From a9f70c9e9f37687e44ffa374866063c8a420d73a Mon Sep 17 00:00:00 2001
From: wheaney <42350981+wheaney@users.noreply.github.com>
Date: Fri, 22 Sep 2023 22:59:10 -0700
Subject: [PATCH] Add support for runtime uniform variables, using shared
 memory for cross-process communication

---
 src/reshade_uniforms.cpp | 65 ++++++++++++++++++++++++++++++++++++++++
 src/reshade_uniforms.hpp | 14 +++++++++
 2 files changed, 79 insertions(+)

diff --git a/src/reshade_uniforms.cpp b/src/reshade_uniforms.cpp
index b66670d8..2c7cee66 100644
--- a/src/reshade_uniforms.cpp
+++ b/src/reshade_uniforms.cpp
@@ -4,11 +4,14 @@
 #include <ctime>
 #include <cstdlib>
 #include <cmath>
+#include <sys/shm.h>
 
 #include <algorithm>
 
 #include "logger.hpp"
 
+const std::string defaultRuntimePathnamePrefix = "/tmp/shader_runtime_";
+
 namespace vkBasalt
 {
     void enumerateReshadeUniforms(reshadefx::module module)
@@ -76,6 +79,10 @@ namespace vkBasalt
             {
                 uniforms.push_back(std::shared_ptr<ReshadeUniform>(new DepthUniform(uniform)));
             }
+            else if (!source.empty())
+            {
+                uniforms.push_back(std::shared_ptr<ReshadeUniform>(new RuntimeUniform(uniform)));
+            }
         }
         return uniforms;
     }
@@ -380,4 +387,62 @@ namespace vkBasalt
     DepthUniform::~DepthUniform()
     {
     }
+
+    //////////////////////////////////////////////////////////////////////////////////////////////////////////
+    RuntimeUniform::RuntimeUniform(reshadefx::uniform_info uniformInfo)
+    {
+        auto source = std::find_if(uniformInfo.annotations.begin(), uniformInfo.annotations.end(), [](const auto& a) { return a.name == "source"; });
+        defaultValue = 0.0;
+        if (auto defaultValueAnnotation =
+                std::find_if(uniformInfo.annotations.begin(), uniformInfo.annotations.end(), [](const auto& a) { return a.name == "defaultValue"; });
+            defaultValueAnnotation != uniformInfo.annotations.end())
+        {
+            defaultValue = defaultValueAnnotation->type.is_floating_point() ? defaultValueAnnotation->value.as_float[0] : 0.0f;
+        }
+
+        if (auto pathnameAnnotation =
+                std::find_if(uniformInfo.annotations.begin(), uniformInfo.annotations.end(), [](const auto& a) { return a.name == "pathname"; });
+            pathnameAnnotation != uniformInfo.annotations.end())
+        {
+            pathname = new char[pathnameAnnotation->value.string_data.length() + 1];
+            strcpy(pathname, pathnameAnnotation->value.string_data.c_str());
+        }
+        else
+        {
+            pathname = new char[defaultRuntimePathnamePrefix.length() + source->value.string_data.length() + 1];
+            std::string tmp_pathname = defaultRuntimePathnamePrefix + source->value.string_data;
+            strcpy(pathname, tmp_pathname.c_str());
+        }
+
+        projId = 0;
+        if (auto projIdAnnotation =
+                std::find_if(uniformInfo.annotations.begin(), uniformInfo.annotations.end(), [](const auto& a) { return a.name == "projId"; });
+            projIdAnnotation != uniformInfo.annotations.end())
+        {
+            projId = projIdAnnotation->value.as_int[0];
+        }
+        shmKey = ftok(pathname, projId);
+
+        Logger::debug("Found runtime uniform: " + std::to_string(defaultValue) + " " + pathname + " " + std::to_string(projId) + "\n");
+        offset = uniformInfo.offset;
+        size   = uniformInfo.size;
+    }
+    void RuntimeUniform::update(void* mapedBuffer)
+    {
+        float *value = &defaultValue;
+        bool needs_detach = false;
+        if (shmKey != -1) {
+            int shmId = shmget(shmKey,sizeof(*value),0444); // read-only
+            if (shmId != -1) {
+                value = (float*) shmat(shmId,(void*)0,0);
+                needs_detach = true;
+            }
+        }
+        std::memcpy((uint8_t*) mapedBuffer + offset, value, sizeof(*value));
+        if (needs_detach)
+            shmdt(value);
+    }
+    RuntimeUniform::~RuntimeUniform()
+    {
+    }
 } // namespace vkBasalt
diff --git a/src/reshade_uniforms.hpp b/src/reshade_uniforms.hpp
index a41b28c9..16f698c7 100644
--- a/src/reshade_uniforms.hpp
+++ b/src/reshade_uniforms.hpp
@@ -139,6 +139,20 @@ namespace vkBasalt
         void virtual update(void* mapedBuffer) override;
         virtual ~DepthUniform();
     };
+
+    class RuntimeUniform : public ReshadeUniform
+    {
+    public:
+        RuntimeUniform(reshadefx::uniform_info uniformInfo);
+        void virtual update(void* mapedBuffer) override;
+        virtual ~RuntimeUniform();
+
+    private:
+        float defaultValue;
+        char* pathname;
+        int projId;
+        key_t shmKey;
+    };
 } // namespace vkBasalt
 
 #endif // RESHADE_UNIFORMS_HPP_INCLUDED