fix conditional compilation

5 files changed, 357 insertions, 337 deletions

diff --git a/src/control.zig b/src/control.zig
index dfdd55d..0ea6712 100644
--- a/src/control.zig
+++ b/src/control.zig
@@ -3,7 +3,6 @@ const gl = @import("gl.zig");
 const video = @import("video.zig");
 const std = @import("std");
 const cfg = @import("config.zig");
-const build_config = @import("build_config");
 
 fn verify_args(expected: u8, got: []const u8) !void {
     for (got) |typ| {
@@ -96,7 +95,6 @@ fn set_texture(
     argv: [*c][*c]c.lo_arg,
     types: []const u8,
 ) !void {
-    if (!build_config.have_ffmpeg) return error.texturesDisabled;
     if (argc != 1 or types[0] != 's') return error.invalidType;
 
     if (dest.*) |old| {
diff --git a/src/video.zig b/src/video.zig
index 98772b6..9cf50eb 100644
--- a/src/video.zig
+++ b/src/video.zig
@@ -1,338 +1,16 @@
 const std = @import("std");
 const c = @import("c.zig");
 const gl = @import("gl.zig");
+const build_config = @import("build_config");
+const dec = @import("video/decoder.zig");
+const ffmpeg = if (build_config.have_ffmpeg) @import("video/ffmpeg.zig") else unreachable;
+const hap = if (build_config.have_hap) @import("video/hap.zig") else unreachable;
 
-pub const Errors = error{
-    AVGenericError,
-    AVAllocationError,
-    HAPBadArguments,
-    HAPBufferTooSmall,
-    HAPBadFrame,
-    HAPInternalError,
-    UnsupportedCodec,
-    OutOfMemory,
-    NoFrames,
-};
-
-fn check(err: c_int) Errors!void {
-    if (err >= 0) return;
-    var buf: [c.AV_ERROR_MAX_STRING_SIZE]u8 = undefined;
-    _ = c.av_make_error_string(&buf, buf.len, err);
-    std.debug.print("libav error: {s}\n", .{buf});
-    return error.AVGenericError;
-}
-
-fn hapCheck(err: c_uint) Errors!void {
-    return switch (err) {
-        c.HapResult_No_Error => return,
-        c.HapResult_Bad_Arguments => return error.HAPBadArguments,
-        c.HapResult_Buffer_Too_Small => return error.HAPBufferTooSmall,
-        c.HapResult_Bad_Frame => return error.HAPBadFrame,
-        c.HapResult_Internal_Error => return error.HAPInternalError,
-        else => unreachable,
-    };
-}
-
-const Decoder = struct {
-    num_frames: i32,
-
-    process_packet_fn: *const fn (self: *Decoder, packet: *c.AVPacket, texture: ?*const gl.Texture) Errors!bool,
-    init_texture_fn: *const fn (self: *Decoder, texture: *const gl.Texture) void,
-    reset_fn: ?*const fn (self: *Decoder) void,
-    deinit_fn: *const fn (self: *Decoder, allocator: std.mem.Allocator) void,
-
-    fn processStream(
-        self: *Decoder,
-        progress: std.Progress.Node,
-        format: *c.AVFormatContext,
-        stream: *c.AVStream,
-        texture: ?*const gl.Texture,
-    ) Errors!void {
-        defer progress.end();
-
-        try check(c.avformat_seek_file(format, stream.index, 0, 0, 0, 0));
-        if (self.reset_fn) |reset_fn| reset_fn(self);
-
-        var packet = c.av_packet_alloc();
-        defer c.av_packet_free(&packet);
-
-        self.num_frames = 0;
-        var res = c.av_read_frame(format, packet);
-        while (res >= 0) : (res = c.av_read_frame(format, packet)) {
-            if (packet.*.stream_index == stream.index) {
-                const more = try self.process_packet_fn(self, packet, texture);
-                progress.setCompletedItems(@intCast(self.num_frames));
-                if (!more) break;
-            }
-            c.av_packet_unref(packet);
-        } else {
-            if (res != c.AVERROR_EOF) try check(res);
-        }
-    }
-
-    pub fn createTexture(
-        self: *Decoder,
-        outer_progress: std.Progress.Node,
-        format: *c.AVFormatContext,
-        stream: *c.AVStream,
-        texture_type: gl.Texture.Type,
