1#import bevy_pbr::{
2    prepass_bindings,
3    mesh_bindings::mesh,
4    mesh_functions,
5    prepass_io::{Vertex, VertexOutput, FragmentOutput},
6    skinning,
7    morph,
8    mesh_view_bindings::view,
9    view_transformations::position_world_to_clip,
10}
11
12#ifdef DEFERRED_PREPASS
13#import bevy_pbr::rgb9e5
14#endif
15
16#ifdef MORPH_TARGETS
17fn morph_vertex(vertex_in: Vertex) -> Vertex {
18    var vertex = vertex_in;
19    let first_vertex = mesh[vertex.instance_index].first_vertex_index;
20    let vertex_index = vertex.index - first_vertex;
21
22    let weight_count = morph::layer_count();
23    for (var i: u32 = 0u; i < weight_count; i ++) {
24        let weight = morph::weight_at(i);
25        if weight == 0.0 {
26            continue;
27        }
28        vertex.position += weight * morph::morph(vertex_index, morph::position_offset, i);
29#ifdef VERTEX_NORMALS
30        vertex.normal += weight * morph::morph(vertex_index, morph::normal_offset, i);
31#endif
32#ifdef VERTEX_TANGENTS
33        vertex.tangent += vec4(weight * morph::morph(vertex_index, morph::tangent_offset, i), 0.0);
34#endif
35    }
36    return vertex;
37}
38
39// Returns the morphed position of the given vertex from the previous frame.
40//
41// This function is used for motion vector calculation, and, as such, it doesn't
42// bother morphing the normals and tangents.
43fn morph_prev_vertex(vertex_in: Vertex) -> Vertex {
44    var vertex = vertex_in;
45    let weight_count = morph::layer_count();
46    for (var i: u32 = 0u; i < weight_count; i ++) {
47        let weight = morph::prev_weight_at(i);
48        if weight == 0.0 {
49            continue;
50        }
51        vertex.position += weight * morph::morph(vertex.index, morph::position_offset, i);
52        // Don't bother morphing normals and tangents; we don't need them for
53        // motion vector calculation.
54    }
55    return vertex;
56}
57#endif  // MORPH_TARGETS
58
59@vertex
60fn vertex(vertex_no_morph: Vertex) -> VertexOutput {
61    var out: VertexOutput;
62
63#ifdef MORPH_TARGETS
64    var vertex = morph_vertex(vertex_no_morph);
65#else
66    var vertex = vertex_no_morph;
67#endif
68
69    let mesh_world_from_local = mesh_functions::get_world_from_local(vertex_no_morph.instance_index);
70
71#ifdef SKINNED
72    var world_from_local = skinning::skin_model(
73        vertex.joint_indices,
74        vertex.joint_weights,
75        vertex_no_morph.instance_index
76    );
77#else // SKINNED
78    // Use vertex_no_morph.instance_index instead of vertex.instance_index to work around a wgpu dx12 bug.
79    // See https://github.com/gfx-rs/naga/issues/2416
80    var world_from_local = mesh_world_from_local;
81#endif // SKINNED
82
83    out.world_position = mesh_functions::mesh_position_local_to_world(world_from_local, vec4<f32>(vertex.position, 1.0));
84    out.position = position_world_to_clip(out.world_position.xyz);
85#ifdef UNCLIPPED_DEPTH_ORTHO_EMULATION
86    out.unclipped_depth = out.position.z;
87    out.position.z = min(out.position.z, 1.0); // Clamp depth to avoid clipping
88#endif // UNCLIPPED_DEPTH_ORTHO_EMULATION
89
90#ifdef VERTEX_UVS_A
91    out.uv = vertex.uv;
92#endif // VERTEX_UVS_A
93
94#ifdef VERTEX_UVS_B
95    out.uv_b = vertex.uv_b;
96#endif // VERTEX_UVS_B
97
98#ifdef NORMAL_PREPASS_OR_DEFERRED_PREPASS
99#ifdef VERTEX_NORMALS
100#ifdef SKINNED
101    out.world_normal = skinning::skin_normals(world_from_local, vertex.normal);
102#else // SKINNED
103    out.world_normal = mesh_functions::mesh_normal_local_to_world(
104        vertex.normal,
105        // Use vertex_no_morph.instance_index instead of vertex.instance_index to work around a wgpu dx12 bug.
106        // See https://github.com/gfx-rs/naga/issues/2416
107        vertex_no_morph.instance_index
108    );
109#endif // SKINNED
110#endif // VERTEX_NORMALS
111
112#ifdef VERTEX_TANGENTS
113    out.world_tangent = mesh_functions::mesh_tangent_local_to_world(
114        world_from_local,
115        vertex.tangent,
116        // Use vertex_no_morph.instance_index instead of vertex.instance_index to work around a wgpu dx12 bug.
