I want to create isometric 2D game. I use modern LWJGL (vertex arrays, shaders etc.) I found true isometric projection with opengl and: I tried to rotate my projection matrix, but it created black triangles on corners of screen. I tried to rotate model matrix, but I found that I can't rotate x and y on ortho matrix (because it's 2D), it does
but I need to rotate x and y axis to get isometric matrix. Then I found this https://www.gamedev.net/blog/33/entry-2250273-isometric-map-in-sfml/ and it says that I only need place tiles on right spots. Who is right? And why in first link they rotate model matrix in old OpenGL even though it's 2D projection matrix and I can't rotate it on modern OpenGL? (Sorry for my bad English)
Edit: How I create model matrix (I use joml for them):
public Matrix4f getModel(GameItem item){
Vector3f rot = item.getRotation();
return new Matrix4f().translate(item.getPosition()).rotateX((float)Math.toRadians(-rot.x)).rotateY((float)Math.toRadians(-rot.y)).rotateZ((float)Math.toRadians(-rot.z)).scale(item.getScale());
}
How I create projection matrix:
public void updateProjectionMatrix(Window window){
projectionMatrix2D.identity().ortho2D(-window.getWidth(), window.getWidth(), -window.getHeight(), window.getHeight());
}
If I rotate matrix before ortho2D() everything is rotated correctly, however there are black triangles on two of screen's corners. If I rotate it after ortho2D() it does exactly like rotating model matrix (shrinks object). In render() I pass matrixes to vertex shader:
#version 330
layout (location=0) in vec3 position;
layout (location=1) in vec2 texCoord;
out vec2 outTexCoord;
uniform mat4 projectionMatrix;
uniform mat4 model;
void main()
{
gl_Position = projectionMatrix* model * vec4(position, 1.0);
outTexCoord = texCoord;
}
Edit 2: Creating view matrix works:
However it does exactly like rotating projection matrix before ortho2D() - it creates black (because that's my clear color) triangles on two of screen's corners:
and there:
How do I get rid of them?
Edit 3: I rewrote my code, but nothing has changed.
To run my code, you should add to project LWJGL library, LWJGL-GLFW, LWJGL-STB, LWJGL-OpenGl and JOML library (it's not downloaded with LWJGL). You will also need a random .png image.
Main class:
import Core.Engine;
public class Main {
public static void main(String[] args){
try{
//Is vsync enabled?
boolean vsync = true;
Engine engine = new Engine("GAME", vsync);
//Start program
engine.start();
}
catch(Exception ex){
ex.printStackTrace();
System.exit(-1);
}
}
}
Engine class:
package Core;
public class Engine implements Runnable{
public static final int TARGET_FPS = 60;
public static final int TARGET_UPS = 30;
private final Window window;
//Program thread
private final Thread gameLoopThread;
//Timer for gameLoop
private final Timer timer;
//Creates everything that is on screen
private final Logic logic;
public Engine(String windowTitle, boolean vSync) throws Exception {
gameLoopThread = new Thread(this, "GAME_LOOP_THREAD");
window = new Window(windowTitle, vSync);
logic = new Logic();
timer = new Timer();
}
public void start() {
String osName = System.getProperty("os.name");
if ( osName.contains("Mac") ) {
gameLoopThread.run();
} else {
gameLoopThread.start();
}
}
@Override
public void run() {
try {
init();
gameLoop();
} catch (Exception excp) {
excp.printStackTrace();
}
}
protected void init() throws Exception {
window.init();
timer.init();
logic.init(this.window);
}
protected void gameLoop() {
float elapsedTime;
float accumulator = 0f;
float interval = 1f / TARGET_UPS;
boolean running = true;
while (running && !window.shouldClose()) {
elapsedTime = timer.getElapsedTime();
accumulator += elapsedTime;
input();
while (accumulator >= interval) {
update(interval);
accumulator -= interval;
}
render();
if (!window.isVsync()) {
sync();
}
}
}
private void sync() {
float loopSlot = 1f / TARGET_FPS;
double endTime = timer.getLastLoopTime() + loopSlot;
while (Timer.getTime() < endTime) {
try {
Thread.sleep(1);
} catch (InterruptedException ie) {
}
}
}
protected void input() {
logic.input(window);
}
protected void update(float interval) {
logic.update(interval,window);
}
protected void render() {
logic.render(window);
window.update();
}
}
Timer class:
package Core;
public class Timer {
private double lastLoopTime;
public void init(){
lastLoopTime = getTime();
}
public static double getTime(){
return (double)((double)System.nanoTime() / (double)1000_000_000L);
}
public float getElapsedTime(){
double time = getTime();
float elapsedTime =(float) (time-lastLoopTime);
lastLoopTime = time;
return elapsedTime;
}
public double getLastLoopTime(){
return lastLoopTime;
}
}
Window class:
package Core;
import static org.lwjgl.glfw.GLFW.*;
import static org.lwjgl.opengl.GL11.*;
import static org.lwjgl.system.MemoryUtil.*;
import org.lwjgl.glfw.GLFW;
import org.lwjgl.glfw.GLFWErrorCallback;
import org.lwjgl.glfw.GLFWVidMode;
import org.lwjgl.opengl.GL;
public class Window {
private long window;
private int width, height;
private boolean vsync;
private String title;
public Window(String title,boolean vsync){
this.title = title;
this.vsync = vsync;
}
public long getInstance(){
return window;
}
public void init(){
GLFWErrorCallback.createPrint(System.err).set();
if(!glfwInit()){
// Throw an error.
