From 1c5c23f101b673ec03f0a8e2557402b471910366 Mon Sep 17 00:00:00 2001
From: Stephen Gutekanst <stephen@hexops.com>
Date: Fri, 11 Mar 2022 22:40:18 -0700
Subject: [PATCH] gpu: fix Queue.submit commands parameter

Signed-off-by: Stephen Gutekanst <stephen@hexops.com>
---
 gpu/examples/main.zig      |  7 +++----
 gpu/src/NativeInstance.zig | 21 ++++++++++++++++++---
 gpu/src/Queue.zig          |  6 +++---
 3 files changed, 24 insertions(+), 10 deletions(-)

diff --git a/gpu/examples/main.zig b/gpu/examples/main.zig
index 27bfb36a..c6728246 100644
--- a/gpu/examples/main.zig
+++ b/gpu/examples/main.zig
@@ -211,12 +211,11 @@ fn frame(params: FrameParams) !void {
     pass.end();
     pass.release();
 
-    var commands = encoder.finish(null);
+    var command = encoder.finish(null);
     encoder.release();
 
-    const buf = gpu.CommandBuffer{ .ptr = &commands, .vtable = undefined };
-    params.queue.submit(1, &buf);
-    commands.release();
+    params.queue.submit(&.{command});
+    command.release();
     pl.swap_chain.?.present();
     back_buffer_view.release();
 }
diff --git a/gpu/src/NativeInstance.zig b/gpu/src/NativeInstance.zig
index 8678809d..4fcf473d 100644
--- a/gpu/src/NativeInstance.zig
+++ b/gpu/src/NativeInstance.zig
@@ -510,7 +510,7 @@ const queue_vtable = Queue.VTable{
         }
     }).release,
     .submit = (struct {
-        pub fn submit(queue: Queue, command_count: u32, commands: *const CommandBuffer) void {
+        pub fn submit(queue: Queue, cmds: []const CommandBuffer) void {
             const wgpu_queue = @ptrCast(c.WGPUQueue, queue.ptr);
 
             if (queue.on_submitted_work_done) |on_submitted_work_done| {
@@ -533,10 +533,25 @@ const queue_vtable = Queue.VTable{
                 c.wgpuQueueOnSubmittedWorkDone(wgpu_queue, signal_value, callback, &mut_on_submitted_work_done);
             }
 
+            var few_commands: [16]c.WGPUCommandBuffer = undefined;
+            const commands = if (cmds.len <= 8) blk: {
+                for (cmds) |cmd, i| {
+                    few_commands[i] = @ptrCast(c.WGPUCommandBuffer, cmd.ptr);
+                }
+                break :blk few_commands[0..cmds.len];
+            } else blk: {
+                const mem = std.heap.page_allocator.alloc(c.WGPUCommandBuffer, cmds.len) catch unreachable;
+                for (cmds) |cmd, i| {
+                    mem[i] = @ptrCast(c.WGPUCommandBuffer, cmd.ptr);
+                }
+                break :blk mem;
+            };
+            defer if (cmds.len > 8) std.heap.page_allocator.free(cmds);
+
             c.wgpuQueueSubmit(
                 wgpu_queue,
-                command_count,
-                @ptrCast(*c.WGPUCommandBuffer, @alignCast(@alignOf(*c.WGPUCommandBuffer), commands.ptr)),
+                @intCast(u32, commands.len),
+                @ptrCast(*c.WGPUCommandBuffer, &commands[0]),
             );
         }
     }).submit,
diff --git a/gpu/src/Queue.zig b/gpu/src/Queue.zig
index 9771f775..ea07c82b 100644
--- a/gpu/src/Queue.zig
+++ b/gpu/src/Queue.zig
@@ -14,7 +14,7 @@ pub const VTable = struct {
     release: fn (ptr: *anyopaque) void,
     // TODO: dawn specific?
     // copyTextureForBrowser: fn (ptr: *anyopaque, source: *const ImageCopyTexture, destination: *const ImageCopyTexture, copy_size: *const Extent3D, options: *const CopyTextureForBrowserOptions) void,
-    submit: fn (queue: Queue, command_count: u32, commands: *const CommandBuffer) void,
+    submit: fn (queue: Queue, commands: []const CommandBuffer) void,
     // TODO:
     // writeBuffer: fn (ptr: *anyopaque, buffer: Buffer, buffer_offset: u64, data: *const anyopaque, size: usize);
     // writeTexture: fn (ptr: *anyopaque, destination: *const ImageCopyTexture, data: *const anyopaque, data_size: usize, data_layout: *const TextureDataLayout, write_size: *const Extent3D);
@@ -28,8 +28,8 @@ pub inline fn release(queue: Queue) void {
     queue.vtable.release(queue.ptr);
 }
 
-pub inline fn submit(queue: Queue, command_count: u32, commands: *const CommandBuffer) void {
-    queue.vtable.submit(queue, command_count, commands);
+pub inline fn submit(queue: Queue, commands: []const CommandBuffer) void {
+    queue.vtable.submit(queue, commands);
 }
 
 pub const OnSubmittedWorkDone = struct {