fix conditional compilation

1 files changed, 93 insertions, 0 deletions

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);
+    }
+};