn fs_main(@builtin(position) frag_coord: vec4<f32>) -> @location(0) vec4<f32> {
     // let value = textureSample(t_diffuse, s_diffuse, position)[0];
     // return vec4<f32>(value, 0.0, 0.0, 1.0);
 
+	let local_frag_coord: vec2<f32> = frag_coord.xy - viewport_position;
+
+    var ray_direction_xy: vec2<f32> = (2.0 * local_frag_coord.xy / viewport_size - 1.0);
 
-    var ray_direction_xy: vec2<f32> = (2.0 * frag_coord.xy / viewport_size - 1.0);
 	ray_direction_xy.x *= aspect_ratio;
 	var ray_direction: vec3<f32> = vec3<f32>(ray_direction_xy, -focal_length);
 	ray_direction = (vec4<f32>(ray_direction, 0.0) * view_model_matrix_without_model_scale).xyz;
@@ -178,6 +182,9 @@ fn fs_main(@builtin(position) frag_coord: vec4<f32>) -> @location(0) vec4<f32> {
         value = vec4<f32>(firstHit, 0.0);
     }
 
+	// value.x = frag_coord.x / viewport_size.x;
+	// value.y = frag_coord.y / viewport_size.y;
+
 	return value;
 
 	// gl_FragDepth = length(position - ray_start) / gl_FragCoord.w;