throw new IllegalStateException("GLFW initialization failed!");
}
glfwWindowHint(GLFW_VISIBLE, GL_TRUE); // the window will stay hidden after creation
glfwWindowHint(GLFW_RESIZABLE, GL_FALSE); // the window will not be resizable
glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 3);
glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 2);
glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE);
glfwWindowHint(GLFW_OPENGL_FORWARD_COMPAT, GL_TRUE);
GLFWVidMode vidmode = glfwGetVideoMode(glfwGetPrimaryMonitor());
width = vidmode.width();
height = vidmode.height() -30;
System.out.println(width + " "+ height);
window = GLFW.glfwCreateWindow(width,height, title,NULL, NULL);
if(window == NULL){
throw new RuntimeException("ERROR with Window");
}
GLFW.glfwSetWindowPos(window, 0, 29);
glfwMakeContextCurrent(window);
if(vsync)
GLFW.glfwSwapInterval(1);
glfwShowWindow(window);
GL.createCapabilities();
glClearColor(0.0f, 0.0f, 0.0f, 0.0f);
glEnable(GL_BLEND);
glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
}
public boolean isKeyPressed(int keyCode) {
return GLFW.glfwGetKey(window, keyCode) == GLFW.GLFW_PRESS;
}
public void setClearColor(float r, float g, float b, float alpha) {
glClearColor(r, g, b, alpha);
}
public boolean shouldClose(){
return glfwWindowShouldClose(window);
}
public void update(){
glfwSwapBuffers(window);
glfwPollEvents();
}
public void setVsync(boolean aflag){
this.vsync = aflag;
}
public boolean isVsync(){
return vsync;
}
public int getWidth(){
return width;
}
public int getHeight(){
return height;
}
}
Logic class:
package Core;
import org.joml.Vector3f;
import org.lwjgl.glfw.GLFW;
public class Logic {
private Renderer render;
private GameItem item;
public void init(Window window) throws Exception {
//create object
float[] positions = new float[]{
-600, 600, 0f,//0
-600, -600, 0f,//1
600, -600, 0,//2
600, 600, 0f//3
};
float[] texCoords = new float[]{
0,0,//0
0,1,//1
1,1,//2
1,0 //3
};
int[] indices = new int[]{
0, 1, 3, 3, 1, 2,
};
render = new Renderer();
render.init(window);
Texture texture = new Texture("Textures/image.png");
Mesh mesh = new Mesh(positions,texCoords,indices,texture);
item = new GameItem(mesh);
item.setPosition(-100, 0, 0);
}
public void input(Window window) {
//move
Vector3f s = item.getPosition();
if(window.isKeyPressed(GLFW.GLFW_KEY_W)){
item.setPosition(s.x, s.y+5, s.z);
}
else if(window.isKeyPressed(GLFW.GLFW_KEY_S)){
item.setPosition(s.x, s.y-5, s.z);
}
else if(window.isKeyPressed(GLFW.GLFW_KEY_A)){
item.setPosition(s.x-5, s.y, s.z);
}
else if(window.isKeyPressed(GLFW.GLFW_KEY_D)){
item.setPosition(s.x+5, s.y, s.z);
}
}
public void update(float interval, Window window) {
}
public void render(Window window) {
render.render(window,item);
}
public void cleanup() {
render.cleanup();
}
}
Renderer class:
package Core;
import static org.lwjgl.opengl.GL11.*;
import org.joml.Matrix4f;
import org.joml.Vector3f;
public class Renderer {
private Matrix4f projectionMatrix2D;
private Matrix4f view;
private ShaderProgram shaderProgram;
public Renderer() {
projectionMatrix2D= new Matrix4f();
}
public void init(Window window) throws Exception {
shaderProgram = new ShaderProgram();
shaderProgram.createVertexShader(Utils.load("Shaders/vertex.vs"));
shaderProgram.createFragmentShader(Utils.load("Shaders/fragment.fs"));
shaderProgram.link();
shaderProgram.createUniform("projectionMatrix");
shaderProgram.createUniform("model");
shaderProgram.createUniform("texture_sampler");
shaderProgram.createUniform("view");
