all: move standalone libraries to libs/ subdirectory

The root dir of our repository has grown quite a lot the past few months.

I'd like to make it more clear where the bulk of the engine lives (`src/`) and
also make it more clear which Mach libraries are consumable as standalone projects.

As for the name of this directory, `libs` was my first choice but there's a bit of
a convention of that being external libraries in Zig projects _today_, while these
are libraries maintained as part of Mach in this repository - not external ones.

We will name this directory `libs`, and if we have a need for external libraries
we will use `external` or `deps` for that directory name. I considered other names
such as `components`, `systems`, `modules` (which are bad as they overlap with
major ECS / engine concepts), and it seems likely the official Zig package manager
will break the convention of using a `libs` dir anyway.

Performed via:

```sh
mkdir libs/
git mv freetype libs/
git mv basisu libs/
git mv gamemode libs/
git mv glfw libs/
git mv gpu libs/
git mv gpu-dawn libs/
git mv sysaudio libs/
git mv sysjs libs/
git mv ecs libs/
```

git-subtree-dir: glfw
git-subtree-mainline: 0d5b853443
git-subtree-split: 572d1144f11b353abdb64fff828b25a4f0fbb7ca

Signed-off-by: Stephen Gutekanst <stephen@hexops.com>

git mv ecs libs/

Signed-off-by: Stephen Gutekanst <stephen@hexops.com>

libs/gpu/src/command_encoder.zig

@@ -0,0 +1,118 @@
+const std = @import("std");
+const ComputePassEncoder = @import("compute_pass_encoder.zig").ComputePassEncoder;
+const RenderPassEncoder = @import("render_pass_encoder.zig").RenderPassEncoder;
+const CommandBuffer = @import("command_buffer.zig").CommandBuffer;
+const Buffer = @import("buffer.zig").Buffer;
+const QuerySet = @import("query_set.zig").QuerySet;
+const RenderPassDescriptor = @import("types.zig").RenderPassDescriptor;
+const ComputePassDescriptor = @import("types.zig").ComputePassDescriptor;
+const ChainedStruct = @import("types.zig").ChainedStruct;
+const ImageCopyBuffer = @import("types.zig").ImageCopyBuffer;
+const ImageCopyTexture = @import("types.zig").ImageCopyTexture;
+const Extent3D = @import("types.zig").Extent3D;
+const Impl = @import("interface.zig").Impl;
+const dawn = @import("dawn.zig");
+
+pub const CommandEncoder = opaque {
+    pub const Descriptor = extern struct {
+        pub const NextInChain = extern union {
+            generic: ?*const ChainedStruct,
+            dawn_encoder_internal_usage_descriptor: *const dawn.EncoderInternalUsageDescriptor,
+        };
+
+        next_in_chain: NextInChain = .{ .generic = null },
+        label: ?[*:0]const u8 = null,
+    };
+
+    pub inline fn beginComputePass(command_encoder: *CommandEncoder, descriptor: ?*const ComputePassDescriptor) *ComputePassEncoder {
+        return Impl.commandEncoderBeginComputePass(command_encoder, descriptor);
+    }
+
+    pub inline fn beginRenderPass(command_encoder: *CommandEncoder, descriptor: *const RenderPassDescriptor) *RenderPassEncoder {
+        return Impl.commandEncoderBeginRenderPass(command_encoder, descriptor);
+    }
+
+    /// Default `offset`: 0
+    /// Default `size`: `gpu.whole_size`
+    pub inline fn clearBuffer(command_encoder: *CommandEncoder, buffer: *Buffer, offset: u64, size: u64) void {
+        Impl.commandEncoderClearBuffer(command_encoder, buffer, offset, size);
+    }
+
+    pub inline fn copyBufferToBuffer(command_encoder: *CommandEncoder, source: *Buffer, source_offset: u64, destination: *Buffer, destination_offset: u64, size: u64) void {
+        Impl.commandEncoderCopyBufferToBuffer(command_encoder, source, source_offset, destination, destination_offset, size);
+    }
