Resolve "Pipeline State Object"

Closes #11 (closed)

include/vkcv/ShaderProgram.hpp

+#pragma once
+/**
+ * @authors Simeon Hermann, Leonie Franken
+ * @file src/vkcv/ShaderProgram.hpp
+ * @brief ShaderProgram class to handle and prepare the shader stages for a graphics pipeline
+ */
+
+#include <unordered_map>
+#include <fstream>
+#include <iostream>
+#include <filesystem>
+#include <vulkan/vulkan.hpp>
+
+namespace vkcv {
+
+    enum class ShaderStage
+    {
+        VERTEX,
+        TESS_CONTROL,
+        TESS_EVAL,
+        GEOMETRY,
+        FRAGMENT,
+        COMPUTE
+    };
+
+    struct Shader
+    {
+        std::vector<char> shaderCode;
+        ShaderStage shaderStage;
+    };
+
+	class ShaderProgram
+	{
+    public:
+        ShaderProgram() noexcept; // ctor
+        ~ShaderProgram() = default; // dtor
+
+        /**
+        * Adds a shader into the shader program.
+        * The shader is only added if the shader program does not contain the particular shader stage already.
+        * Contains: (1) reading of the code, (2) creation of a shader module, (3) creation of a shader stage, (4) adding to the shader stage list, (5) destroying of the shader module
+        * @param[in] flag that signals the respective shaderStage (e.g. VK_SHADER_STAGE_VERTEX_BIT)
+        * @param[in] relative path to the shader code (e.g. "../../../../../shaders/vert.spv")
+        */
+        bool addShader(ShaderStage shaderStage, const std::filesystem::path &shaderPath);
+
+        /**
+        * Returns the shader program's shader of the specified shader.
+        * Needed for the transfer to the pipeline.
+        * @return Shader object consisting of buffer with shader code and shader stage enum
+        */
+        const Shader &getShader(ShaderStage shaderStage) const;
+
+        bool existsShader(ShaderStage shaderStage) const;
+
+	private:
+        std::unordered_map<ShaderStage, Shader> m_Shaders;
+
+	};
+}