-    ) Errors!gl.Texture {
-        try self.processStream(
-            outer_progress.start("scanning video frames", @intCast(stream.nb_frames)),
-            format,
-            stream,
-            null,
-        );
-        if (self.num_frames <= 0) return error.NoFrames;
-
-        const texture = gl.Texture.create(texture_type);
-        errdefer texture.destroy();
-
-        self.init_texture_fn(self, &texture);
-        try self.processStream(
-            outer_progress.start("loading video frames", @intCast(self.num_frames)),
-            format,
-            stream,
-            &texture,
-        );
-        return texture;
-    }
-
-    pub fn deinit(self: *Decoder, allocator: std.mem.Allocator) void {
-        self.deinit_fn(self, allocator);
-    }
-};
-
-const AVDecoder = struct {
-    decoder: Decoder,
-
-    sws_ctx: *c.SwsContext,
-    codec_par: c.AVCodecParameters,
-    codec_ctx: [*c]c.AVCodecContext,
-
-    raw_frame: [*c]c.AVFrame,
-    rgba_frame: [*c]c.AVFrame,
-
-    pub fn init(allocator: std.mem.Allocator, codec_par: c.AVCodecParameters) Errors!*Decoder {
-        const self = try allocator.create(AVDecoder);
-        errdefer allocator.destroy(self);
-
-        const codec = c.avcodec_find_decoder(codec_par.codec_id) orelse return error.UnsupportedCodec;
-
-        var codec_ctx = c.avcodec_alloc_context3(codec) orelse return error.AVAllocationError;
-        errdefer c.avcodec_free_context(&codec_ctx);
-        var raw_frame = c.av_frame_alloc() orelse return error.AVAllocationError;
-        errdefer c.av_frame_free(&raw_frame);
-        var rgba_frame = c.av_frame_alloc() orelse return error.AVAllocationError;
-        errdefer c.av_frame_free(&rgba_frame);
-
-        try check(c.avcodec_parameters_to_context(codec_ctx, &codec_par));
-        try check(c.avcodec_open2(codec_ctx, codec, null));
-        errdefer check(c.avcodec_close(codec_ctx)) catch unreachable;
-
-        const sws_ctx = c.sws_getContext(
-            codec_par.width,
-            codec_par.height,
-            codec_par.format,
-            codec_par.width,
-            codec_par.height,
-            c.AV_PIX_FMT_RGBA,
-            c.SWS_POINT,
-            null,
-            null,
-            0,
-        ) orelse return error.AVGenericError;
-        errdefer c.sws_freeContext(sws_ctx);
-
-        self.* = .{
-            .decoder = .{
-                .process_packet_fn = processPacket,
-                .init_texture_fn = initTexture,
-                .reset_fn = reset,
-                .deinit_fn = deinit,
-                .num_frames = 0,
-            },
-            .sws_ctx = sws_ctx,
-            .codec_par = codec_par,
-            .codec_ctx = codec_ctx,
-            .raw_frame = raw_frame,
-            .rgba_frame = rgba_frame,
-        };
-        return &self.decoder;
-    }
-
-    pub fn deinit(decoder: *Decoder, allocator: std.mem.Allocator) void {
-        const self: *AVDecoder = @fieldParentPtr("decoder", decoder);
-
-        const raw_ptr: [*c][*c]c.AVFrame = &self.raw_frame;
-        const rgba_ptr: [*c][*c]c.AVFrame = &self.rgba_frame;
-        c.av_frame_free(raw_ptr);
-        c.av_frame_free(rgba_ptr);
-
-        c.sws_freeContext(self.sws_ctx);
-        check(c.avcodec_close(self.codec_ctx)) catch unreachable;
-        c.avcodec_free_context(&self.codec_ctx);
-
-        allocator.destroy(self);
-    }
-
-    pub fn reset(decoder: *Decoder) void {
-        const self: *AVDecoder = @fieldParentPtr("decoder", decoder);
-        c.avcodec_flush_buffers(self.codec_ctx);
-    }
-
-    pub fn initTexture(decoder: *Decoder, texture: *const gl.Texture) void {
-        const self: *AVDecoder = @fieldParentPtr("decoder", decoder);
-
-        texture.allocate(