+
+    pub inline fn copyBufferToTexture(command_encoder: *CommandEncoder, source: *const ImageCopyBuffer, destination: *const ImageCopyTexture, copy_size: *const Extent3D) void {
+        Impl.commandEncoderCopyBufferToTexture(command_encoder, source, destination, copy_size);
+    }
+
+    pub inline fn copyTextureToBuffer(command_encoder: *CommandEncoder, source: *const ImageCopyTexture, destination: *const ImageCopyBuffer, copy_size: *const Extent3D) void {
+        Impl.commandEncoderCopyTextureToBuffer(command_encoder, source, destination, copy_size);
+    }
+
+    pub inline fn copyTextureToTexture(command_encoder: *CommandEncoder, source: *const ImageCopyTexture, destination: *const ImageCopyTexture, copy_size: *const Extent3D) void {
+        Impl.commandEncoderCopyTextureToTexture(command_encoder, source, destination, copy_size);
+    }
+
+    // Note: the only difference between this and the non-internal variant is that this one checks
+    // internal usage.
+    pub inline fn copyTextureToTextureInternal(command_encoder: *CommandEncoder, source: *const ImageCopyTexture, destination: *const ImageCopyTexture, copy_size: *const Extent3D) void {
+        Impl.commandEncoderCopyTextureToTextureInternal(command_encoder, source, destination, copy_size);
+    }
+
+    pub inline fn finish(command_encoder: *CommandEncoder, descriptor: ?*const CommandBuffer.Descriptor) *CommandBuffer {
+        return Impl.commandEncoderFinish(command_encoder, descriptor);
+    }
+
+    pub inline fn injectValidationError(command_encoder: *CommandEncoder, message: [*:0]const u8) void {
+        Impl.commandEncoderInjectValidationError(command_encoder, message);
+    }
+
+    pub inline fn insertDebugMarker(command_encoder: *CommandEncoder, marker_label: [*:0]const u8) void {
+        Impl.commandEncoderInsertDebugMarker(command_encoder, marker_label);
+    }
+
+    pub inline fn popDebugGroup(command_encoder: *CommandEncoder) void {
+        Impl.commandEncoderPopDebugGroup(command_encoder);
+    }
+
+    pub inline fn pushDebugGroup(command_encoder: *CommandEncoder, group_label: [*:0]const u8) void {
+        Impl.commandEncoderPushDebugGroup(command_encoder, group_label);
+    }
+
+    pub inline fn resolveQuerySet(command_encoder: *CommandEncoder, query_set: *QuerySet, first_query: u32, query_count: u32, destination: *Buffer, destination_offset: u64) void {
+        Impl.commandEncoderResolveQuerySet(command_encoder, query_set, first_query, query_count, destination, destination_offset);
+    }
+
+    pub inline fn setLabel(command_encoder: *CommandEncoder, label: [*:0]const u8) void {
+        Impl.commandEncoderSetLabel(command_encoder, label);
+    }
+
+    pub inline fn writeBuffer(
+        command_encoder: *CommandEncoder,
+        buffer: *Buffer,
+        buffer_offset_bytes: u64,
+        data_span: anytype,
+    ) void {
+        const data_slice = std.mem.span(data_span);
+        Impl.commandEncoderWriteBuffer(
+            command_encoder,
+            buffer,
+            buffer_offset_bytes,
+            @ptrCast([*]const u8, data_slice.ptr),
+            @intCast(u64, data_slice.len) * @sizeOf(std.meta.Elem(@TypeOf(data_slice))),
+        );
+    }
+
+    pub inline fn writeTimestamp(command_encoder: *CommandEncoder, query_set: *QuerySet, query_index: u32) void {
+        Impl.commandEncoderWriteTimestamp(command_encoder, query_set, query_index);
+    }
+
+    pub inline fn reference(command_encoder: *CommandEncoder) void {
+        Impl.commandEncoderReference(command_encoder);
+    }
+
+    pub inline fn release(command_encoder: *CommandEncoder) void {
+        Impl.commandEncoderRelease(command_encoder);
+    }
+};