add reconstruct_view_space_position

assets/shaders/show_prepass.wgsl

@@ -2,7 +2,7 @@
 #import bevy_pbr::mesh_view_bindings  globals, view
 #import bevy_pbr::prepass_utils
 #import bevy_pbr::mesh_vertex_output  MeshVertexOutput
-#import bevy_pbr::depth_functions
+#import bevy_pbr::depth_functions reconstruct_view_space_position
 
 struct ShowPrepassSettings {
     show_depth: u32,
@@ -29,7 +29,8 @@ fn fragment(
         let frag_coord = mesh.position;
         let uv = frag_coord.xy;
         let world_position = bevy_pbr::depth_functions::depth_to_world_position(uv, depth, view.inverse_projection, view.view);
-        return vec4(world_position, 1.0);
+        let view_pos = reconstruct_view_space_position(depth, uv);
+        return vec4(view_pos, 1.0);
     } else if settings.show_normals == 1u {
         let normal = bevy_pbr::prepass_utils::prepass_normal(mesh.position, sample_index);
         return vec4(normal, 1.0);

crates/bevy_pbr/src/render/depth_functions.wgsl

@@ -5,10 +5,21 @@
 // and then you make p_ndc = vec4(xy, depth_ndc, 1.0); p_view_homogeneous = view.inverse_projection * p_ndc; p_view = p_view_homogeneous.xyz / p_view_homogeneous.w; p_world = view.view * vec4(p_view, 1.0);
 
 fn depth_to_world_position(uv: vec2<f32>, depth: f32, inverse_projection: mat4x4<f32>, view: mat4x4<f32>) -> vec3<f32>{
-    let xy = uv * vec2(2.0, -2.0) + vec2(-1.0, 1.0);
-    let p_ndc = vec4(xy, depth, 1.0);
+    let clip_xy = uv_to_clip(uv);
+    let p_ndc = vec4(clip_xy, depth, 1.0);
     let p_view_homogeneous = inverse_projection * p_ndc;
     let p_view  = p_view_homogeneous.xyz / p_view_homogeneous.w;
     let p_world = view * vec4(p_view, 1.0);
     return p_world.xyz;
+}
+
+fn reconstruct_view_space_position(uv: vec2<f32>, depth: f32, inverse_projection: mat4x4<f32>) -> vec3<f32> {
+    let clip_xy = uv_to_clip(uv);
+    let t = inverse_projection * vec4(clip_xy, depth, 1.0);
+    let view_xyz = t.xyz / t.w;
+    return view_xyz;
+}
+
+fn uv_to_clip(uv: vec2<f32>) -> vec2<f32>{
+    return uv * vec2(2.0, -2.0) + vec2(-1.0, 1.0);
 }

crates/bevy_pbr/src/ssao/gtao.wgsl

@@ -9,6 +9,7 @@
 #import bevy_pbr::utils PI, HALF_PI
 #import bevy_render::view View
 #import bevy_render::globals Globals
+#import bevy_pbr::depth_functions reconstruct_view_space_position
 
 @group(0) @binding(0) var preprocessed_depth: texture_2d<f32>;
 @group(0) @binding(1) var normals: texture_2d<f32>;
@@ -78,16 +79,9 @@ fn load_normal_view_space(uv: vec2<f32>) -> vec3<f32> {
     return inverse_view * world_normal;
 }
 
-fn reconstruct_view_space_position(depth: f32, uv: vec2<f32>) -> vec3<f32> {
-    let clip_xy = vec2<f32>(uv.x * 2.0 - 1.0, 1.0 - 2.0 * uv.y);
-    let t = view.inverse_projection * vec4<f32>(clip_xy, depth, 1.0);
-    let view_xyz = t.xyz / t.w;
-    return view_xyz;
-}
-
 fn load_and_reconstruct_view_space_position(uv: vec2<f32>, sample_mip_level: f32) -> vec3<f32> {
     let depth = textureSampleLevel(preprocessed_depth, point_clamp_sampler, uv, sample_mip_level).r;
-    return reconstruct_view_space_position(depth, uv);
+    return reconstruct_view_space_position(uv, depth, view.inverse_projection);
 }
 
 @compute
@@ -107,7 +101,7 @@ fn gtao(@builtin(global_invocation_id) global_id: vec3<u32>) {
     var pixel_depth = calculate_neighboring_depth_differences(pixel_coordinates);
     pixel_depth += 0.00001; // Avoid depth precision issues
 
-    let pixel_position = reconstruct_view_space_position(pixel_depth, uv);
+    let pixel_position = reconstruct_view_space_position(uv, pixel_depth, view.inverse_projection);
     let pixel_normal = load_normal_view_space(uv);
     let view_vec = normalize(-pixel_position);