#import bevy_pbr::mesh_bindings    mesh
#import bevy_pbr::mesh_functions   get_model_matrix, mesh_position_local_to_clip
#import bevy_pbr::morph

#ifdef SKINNED
    #import bevy_pbr::skinning
#endif

struct Vertex {
    @builtin(instance_index) instance_index: u32,
    @location(0) position: vec3<f32>,
#ifdef SKINNED
    @location(5) joint_indexes: vec4<u32>,
    @location(6) joint_weights: vec4<f32>,
#endif
#ifdef MORPH_TARGETS
    @builtin(vertex_index) index: u32,
#endif
};

struct VertexOutput {
    @builtin(position) clip_position: vec4<f32>,
};


#ifdef MORPH_TARGETS
fn morph_vertex(vertex_in: Vertex) -> Vertex {
    var vertex = vertex_in;
    let weight_count = bevy_pbr::morph::layer_count();
    for (var i: u32 = 0u; i < weight_count; i ++) {
        let weight = bevy_pbr::morph::weight_at(i);
        if weight == 0.0 {
            continue;
        }
        vertex.position += weight * bevy_pbr::morph::morph(vertex.index, bevy_pbr::morph::position_offset, i);
    }
    return vertex;
}
#endif

@vertex
fn vertex(vertex_no_morph: Vertex) -> VertexOutput {

#ifdef MORPH_TARGETS
    var vertex = morph_vertex(vertex_no_morph);
#else
    var vertex = vertex_no_morph;
#endif

#ifdef SKINNED
    let model = bevy_pbr::skinning::skin_model(vertex.joint_indexes, vertex.joint_weights);
#else
    // Use vertex_no_morph.instance_index instead of vertex.instance_index to work around a wgpu dx12 bug.
    // See https://github.com/gfx-rs/naga/issues/2416 .
    let model = get_model_matrix(vertex_no_morph.instance_index);
#endif

    var out: VertexOutput;
    out.clip_position = mesh_position_local_to_clip(model, vec4<f32>(vertex.position, 1.0));
    return out;
}

@fragment
fn fragment() -> @location(0) vec4<f32> {
    return vec4<f32>(1.0, 1.0, 1.0, 1.0);
}