reset_indirect_batch_sets.wgsl

// Resets the indirect draw counts to zero.
//
// This shader is needed because we reuse the same indirect batch set count
// buffer (i.e. the buffer that gets passed to `multi_draw_indirect_count` to
// determine how many objects to draw) between phases (early, late, and main).
// Before launching `build_indirect_params.wgsl`, we need to reinitialize the
// value to 0.

#import bevy_pbr::mesh_preprocess_types::IndirectBatchSet

@group(0) @binding(0) var<storage, read_write> indirect_batch_sets: array<IndirectBatchSet>;

@compute
@workgroup_size(64)
fn main(@builtin(global_invocation_id) global_invocation_id: vec3<u32>) {
    // Figure out our instance index. If this thread doesn't correspond to any
    // index, bail.
    let instance_index = global_invocation_id.x;
    if (instance_index >= arrayLength(&indirect_batch_sets)) {
        return;
    }

    // Reset the number of batch sets to 0.
    atomicStore(&indirect_batch_sets[instance_index].indirect_parameters_count, 0u);
}