117        // See https://github.com/gfx-rs/naga/issues/2416
118        vertex_no_morph.instance_index
119    );
120#endif // VERTEX_TANGENTS
121#endif // NORMAL_PREPASS_OR_DEFERRED_PREPASS
122
123#ifdef VERTEX_COLORS
124    out.color = vertex.color;
125#endif
126
127    // Compute the motion vector for TAA among other purposes. For this we need
128    // to know where the vertex was last frame.
129#ifdef MOTION_VECTOR_PREPASS
130
131    // Take morph targets into account.
132#ifdef MORPH_TARGETS
133
134#ifdef HAS_PREVIOUS_MORPH
135    let prev_vertex = morph_prev_vertex(vertex_no_morph);
136#else   // HAS_PREVIOUS_MORPH
137    let prev_vertex = vertex_no_morph;
138#endif  // HAS_PREVIOUS_MORPH
139
140#else   // MORPH_TARGETS
141    let prev_vertex = vertex_no_morph;
142#endif  // MORPH_TARGETS
143
144    // Take skinning into account.
145#ifdef SKINNED
146
147#ifdef HAS_PREVIOUS_SKIN
148    let prev_model = skinning::skin_prev_model(
149        prev_vertex.joint_indices,
150        prev_vertex.joint_weights,
151        vertex_no_morph.instance_index
152    );
153#else   // HAS_PREVIOUS_SKIN
154    let prev_model = mesh_functions::get_previous_world_from_local(prev_vertex.instance_index);
155#endif  // HAS_PREVIOUS_SKIN
156
157#else   // SKINNED
158    let prev_model = mesh_functions::get_previous_world_from_local(prev_vertex.instance_index);
159#endif  // SKINNED
160
161    out.previous_world_position = mesh_functions::mesh_position_local_to_world(
162        prev_model,
163        vec4<f32>(prev_vertex.position, 1.0)
164    );
165#endif // MOTION_VECTOR_PREPASS
166
167#ifdef VERTEX_OUTPUT_INSTANCE_INDEX
168    // Use vertex_no_morph.instance_index instead of vertex.instance_index to work around a wgpu dx12 bug.
169    // See https://github.com/gfx-rs/naga/issues/2416
170    out.instance_index = vertex_no_morph.instance_index;
171#endif
172
173#ifdef VISIBILITY_RANGE_DITHER
174    out.visibility_range_dither = mesh_functions::get_visibility_range_dither_level(
175        vertex_no_morph.instance_index, mesh_world_from_local[3]);
176#endif  // VISIBILITY_RANGE_DITHER
177
178    return out;
179}
180
181#ifdef PREPASS_FRAGMENT
182@fragment
183fn fragment(in: VertexOutput) -> FragmentOutput {
184    var out: FragmentOutput;
185
186#ifdef NORMAL_PREPASS
187    out.normal = vec4(in.world_normal * 0.5 + vec3(0.5), 1.0);
188#endif
189
190#ifdef UNCLIPPED_DEPTH_ORTHO_EMULATION
191    out.frag_depth = in.unclipped_depth;
192#endif // UNCLIPPED_DEPTH_ORTHO_EMULATION
193
194#ifdef MOTION_VECTOR_PREPASS
195    let clip_position_t = view.unjittered_clip_from_world * in.world_position;
196    let clip_position = clip_position_t.xy / clip_position_t.w;
197    let previous_clip_position_t = prepass_bindings::previous_view_uniforms.clip_from_world * in.previous_world_position;
198    let previous_clip_position = previous_clip_position_t.xy / previous_clip_position_t.w;
199    // These motion vectors are used as offsets to UV positions and are stored
200    // in the range -1,1 to allow offsetting from the one corner to the
201    // diagonally-opposite corner in UV coordinates, in either direction.
202    // A difference between diagonally-opposite corners of clip space is in the
203    // range -2,2, so this needs to be scaled by 0.5. And the V direction goes
204    // down where clip space y goes up, so y needs to be flipped.
205    out.motion_vector = (clip_position - previous_clip_position) * vec2(0.5, -0.5);
206#endif // MOTION_VECTOR_PREPASS
207
208#ifdef DEFERRED_PREPASS
209    // There isn't any material info available for this default prepass shader so we are just writing 
210    // emissive magenta out to the deferred gbuffer to be rendered by the first deferred lighting pass layer.
211    // This is here so if the default prepass fragment is used for deferred magenta will be rendered, and also
212    // as an example to show that a user could write to the deferred gbuffer if they were to start from this shader.
213    out.deferred = vec4(0u, bevy_pbr::rgb9e5::vec3_to_rgb9e5_(vec3(1.0, 0.0, 1.0)), 0u, 0u);
214    out.deferred_lighting_pass_id = 1u;
215#endif
216
217    return out;
218}
219#endif // PREPASS_FRAGMENT