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#ifdef SKINNED
70    var world_from_local = skinning::skin_model(vertex.joint_indices, vertex.joint_weights);
71#else // SKINNED
72    // Use vertex_no_morph.instance_index instead of vertex.instance_index to work around a wgpu dx12 bug.
73    // See https://github.com/gfx-rs/naga/issues/2416
74    var world_from_local = mesh_functions::get_world_from_local(vertex_no_morph.instance_index);
75#endif // SKINNED
76
77    out.world_position = mesh_functions::mesh_position_local_to_world(world_from_local, vec4<f32>(vertex.position, 1.0));
78    out.position = position_world_to_clip(out.world_position.xyz);
79#ifdef DEPTH_CLAMP_ORTHO
80    out.clip_position_unclamped = out.position;
81    out.position.z = min(out.position.z, 1.0);
82#endif // DEPTH_CLAMP_ORTHO
83
84#ifdef VERTEX_UVS_A
85    out.uv = vertex.uv;
86#endif // VERTEX_UVS_A
87
88#ifdef VERTEX_UVS_B
89    out.uv_b = vertex.uv_b;
90#endif // VERTEX_UVS_B
91
92#ifdef NORMAL_PREPASS_OR_DEFERRED_PREPASS
93#ifdef SKINNED
94    out.world_normal = skinning::skin_normals(world_from_local, vertex.normal);
95#else // SKINNED
96    out.world_normal = mesh_functions::mesh_normal_local_to_world(
97        vertex.normal,
98        // Use vertex_no_morph.instance_index instead of vertex.instance_index to work around a wgpu dx12 bug.
99        // See https://github.com/gfx-rs/naga/issues/2416
100        vertex_no_morph.instance_index
101    );
102#endif // SKINNED
103
104#ifdef VERTEX_TANGENTS
105    out.world_tangent = mesh_functions::mesh_tangent_local_to_world(
106        world_from_local,
107        vertex.tangent,
108        // Use vertex_no_morph.instance_index instead of vertex.instance_index to work around a wgpu dx12 bug.
109        // See https://github.com/gfx-rs/naga/issues/2416
110        vertex_no_morph.instance_index
111    );
112#endif // VERTEX_TANGENTS
113#endif // NORMAL_PREPASS_OR_DEFERRED_PREPASS
114
115#ifdef VERTEX_COLORS
116    out.color = vertex.color;
117#endif
118
119    // Compute the motion vector for TAA among other purposes. For this we need
120    // to know where the vertex was last frame.
121#ifdef MOTION_VECTOR_PREPASS
122
123    // Take morph targets into account.
124#ifdef MORPH_TARGETS
125
126#ifdef HAS_PREVIOUS_MORPH
127    let prev_vertex = morph_prev_vertex(vertex_no_morph);
128#else   // HAS_PREVIOUS_MORPH
129    let prev_vertex = vertex_no_morph;
130#endif  // HAS_PREVIOUS_MORPH
131
132#else   // MORPH_TARGETS
133    let prev_vertex = vertex_no_morph;
134#endif  // MORPH_TARGETS
135
136    // Take skinning into account.
137#ifdef SKINNED
138
139#ifdef HAS_PREVIOUS_SKIN
140    let prev_model = skinning::skin_prev_model(
141        prev_vertex.joint_indices,
142        prev_vertex.joint_weights,
143    );
144#else   // HAS_PREVIOUS_SKIN
145    let prev_model = mesh_functions::get_previous_world_from_local(prev_vertex.instance_index);
146#endif  // HAS_PREVIOUS_SKIN
147
148#else   // SKINNED
149    let prev_model = mesh_functions::get_previous_world_from_local(prev_vertex.instance_index);
150#endif  // SKINNED
151
152    out.previous_world_position = mesh_functions::mesh_position_local_to_world(
153        prev_model,
154        vec4<f32>(prev_vertex.position, 1.0)
155    );
156#endif // MOTION_VECTOR_PREPASS
157
158#ifdef VERTEX_OUTPUT_INSTANCE_INDEX
159    // Use vertex_no_morph.instance_index instead of vertex.instance_index to work around a wgpu dx12 bug.
160    // See https://github.com/gfx-rs/naga/issues/2416
161    out.instance_index = vertex_no_morph.instance_index;
162#endif
163
164    return out;
165}
166
167#ifdef PREPASS_FRAGMENT
168@fragment
169fn fragment(in: VertexOutput) -> FragmentOutput {
170    var out: FragmentOutput;
171
172#ifdef NORMAL_PREPASS
173    out.normal = vec4(in.world_normal * 0.5 + vec3(0.5), 1.0);
174#endif
175
176#ifdef DEPTH_CLAMP_ORTHO
177    out.frag_depth = in.clip_position_unclamped.z;
178#endif // DEPTH_CLAMP_ORTHO
179
180#ifdef MOTION_VECTOR_PREPASS
181    let clip_position_t = view.unjittered_clip_from_world * in.world_position;
182    let clip_position = clip_position_t.xy / clip_position_t.w;
183    let previous_clip_position_t = prepass_bindings::previous_view_uniforms.clip_from_world * in.previous_world_position;
184    let previous_clip_position = previous_clip_position_t.xy / previous_clip_position_t.w;
185    // These motion vectors are used as offsets to UV positions and are stored
186    // in the range -1,1 to allow offsetting from the one corner to the
187    // diagonally-opposite corner in UV coordinates, in either direction.
188    // A difference between diagonally-opposite corners of clip space is in the
189    // range -2,2, so this needs to be scaled by 0.5. And the V direction goes
190    // down where clip space y goes up, so y needs to be flipped.
191    out.motion_vector = (clip_position - previous_clip_position) * vec2(0.5, -0.5);
192#endif // MOTION_VECTOR_PREPASS
193
194#ifdef DEFERRED_PREPASS
195    // There isn't any material info available for this default prepass shader so we are just writing 
196    // emissive magenta out to the deferred gbuffer to be rendered by the first deferred lighting pass layer.
197    // This is here so if the default prepass fragment is used for deferred magenta will be rendered, and also
198    // as an example to show that a user could write to the deferred gbuffer if they were to start from this shader.
199    out.deferred = vec4(0u, bevy_pbr::rgb9e5::vec3_to_rgb9e5_(vec3(1.0, 0.0, 1.0)), 0u, 0u);
200    out.deferred_lighting_pass_id = 1u;
201#endif
202
203    return out;
204}
205#endif // PREPASS_FRAGMENT