feat(render): relative-to-eye for mesh, image, face3d and hatch pipelines

Switch the remaining world-space shaders (mesh, image, face3d, hatch,
hatch_batched) to the same relative-to-eye transform the wire pipeline
uses: subtract the eye (high+low f32) per vertex and multiply by the
rotation-only view-projection. Each shader's Uniforms struct is widened
to the full shared layout so the appended RTE fields land at the correct
offsets. Math is unchanged (proj·R·(pos−eye)); large coordinates no
longer jitter on camera movement.

Co-Authored-By: Claude Opus 4.8 <[email protected]>

src/shaders/face3d.wgsl

@@ -5,9 +5,20 @@
 //   color     [f32; 4]   offset 12   16 B
 
 struct Uniforms {
-    view_proj: mat4x4<f32>,
-    viewport:  vec2<f32>,
-    _pad:      vec2<f32>,
+    view_proj:           mat4x4<f32>,
+    camera_pos:          vec4<f32>,
+    viewport_size:       vec2<f32>,
+    world_per_pixel:     f32,
+    lwdisplay_enable:    f32,
+    flat_shade:          f32,
+    transparency_enable: f32,
+    _pad:                vec2<f32>,
+    // Relative-to-eye (double-single): see wire.wgsl.
+    view_rot:            mat4x4<f32>,
+    eye_high:            vec3<f32>,
+    _pad_eh:             f32,
+    eye_low:             vec3<f32>,
+    _pad_el:             f32,
 };
 
 @group(0) @binding(0)
@@ -31,7 +42,7 @@ const DRAW_ORDER_BIAS: f32 = 0.001;
 @vertex
 fn vs_main(v: VertexIn) -> VertexOut {
     var out: VertexOut;
-    out.clip_pos = u.view_proj * vec4<f32>(v.position, 1.0);
+    out.clip_pos = u.view_rot * vec4<f32>((v.position - u.eye_high) - u.eye_low, 1.0);
     out.clip_pos.z = out.clip_pos.z - v.draw_depth * DRAW_ORDER_BIAS * out.clip_pos.w;
     out.color    = v.color;
     return out;

src/shaders/hatch.wgsl

@@ -13,11 +13,20 @@
 // ── Group 0: frame uniforms (shared) ──────────────────────────────────────
 
 struct Uniforms {
-    view_proj:       mat4x4<f32>,
-    camera_pos:      vec4<f32>,
-    viewport_size:   vec2<f32>,
-    world_per_pixel: f32,
-    _pad:            f32,
+    view_proj:           mat4x4<f32>,
+    camera_pos:          vec4<f32>,
+    viewport_size:       vec2<f32>,
+    world_per_pixel:     f32,
+    lwdisplay_enable:    f32,
+    flat_shade:          f32,
+    transparency_enable: f32,
+    _pad:                vec2<f32>,
+    // Relative-to-eye (double-single): see wire.wgsl.
+    view_rot:            mat4x4<f32>,
+    eye_high:            vec3<f32>,
+    _pad_eh:             f32,
+    eye_low:             vec3<f32>,
+    _pad_el:             f32,
 }
 @group(0) @binding(0) var<uniform> u: Uniforms;
 
@@ -96,7 +105,7 @@ struct VOut {
     // fragment shader stays at full f32 precision so the in_polygon /
     // pattern math doesn't catastrophically cancel.
     let world = vec3<f32>(v.pos.x + h.origin.x, v.pos.y + h.origin.y, v.pos.z);
-    o.clip = u.view_proj * vec4<f32>(world, 1.0);
+    o.clip = u.view_rot * vec4<f32>((world - u.eye_high) - u.eye_low, 1.0);
     o.xz   = vec2<f32>(v.pos.x, v.pos.y);
     return o;
 }

src/shaders/hatch_batched.wgsl

@@ -18,11 +18,20 @@
 // ── Group 0: shared frame uniforms (matches hatch.wgsl) ──────────────────
 
