Organized client code a bit more, and added GUI crosshair thing.

client/src/main/java/nl/andrewl/aos2_client/render/GameRenderer.java

@@ -1,13 +1,19 @@
 package nl.andrewl.aos2_client.render;
 
 import nl.andrewl.aos2_client.Camera;
+import nl.andrewl.aos2_client.render.chunk.ChunkRenderer;
+import nl.andrewl.aos2_client.render.gui.GUIRenderer;
+import nl.andrewl.aos2_client.render.gui.GUITexture;
 import nl.andrewl.aos_core.model.World;
 import org.joml.Matrix4f;
 import org.lwjgl.glfw.*;
 import org.lwjgl.opengl.GL;
+import org.lwjgl.opengl.GLUtil;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
+import java.io.IOException;
+
 import static org.lwjgl.glfw.GLFW.*;
 import static org.lwjgl.opengl.GL46.*;
 
@@ -23,6 +29,7 @@ public class GameRenderer {
 	private static final float Z_FAR = 500f;
 
 	private final ChunkRenderer chunkRenderer;
+	private final GUIRenderer guiRenderer;
 	private final Camera camera;
 	private final World world;
 
@@ -38,6 +45,7 @@ public class GameRenderer {
 	public GameRenderer(World world) {
 		this.world = world;
 		this.chunkRenderer = new ChunkRenderer();
+		this.guiRenderer = new GUIRenderer();
 		this.camera = new Camera();
 		this.perspectiveTransform = new Matrix4f();
 
@@ -52,6 +60,7 @@ public class GameRenderer {
 
 		primaryMonitorSettings = glfwGetVideoMode(glfwGetPrimaryMonitor());
 		if (primaryMonitorSettings == null) throw new IllegalStateException("Could not get information about the primary monitory.");
+		log.debug("Primary monitor settings: Width: {}, Height: {}", primaryMonitorSettings.width(), primaryMonitorSettings.height());
 		windowHandle = glfwCreateWindow(screenWidth, screenHeight, "Ace of Shades 2", 0, 0);
 		if (windowHandle == 0) throw new RuntimeException("Failed to create GLFW window.");
 		fullscreen = false;
@@ -80,6 +89,16 @@ public class GameRenderer {
 		log.debug("Initialized OpenGL context.");
 
 		chunkRenderer.setupShaderProgram();
+		guiRenderer.setup();
+		// TODO: More organized way to load textures for GUI.
+		try {
+			var crosshairTexture = new GUITexture("gui/crosshair.png");
+			float size = 32;
+			crosshairTexture.getScale().set(size / screenWidth, size / screenHeight);
+			guiRenderer.addTexture(crosshairTexture);
+		} catch (IOException e) {
+			throw new RuntimeException(e);
+		}
 		updatePerspective();
 	}
 
@@ -143,12 +162,14 @@ public class GameRenderer {
 		glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
 
 		chunkRenderer.draw(camera, world);
+		guiRenderer.draw();
 
 		glfwSwapBuffers(windowHandle);
 		glfwPollEvents();
 	}
 
 	public void freeWindow() {
+		guiRenderer.free();
 		chunkRenderer.free();
 		GL.destroy();
 		Callbacks.glfwFreeCallbacks(windowHandle);

client/src/main/java/nl/andrewl/aos2_client/render/ShaderProgram.java

@@ -28,10 +28,18 @@ public class ShaderProgram {
 		glUseProgram(id);
 	}
 
+	public void stopUsing() {
+		glUseProgram(0);
+	}
+
 	public int getUniform(String name) {
 		return glGetUniformLocation(id, name);
 	}
 
+	public void bindAttribute(int attribute, String variableName) {
+		glBindAttribLocation(id, attribute, variableName);
+	}
+
 	public void free() {
 		glDeleteProgram(id);
 	}

client/src/main/java/nl/andrewl/aos2_client/render/chunk/BlockVertexData.java

@@ -1,4 +1,4 @@
-package nl.andrewl.aos2_client.render;
+package nl.andrewl.aos2_client.render.chunk;
 
 import org.joml.Vector3f;
 

client/src/main/java/nl/andrewl/aos2_client/render/chunk/ChunkMesh.java

@@ -1,4 +1,4 @@
-package nl.andrewl.aos2_client.render;
+package nl.andrewl.aos2_client.render.chunk;
 