view = new Matrix4f().lookAt(new Vector3f(1,1,1), new Vector3f(0), new Vector3f(0,1,0));
updateProjectionMatrix(window);
}
public void clear() {
glClear(GL_COLOR_BUFFER_BIT);
}
public void render(Window window,GameItem item) {
clear();
updateProjectionMatrix(window);
shaderProgram.bind();
shaderProgram.setUniform("projectionMatrix", projectionMatrix2D);
shaderProgram.setUniform("view", view);
shaderProgram.setUniform("texture_sampler", 0);
Vector3f rot = item.getRotation();
Matrix4f model = new Matrix4f().translate(item.getPosition()).rotateX((float)Math.toRadians(-rot.x))
.rotateY((float)Math.toRadians(-rot.y))
.rotateZ((float)Math.toRadians(-rot.z))
.scale(item.getScale());
shaderProgram.setUniform("model", model);
item.getMesh().render();
shaderProgram.unbind();
}
public void updateProjectionMatrix(Window window){
projectionMatrix2D.identity().ortho2D(-window.getWidth(), window.getWidth(), -window.getHeight(), window.getHeight());
//it creates weird triangle on right screen corner
// projectionMatrix2D.identity().ortho2D(-1, 1, -1, 1);
}
public void cleanup() {
if (shaderProgram != null) {
shaderProgram.cleanup();
}
}
}
ShaderProgram class:
package Core;
import static org.lwjgl.opengl.GL20.*;
import java.nio.FloatBuffer;
import java.util.HashMap;
import java.util.Map;
import org.joml.Matrix4f;
import org.joml.Vector2f;
import org.joml.Vector3f;
import org.lwjgl.system.MemoryStack;
public class ShaderProgram {
private final int programId;
private int vertexShaderId;
private int fragmentShaderId;
private final Map<String, Integer> uniforms;
public ShaderProgram() throws Exception {
programId = glCreateProgram();
if (programId == 0) {
throw new Exception("Could not create Shader");
}
uniforms = new HashMap<>();
}
public void createUniform(String uniformName) throws Exception {
int uniformLocation = glGetUniformLocation(programId, uniformName);
if (uniformLocation < 0) {
throw new Exception("Could not find uniform:" + uniformName);
}
uniforms.put(uniformName, uniformLocation);
}
public void setUniform(String uniformName, Matrix4f value) {
try (MemoryStack stack = MemoryStack.stackPush()) {
FloatBuffer fb = stack.mallocFloat(16);
value.get(fb);
glUniformMatrix4fv(uniforms.get(uniformName), false, fb);
}
}
public void setUniform(String uniformName, int value) {
glUniform1i(uniforms.get(uniformName), value);
}
public void setUniform(String uniformName, float value) {
glUniform1f(uniforms.get(uniformName), value);
}
public void setUniform(String uniformName, Vector3f value) {
glUniform3f(uniforms.get(uniformName), value.x, value.y, value.z);
}
public void setUniform(String uniformName, org.joml.Vector4f value) {
glUniform4f(uniforms.get(uniformName), value.x, value.y, value.z, value.w);
}
public void setUniform(String uniformName, Vector2f vector2f) {
glUniform2f(uniforms.get(uniformName),vector2f.x,vector2f.y);
}
public void createVertexShader(String shaderCode) throws Exception {
vertexShaderId = createShader(shaderCode, GL_VERTEX_SHADER);
}
public void createFragmentShader(String shaderCode) throws Exception {
fragmentShaderId = createShader(shaderCode, GL_FRAGMENT_SHADER);
}
protected int createShader(String shaderCode, int shaderType) throws Exception {
int shaderId = glCreateShader(shaderType);
if (shaderId == 0) {
throw new Exception("Error creating shader. Type: " + shaderType);
}
glShaderSource(shaderId, shaderCode);
glCompileShader(shaderId);
if (glGetShaderi(shaderId, GL_COMPILE_STATUS) == 0) {
throw new Exception("Error compiling Shader code: " + glGetShaderInfoLog(shaderId, 1024));
