From cc57914bbfb115136f694fd21c0a7ecc4d79318f Mon Sep 17 00:00:00 2001
From: Rachael Alexanderson <madame-rachelle@users.noreply.github.com>
Date: Tue, 1 Feb 2022 05:32:16 -0500
Subject: [PATCH] - fully implement uniform cvars

---
 source/common/console/c_cvars.cpp | 22 ++++++++
 source/common/console/c_cvars.h   |  8 +++
 source/core/r_data/gldefs.cpp     | 90 ++++++++++++++++++++++++++++++-
 3 files changed, 119 insertions(+), 1 deletion(-)

diff --git a/source/common/console/c_cvars.cpp b/source/common/console/c_cvars.cpp
index 6510d561e..b9d8a3efc 100644
--- a/source/common/console/c_cvars.cpp
+++ b/source/common/console/c_cvars.cpp
@@ -145,6 +145,28 @@ FBaseCVar::~FBaseCVar ()
 	}
 }
 
+void FBaseCVar::SetCallback(void *callback)
+{
+	m_Callback = reinterpret_cast<void (__cdecl *)(FBaseCVar &)>(callback);
+	m_UseCallback = true;
+}
+
+void FBaseCVar::ClearCallback()
+{
+	m_Callback = nullptr;
+	m_UseCallback = false;
+}
+
+void FBaseCVar::SetExtraDataPointer(void *pointer)
+{
+	m_ExtraDataPointer = pointer;
+}
+
+void* FBaseCVar::GetExtraDataPointer()
+{
+	return m_ExtraDataPointer;
+}
+
 const char *FBaseCVar::GetHumanString(int precision) const
 {
 	return GetGenericRep(CVAR_String).String;
diff --git a/source/common/console/c_cvars.h b/source/common/console/c_cvars.h
index 7d5201a1d..fd65f14b5 100644
--- a/source/common/console/c_cvars.h
+++ b/source/common/console/c_cvars.h
@@ -184,6 +184,12 @@ public:
 		ToggleMessages[1] = on;
 	}
 
+	void SetCallback(void *callback);
+	void ClearCallback();
+
+	void SetExtraDataPointer(void *pointer);
+
+	void* GetExtraDataPointer();
 
 protected:
 	virtual void DoSet (UCVarValue value, ECVarType type) = 0;
@@ -213,6 +219,8 @@ private:
 	static bool m_UseCallback;
 	static bool m_DoNoSet;
 
+	void *m_ExtraDataPointer;
+
 	// These need to go away!
 	friend FString C_GetMassCVarString (uint32_t filter, bool compact);
 	friend void C_SerializeCVars(FSerializer& arc, const char* label, uint32_t filter);
diff --git a/source/core/r_data/gldefs.cpp b/source/core/r_data/gldefs.cpp
index 4e334b128..aacb25a0e 100644
--- a/source/core/r_data/gldefs.cpp
+++ b/source/core/r_data/gldefs.cpp
@@ -60,6 +60,46 @@ extern int AttenuationIsSet;
 #endif
 
 
+struct ExtraUniformCVARData
+{
+	FString Shader;
+	FString Uniform;
+	double* vec4 = nullptr;
+};
+
+static void do_uniform_set(float value, ExtraUniformCVARData* data)
+{
+	if (!(data->vec4))
+	{
+		for (unsigned int i = 0; i < PostProcessShaders.Size(); i++)
+		{
+			PostProcessShader& shader = PostProcessShaders[i];
+			if (strcmp(shader.Name, data->Shader) == 0)
+			{
+				data->vec4 = shader.Uniforms[data->Uniform].Values;
+			}
+		}
+	}
+	double* vec4 = data->vec4;
+	if (vec4)
+	{
+		vec4[0] = value;
+		vec4[1] = 0.0;
+		vec4[2] = 0.0;
+		vec4[3] = 1.0;
+	}
+}
+
+void uniform_callback_int(FIntCVar &self)
+{
+	do_uniform_set ((float)self, (ExtraUniformCVARData*)self.GetExtraDataPointer());
+}
+
+void uniform_callback_float(FFloatCVar &self)
+{
+	do_uniform_set ((float)self, (ExtraUniformCVARData*)self.GetExtraDataPointer());
+}
+
 //-----------------------------------------------------------------------------
 //
 // ParseVavoomSkybox
@@ -1457,8 +1497,10 @@ class GLDefsParser
 					sc.MustGetString();
 					shaderdesc.Name = sc.String;
 				}
-				else if (sc.Compare("uniform"))
+				else if (sc.Compare("uniform") || sc.Compare("cvar_uniform"))
 				{
+					bool is_cvar = sc.Compare("cvar_uniform");
+
 					sc.MustGetString();
 					FString uniformType = sc.String;
 					uniformType.ToLower();
@@ -1479,8 +1521,54 @@ class GLDefsParser
 					else
 						sc.ScriptError("Unrecognized uniform type '%s'", sc.String);
 
+					auto strUniformType = sc.String;
+
 					if (parsedType != PostProcessUniformType::Undefined)
 						shaderdesc.Uniforms[uniformName].Type = parsedType;
+
+					if (is_cvar)
+					{
+						if (!shaderdesc.Name.GetChars())
+							sc.ScriptError("Shader must have a name to use cvar uniforms");
+
+						ECVarType cvartype = CVAR_Dummy;
+						int cvarflags = CVAR_MOD|CVAR_ARCHIVE|CVAR_VIRTUAL;
+						FBaseCVar *cvar;
+						void* callback = NULL;
+						FString cvarname;
+						switch (parsedType)
+						{
+						case PostProcessUniformType::Int:
+							cvartype = CVAR_Int;
+							callback = uniform_callback_int;
+							break;
+						case PostProcessUniformType::Float:
+							cvartype = CVAR_Float;
+							callback = uniform_callback_float;
+							break;
+						default:
+							sc.ScriptError("'%s' not supported for CVAR uniforms!", strUniformType);
+							break;
+						}
+						sc.MustGetString();
+						cvarname = sc.String;
+						cvar = C_CreateCVar(cvarname, cvartype, cvarflags);
+						
+						UCVarValue val;
+						sc.MustGetNumber();
+						
+						val.Float = sc.Number;
+						shaderdesc.Uniforms[uniformName].Values[0] = sc.Number;
+
+						cvar->SetGenericRepDefault(val, CVAR_Float);
+						
+						if (callback)
+							cvar->SetCallback(callback);
+						ExtraUniformCVARData* extra = new ExtraUniformCVARData;
+						extra->Shader = shaderdesc.Name.GetChars();
+						extra->Uniform = uniformName.GetChars();
+						cvar->SetExtraDataPointer(extra);
+					}
 				}
 				else if (sc.Compare("texture"))
 				{