-            self.codec_par.width,
-            self.codec_par.height,
-            self.decoder.num_frames,
-            c.GL_COMPRESSED_RGBA_S3TC_DXT1_EXT,
-        );
-    }
-
-    pub fn processPacket(decoder: *Decoder, packet: *c.AVPacket, texture: ?*const gl.Texture) Errors!bool {
-        const self: *AVDecoder = @fieldParentPtr("decoder", decoder);
-
-        try check(c.avcodec_send_packet(self.codec_ctx, packet));
-        while (true) {
-            const ires = c.avcodec_receive_frame(self.codec_ctx, self.raw_frame);
-            if (ires == c.AVERROR_EOF) return false;
-            if (ires == c.AVERROR(c.EAGAIN)) return true;
-            try check(ires);
-            try check(c.sws_scale_frame(self.sws_ctx, self.rgba_frame, self.raw_frame));
-
-            c.glPixelStorei(c.GL_UNPACK_ROW_LENGTH, @divFloor(self.rgba_frame.*.linesize[0], @sizeOf(u8) * 4));
-
-            if (texture) |tex| {
-                tex.setLayer(
-                    self.rgba_frame.*.width,
-                    self.rgba_frame.*.height,
-                    self.decoder.num_frames,
-                    c.GL_RGBA,
-                    self.rgba_frame.*.data[0],
-                );
-
-                if (tex.type == .TEXTURE_2D) return false;
-            }
-
-            self.decoder.num_frames += 1;
-        }
-    }
-};
-
-const HAPDecoder = struct {
-    decoder: Decoder,
-
-    codec_par: c.AVCodecParameters,
-    format: ?c.HapTextureFormat,
-    gl_format: c.GLenum,
-
-    pub fn init(allocator: std.mem.Allocator, codec_par: c.AVCodecParameters) Errors!*Decoder {
-        const self = try allocator.create(HAPDecoder);
-
-        self.* = .{
-            .decoder = .{
-                .process_packet_fn = processPacket,
-                .init_texture_fn = initTexture,
-                .reset_fn = null,
-                .deinit_fn = deinit,
-                .num_frames = 0,
-            },
-            .codec_par = codec_par,
-            .format = null,
-            .gl_format = undefined,
-        };
-        return &self.decoder;
-    }
-
-    pub fn deinit(decoder: *Decoder, allocator: std.mem.Allocator) void {
-        const self: *HAPDecoder = @fieldParentPtr("decoder", decoder);
-        allocator.destroy(self);
-    }
-
-    pub fn initTexture(decoder: *Decoder, texture: *const gl.Texture) void {
-        const self: *HAPDecoder = @fieldParentPtr("decoder", decoder);
-
-        texture.allocate(
-            self.codec_par.width,
-            self.codec_par.height,
-            self.decoder.num_frames,
-            self.gl_format,
-        );
-    }
-
-    fn launchThread(workfn: c.HapDecodeWorkFunction, p: ?*anyopaque, count: c_uint, info: ?*anyopaque) callconv(.C) void {
-        _ = info;
-
-        var i: c_uint = 0;
-        while (i < count) : (i += 1) {
-            workfn.?(p, i);
-        }
-    }
-
-    pub fn processPacket(decoder: *Decoder, packet: *c.AVPacket, texture: ?*const gl.Texture) Errors!bool {
-        const self: *HAPDecoder = @fieldParentPtr("decoder", decoder);
-
-        var textureCount: u32 = undefined;
-        try hapCheck(c.HapGetFrameTextureCount(packet.data, @intCast(packet.size), &textureCount));
-        if (textureCount != 1) {
-            return error.UnsupportedCodec;
-        }
-
-        var format: c.HapTextureFormat = undefined;
-
-        if (texture) |tex| {
-            var buffer: [16 * 1024 * 1024]u8 = undefined;
-            var length: c_ulong = undefined;
-            try hapCheck(c.HapDecode(
-                packet.data,
-                @intCast(packet.size),
-                0,
-                launchThread,
-                self,
-                &buffer,
-                buffer.len,
