OpenGL Java, LWJGL

/* this class should be extended to provide an event-driven, graphical application The extending class should have its own constructor where things can be set up before the window is prepared, with a call to super( window title, width in pixels, height in pixels, nanoseconds in a step ) Override these methods: init: do things to be done once at the begining after the window is ready to go display: draw the game world processInputs: scan InputInfo queue and process all waiting input events with appropriate changes to game objects update: advance the simulation one full time step */ // LWJGL release = 3.0.0 build 90 // (earlier LWJGL3 download failed---Sys class seems to have disappeared, // but the code wasn't using it, anyway; a few other little changes) import org.lwjgl.glfw.*; import org.lwjgl.opengl.*; import java.nio.ByteBuffer; import static org.lwjgl.glfw.Callbacks.*; import static org.lwjgl.glfw.GLFW.*; import static org.lwjgl.opengl.GL11.*; import static org.lwjgl.opengl.GL21.*; import static org.lwjgl.opengl.GL33.*; import static org.lwjgl.system.MemoryUtil.*; public class Basic{ // We need to strongly reference callback instances. private GLFWKeyCallback keyCallback; private GLFWCursorPosCallback cursorPosCallback; private GLFWMouseButtonCallback mouseButtonCallback; // The window handle private long window; private String title; private int width, height; // in pixel units private int stepNumber; private long timeStep; // amount of time in a step in nanoseconds private long startTime; private int mouseX, mouseY; // current mouse cursor position // create window given title, size in pixels, step time in nanoseconds public Basic( String windowLabel, int pw, int ph, long timeInNanos ) { title = windowLabel; width = pw; height = ph; stepNumber = 0; timeStep = timeInNanos; startTime = System.nanoTime(); } public void start() { try{ setup(); // get window ready to go loop(); // Release window and window callbacks glfwFreeCallbacks(window); glfwDestroyWindow(window); } finally { // Terminate GLFW glfwTerminate(); } }// start private void setup() { // Initialize GLFW. Most GLFW functions will not work before doing this. if( !glfwInit() ) throw new IllegalStateException("Unable to initialize GLFW"); // Note: these 4 hints seem necessary (at least on my Mac) to // get OpenGL version 3.3, but may cause problems in Windows //-------------------------------------------------- // Configure the window, choosing OpenGL version // and the core profile and forward compatibility glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 3); glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 3); glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE); glfwWindowHint(GLFW_OPENGL_FORWARD_COMPAT, GL_TRUE); //-------------------------------------------------- glfwWindowHint(GLFW_VISIBLE, 0 ); // the window will stay hidden after creation glfwWindowHint(GLFW_RESIZABLE, 0 ); // the window will not be resizable // Get the usable resolution of the primary monitor /* could use this to detect full screen size on any monitor // doesn't work! GLFWVidMode vidmode = glfwGetVideoMode(glfwGetPrimaryMonitor()); width = GLFWVidMode.width(vidmode); height = GLFWVidMode.height(vidmode); System.out.println("width = " + width + " height = " + height ); */ // Create the window window = glfwCreateWindow(width, height, title, NULL, NULL); if( window == NULL ) throw new RuntimeException("Failed to create the GLFW window"); // Set up a key callback. // It will be called every time a key is pressed, repeated or released. glfwSetKeyCallback(window, keyCallback = new GLFWKeyCallback() { public void invoke(long window, int key, int scancode, int action, int mods) { // whenever a key is pressed, the callback function // puts it in the InputInfo queue for processing later in an app InputInfo.add( new InputInfo( 'k', key, action, mods ) ); } } ); glfwSetCursorPosCallback( window, cursorPosCallback = new GLFWCursorPosCallback() { public void invoke(long window, double xpos, double ypos ) { // whenever cursor moves, add input info InputInfo.add( new InputInfo( 'm', (int) Math.round(xpos), (int) Math.round(ypos) ) ); } } ); glfwSetMouseButtonCallback( window, mouseButtonCallback = new GLFWMouseButtonCallback() { public void invoke(long window, int button, int action, int mods ) { // whenever mouse button is pressed, released, or repeated, make input info InputInfo.add( new InputInfo( 'b', button, action, mods ) ); } } ); glfwSetWindowPos( window, 0, 50 ); // Make the OpenGL context current glfwMakeContextCurrent(window); // Enable v-sync glfwSwapInterval(1); glfwSetInputMode(window, GLFW_CURSOR, GLFW_CURSOR_NORMAL ); // Make the window visible glfwShowWindow(window); } private final static int NUMDELAYSPERYIELD = 5; // hope not important private void loop() { // This line is critical for LWJGL's interoperation with GLFW's // OpenGL context, or any context that is managed externally. // LWJGL detects the context that is current in the current thread, // creates the ContextCapabilities instance and makes the OpenGL // bindings available for use. // GLContext.createFromCurrent(); GL.createCapabilities(); // show version information System.out.println("OpenGL vendor: " + glGetString( GL_RENDERER ) ); System.out.println("OpenGL version: " + glGetString( GL_VERSION ) ); System.out.println("GLSL version: " + glGetString( GL20.GL_SHADING_LANGUAGE_VERSION ) ); init(); // Run the rendering loop until the window wants to close long prevTime = System.nanoTime(); long overTime = 0L; int numDelays = 0; while( ! glfwWindowShouldClose(window) ) { stepNumber++; display(); processInputs(); update(); long currentTime = System.nanoTime(); // figure time spent on this step already in nanoseconds long elapsedTime = currentTime - prevTime; long sleepTime = timeStep - elapsedTime - overTime; if( sleepTime > 0 ) {// have some time to sleep try{ Thread.sleep( sleepTime/1000000L ); // sleep this many milliseconds } catch(InterruptedException ie) {} prevTime = System.nanoTime(); // will be the new before step time // figure how much too long it took with overhead from sleeping overTime = prevTime - currentTime - sleepTime; } else {// step took longer than timeStep overTime = 0L; prevTime = System.nanoTime(); numDelays++; if( numDelays >= NUMDELAYSPERYIELD ) {// give another thread a chance Thread.yield(); numDelays = 0; } } glfwSwapBuffers(window); // swap the color buffers // Poll for window events. The key callback above will only be // invoked during this call. glfwPollEvents(); } } // ---------------------- methods that can be called in app ------- public int getStepNumber() { return stepNumber; } // return time from start of application // in milliseconds public long getTime() { return (System.nanoTime() - startTime) / 1000000L; } public double getTimeStep() { return timeStep/1e9; //convert from nanoseconds to seconds } public void restartStepNumbering() { stepNumber = 0; } public int getMouseX() { return mouseX; } public int getMouseY() { return mouseY; } public int getPixelWidth() { return width; } public int getPixelHeight() { return height; } // ---------------------- methods that can and should be overridden ------- protected void init() { // Set the clear color once and for all glClearColor(1.0f, 0.0f, 0.0f, 0.0f); } protected void processInputs() { while( InputInfo.size() > 0 ) {// process next input info InputInfo info = InputInfo.get(); System.out.println( info ); } } protected void update() { } protected void display() { // clear the framebuffer glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT); System.out.println("Step " + getStepNumber() ); } public static void main(String[] args) { Basic t = new Basic( "Basic App (should be extended)", 800, 600, 33333333L ); t.start(); } }