For anyone interested in experimenting with building csound plugins in zig, here is an example plugin. One interesting aspect is that zig can cross compile to any platform so from one local build it is possible to produce binaries for many platforms.
const std = @import(“std”);
const cs = @cImport({
@cInclude(“csound/csdl.h”);
});
const TestGain = extern struct {
h: cs.OPDS,
out: []f64,
in: []f64,
kgain: *f64
};
fn testgain_init(csoundptr: [*c]cs.CSOUND, p: ?*anyopaque) callconv(.C) c_int {
_ = csoundptr;
_ = p;
// std.debug.print(“testgain_init\n”, .{});
return cs.OK;
}
fn testgain_perf(csoundptr: [c]cs.CSOUND, p0: ?anyopaque) callconv(.C) c_int {
_ = &csoundptr[0];
const p: TestGain = @ptrCast(@alignCast(p0));
const nsmps = cs.GetLocalKsmps(&p.h);
var i: u32 = 0;
var out: []f64 = p..out;
const in: []f64 = p..in;
const gain: f64 = p..kgain.*;
while (i <= nsmps) : (i += 1) {
out[i] = in[i] * gain;
}
return cs.OK;
}
const localops7: []const cs.OENTRY = &.{
.{.opname=@constCast(“testgain”), .dsblksiz=@sizeOf(TestGain), .flags=0, .outypes=@constCast(“a”), .intypes=@constCast(“ak”), .init=&testgain_init, .perf=&testgain_perf}
};
export fn csound_opcode_init(csound: cs.CSOUND, ep: []cs.OENTRY) i64 {
_ = csound;
ep. = @constCast(localops7.ptr);
return @sizeOf(cs.OENTRY) * localops7.len;
}
export fn csoundModuleInfo() i32 {
const version = ((cs.CS_VERSION << 16) + (cs.CS_SUBVER << 8) + @sizeOf(cs.MYFLT));
// std.debug.print(“testgain - module info. version: {}\n”, .{version});
return version;
}
Saved to a file “testplugin.zig”, it can be compiled with “zig build-lib -dynamic -lc -I/usr/local/include testplugin.zig”, the folders need to be adapted to the local system.
cheers,
Eduardo
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