-                &length,
-                &format,
-            ));
-
-            tex.setLayerCompressed(
-                self.codec_par.width,
-                self.codec_par.height,
-                self.decoder.num_frames,
-                self.gl_format,
-                buffer[0..length],
-            );
-
-            if (tex.type == .TEXTURE_2D) return false;
-        } else {
-            try hapCheck(c.HapGetFrameTextureFormat(packet.data, @intCast(packet.size), 0, &format));
-            if (self.format) |fmt| {
-                if (fmt != format) return error.UnsupportedCodec;
-            } else {
-                self.format = format;
-                self.gl_format = switch (format) {
-                    c.HapTextureFormat_RGB_DXT1 => c.GL_COMPRESSED_RGB_S3TC_DXT1_EXT,
-                    c.HapTextureFormat_RGBA_DXT5 => c.GL_COMPRESSED_RGBA_S3TC_DXT5_EXT,
-                    c.HapTextureFormat_YCoCg_DXT5,
-                    c.HapTextureFormat_A_RGTC1,
-                    c.HapTextureFormat_RGBA_BPTC_UNORM,
-                    c.HapTextureFormat_RGB_BPTC_UNSIGNED_FLOAT,
-                    c.HapTextureFormat_RGB_BPTC_SIGNED_FLOAT,
-                    => return error.UnsupportedCodec,
-                    else => unreachable,
-                };
-            }
-        }
-
-        self.decoder.num_frames += 1;
-        return true;
-    }
-};
+const check = dec.check;
 
 pub fn loadVideo(progress_root: std.Progress.Node, filename: [*:0]const u8, texture_type: gl.Texture.Type) !gl.Texture {
+    if (!build_config.have_ffmpeg) return error.texturesDisabled;
+
     const progress = progress_root.start("loading texture", 2);
     defer progress.end();
 
@@ -356,12 +34,12 @@ pub fn loadVideo(progress_root: std.Progress.Node, filename: [*:0]const u8, text
 
         const allocator = std.heap.c_allocator;
 
-        const decoder = switch (codec_par.codec_tag) {
-            c.MKTAG('H', 'a', 'p', '1'),
-            c.MKTAG('H', 'a', 'p', '5'),
-            => try HAPDecoder.init(allocator, codec_par),
-            else => try AVDecoder.init(allocator, codec_par),
-        };
+        const is_hap = codec_par.codec_tag == c.MKTAG('H', 'a', 'p', '1') or codec_par.codec_tag == c.MKTAG('H', 'a', 'p', '5');
+        const decoder = if (is_hap and build_config.have_hap)
+            try hap.HAPDecoder.init(allocator, codec_par)
+        else
+            try ffmpeg.AVDecoder.init(allocator, codec_par);
+
         defer decoder.deinit(allocator);
 
         return try decoder.createTexture(progress, format, video_stream, texture_type);
diff --git a/src/video/decoder.zig b/src/video/decoder.zig
new file mode 100644
index 0000000..4c78374
--- /dev/null
+++ b/src/video/decoder.zig
@@ -0,0 +1,93 @@
+const std = @import("std");
+const c = @import("../c.zig");
+const gl = @import("../gl.zig");
+
+pub const Errors = error{
+    AVGenericError,
+    AVAllocationError,
+    HAPBadArguments,
+    HAPBufferTooSmall,
+    HAPBadFrame,
+    HAPInternalError,
+    UnsupportedCodec,
+    OutOfMemory,
+    NoFrames,
+};
+
+pub fn check(err: c_int) Errors!void {
+    if (err >= 0) return;
+    var buf: [c.AV_ERROR_MAX_STRING_SIZE]u8 = undefined;
+    _ = c.av_make_error_string(&buf, buf.len, err);
+    std.debug.print("libav error: {s}\n", .{buf});
+    return error.AVGenericError;
+}
+
+pub const Decoder = struct {
+    num_frames: i32,
+
+    process_packet_fn: *const fn (self: *Decoder, packet: *c.AVPacket, texture: ?*const gl.Texture) Errors!bool,
+    init_texture_fn: *const fn (self: *Decoder, texture: *const gl.Texture) void,
+    reset_fn: ?*const fn (self: *Decoder) void,
+    deinit_fn: *const fn (self: *Decoder, allocator: std.mem.Allocator) void,
+