 struct Uniforms {
-    view_proj:       mat4x4<f32>,
-    camera_pos:      vec4<f32>,
-    viewport_size:   vec2<f32>,
-    world_per_pixel: f32,
-    _pad:            f32,
+    view_proj:           mat4x4<f32>,
+    camera_pos:          vec4<f32>,
+    viewport_size:       vec2<f32>,
+    world_per_pixel:     f32,
+    lwdisplay_enable:    f32,
+    flat_shade:          f32,
+    transparency_enable: f32,
+    _pad:                vec2<f32>,
+    // Relative-to-eye (double-single): see wire.wgsl.
+    view_rot:            mat4x4<f32>,
+    eye_high:            vec3<f32>,
+    _pad_eh:             f32,
+    eye_low:             vec3<f32>,
+    _pad_el:             f32,
 }
 @group(0) @binding(0) var<uniform> u: Uniforms;
 
@@ -126,7 +135,7 @@ fn corner_xy(c: u32, aabb: vec4<f32>) -> vec2<f32> {
     let world = vec3<f32>(local.x + inst.world_origin.x,
                           local.y + inst.world_origin.y,
                           0.0);
-    o.clip = u.view_proj * vec4<f32>(world, 1.0);
+    o.clip = u.view_rot * vec4<f32>((world - u.eye_high) - u.eye_low, 1.0);
     o.clip.z = o.clip.z - inst.draw_depth * DRAW_ORDER_BIAS * o.clip.w;
     o.xz = local;
     o.instance_index = v.instance_index;

src/shaders/image.wgsl

@@ -12,6 +12,12 @@ struct Uniforms {
     flat_shade:         f32,
     transparency_enable: f32,
     _pad:               vec2<f32>,
+    // Relative-to-eye (double-single): see wire.wgsl.
+    view_rot:           mat4x4<f32>,
+    eye_high:           vec3<f32>,
+    _pad_eh:            f32,
+    eye_low:            vec3<f32>,
+    _pad_el:            f32,
 };
 
 @group(0) @binding(0) var<uniform> u: Uniforms;
@@ -46,7 +52,7 @@ struct VertOut {
 @vertex
 fn vs_main(in: VertIn) -> VertOut {
     var out: VertOut;
-    out.clip_pos = u.view_proj * vec4<f32>(in.pos, 1.0);
+    out.clip_pos = u.view_rot * vec4<f32>((in.pos - u.eye_high) - u.eye_low, 1.0);
     out.clip_pos.z = out.clip_pos.z - img_params.draw_depth * DRAW_ORDER_BIAS * out.clip_pos.w;
     out.uv = in.uv;
     return out;

src/shaders/mesh.wgsl

@@ -10,15 +10,20 @@
 //     flat shade (FlatShaded).
 
 struct Uniforms {
-    view_proj:        mat4x4<f32>,
-    camera_pos:       vec4<f32>,
-    viewport_size:    vec2<f32>,
-    world_per_pixel:  f32,
-    lwdisplay_enable: f32,
-    flat_shade:       f32,
-    _pad0:            f32,
-    _pad1:            f32,
-    _pad2:            f32,
+    view_proj:           mat4x4<f32>,
+    camera_pos:          vec4<f32>,
+    viewport_size:       vec2<f32>,
+    world_per_pixel:     f32,
+    lwdisplay_enable:    f32,
+    flat_shade:          f32,
+    transparency_enable: f32,
+    _pad:                vec2<f32>,
+    // Relative-to-eye (double-single): see wire.wgsl.
+    view_rot:            mat4x4<f32>,
+    eye_high:            vec3<f32>,
+    _pad_eh:             f32,
+    eye_low:             vec3<f32>,
+    _pad_el:             f32,
 };
 
 @group(0) @binding(0)
@@ -40,7 +45,7 @@ struct VertexOut {
 @vertex
 fn vs_main(v: VertexIn) -> VertexOut {
     var out: VertexOut;
-    out.clip_pos  = u.view_proj * vec4<f32>(v.position, 1.0);
+    out.clip_pos  = u.view_rot * vec4<f32>((v.position - u.eye_high) - u.eye_low, 1.0);
     out.color     = v.color;
     out.normal    = v.normal;
     out.world_pos = v.position;