Crt, Ripple and Glitch take a level, 0 to 3, tunable at run time

Coordinator's request: `Crt 0..3` (likewise Ripple, Glitch), 0 off, `on`
the default level 2 (the polished rewrite), `off` and a bare word as
before. The level is one uniform (pardesLevel, beside pardesOpaque in the
prefix's own block); each pass picks its constants by it. Level 3 is at
least as strong as the old effects, measured as pixels changed by more
than 8 in a channel against a plain frame: Crt 18.3% (old 17.4%), Ripple
11.1% (9.5%), Glitch 9.3% a frame (8.1%); Glitch's level raises how often
it bursts as well as how hard. Config and ctl report `Crt 2` / `Crt off`.

Shared files touched: ninep/ctl.zig (the report line). Not touched:
pardes.zig, Messages.zig, mouse.zig, gui.zig, detached/*.

1 files changed, 4 insertions, 2 deletions

diff --git a/src/gui/Post.zig b/src/gui/Post.zig
index c529efc0..d9d3d53e 100644
--- a/src/gui/Post.zig
+++ b/src/gui/Post.zig
@@ -69,6 +69,8 @@ pub const Uniforms = extern struct {
 
 pub const Pass = struct {
     scene: ?Scene = null,
+    /// A bundled pass's strength (pardesLevel); 0 for a file.
+    level: u8 = 0,
     /// A user's file, owned; empty for a bundled pass.
     path: []u8 = &.{},
     pipeline: ?*Pipeline = null,
@@ -117,7 +119,7 @@ pub fn sync(post: *Post, gpa: std.mem.Allocator, io: std.Io, device: *c.SDL_GPUD
     for (chain.list(), 0..) |entry, i| {
         if (entry.scene) |scene| {
             if (post.bundled.get(scene) == null) post.bundled.set(scene, makePipeline(device, format, bundled_spv.get(scene)) catch null);
-            next[i] = .{ .scene = scene, .pipeline = post.bundled.get(scene) };
+            next[i] = .{ .scene = scene, .level = entry.level, .pipeline = post.bundled.get(scene) };
             continue;
         }
         // A file already in the chain keeps its pipeline and its path.
@@ -405,7 +407,6 @@ pub fn draw(post: *Post, device: *c.SDL_GPUDevice, cmd: *c.SDL_GPUCommandBuffer,
     const day = epoch.getEpochDay().calculateYearDay();
     const month = day.calculateMonthDay();
     u.date = .{ @floatFromInt(day.year), @floatFromInt(month.month.numeric() - 1), @floatFromInt(month.day_index + 1), @floatFromInt(epoch.getDaySeconds().secs) };
-    const own: [4]f32 = .{ @floatFromInt(@intFromBool(opaque_window)), 0, 0, 0 };
 
     var input = source;
     var index: usize = 0;
@@ -423,6 +424,7 @@ pub fn draw(post: *Post, device: *c.SDL_GPUDevice, cmd: *c.SDL_GPUCommandBuffer,
         const binding = c.SDL_GPUTextureSamplerBinding{ .texture = input, .sampler = sampler };
         c.SDL_BindGPUFragmentSamplers(pass_rp, 0, &binding, 1);
         c.SDL_PushGPUFragmentUniformData(cmd, 0, u, @sizeOf(Uniforms));
+        const own: [4]f32 = .{ @floatFromInt(@intFromBool(opaque_window)), @floatFromInt(pass.level), 0, 0 };
         c.SDL_PushGPUFragmentUniformData(cmd, 1, &own, @sizeOf(@TypeOf(own)));
         c.SDL_DrawGPUPrimitives(pass_rp, 3, 1, 0, 0);
         c.SDL_EndGPURenderPass(pass_rp);