+    fn processStream(
+        self: *Decoder,
+        progress: std.Progress.Node,
+        format: *c.AVFormatContext,
+        stream: *c.AVStream,
+        texture: ?*const gl.Texture,
+    ) Errors!void {
+        defer progress.end();
+
+        try check(c.avformat_seek_file(format, stream.index, 0, 0, 0, 0));
+        if (self.reset_fn) |reset_fn| reset_fn(self);
+
+        var packet = c.av_packet_alloc();
+        defer c.av_packet_free(&packet);
+
+        self.num_frames = 0;
+        var res = c.av_read_frame(format, packet);
+        while (res >= 0) : (res = c.av_read_frame(format, packet)) {
+            if (packet.*.stream_index == stream.index) {
+                const more = try self.process_packet_fn(self, packet, texture);
+                progress.setCompletedItems(@intCast(self.num_frames));
+                if (!more) break;
+            }
+            c.av_packet_unref(packet);
+        } else {
+            if (res != c.AVERROR_EOF) try check(res);
+        }
+    }
+
+    pub fn createTexture(
+        self: *Decoder,
+        outer_progress: std.Progress.Node,
+        format: *c.AVFormatContext,
+        stream: *c.AVStream,
+        texture_type: gl.Texture.Type,
+    ) Errors!gl.Texture {
+        try self.processStream(
+            outer_progress.start("scanning video frames", @intCast(stream.nb_frames)),
+            format,
+            stream,
+            null,
+        );
+        if (self.num_frames <= 0) return error.NoFrames;
+
+        const texture = gl.Texture.create(texture_type);
+        errdefer texture.destroy();
+
+        self.init_texture_fn(self, &texture);
+        try self.processStream(
+            outer_progress.start("loading video frames", @intCast(self.num_frames)),
+            format,
+            stream,
+            &texture,
+        );
+        return texture;
+    }
+
+    pub fn deinit(self: *Decoder, allocator: std.mem.Allocator) void {
+        self.deinit_fn(self, allocator);
+    }
+};
diff --git a/src/video/ffmpeg.zig b/src/video/ffmpeg.zig
new file mode 100644
index 0000000..03456d5
--- /dev/null
+++ b/src/video/ffmpeg.zig
@@ -0,0 +1,126 @@
+const std = @import("std");
+const c = @import("../c.zig");
+const gl = @import("../gl.zig");
+const build_config = @import("build_config");
+const dec = @import("decoder.zig");
+
+const check = dec.check;
+
+pub const AVDecoder = struct {
+    decoder: dec.Decoder,
+
+    sws_ctx: *c.SwsContext,
+    codec_par: c.AVCodecParameters,
+    codec_ctx: [*c]c.AVCodecContext,
+
+    raw_frame: [*c]c.AVFrame,
+    rgba_frame: [*c]c.AVFrame,
+
+    pub fn init(allocator: std.mem.Allocator, codec_par: c.AVCodecParameters) dec.Errors!*dec.Decoder {
+        const self = try allocator.create(AVDecoder);
+        errdefer allocator.destroy(self);
+
+        const codec = c.avcodec_find_decoder(codec_par.codec_id) orelse return error.UnsupportedCodec;
+
+        var codec_ctx = c.avcodec_alloc_context3(codec) orelse return error.AVAllocationError;
+        errdefer c.avcodec_free_context(&codec_ctx);
+        var raw_frame = c.av_frame_alloc() orelse return error.AVAllocationError;
+        errdefer c.av_frame_free(&raw_frame);
+        var rgba_frame = c.av_frame_alloc() orelse return error.AVAllocationError;
+        errdefer c.av_frame_free(&rgba_frame);
+
+        try check(c.avcodec_parameters_to_context(codec_ctx, &codec_par));
+        try check(c.avcodec_open2(codec_ctx, codec, null));
+        errdefer check(c.avcodec_close(codec_ctx)) catch unreachable;
+
+        const sws_ctx = c.sws_getContext(
+            codec_par.width,
+            codec_par.height,
+            codec_par.format,
+            codec_par.width,
+            codec_par.height,
