#include "shader.h" #include #include using std::cout; using std::endl; const int PROGRAM = 0; GLuint loadShader(const char * filename, GLuint type); GLuint makeProgram(GLuint vShader, GLuint fShader); const char * readFile(const char * filename); bool checkErrors(GLuint id, GLuint type); void outputInfoLog(GLuint id, GLuint type); const char * getName(GLuint type); GLuint loadProgram(const char * vFilename, const char * fFilename) { GLuint vShader = loadShader(vFilename, GL_VERTEX_SHADER); GLuint fShader = loadShader(fFilename, GL_FRAGMENT_SHADER); GLuint program = makeProgram(vShader, fShader); return program; } GLuint loadShader(const char * filename, GLuint type) { const char * source; GLuint shader; // read the shader's source code from file source = readFile(filename); // if failed, return 0 as failure if (source == nullptr) return 0; // build and compile the shader shader = glCreateShader(type); glShaderSource(shader, 1, &source, nullptr); glCompileShader(shader); // if errors occur, uninitialize and return 0 as failure if (!checkErrors(shader, type)) { outputInfoLog(shader, type); glDeleteShader(shader); return 0; } delete[] source; return shader; } GLuint makeProgram(GLuint vShader, GLuint fShader) { // if any one of the vertex and fragment shader failed to be loaded, return 0 as failure if (vShader == 0 || fShader == 0) { cout << "Failed to create shader program!\n"; return 0; } // build and link the program GLuint program = glCreateProgram(); glAttachShader(program, vShader); glAttachShader(program, fShader); glLinkProgram(program); // if errors occur, uninitialize and return 0 as failure if (!checkErrors(program, PROGRAM)) { outputInfoLog(program, PROGRAM); glDeleteShader(vShader); glDeleteShader(fShader); glDeleteProgram(program); return 0; } // delete the shaders (they are no longer used) glDeleteShader(vShader); glDeleteShader(fShader); return program; } const char * readFile(const char * filename) { std::ifstream fin; char * source; int size = 0; // open the shader file fin.open(filename); if (!fin.is_open()) { cout << "Failed to open file " << filename << " (maybe not exist)!\n"; return nullptr; } // allocate enough memory to store the shader source fin.seekg(0, std::ios_base::end); source = new char[(int)fin.tellg() + 1]; // read the source code fin.seekg(0, std::ios_base::beg); while (!fin.eof()) { source[size] = fin.get(); size++; } source[size] = '\0'; return source; } bool checkErrors(GLuint id, GLuint type) { GLint status; if (type != PROGRAM) glGetShaderiv(id, GL_COMPILE_STATUS, &status); else glGetProgramiv(id, GL_LINK_STATUS, &status); return status == GL_TRUE; } void outputInfoLog(GLuint id, GLuint type) { char * infoLog; int size; if (type != PROGRAM) { glGetShaderiv(id, GL_INFO_LOG_LENGTH, &size); infoLog = new char[size + 1]; glGetShaderInfoLog(id, size + 1, nullptr, infoLog); cout << "Failed to compile shader, type: " << getName(type) << ", info log:\n" << infoLog << endl; delete[] infoLog; } else { glGetProgramiv(id, GL_INFO_LOG_LENGTH, &size); infoLog = new char[size + 1]; glGetProgramInfoLog(id, size + 1, nullptr, infoLog); cout << "Failed to link program, info log:\n" << infoLog << endl; delete[] infoLog; } } const char * getName(GLuint type) { switch (type) { case GL_VERTEX_SHADER: return "vertex"; case GL_FRAGMENT_SHADER: return "fragment"; default: return "unknown"; } }