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    morph::{morph_position, morph_normal, morph_tangent},
9    mesh_view_bindings::view,
10    view_transformations::position_world_to_clip,
11}
12
13#ifdef DEFERRED_PREPASS
14#import bevy_pbr::rgb9e5
15#endif
16
17#ifdef MORPH_TARGETS
18// The instance_index parameter must match vertex_in.instance_index. This is a work around for a wgpu dx12 bug.
19// See https://github.com/gfx-rs/naga/issues/2416
20fn morph_vertex(vertex_in: Vertex, instance_index: u32) -> Vertex {
21    var vertex = vertex_in;
22    let first_vertex = mesh[instance_index].first_vertex_index;
23    let vertex_index = vertex.index - first_vertex;
24
25    let weight_count = morph::layer_count(instance_index);
26    for (var i: u32 = 0u; i < weight_count; i ++) {
27        let weight = morph::weight_at(i, instance_index);
28        if weight == 0.0 {
29            continue;
30        }
31        vertex.position += weight * morph_position(vertex_index, i, instance_index);
32#ifdef VERTEX_NORMALS
33        vertex.normal += weight * morph_normal(vertex_index, i, instance_index);
34#endif
35#ifdef VERTEX_TANGENTS
36        vertex.tangent += vec4(weight * morph_tangent(vertex_index, i, instance_index), 0.0);
37#endif
38    }
39    return vertex;
40}
41
42// Returns the morphed position of the given vertex from the previous frame.
43//
44// This function is used for motion vector calculation, and, as such, it doesn't
45// bother morphing the normals and tangents.
46//
47// The instance_index parameter must match vertex_in.instance_index. This is a work around for a wgpu dx12 bug.
48// See https://github.com/gfx-rs/naga/issues/2416
49fn morph_prev_vertex(vertex_in: Vertex, instance_index: u32) -> Vertex {
50    var vertex = vertex_in;
51    let first_vertex = mesh[instance_index].first_vertex_index;
52    let vertex_index = vertex.index - first_vertex;
53    let weight_count = morph::layer_count(instance_index);
54    for (var i: u32 = 0u; i < weight_count; i ++) {
55        let weight = morph::prev_weight_at(i, instance_index);
56        if weight == 0.0 {
57            continue;
58        }
59        vertex.position += weight * morph_position(vertex_index, i, instance_index);
60        // Don't bother morphing normals and tangents; we don't need them for
61        // motion vector calculation.
62    }
63    return vertex;
64}
65#endif  // MORPH_TARGETS
66
67@vertex
68fn vertex(vertex_no_morph: Vertex) -> VertexOutput {
69    var out: VertexOutput;
70
71#ifdef MORPH_TARGETS
72    var vertex = morph_vertex(vertex_no_morph, vertex_no_morph.instance_index);
73#else
74    var vertex = vertex_no_morph;
75#endif
76
77    let mesh_world_from_local = mesh_functions::get_world_from_local(vertex_no_morph.instance_index);
78
79#ifdef SKINNED
80    // Use vertex_no_morph.instance_index instead of vertex.instance_index to work around a wgpu dx12 bug.
81    // See https://github.com/gfx-rs/naga/issues/2416
82    var world_from_local = skinning::skin_model(
83        vertex.joint_indices,
84        vertex.joint_weights,
85        vertex_no_morph.instance_index
86    );
87#else // SKINNED
88    var world_from_local = mesh_world_from_local;
89#endif // SKINNED
90
91    out.world_position = mesh_functions::mesh_position_local_to_world(world_from_local, vec4<f32>(vertex.position, 1.0));
92    out.position = position_world_to_clip(out.world_position.xyz);
93#ifdef UNCLIPPED_DEPTH_ORTHO_EMULATION
94    out.unclipped_depth = out.position.z;
95    out.position.z = min(out.position.z, 1.0); // Clamp depth to avoid clipping
96#endif // UNCLIPPED_DEPTH_ORTHO_EMULATION
97
98#ifdef VERTEX_UVS_A
99    out.uv = vertex.uv;
100#endif // VERTEX_UVS_A
101
102#ifdef VERTEX_UVS_B
103    out.uv_b = vertex.uv_b;
104#endif // VERTEX_UVS_B
105
106#ifdef NORMAL_PREPASS_OR_DEFERRED_PREPASS
107#ifdef VERTEX_NORMALS
108#ifdef SKINNED
109    out.world_normal = skinning::skin_normals(world_from_local, vertex.normal);
110#else // SKINNED
111    out.world_normal = mesh_functions::mesh_normal_local_to_world(
112        vertex.normal,
113        // Use vertex_no_morph.instance_index instead of vertex.instance_index to work around a wgpu dx12 bug.
114        // See https://github.com/gfx-rs/naga/issues/2416
115        vertex_no_morph.instance_index
116    );
117#endif // SKINNED
118#endif // VERTEX_NORMALS
119
120#ifdef VERTEX_TANGENTS
121    out.world_tangent = mesh_functions::mesh_tangent_local_to_world(
122        world_from_local,
123        vertex.tangent,
124        // Use vertex_no_morph.instance_index instead of vertex.instance_index to work around a wgpu dx12 bug.