+            c.AV_PIX_FMT_RGBA,
+            c.SWS_POINT,
+            null,
+            null,
+            0,
+        ) orelse return error.AVGenericError;
+        errdefer c.sws_freeContext(sws_ctx);
+
+        self.* = .{
+            .decoder = .{
+                .process_packet_fn = processPacket,
+                .init_texture_fn = initTexture,
+                .reset_fn = reset,
+                .deinit_fn = deinit,
+                .num_frames = 0,
+            },
+            .sws_ctx = sws_ctx,
+            .codec_par = codec_par,
+            .codec_ctx = codec_ctx,
+            .raw_frame = raw_frame,
+            .rgba_frame = rgba_frame,
+        };
+        return &self.decoder;
+    }
+
+    pub fn deinit(decoder: *dec.Decoder, allocator: std.mem.Allocator) void {
+        const self: *AVDecoder = @fieldParentPtr("decoder", decoder);
+
+        const raw_ptr: [*c][*c]c.AVFrame = &self.raw_frame;
+        const rgba_ptr: [*c][*c]c.AVFrame = &self.rgba_frame;
+        c.av_frame_free(raw_ptr);
+        c.av_frame_free(rgba_ptr);
+
+        c.sws_freeContext(self.sws_ctx);
+        check(c.avcodec_close(self.codec_ctx)) catch unreachable;
+        c.avcodec_free_context(&self.codec_ctx);
+
+        allocator.destroy(self);
+    }
+
+    pub fn reset(decoder: *dec.Decoder) void {
+        const self: *AVDecoder = @fieldParentPtr("decoder", decoder);
+        c.avcodec_flush_buffers(self.codec_ctx);
+    }
+
+    pub fn initTexture(decoder: *dec.Decoder, texture: *const gl.Texture) void {
+        const self: *AVDecoder = @fieldParentPtr("decoder", decoder);
+
+        texture.allocate(
+            self.codec_par.width,
+            self.codec_par.height,
+            self.decoder.num_frames,
+            c.GL_COMPRESSED_RGBA_S3TC_DXT1_EXT,
+        );
+    }
+
+    pub fn processPacket(decoder: *dec.Decoder, packet: *c.AVPacket, texture: ?*const gl.Texture) dec.Errors!bool {
+        const self: *AVDecoder = @fieldParentPtr("decoder", decoder);
+
+        try check(c.avcodec_send_packet(self.codec_ctx, packet));
+        while (true) {
+            const ires = c.avcodec_receive_frame(self.codec_ctx, self.raw_frame);
+            if (ires == c.AVERROR_EOF) return false;
+            if (ires == c.AVERROR(c.EAGAIN)) return true;
+            try check(ires);
+            try check(c.sws_scale_frame(self.sws_ctx, self.rgba_frame, self.raw_frame));
+
+            c.glPixelStorei(c.GL_UNPACK_ROW_LENGTH, @divFloor(self.rgba_frame.*.linesize[0], @sizeOf(u8) * 4));
+
+            if (texture) |tex| {
+                tex.setLayer(
+                    self.rgba_frame.*.width,
+                    self.rgba_frame.*.height,
+                    self.decoder.num_frames,
+                    c.GL_RGBA,
+                    self.rgba_frame.*.data[0],
+                );
+
+                if (tex.type == .TEXTURE_2D) return false;
+            }
+
+            self.decoder.num_frames += 1;
+        }
+    }
+};
diff --git a/src/video/hap.zig b/src/video/hap.zig
new file mode 100644
index 0000000..70b194a
--- /dev/null
+++ b/src/video/hap.zig
@@ -0,0 +1,125 @@
+const std = @import("std");
+const c = @import("../c.zig");
+const gl = @import("../gl.zig");
+const dec = @import("decoder.zig");
+
+fn check(err: c_uint) dec.Errors!void {
+    return switch (err) {
+        c.HapResult_No_Error => return,
+        c.HapResult_Bad_Arguments => return error.HAPBadArguments,
+        c.HapResult_Buffer_Too_Small => return error.HAPBufferTooSmall,
+        c.HapResult_Bad_Frame => return error.HAPBadFrame,
+        c.HapResult_Internal_Error => return error.HAPInternalError,
+        else => unreachable,
+    };
+}
+
+pub const HAPDecoder = struct {
+    decoder: dec.Decoder,