}
glAttachShader(programId, shaderId);
return shaderId;
}
public void link() throws Exception {
glLinkProgram(programId);
if (glGetProgrami(programId, GL_LINK_STATUS) == 0) {
throw new Exception("Error linking Shader code: " + glGetProgramInfoLog(programId, 1024));
}
if (vertexShaderId != 0) {
glDetachShader(programId, vertexShaderId);
}
if (fragmentShaderId != 0) {
glDetachShader(programId, fragmentShaderId);
}
glValidateProgram(programId);
if (glGetProgrami(programId, GL_VALIDATE_STATUS) == 0) {
System.err.println("Warning validating Shader code: " + glGetProgramInfoLog(programId, 1024));
}
}
public void bind() {
glUseProgram(programId);
}
public void unbind() {
glUseProgram(0);
}
public void cleanup() {
unbind();
if (programId != 0) {
glDeleteProgram(programId);
}
}
}
GameItem class:
package Core;
import org.joml.Vector3f;
public class GameItem {
//Mesh for this gameItem
private Mesh mesh;
private final Vector3f position;
private float scale = 1;
private final Vector3f rotation;
public GameItem() {
position = new Vector3f(0, 0, 0);
scale = 1;
rotation = new Vector3f(0, 0, 0);
}
public GameItem(Mesh mesh) {
this();
this.mesh = mesh;
}
public GameItem(GameItem item){
this();
position.set(item.position);
scale =1;
rotation.set(item.rotation);
this.mesh = item.mesh;
}
public Vector3f getPosition() {
return position;
}
public void setPosition(float x, float y, float z) {
this.position.x = x;
this.position.y = y;
this.position.z = z;
}
public float getScale() {
return scale;
}
public void setScale(float scale) {
this.scale = scale;
}
public Vector3f getRotation() {
return rotation;
}
public void setRotation(float x, float y, float z) {
this.rotation.x = x;
this.rotation.y = y;
this.rotation.z = z;
}
public Mesh getMesh() {
return mesh;
}
public void setMesh(Mesh mesh){
this.mesh = mesh;
}
}
Utils class:
package Core;
import java.io.BufferedReader;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
public class Utils {
//Load strings
public static String load(String path){
StringBuilder builder = new StringBuilder();
try (InputStream in = new FileInputStream(path);
BufferedReader reader = new BufferedReader(new InputStreamReader(in))) {
String line;
while ((line = reader.readLine()) != null) {
builder.append(line).append("\n");
}
} catch (IOException ex) {
throw new RuntimeException("Failed to load a shader file!"
+ System.lineSeparator() + ex.getMessage());
}
String source = builder.toString();
return source;
}
}
Mesh class:
package Core;
import java.util.List;
import org.lwjgl.system.MemoryUtil;
import java.nio.FloatBuffer;
import java.nio.IntBuffer;
import java.util.ArrayList;
import static org.lwjgl.opengl.GL15.*;
import static org.lwjgl.opengl.GL20.*;
import static org.lwjgl.opengl.GL30.*;
public class Mesh{
private final int vaoId;
private final List<Integer> vboIdList;
private final int vertexCount;
private Texture texture;
public Mesh(float[] positions, float[] textCoords, int[] indices,Texture texture) {
this.texture = texture;
FloatBuffer posBuffer = null;
FloatBuffer textCoordsBuffer = null;
IntBuffer indicesBuffer = null;
try {
vertexCount = indices.length;
vboIdList = new ArrayList<>();
vaoId = glGenVertexArrays();
glBindVertexArray(vaoId);
// Position
int vboId = glGenBuffers();
vboIdList.add(vboId);
posBuffer = MemoryUtil.memAllocFloat(positions.length);
posBuffer.put(positions).flip();
glBindBuffer(GL_ARRAY_BUFFER, vboId);
glBufferData(GL_ARRAY_BUFFER, posBuffer, GL_STATIC_DRAW);
glVertexAttribPointer(0, 3, GL_FLOAT, false, 0, 0);