125        // See https://github.com/gfx-rs/naga/issues/2416
126        vertex_no_morph.instance_index
127    );
128#endif // VERTEX_TANGENTS
129#endif // NORMAL_PREPASS_OR_DEFERRED_PREPASS
130
131#ifdef VERTEX_COLORS
132    out.color = vertex.color;
133#endif
134
135    // Compute the motion vector for TAA among other purposes. For this we need
136    // to know where the vertex was last frame.
137#ifdef MOTION_VECTOR_PREPASS
138
139    // Take morph targets into account.
140#ifdef MORPH_TARGETS
141
142#ifdef HAS_PREVIOUS_MORPH
143    let prev_vertex = morph_prev_vertex(vertex_no_morph, vertex_no_morph.instance_index);
144#else   // HAS_PREVIOUS_MORPH
145    let prev_vertex = vertex_no_morph;
146#endif  // HAS_PREVIOUS_MORPH
147
148#else   // MORPH_TARGETS
149    let prev_vertex = vertex_no_morph;
150#endif  // MORPH_TARGETS
151
152    // Take skinning into account.
153#ifdef SKINNED
154
155#ifdef HAS_PREVIOUS_SKIN
156    let prev_model = skinning::skin_prev_model(
157        prev_vertex.joint_indices,
158        prev_vertex.joint_weights,
159        vertex_no_morph.instance_index
160    );
161#else   // HAS_PREVIOUS_SKIN
162    // Use vertex_no_morph.instance_index instead of prev_vertex.instance_index to work around a wgpu dx12 bug.
163    // See https://github.com/gfx-rs/naga/issues/2416
164    let prev_model = mesh_functions::get_previous_world_from_local(vertex_no_morph.instance_index);
165#endif  // HAS_PREVIOUS_SKIN
166
167#else   // SKINNED
168    // Use vertex_no_morph.instance_index instead of prev_vertex.instance_index to work around a wgpu dx12 bug.
169    // See https://github.com/gfx-rs/naga/issues/2416
170    let prev_model = mesh_functions::get_previous_world_from_local(vertex_no_morph.instance_index);
171#endif  // SKINNED
172
173    out.previous_world_position = mesh_functions::mesh_position_local_to_world(
174        prev_model,
175        vec4<f32>(prev_vertex.position, 1.0)
176    );
177#endif // MOTION_VECTOR_PREPASS
178
179#ifdef VERTEX_OUTPUT_INSTANCE_INDEX
180    // Use vertex_no_morph.instance_index instead of vertex.instance_index to work around a wgpu dx12 bug.
181    // See https://github.com/gfx-rs/naga/issues/2416
182    out.instance_index = vertex_no_morph.instance_index;
183#endif
184
185#ifdef VISIBILITY_RANGE_DITHER
186    out.visibility_range_dither = mesh_functions::get_visibility_range_dither_level(
187        vertex_no_morph.instance_index, mesh_world_from_local[3]);
188#endif  // VISIBILITY_RANGE_DITHER
189
190    return out;
191}
192
193#ifdef PREPASS_FRAGMENT
194@fragment
195fn fragment(in: VertexOutput) -> FragmentOutput {
196    var out: FragmentOutput;
197
198#ifdef NORMAL_PREPASS
199    out.normal = vec4(in.world_normal * 0.5 + vec3(0.5), 1.0);
200#endif
201
202#ifdef UNCLIPPED_DEPTH_ORTHO_EMULATION
203    out.frag_depth = in.unclipped_depth;
204#endif // UNCLIPPED_DEPTH_ORTHO_EMULATION
205
206#ifdef MOTION_VECTOR_PREPASS
207    let clip_position_t = view.unjittered_clip_from_world * in.world_position;
208    let clip_position = clip_position_t.xy / clip_position_t.w;
209    let previous_clip_position_t = prepass_bindings::previous_view_uniforms.clip_from_world * in.previous_world_position;
210    let previous_clip_position = previous_clip_position_t.xy / previous_clip_position_t.w;
211    // These motion vectors are used as offsets to UV positions and are stored
212    // in the range -1,1 to allow offsetting from the one corner to the
213    // diagonally-opposite corner in UV coordinates, in either direction.
214    // A difference between diagonally-opposite corners of clip space is in the
215    // range -2,2, so this needs to be scaled by 0.5. And the V direction goes
216    // down where clip space y goes up, so y needs to be flipped.
217    out.motion_vector = (clip_position - previous_clip_position) * vec2(0.5, -0.5);
218#endif // MOTION_VECTOR_PREPASS
219
220#ifdef DEFERRED_PREPASS
221    // There isn't any material info available for this default prepass shader so we are just writing 
222    // emissive magenta out to the deferred gbuffer to be rendered by the first deferred lighting pass layer.
223    // This is here so if the default prepass fragment is used for deferred magenta will be rendered, and also
224    // as an example to show that a user could write to the deferred gbuffer if they were to start from this shader.
225    out.deferred = vec4(0u, bevy_pbr::rgb9e5::vec3_to_rgb9e5_(vec3(1.0, 0.0, 1.0)), 0u, 0u);
226    out.deferred_lighting_pass_id = 1u;
227#endif
228
229    return out;
230}
231#endif // PREPASS_FRAGMENT