+
+    codec_par: c.AVCodecParameters,
+    format: ?c.HapTextureFormat,
+    gl_format: c.GLenum,
+
+    pub fn init(allocator: std.mem.Allocator, codec_par: c.AVCodecParameters) dec.Errors!*dec.Decoder {
+        const self = try allocator.create(HAPDecoder);
+
+        self.* = .{
+            .decoder = .{
+                .process_packet_fn = processPacket,
+                .init_texture_fn = initTexture,
+                .reset_fn = null,
+                .deinit_fn = deinit,
+                .num_frames = 0,
+            },
+            .codec_par = codec_par,
+            .format = null,
+            .gl_format = undefined,
+        };
+        return &self.decoder;
+    }
+
+    pub fn deinit(decoder: *dec.Decoder, allocator: std.mem.Allocator) void {
+        const self: *HAPDecoder = @fieldParentPtr("decoder", decoder);
+        allocator.destroy(self);
+    }
+
+    pub fn initTexture(decoder: *dec.Decoder, texture: *const gl.Texture) void {
+        const self: *HAPDecoder = @fieldParentPtr("decoder", decoder);
+
+        texture.allocate(
+            self.codec_par.width,
+            self.codec_par.height,
+            self.decoder.num_frames,
+            self.gl_format,
+        );
+    }
+
+    fn launchThread(workfn: c.HapDecodeWorkFunction, p: ?*anyopaque, count: c_uint, info: ?*anyopaque) callconv(.C) void {
+        _ = info;
+
+        var i: c_uint = 0;
+        while (i < count) : (i += 1) {
+            workfn.?(p, i);
+        }
+    }
+
+    pub fn processPacket(decoder: *dec.Decoder, packet: *c.AVPacket, texture: ?*const gl.Texture) dec.Errors!bool {
+        const self: *HAPDecoder = @fieldParentPtr("decoder", decoder);
+
+        var textureCount: u32 = undefined;
+        try check(c.HapGetFrameTextureCount(packet.data, @intCast(packet.size), &textureCount));
+        if (textureCount != 1) {
+            return error.UnsupportedCodec;
+        }
+
+        var format: c.HapTextureFormat = undefined;
+
+        if (texture) |tex| {
+            var buffer: [16 * 1024 * 1024]u8 = undefined;
+            var length: c_ulong = undefined;
+            try check(c.HapDecode(
+                packet.data,
+                @intCast(packet.size),
+                0,
+                launchThread,
+                self,
+                &buffer,
+                buffer.len,
+                &length,
+                &format,
+            ));
+
+            tex.setLayerCompressed(
+                self.codec_par.width,
+                self.codec_par.height,
+                self.decoder.num_frames,
+                self.gl_format,
+                buffer[0..length],
+            );
+
+            if (tex.type == .TEXTURE_2D) return false;
+        } else {
+            try check(c.HapGetFrameTextureFormat(packet.data, @intCast(packet.size), 0, &format));
+            if (self.format) |fmt| {
+                if (fmt != format) return error.UnsupportedCodec;
+            } else {
+                self.format = format;
+                self.gl_format = switch (format) {
+                    c.HapTextureFormat_RGB_DXT1 => c.GL_COMPRESSED_RGB_S3TC_DXT1_EXT,
+                    c.HapTextureFormat_RGBA_DXT5 => c.GL_COMPRESSED_RGBA_S3TC_DXT5_EXT,
+                    c.HapTextureFormat_YCoCg_DXT5,
+                    c.HapTextureFormat_A_RGTC1,
+                    c.HapTextureFormat_RGBA_BPTC_UNORM,
+                    c.HapTextureFormat_RGB_BPTC_UNSIGNED_FLOAT,
+                    c.HapTextureFormat_RGB_BPTC_SIGNED_FLOAT,
+                    => return error.UnsupportedCodec,
+                    else => unreachable,
+                };
+            }
+        }
+
+        self.decoder.num_frames += 1;
+        return true;
+    }
+};