// Texture coordinates
vboId = glGenBuffers();
vboIdList.add(vboId);
textCoordsBuffer = MemoryUtil.memAllocFloat(textCoords.length);
textCoordsBuffer.put(textCoords).flip();
glBindBuffer(GL_ARRAY_BUFFER, vboId);
glBufferData(GL_ARRAY_BUFFER, textCoordsBuffer, GL_STATIC_DRAW);
glVertexAttribPointer(1, 2, GL_FLOAT, false, 0, 0);
// Index
vboId = glGenBuffers();
vboIdList.add(vboId);
indicesBuffer = MemoryUtil.memAllocInt(indices.length);
indicesBuffer.put(indices).flip();
glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, vboId);
glBufferData(GL_ELEMENT_ARRAY_BUFFER, indicesBuffer, GL_STATIC_DRAW);
glBindBuffer(GL_ARRAY_BUFFER, 0);
glBindVertexArray(0);
} finally {
if (posBuffer != null) {
MemoryUtil.memFree(posBuffer);
}
if (textCoordsBuffer != null) {
MemoryUtil.memFree(textCoordsBuffer);
}
if (indicesBuffer != null) {
MemoryUtil.memFree(indicesBuffer);
}
}
}
public Texture getTexture() {
return texture;
}
public void setTexture(Texture texture) {
this.texture = texture;
}
public int getVaoId() {
return vaoId;
}
public int getVertexCount() {
return vertexCount;
}
public void cleanUp() {
glDisableVertexAttribArray(0);
glDisableVertexAttribArray(1);
glBindBuffer(GL_ARRAY_BUFFER, 0);
for (int vboId : vboIdList) {
glDeleteBuffers(vboId);
}
texture.cleanup();
glBindVertexArray(0);
glDeleteVertexArrays(vaoId);
}
public void render(){
glBindVertexArray(getVaoId());
glEnableVertexAttribArray(0);
glEnableVertexAttribArray(1);
glDrawElements(GL_TRIANGLES, getVertexCount(), GL_UNSIGNED_INT, 0);
glDisableVertexAttribArray(0);
glDisableVertexAttribArray(1);
glBindVertexArray(0);
}
}
Texture class:
package Core;
import java.nio.ByteBuffer;
import java.nio.IntBuffer;
import org.lwjgl.system.MemoryStack;
import static org.lwjgl.opengl.GL11.*;
import static org.lwjgl.opengl.GL30.glGenerateMipmap;
import static org.lwjgl.stb.STBImage.*;
public class Texture {
private final int id;
public Texture(String fileName) throws Exception {
this(loadTexture(fileName));
}
public Texture(int id) {
this.id = id;
}
public void bind() {
glBindTexture(GL_TEXTURE_2D, id);
}
public int getId() {
return id;
}
private static int loadTexture(String fileName) throws Exception {
int width;
int height;
ByteBuffer buf;
try (MemoryStack stack = MemoryStack.stackPush()) {
IntBuffer w = stack.mallocInt(1);
IntBuffer h = stack.mallocInt(1);
IntBuffer channels = stack.mallocInt(1);
buf = stbi_load(fileName, w, h, channels, 4);
if (buf == null) {
throw new Exception("Image file " + fileName + " not loaded: " + stbi_failure_reason());
}
width = w.get();
height = h.get();
}
int textureId = glGenTextures();
glBindTexture(GL_TEXTURE_2D, textureId);
glPixelStorei(GL_UNPACK_ALIGNMENT, 1);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, width, height, 0,
GL_RGBA, GL_UNSIGNED_BYTE, buf);
glGenerateMipmap(GL_TEXTURE_2D);
stbi_image_free(buf);
return textureId;
}
public void cleanup() {
glDeleteTextures(id);
}
}
Vertex shader:
#version 330
layout (location=0) in vec3 position;
layout (location=1) in vec2 texCoord;
out vec2 outTexCoord;
uniform mat4 projectionMatrix;
uniform mat4 model;
uniform mat4 view;
void main()
{
gl_Position = projectionMatrix * view * model * vec4(position, 1.0); // if view is after vec4 it creates actually object, but it creates black triangles as well. Without view matrix it is just a normal square
outTexCoord = texCoord;
}
Fragment shader:
#version 330
in vec2 outTexCoord;
out vec4 fragColor;
uniform sampler2D texture_sampler;
void main()
{
fragColor = texture(texture_sampler,outTexCoord);
}
