Copy changes from the no-history fork, generated back in 2023

Original commit message:
> commit f138311d2d2e0cc9ba0496d523bb46f2c1c9fb73
> Author: rtk0c <[email protected]>
> Date:   Wed Sep 20 23:58:58 2023 -0700
>
>     Copy from the PlasticSCM repo, replace vendored glm wtih conan

In reality, this also introduced a few uncommitted changes in the
original PlasticSCM repo. See the modified and new files in this patch.

1 files changed, 40 insertions, 33 deletions

diff --git a/source/30-game/Shader.hpp b/source/30-game/Shader.hpp
index 707e6cc..cb980cd 100644
--- a/source/30-game/Shader.hpp
+++ b/source/30-game/Shader.hpp
@@ -7,8 +7,10 @@
 
 #include <glad/glad.h>
 #include <robin_hood.h>
+#include <json_dto/pub.hpp>
 #include <memory>
 #include <string_view>
+#include <variant>
 #include <vector>
 
 // TODO move to variable after pattern matching is in the language
@@ -17,44 +19,44 @@
 class Shader;
 class IresShader;
 
-struct ShaderVariable {
-	enum Kind {
-		KD_Math,
-		KD_Sampler,
-	};
-
+struct ShaderMathVariable {
 	std::string name;
-	Kind kind;
 	GLuint location;
 	Tags::VertexElementSemantic semantic = Tags::VES_Generic;
-
-	virtual void ShowInfo() const = 0;
-
-protected:
-	ShaderVariable(Kind kind)
-		: kind{ kind } {}
-};
-
-struct ShaderMathVariable : public ShaderVariable {
 	GLenum scalarType;
-	int arrayLength;
 	int width;
 	int height;
+	int arrayLength = 1;
 
-	ShaderMathVariable()
-		: ShaderVariable(KD_Math) {}
+	void ShowInfo() const;
 
-	virtual void ShowInfo() const override;
+	template <typename TJsonIo>
+	void json_io(TJsonIo& io) {
+		io& json_dto::mandatory("Name", name);
+		io& json_dto::mandatory("Semantic", static_cast<int>(semantic));
+		io& json_dto::mandatory("ScalarType", scalarType);
+		io& json_dto::mandatory("Width", width);
+		io& json_dto::mandatory("Height", height);
+		io& json_dto::optional("ArrayLength", arrayLength, 1);
+	}
 };
 
-struct ShaderSamplerVariable : public ShaderVariable {
-	GLenum type;
-	int arrayLength;
+struct ShaderSamplerVariable {
+	std::string name;
+	GLuint location;
+	Tags::VertexElementSemantic semantic = Tags::VES_Generic;
+	GLenum samplerType;
+	int arrayLength = 1;
 
-	ShaderSamplerVariable()
-		: ShaderVariable(KD_Sampler) {}
+	void ShowInfo() const;
 
-	virtual void ShowInfo() const override;
+	template <typename TJsonIo>
+	void json_io(TJsonIo& io) {
+		io& json_dto::mandatory("Name", name);
+		io& json_dto::mandatory("Semantic", static_cast<int>(semantic));
+		io& json_dto::mandatory("SamplerType", samplerType);
+		io& json_dto::optional("ArrayLength", arrayLength, 1);
+	}
 };
 
 struct ShaderThingId {
@@ -62,24 +64,29 @@ struct ShaderThingId {
 		KD_Input,
 		KD_Output,
 		KD_Uniform,
-		KD_Invalid,
 	};
 
-	Kind kind = KD_Invalid;
-	int index = 0;
-
-	bool IsValid() const;
+	Kind kind;
+	int index;
 };
 
 struct ShaderInfo {
 	robin_hood::unordered_map<std::string, ShaderThingId, StringHash, StringEqual> things;
 	std::vector<ShaderMathVariable> inputs;
 	std::vector<ShaderMathVariable> outputs;
-	std::vector<std::unique_ptr<ShaderVariable>> uniforms;
+	std::vector<std::variant<ShaderMathVariable, ShaderSamplerVariable>> uniforms;
 
+	// Find the first variable with the matching semantic
 	GLuint FindInputLocation(Tags::VertexElementSemantic semantic);
 	GLuint FindOutputLocation(Tags::VertexElementSemantic semantic);
-	ShaderVariable* FindVariable(const ShaderThingId& thing);
+
+	template <typename TJsonIo>
+	void json_io(TJsonIo& io) {
+		io& json_dto::mandatory("Inputs", inputs);
+		io& json_dto::mandatory("Outputs", outputs);
+		// TODO make json_dto support std::variant
+//		io& json_dto::mandatory("Uniforms", uniforms);
+	}
 };
 
 class Shader : public RefCounted {