call sf_seek before main plugin loop

doc/README.md

@@ -100,9 +100,23 @@ Run the Early Reflection Reverb from the Invada Studio plugins.
 Run the High Pass Filter from the Invada Studio plugins.
 
 Parameters:
- - `freq`: Frequency. 20-20000, default 1000
- - `gain`: Gain, 0-12, default 0
- - `noClip`: Soft Clip (assumed boolean), 0-1, default 0
+ - `freq`: Frequency. 20..20000, default 1000
+ - `gain`: Gain, 0..12, default 0
+ - `noClip`: Soft Clip (assumed boolean), 0..1, default 0
+
+## `delay seed gain`
+
+Parameters:
+ - `seed`: Random seed, 0..1000, default 0
+ - `gain`: Input gain (dB), -96..24, default 0
+ - `feedback_pc`: Feedback (%), 0..100, default 0
+ - `tap_count`: Number of taps, 2..128, default 2
+ - `first_delay`: First delay (s), 0..5, default 0
+ - `delay_range`: Delay range (s), 0..6, default 6
+ - `delay_scale`: Delay change, 0..5, default 1
+ - `delay_rand_pc`: Delay random (%), 0..100, default 0
+ - `gain_scale`: Amplitude change, 0.2..5, default 1
+ - `wet`: Dry/wet mix, 0..1, default 1
 
 ## TODO `echo split index delay`
 

examples/delay.scri

@@ -0,0 +1,3 @@
+load :0;
+delay 3 1 0 0 0 2 0 6 1 0 1 1;
+quicksave;

src/image.zig

@@ -284,9 +284,11 @@ pub const Image = struct {
             out_file,
             file_copy_buf,
             usize(0),
-            seek_pos.start - 1,
+            seek_pos.start + @mod(seek_pos.start, BufferSize),
         );
 
+        _ = c.sf_seek(self.sndfile, @intCast(i64, seek_pos.start), c.SEEK_SET);
+
         var i: usize = seek_pos.start;
         std.debug.warn("\tseek pos start: {} end: {}\n", seek_pos.start, seek_pos.end);
 
@@ -301,12 +303,14 @@ pub const Image = struct {
             try swrite(out_file, rctx.out_buf.ptr, 1);
         }
 
+        _ = c.sf_seek(self.sndfile, @intCast(i64, seek_pos.end), c.SEEK_SET);
+
         // post-plugin copy
         try self.copyBytes(
             out_file,
             file_copy_buf,
             seek_pos.end + 1,
-            file_end,
+            file_end + @mod(file_end, BufferSize),
         );
 
         c.sf_write_sync(out_file);

src/lang.zig

@@ -23,6 +23,7 @@ pub const CommandType = enum {
     PitchScaler,
     Reverb,
     Highpass,
+    Delay,
 };
 
 pub const Command = struct {
@@ -137,6 +138,7 @@ pub const Lang = struct {
         _ = try self.keywords.put("pitchscaler", .PitchScaler);
         _ = try self.keywords.put("reverb", .Reverb);
         _ = try self.keywords.put("highpass", .Highpass);
+        _ = try self.keywords.put("delay", .Delay);
     }
 
     pub fn parse(self: *Lang, data: []const u8) !CommandList {

src/runner.zig

@@ -230,6 +230,11 @@ pub const Runner = struct {
         try image.runPlugin("http://invadarecords.com/plugins/lv2/filter/hpf/mono", pos, params);
     }
 
+    fn delayCmd(self: *Runner, pos: Position, params: ParamList) !void {
+        var image = try self.getImage();
+        try image.runPlugin("http://plugin.org.uk/swh-plugins/delayorama", pos, params);
+    }
+
     fn runCommand(self: *Runner, cmd: *lang.Command) !void {
         var params = ParamList.init(self.allocator);
         defer params.deinit();
@@ -328,6 +333,23 @@ pub const Runner = struct {
                 try self.highpassCmd(pos, params);
             },
 
+            .Delay => blk: {
+                const pos = try cmd.consumePosition();
+
+                try cmd.appendParam(&params, "seed");
+                try cmd.appendParam(&params, "gain");
+                try cmd.appendParam(&params, "feedback_pc");
+                try cmd.appendParam(&params, "tap_count");
+                try cmd.appendParam(&params, "first_delay");
+                try cmd.appendParam(&params, "delay_range");
+                try cmd.appendParam(&params, "delay_scale");
+                try cmd.appendParam(&params, "delay_rand_pc");
+                try cmd.appendParam(&params, "gain_scale");
+                try cmd.appendParam(&params, "wet");
+
+                try self.delayCmd(pos, params);
+            },
+
             else => blk: {
                 std.debug.warn("Unsupported command: {}\n", cmd.command);
                 break :blk RunError.UnknownCommand;