feat!: rework header files

inc/core/shader.hpp

@@ -0,0 +1,35 @@
+#ifndef SHADER_HPP
+#define SHADER_HPP
+
+#include "glad/glad.h"
+
+class Shader
+{
+ private:
+  GLuint vertexShaderID;      // vertex shader id
+  GLuint fragmentShaderID;    // fragment shader id
+
+  // final compiled shader program id used by the gpu
+  GLuint shaderProgramID;
+
+  // compile vertex shader source code
+  void addVertShader(const char* vertexSource);
+  // compile fragment shader source code
+  void addFragShader(const char* fragmentSource);
+  // link both compile vertex and fragment shader
+  void compileInProgram();
+
+ public:
+  // Does nothing apart initializing all IDs to 0
+  Shader();
+  // compile and link vertex and fragment into the shader struct
+  void compile(const char* vertexSource, const char* fragmentSource);
+  // free shader program
+  ~Shader();
+
+  GLuint getShaderProgramID() const;
+  // activate shader program into gpu pipeline
+  void use() const;
+};
+
+#endif