--- a/Shark.cpp	Wed Nov 29 01:27:05 2023 +0100
+++ b/Shark.cpp	Fri Dec 01 20:25:49 2023 +0100
@@ -24,15 +24,25 @@
 }
 
 Shark::~Shark() {
+	// TODO: more SBRM
+	shaders.clear();
+	shaderProgram = nullptr;
+	XFree(vi);
+	// for (auto page : pdfTextures) glDeleteTextures(1, &page.texture);
+	glXMakeCurrent(dpy, None, NULL);
+	glXDestroyContext(dpy, glc);
+	XDestroyWindow(dpy, win);
+	XCloseDisplay(dpy);
+	// std::cerr << "~Shark()" << std::endl;
 }
 
 void Shark::run() {
-	Display* dpy = XOpenDisplay(NULL);
+	dpy = XOpenDisplay(NULL);
 
 	if (dpy == NULL) throw std::logic_error("Unable to connect to X server");
 
 	GLint att[] = {GLX_RGBA, GLX_DEPTH_SIZE, 24, GLX_DOUBLEBUFFER, None};
-	XVisualInfo* vi = glXChooseVisual(dpy, 0, att);
+	vi = glXChooseVisual(dpy, 0, att);
 	Window root = DefaultRootWindow(dpy);
 	Window parent = cfg.rootWindow ? cfg.rootWindow : root;
 
@@ -52,7 +62,7 @@
 		height = parentAttr.height;
 	}
 
-	Window win = XCreateWindow(
+	win = XCreateWindow(
 			dpy, parent, 0, 0, width, height, 0,
 			vi->depth, InputOutput, vi->visual,
 			CWColormap | CWEventMask, &swa);
@@ -62,7 +72,7 @@
 	setX11PID(dpy, win);
 	// XSetWindowBackground(dpy, win, 0) vs. glClearColor()
 
-	GLXContext glc = glXCreateContext(dpy, vi, NULL, GL_TRUE);
+	glc = glXCreateContext(dpy, vi, NULL, GL_TRUE);
 	glXMakeCurrent(dpy, win, glc);
 
 	clear();
@@ -209,14 +219,6 @@
 			}
 		}
 	}
-
-	XFree(vi);
-	// for (auto page : pdfTextures) glDeleteTextures(1, &page.texture);
-
-	glXMakeCurrent(dpy, None, NULL);
-	glXDestroyContext(dpy, glc);
-	XDestroyWindow(dpy, win);
-	XCloseDisplay(dpy);
 }
 
 void Shark::clear() {
@@ -229,7 +231,7 @@
 }
 
 void Shark::runShaders() {
-	glUseProgram(shaderProgram);
+	shaderProgram->use();
 	checkError(&std::cerr);
 
 	clear();
@@ -358,7 +360,7 @@
 	}
 }
 
-GLuint Shark::loadShaders() {
+std::shared_ptr<Program> Shark::loadShaders() {
 	try {
 		// Vertex Array Object (VAO)
 		GLuint vao;
@@ -379,36 +381,17 @@
 			"shaders/first.frag",
 		};
 
-		std::vector<GLuint> shaders;
-
-		GLuint program = glCreateProgram();
+		std::shared_ptr<Program> program = std::make_shared<Program>();
 
 		// glBindFragDataLocation(program, 0, "outColor");
 		// glBindAttribLocation(program, LOC.input, "vertices");
 
 		for (const std::string& fileName : fileNames) {
 			MappedFile file(fileName);
-			GLuint shader = glCreateShader(toShaderType(fileName));
-			auto fileData = file.getData();
-			GLint fileSize = file.getSize();
-			glShaderSource(shader, 1, &fileData, &fileSize);
-			glCompileShader(shader);
+			std::shared_ptr<Shader> shader = std::make_shared<Shader>(
+					toShaderType(fileName), file, fileName);
 
-			GLint compileStatus;
-			glGetShaderiv(shader, GL_COMPILE_STATUS, &compileStatus);
-			std::cerr << "GLSL shader compile status: "
-					<< compileStatus
-					<< (compileStatus == GL_TRUE ? " = OK" : " = ERROR")
-					<< std::endl;
-
-			if (compileStatus != GL_TRUE) {
-				char error[512];
-				glGetShaderInfoLog(shader, sizeof (error), NULL, error);
-				std::cerr << "GLSL shader error: " << error;
-				throw std::logic_error("GLSL: shader failed to compile");
-			}
-
-			glAttachShader(program, shader);
+			program->attachShader(*shader.get());
 			shaders.push_back(shader);
 			std::cerr << "GLSL loaded: " << fileName.c_str() << std::endl;
 		}
@@ -419,27 +402,18 @@
 		// the variable is still deleted and considered „inactive“.
 		// Functions glGetAttribLocation() and glGetUniformLocation() return -1.
 
-		glLinkProgram(program);
+		program->link();
 
-		ProgAttr.aVertexXYZ = glGetAttribLocation(program, "aVertexXYZ");
-		ProgAttr.aTextureXY = glGetAttribLocation(program, "aTextureXY");
-		ProgAttr.uModel = glGetUniformLocation(program, "uModel");
-		ProgAttr.uView = glGetUniformLocation(program, "uView");
-		ProgAttr.uProjection = glGetUniformLocation(program, "uProjection");
-		ProgAttr.uTexture = glGetUniformLocation(program, "uTexture");
-		ProgAttr.fColor = glGetFragDataLocation(program, "fColor");
-		glBindFragDataLocation(program, ProgAttr.fColor, "fColor");
+		ProgAttr.aVertexXYZ = program->getAttribLocation("aVertexXYZ");
+		ProgAttr.aTextureXY = program->getAttribLocation("aTextureXY");
+		ProgAttr.uModel = program->getUniformLocation("uModel");
+		ProgAttr.uView = program->getUniformLocation("uView");
+		ProgAttr.uProjection = program->getUniformLocation("uProjection");
+		ProgAttr.uTexture = program->getUniformLocation("uTexture");
+		ProgAttr.fColor = program->getFragDataLocation("fColor");
+		program->bindFragDataLocation("fColor", ProgAttr.fColor);
 		// listVariables(program);
-		GLint linkStatus;
-		glGetProgramiv(program, GL_LINK_STATUS, &linkStatus);
-		if (linkStatus != GL_TRUE) {
-			char error[512];
-			glGetProgramInfoLog(program, sizeof (error), NULL, error);
-			std::cerr << "GLSL program error: " << error;
-			throw std::logic_error("GLSL: program failed to link");
-		}
 		std::cerr << "GLSL shader count: " << shaders.size() << std::endl;
-
 		return program;
 	} catch (const std::exception& e) {
 		std::cerr << "Error while loading shaders: " << e.what() << std::endl;