Shader.h

// Shader.h
#ifndef SHADER_H
#define SHADER_H

#include <GL/glew.h>
#include <string>
#include <fstream>
#include <sstream>
#include <iostream>

class Shader {
public:
	// Program ID
	unsigned int ID;

	// Constructor reads and builds the shader
	Shader(const char* vertexPath, const char* fragmentPath) {
		// Retrieve source code
		std::string vertexCode;
		std::string fragmentCode;
		std::ifstream vShaderFile;
		std::ifstream fShaderFile;

		// Ensure ifstream objects can throw exceptions
		vShaderFile.exceptions(std::ifstream::failbit | std::ifstream::badbit);
		fShaderFile.exceptions(std::ifstream::failbit | std::ifstream::badbit);
		try {
			// Open files
			vShaderFile.open(vertexPath);
			fShaderFile.open(fragmentPath);
			std::stringstream vShaderStream, fShaderStream;
			// Read file's buffer contents
			vShaderStream << vShaderFile.rdbuf();
			fShaderStream << fShaderFile.rdbuf();
			// Close file handlers
			vShaderFile.close();
			fShaderFile.close();
			// Convert stream into string
			vertexCode = vShaderStream.str();
			fragmentCode = fShaderStream.str();
		}
		catch (std::ifstream::failure& e) {
			std::cerr << "ERROR: Shader file not successfully read\n";
		}
		const char* vShaderCode = vertexCode.c_str();
		const char* fShaderCode = fragmentCode.c_str();

		// Compile shaders
		unsigned int vertex, fragment;
		int success;
		char infoLog[512];

		// Vertex Shader
		vertex = glCreateShader(GL_VERTEX_SHADER);
		glShaderSource(vertex, 1, &vShaderCode, NULL);
		glCompileShader(vertex);
		// Check for errors
		glGetShaderiv(vertex, GL_COMPILE_STATUS, &success);
		if (!success) {
			glGetShaderInfoLog(vertex, 512, NULL, infoLog);
			std::cerr << "ERROR: Vertex Shader compilation failed\n" << infoLog << '\n';
		}

		// Fragment Shader
		fragment = glCreateShader(GL_FRAGMENT_SHADER);
		glShaderSource(fragment, 1, &fShaderCode, NULL);
		glCompileShader(fragment);
		// Check for errors
		glGetShaderiv(fragment, GL_COMPILE_STATUS, &success);
		if (!success) {
			glGetShaderInfoLog(fragment, 512, NULL, infoLog);
			std::cerr << "ERROR: Fragment Shader compilation failed\n" << infoLog << '\n';
		}

		// Shader Program
		ID = glCreateProgram();
		glAttachShader(ID, vertex);
		glAttachShader(ID, fragment);
		glLinkProgram(ID);
		// Check for errors
		glGetProgramiv(ID, GL_LINK_STATUS, &success);
		if (!success) {
			glGetProgramInfoLog(ID, 512, NULL, infoLog);
			std::cerr << "ERROR: Shader Program linking failed\n" << infoLog << '\n';
		}

		// Delete shaders
		glDeleteShader(vertex);
		glDeleteShader(fragment);
	}

	// Use the shader
	void use() {
		glUseProgram(ID);
	}

	// Utility functions
	void setBool(const std::string& name, bool value) const {
		glUniform1i(glGetUniformLocation(ID, name.c_str()), (int)value);
	}
	void setInt(const std::string& name, int value) const {
		glUniform1i(glGetUniformLocation(ID, name.c_str()), value);
	}
	void setFloat(const std::string& name, float value) const {
		glUniform1f(glGetUniformLocation(ID, name.c_str()), value);
	}
	void setMat4(const std::string& name, glm::mat4& mat) const {
		glUniformMatrix4fv(glGetUniformLocation(ID, name.c_str()), 1, GL_FALSE, &mat[0][0]);
	}
	void setVec3(const std::string& name, const glm::vec3& value) const {
		glUniform3fv(glGetUniformLocation(ID, name.c_str()), 1, &value[0]);
	}


	// Add this method inside the Shader class
	void setVec4(const std::string& name, const glm::vec4& value) const {
		glUniform4fv(glGetUniformLocation(ID, name.c_str()), 1, &value[0]);
	}

};

#endif // SHADER_H