From af0165f8afc25273d28e6b2393e66b16819b5cfe Mon Sep 17 00:00:00 2001
From: Steffen Ohrendorf <steffen.ohrendorf@gmx.de>
Date: Tue, 26 Oct 2021 21:20:12 +0200
Subject: [PATCH] make local shader time invariant across effect pipeline
 reconstructions

---
 src/render/pass/effectpass.cpp | 10 ++++++----
 src/render/pass/effectpass.h   | 11 ++++++++---
 src/render/renderpipeline.cpp  |  2 +-
 src/render/renderpipeline.h    |  9 +++++++++
 4 files changed, 24 insertions(+), 8 deletions(-)

diff --git a/src/render/pass/effectpass.cpp b/src/render/pass/effectpass.cpp
index c0e0d4985..d39960560 100644
--- a/src/render/pass/effectpass.cpp
+++ b/src/render/pass/effectpass.cpp
@@ -1,6 +1,7 @@
 #include "effectpass.h"
 
 #include "config.h"
+#include "render/renderpipeline.h"
 #include "render/scene/mesh.h"
 #include "render/scene/rendercontext.h"
 #include "render/scene/rendermode.h"
@@ -28,10 +29,12 @@ class Node;
 
 namespace render::pass
 {
-EffectPass::EffectPass(std::string name,
+EffectPass::EffectPass(gsl::not_null<const RenderPipeline*> renderPipeline,
+                       std::string name,
                        gsl::not_null<std::shared_ptr<scene::Material>> material,
                        const gsl::not_null<std::shared_ptr<gl::TextureHandle<gl::Texture2D<gl::SRGB8>>>>& input)
-    : m_name{std::move(name)}
+    : m_renderPipeline{std::move(renderPipeline)}
+    , m_name{std::move(name)}
     , m_material{std::move(material)}
     , m_mesh{scene::createScreenQuad(m_material, m_name)}
     , m_colorBuffer{std::make_shared<gl::Texture2D<gl::SRGB8>>(input->getTexture()->size(), m_name + "-color")}
@@ -69,8 +72,7 @@ void EffectPass::render(bool inWater)
   m_mesh->bind("u_time",
                [this](const scene::Node&, const scene::Mesh& /*mesh*/, gl::Uniform& uniform)
                {
-                 const auto now = std::chrono::duration_cast<std::chrono::milliseconds>(
-                   std::chrono::high_resolution_clock::now() - m_creationTime);
+                 const auto now = m_renderPipeline->getLocalTime();
                  uniform.set(gsl::narrow_cast<float>(now.count()));
                });
   m_mesh->render(context);
diff --git a/src/render/pass/effectpass.h b/src/render/pass/effectpass.h
index 1353719b1..a7a153633 100644
--- a/src/render/pass/effectpass.h
+++ b/src/render/pass/effectpass.h
@@ -1,6 +1,5 @@
 #pragma once
 
-#include <chrono>
 #include <gl/pixel.h>
 #include <gl/soglb_fwd.h>
 #include <gsl/gsl-lite.hpp>
@@ -8,6 +7,11 @@
 #include <string>
 #include <utility>
 
+namespace render
+{
+class RenderPipeline;
+}
+
 namespace render::scene
 {
 class Material;
@@ -19,7 +23,8 @@ namespace render::pass
 class EffectPass final
 {
 public:
-  explicit EffectPass(std::string name,
+  explicit EffectPass(gsl::not_null<const RenderPipeline*> renderPipeline,
+                      std::string name,
                       gsl::not_null<std::shared_ptr<scene::Material>> material,
                       const gsl::not_null<std::shared_ptr<gl::TextureHandle<gl::Texture2D<gl::SRGB8>>>>& input);
 
@@ -42,12 +47,12 @@ class EffectPass final
   }
 
 private:
+  const gsl::not_null<const RenderPipeline*> m_renderPipeline;
   const std::string m_name;
   const gsl::not_null<std::shared_ptr<scene::Material>> m_material;
   gsl::not_null<std::shared_ptr<scene::Mesh>> m_mesh;
   gsl::not_null<std::shared_ptr<gl::Texture2D<gl::SRGB8>>> m_colorBuffer;
   gsl::not_null<std::shared_ptr<gl::TextureHandle<gl::Texture2D<gl::SRGB8>>>> m_colorBufferHandle;
   gsl::not_null<std::shared_ptr<gl::Framebuffer>> m_fb;
-  const std::chrono::high_resolution_clock::time_point m_creationTime = std::chrono::high_resolution_clock::now();
 };
 } // namespace render::pass
diff --git a/src/render/renderpipeline.cpp b/src/render/renderpipeline.cpp
index 78f680c86..b3d2fa9f2 100644
--- a/src/render/renderpipeline.cpp
+++ b/src/render/renderpipeline.cpp
@@ -80,7 +80,7 @@ void RenderPipeline::resize(scene::MaterialManager& materialManager,
   auto addEffect =
     [this, &fxSource](const std::string& name, const gsl::not_null<std::shared_ptr<render::scene::Material>>& material)
   {
-    auto fx = std::make_shared<pass::EffectPass>("fx:" + name, material, fxSource);
+    auto fx = std::make_shared<pass::EffectPass>(gsl::not_null{this}, "fx:" + name, material, fxSource);
     m_effects.emplace_back(fx);
     fxSource = fx->getOutput();
     return fx;
diff --git a/src/render/renderpipeline.h b/src/render/renderpipeline.h
index 95ce475ab..d11eb3cfd 100644
--- a/src/render/renderpipeline.h
+++ b/src/render/renderpipeline.h
@@ -2,6 +2,7 @@
 
 #include "rendersettings.h"
 
+#include <chrono>
 #include <gl/soglb_fwd.h>
 #include <glm/vec2.hpp>
 #include <memory>
@@ -33,6 +34,8 @@ class EffectPass;
 class RenderPipeline
 {
 private:
+  const std::chrono::high_resolution_clock::time_point m_creationTime = std::chrono::high_resolution_clock::now();
+
   RenderSettings m_renderSettings{};
   glm::ivec2 m_renderSize{-1};
   glm::ivec2 m_displaySize{-1};
@@ -63,5 +66,11 @@ class RenderPipeline
               bool force = false);
 
   void apply(const RenderSettings& renderSettings, scene::MaterialManager& materialManager);
+
+  [[nodiscard]] auto getLocalTime() const
+  {
+    return std::chrono::duration_cast<std::chrono::milliseconds>(std::chrono::high_resolution_clock::now()
+                                                                 - m_creationTime);
+  }
 };
 } // namespace render