scritcher/src/custom.zig

// Custom plugins
const std = @import("std");
const lv2 = @import("lv2_helpers.zig");
const plugins = @import("plugin.zig");
const image = @import("image.zig");

const log = std.log.scoped(.scritcher_custom);
const c = lv2.c;

const RunBuffers = plugins.RunBuffers;

pub const RandomNoise = struct {
    r: std.rand.DefaultPrng,
    rand_buf: ?[]f32 = null,
    allocator: ?std.mem.Allocator = null,
    cnt: usize = 0,

    pub fn init(
        allocator: std.mem.Allocator,
        params: anytype,
    ) ?RandomNoise {
        var r = std.rand.DefaultPrng.init(params.seed);

        if (params.fill_bytes > 0) {
            var rand_buf = allocator.alloc(f32, params.fill_bytes) catch return null;

            for (rand_buf, 0..) |_, idx| {
                rand_buf[idx] = r.random().float(f32);
            }

            return RandomNoise{
                .r = r,
                .allocator = allocator,
                .rand_buf = rand_buf,
            };
        } else {
            return RandomNoise{
                .r = r,
            };
        }
    }

    pub fn deinit(self: *RandomNoise) void {
        if (self.allocator == null) return;
        if (self.rand_buf == null) return;
        self.allocator.?.free(self.rand_buf.?);
    }

    pub fn run(self: *RandomNoise, bufs: *RunBuffers) void {
        if (self.rand_buf) |rand_buf| {
            if (self.cnt >= rand_buf.len) self.cnt = 0;
            bufs.out[0] = rand_buf[self.cnt];
            self.cnt += 1;
        } else {
            bufs.out[0] = self.r.random().float(f32);
        }
    }
};

pub const WildNoise = struct {
    r: std.rand.DefaultPrng,
    rand_buf: ?[]f32 = null,
    allocator: ?std.mem.Allocator = null,
    cnt: usize = 0,

    pub fn init(
        allocator: std.mem.Allocator,
        params: anytype,
    ) ?WildNoise {
        var r = std.rand.DefaultPrng.init(params.seed);

        if (params.fill_bytes > 0) {
            var rand_buf = allocator.alloc(f32, params.fill_bytes) catch return null;

            for (rand_buf, 0..) |_, idx| {
                rand_buf[idx] = @as(f32, @floatFromInt(r.random().int(u1)));
            }

            return WildNoise{
                .r = r,
                .rand_buf = rand_buf,
            };
        } else {
            return WildNoise{
                .r = r,
            };
        }
    }

    pub fn deinit(self: *WildNoise) void {
        if (self.allocator == null) return;
        if (self.rand_buf == null) return;
        self.allocator.?.free(self.rand_buf.?);
    }

    pub fn run(self: *WildNoise, bufs: *RunBuffers) void {
        if (self.rand_buf) |rand_buf| {
            if (self.cnt >= rand_buf.len) self.cnt = 0;
            bufs.out[0] = rand_buf[self.cnt];
            self.cnt += 1;
        } else {
            bufs.out[0] = @as(f32, @floatFromInt(self.r.random().int(u1)));
        }
    }
};

/// Write any float to the image.
/// Keep in mind that the bit representation of the float will clash with
/// the format of BMP pixel data, which means writing 0 everywhere won't give
/// you the black color.
pub const Write = struct {
    data: f32,

    pub fn init(
        allocator: std.mem.Allocator,
        params: anytype,
    ) Write {
        _ = allocator;
        return Write{
            .data = params.data,
        };
    }

    pub fn deinit(self: *Write) void {
        _ = self;
    }

    pub fn run(self: *Write, bufs: *RunBuffers) void {
        bufs.out[0] = self.data;
    }
};

pub const Embed = struct {
    allocator: std.mem.Allocator,
    filepath: []const u8,

    sndfile: *c.SNDFILE = undefined,
    buf: []f32 = undefined,

    pub fn init(allocator: std.mem.Allocator, params: anytype) @This() {
        return Embed{
            .allocator = allocator,
            .filepath = params.path,
        };
    }

    pub fn setup(self: *@This()) !void {
        var in_fmt = c.SF_INFO{
            .frames = @as(c_int, 0),
            .samplerate = @as(c_int, 0),
            .channels = @as(c_int, 0),
            .format = @as(c_int, 0),
            .sections = @as(c_int, 0),
            .seekable = @as(c_int, 0),
        };

        self.sndfile = try image.sopen(
            self.allocator,
            self.filepath,
            c.SFM_READ,
            &in_fmt,
        );

        image.sseek(self.sndfile, 0);

        self.buf = try self.allocator.alloc(f32, @as(usize, @intCast(in_fmt.channels)));
    }

    pub fn deinit(self: *@This()) void {
        _ = self;
    }

    pub fn run(self: *@This(), bufs: *RunBuffers) void {
        const read_bytes = c.sf_readf_float(self.sndfile, self.buf.ptr, 1);

        if (read_bytes == 0) {
            bufs.out[0] = bufs.in[0];
            return;
        }

        if (read_bytes < 0) {
            const st: i32 = c.sf_error(self.sndfile);
            log.debug("Failed to read {s} ({s})", .{
                self.filepath,
                c.sf_error_number(st),
            });
            return;
        }

        bufs.out[0] = bufs.in[0] + self.buf[0];
    }
};