From 7041babc9e5333d01191f3eb80fd711bd26cd4f7 Mon Sep 17 00:00:00 2001
From: skal <pascal.massimino@gmail.com>
Date: Tue, 17 Feb 2026 08:46:01 +0100
Subject: feat: add time-based effect activation with auto-passthrough

Effects now accept start/end time parameters and automatically passthrough
when inactive. Implements buffer chain integrity via compile-time validation.

- Effect base class: dispatch_render() checks time bounds, auto-passthroughs
  1:1 input/output effects outside [start, end] interval
- seq_compiler.py: validates producer/consumer lifespan constraints for
  multi-output effects, adds --validate flag, always validates before codegen
- Updated all 9 effect classes and test fixtures to pass start/end times
- check_all.sh: includes timeline validation step
- Tests: 34/34 passing, demo runs successfully

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>
---
 src/gpu/effect.cc | 57 +++++++++++++++++++++++++++++++++++++++++++++++++++++--
 1 file changed, 55 insertions(+), 2 deletions(-)

(limited to 'src/gpu/effect.cc')

diff --git a/src/gpu/effect.cc b/src/gpu/effect.cc
index b729321..117ede2 100644
--- a/src/gpu/effect.cc
+++ b/src/gpu/effect.cc
@@ -1,11 +1,64 @@
 // Effect implementation
 
 #include "gpu/effect.h"
+#include "gpu/gpu.h"
+#include "gpu/sequence.h"
 #include "util/fatal_error.h"
 
 Effect::Effect(const GpuContext& ctx, const std::vector<std::string>& inputs,
-               const std::vector<std::string>& outputs)
-    : ctx_(ctx), input_nodes_(inputs), output_nodes_(outputs) {
+               const std::vector<std::string>& outputs, float start_time,
+               float end_time)
+    : ctx_(ctx), input_nodes_(inputs), output_nodes_(outputs),
+      start_time_(start_time), end_time_(end_time) {
   FATAL_CHECK(!inputs.empty(), "Effect must have at least one input\n");
   FATAL_CHECK(!outputs.empty(), "Effect must have at least one output\n");
+  FATAL_CHECK(start_time <= end_time, "Invalid time range: %f > %f\n",
+              start_time, end_time);
+}
+
+void Effect::dispatch_render(WGPUCommandEncoder encoder,
+                              const UniformsSequenceParams& params,
+                              NodeRegistry& nodes) {
+  // Check if effect is active at current time
+  const bool active =
+      (params.time >= start_time_ && params.time < end_time_);
+
+  // Auto-passthrough for 1:1 input/output effects outside active range
+  if (!active && input_nodes_.size() == 1 && output_nodes_.size() == 1) {
+    blit_input_to_output(encoder, nodes);
+  } else if (active) {
+    render(encoder, params, nodes);
+  }
+  // Multi-output effects: output undefined when inactive (validated at compile time)
+}
+
+void Effect::blit_input_to_output(WGPUCommandEncoder encoder,
+                                   NodeRegistry& nodes) {
+  HEADLESS_RETURN_IF_NULL(encoder);
+
+  WGPUTexture src = nodes.get_texture(input_nodes_[0]);
+  WGPUTexture dst = nodes.get_texture(output_nodes_[0]);
+
+  // Skip passthrough if textures are external (source/sink) or invalid
+  if (!src || !dst) {
+    return;
+  }
+
+#if defined(DEMO_CROSS_COMPILE_WIN32)
+  WGPUImageCopyTexture src_copy = {
+      .texture = src, .mipLevel = 0, .origin = {0, 0, 0}};
+  WGPUImageCopyTexture dst_copy = {
+      .texture = dst, .mipLevel = 0, .origin = {0, 0, 0}};
+#else
+  WGPUTexelCopyTextureInfo src_copy = {
+      .texture = src, .mipLevel = 0, .origin = {0, 0, 0}};
+  WGPUTexelCopyTextureInfo dst_copy = {
+      .texture = dst, .mipLevel = 0, .origin = {0, 0, 0}};
+#endif
+
+  WGPUExtent3D extent = {static_cast<unsigned int>(width_),
+                         static_cast<unsigned int>(height_), 1};
+
+  wgpuCommandEncoderCopyTextureToTexture(encoder, &src_copy, &dst_copy,
+                                         &extent);
 }
-- 
cgit v1.2.3