From 60db3b8a87b4d356ab3c2c43e24a2c060961cd96 Mon Sep 17 00:00:00 2001
From: s-ol <s+removethis@s-ol.nu>
Date: Sat, 10 Jan 2026 17:06:04 +0100
Subject: pipe raw video to stdout

---
 src/control.zig |  7 ++++++-
 src/gl.zig      | 15 +++++++++++++++
 src/main.zig    | 20 +++++++++++++++++++-
 3 files changed, 40 insertions(+), 2 deletions(-)

diff --git a/src/control.zig b/src/control.zig
index 053f985..9810645 100644
--- a/src/control.zig
+++ b/src/control.zig
@@ -110,6 +110,8 @@ pub const ControlServer = struct {
     progress: std.Progress.Node,
     allocator: std.mem.Allocator,
 
+    dirty: bool,
+
     pub fn init(
         allocator: std.mem.Allocator,
         progress: std.Progress.Node,
@@ -127,6 +129,8 @@ pub const ControlServer = struct {
             .constants = constants,
             .progress = progress,
             .allocator = allocator,
+
+            .dirty = false,
         };
 
         self.server = c.lo_server_new_from_url(config.osc.ptr, handle_error);
@@ -221,7 +225,8 @@ pub const ControlServer = struct {
         const code: [*:0]const u8 = @ptrCast(&argv[0].*.s);
         try self.cache.shader.loadString(std.mem.span(code));
         try self.cache.refresh();
-        std.debug.print("reloaded\n", .{});
+        self.dirty = true;
+
         return true;
     }
 
diff --git a/src/gl.zig b/src/gl.zig
index 7cdc204..2c7c865 100644
--- a/src/gl.zig
+++ b/src/gl.zig
@@ -1008,6 +1008,21 @@ pub const FramebufferObject = struct {
         c.glBindFramebuffer(c.GL_FRAMEBUFFER, 0);
     }
 
+    pub fn read(self: FramebufferObject, width: c.GLint, height: c.GLint, data: []u8) void {
+        _ = self;
+        c.glReadBuffer(c.GL_COLOR_ATTACHMENT0);
+        c.glReadnPixels(
+            0,
+            0,
+            width,
+            height,
+            c.GL_RGBA,
+            c.GL_UNSIGNED_BYTE,
+            @intCast(data.len),
+            data.ptr,
+        );
+    }
+
     pub fn create(width: i32, height: i32) !FramebufferObject {
         var self: FramebufferObject = undefined;
         c.glGenFramebuffers(1, &self.buffer_id);
diff --git a/src/main.zig b/src/main.zig
index 6d70a14..fbe006e 100644
--- a/src/main.zig
+++ b/src/main.zig
@@ -118,6 +118,15 @@ pub fn main() !void {
     defer control.destroy();
 
     var loops: u8 = 0;
+
+    const stdout = std.fs.File.stdout();
+    var tex_buffer: ?[]u8 = null;
+
+    if (!stdout.isTty()) {
+        tex_buffer = try std.heap.c_allocator.alloc(u8, @intCast(config.width * config.height * 4));
+    }
+    defer if (tex_buffer) |buf| std.heap.c_allocator.free(buf);
+
     while (c.glfwWindowShouldClose(window) == c.GL_FALSE) {
         c.glfwMakeContextCurrent(window);
 
@@ -135,7 +144,7 @@ pub fn main() !void {
         //     control.reload_requested = false;
         // }
 
-        {
+        if (control.dirty) {
             c.glFinish();
             var timer = try std.time.Timer.start();
 
@@ -144,6 +153,13 @@ pub fn main() !void {
 
             main_program.bind();
             constants.normalized_quad.draw();
+
+            if (tex_buffer) |buf| {
+                fbo.read(config.width, config.height, buf);
+                std.debug.print("writing {} bytes\n", .{buf.len});
+                _ = try stdout.write(buf);
+            }
+
             fbo.unbind();
 
             c.glFinish();
@@ -152,6 +168,8 @@ pub fn main() !void {
             if (loops == 0) {
                 std.debug.print("\rrendered in {d:.2}ms\n", .{@as(f64, @floatFromInt(fps)) / std.time.ns_per_ms});
             }
+
+            control.dirty = false;
         }
 
         for (outputs.items, 0..) |output, i| {
-- 
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