loadShader.cpp

#include "loadShaders.h"

using namespace std;

GLuint LoadShaders(const char* vertexFilePath, const char* fragmentFilePath) {
	// create shaders
	GLuint VertexShaderID = glCreateShader(GL_VERTEX_SHADER);
	GLuint FragmentShaderID = glCreateShader(GL_FRAGMENT_SHADER);

	// retrieving vertex shader code from aforementioned file
	string VertexShaderCode;
	ifstream VertexShaderStream(vertexFilePath, ios::in);
	if (VertexShaderStream.is_open()) {
		stringstream sstr;
		sstr << VertexShaderStream.rdbuf();
		VertexShaderCode = sstr.str();
		VertexShaderStream.close();
	}
	else {
		cout << "Wrong directory.\n";
		getchar();
		return 0;
	}

	// read the fragment shader code from the file
	string FragmentShaderCode;
	ifstream FragmentShaderStream(fragmentFilePath, ios::in);
	if (FragmentShaderStream.is_open()) {
		stringstream sstr;
		sstr << FragmentShaderStream.rdbuf();
		FragmentShaderCode = sstr.str();
		FragmentShaderStream.close();
	}

	GLint Result = GL_FALSE;
	int InfoLogLength;

	// compiling Vertex Shader
	cout << "Compiling Shader: " << vertexFilePath << "\n";
	const char* VertexSourcePointer = VertexShaderCode.c_str();
	glShaderSource(VertexShaderID, 1, &VertexSourcePointer, NULL);
	glCompileShader(VertexShaderID);

	// check vertex shader
	glGetShaderiv(VertexShaderID, GL_COMPILE_STATUS, &Result);
	glGetShaderiv(VertexShaderID, GL_INFO_LOG_LENGTH, &InfoLogLength);
	if (InfoLogLength > 0) {
		vector<char> VertexShaderErrorMessage(InfoLogLength + 1);
		glGetShaderInfoLog(VertexShaderID, InfoLogLength, NULL, &VertexShaderErrorMessage[0]);
		cout << VertexShaderErrorMessage[0] << "\n";
	}

	// compile fragment shader
	cout << "Compiling shader: " << fragmentFilePath << "\n";
	const char* FragmentSourcePointer = FragmentShaderCode.c_str();
	glShaderSource(FragmentShaderID, 1, &FragmentSourcePointer, NULL);
	glCompileShader(FragmentShaderID);

	// check compile result for fragment
	glGetShaderiv(FragmentShaderID, GL_COMPILE_STATUS, &Result);
	glGetShaderiv(FragmentShaderID, GL_INFO_LOG_LENGTH, &InfoLogLength);
	if (InfoLogLength > 0) {
		vector<char> FragmentShaderErrorMessage(InfoLogLength + 1);
		glGetShaderInfoLog(FragmentShaderID, InfoLogLength, NULL, &FragmentShaderErrorMessage[0]);
		cout << FragmentShaderErrorMessage[0] << "\n";
	}

	// link the program
	cout << "Linking program\n";
	GLuint ProgramID = glCreateProgram();
	glAttachShader(ProgramID, VertexShaderID);
	glAttachShader(ProgramID, FragmentShaderID);
	glLinkProgram(ProgramID);

	// check program
	glGetProgramiv(ProgramID, GL_LINK_STATUS, &Result);
	glGetProgramiv(ProgramID, GL_INFO_LOG_LENGTH, &InfoLogLength);
	if (InfoLogLength > 0) {
		vector<char> ProgramErrorMessage(InfoLogLength + 1);
		glGetProgramInfoLog(ProgramID, InfoLogLength, NULL, &ProgramErrorMessage[0]);
		cout << ProgramErrorMessage[0] << "\n";
	}

	glDetachShader(ProgramID, VertexShaderID);
	glDetachShader(ProgramID, FragmentShaderID);
	glDeleteShader(VertexShaderID);
	glDeleteShader(FragmentShaderID);

	return ProgramID;

}