 import nl.andrewl.aos_core.model.Chunk;
 import nl.andrewl.aos_core.model.World;
@@ -89,8 +89,15 @@ public class ChunkMesh {
 	 */
 	public void draw() {
 		glBindVertexArray(vaoId);
+		glEnableVertexAttribArray(0);
+		glEnableVertexAttribArray(1);
+		glEnableVertexAttribArray(2);
 		glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, eboId);
 		glDrawElements(GL_TRIANGLES, indexCount, GL_UNSIGNED_INT, 0);
+		glDisableVertexAttribArray(0);
+		glDisableVertexAttribArray(1);
+		glDisableVertexAttribArray(2);
+		glBindVertexArray(0);
 	}
 
 	public void free() {

client/src/main/java/nl/andrewl/aos2_client/render/chunk/ChunkMeshData.java

@@ -1,4 +1,4 @@
-package nl.andrewl.aos2_client.render;
+package nl.andrewl.aos2_client.render.chunk;
 
 import java.nio.FloatBuffer;
 import java.nio.IntBuffer;

client/src/main/java/nl/andrewl/aos2_client/render/chunk/ChunkMeshGenerator.java

@@ -1,4 +1,4 @@
-package nl.andrewl.aos2_client.render;
+package nl.andrewl.aos2_client.render.chunk;
 
 import nl.andrewl.aos_core.model.Chunk;
 import nl.andrewl.aos_core.model.World;

client/src/main/java/nl/andrewl/aos2_client/render/chunk/ChunkRenderer.java

@@ -1,6 +1,7 @@
-package nl.andrewl.aos2_client.render;
+package nl.andrewl.aos2_client.render.chunk;
 
 import nl.andrewl.aos2_client.Camera;
+import nl.andrewl.aos2_client.render.ShaderProgram;
 import nl.andrewl.aos_core.model.Chunk;
 import nl.andrewl.aos_core.model.World;
 import org.joml.Matrix4f;

client/src/main/java/nl/andrewl/aos2_client/render/gui/GUIRenderer.java

@@ -0,0 +1,86 @@
+package nl.andrewl.aos2_client.render.gui;
+
+import nl.andrewl.aos2_client.render.ShaderProgram;
+import org.joml.Matrix4f;
+import org.lwjgl.BufferUtils;
+
+import java.nio.FloatBuffer;
+import java.util.ArrayList;
+import java.util.List;
+
+import static org.lwjgl.opengl.GL46.*;
+
+/**
+ * Manages rendering of 2D GUI components like cross-hairs, inventory stuff, etc.
+ */
+public class GUIRenderer {
+	private int vaoId;
+	private int vboId;
+	private int vertexCount;
+	private ShaderProgram shaderProgram;
+	private int transformUniformLocation;
+
+
+	private final List<GUITexture> guiTextures = new ArrayList<>();
+
+	public void addTexture(GUITexture texture) {
+		guiTextures.add(texture);
+	}
+
+	public void setup() {
+		vaoId = glGenVertexArrays();
+		vboId = glGenBuffers();
+		FloatBuffer buffer = BufferUtils.createFloatBuffer(8);
+		buffer.put(new float[]{
+				-1, 1,
+				-1, -1,
+				1, 1,
+				1, -1
+		});
+		buffer.flip();
+		vertexCount = buffer.limit();
+		glBindBuffer(GL_ARRAY_BUFFER, vboId);
+		glBufferData(GL_ARRAY_BUFFER, buffer, GL_STATIC_DRAW);
+
+		glBindVertexArray(vaoId);
+		glEnableVertexAttribArray(0);
+		glVertexAttribPointer(0, 2, GL_FLOAT, false, 2 * Float.BYTES, 0);
+		shaderProgram = new ShaderProgram.Builder()
+				.withShader("shader/gui/vertex.glsl", GL_VERTEX_SHADER)
+				.withShader("shader/gui/fragment.glsl", GL_FRAGMENT_SHADER)
+				.build();
+		transformUniformLocation = shaderProgram.getUniform("transform");
+		shaderProgram.bindAttribute(0, "position");
+	}
+
+	public void draw() {
+		shaderProgram.use();
+		glBindVertexArray(vaoId);
+		glEnableVertexAttribArray(0);
+		glEnable(GL_BLEND);
+		glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
+		glDisable(GL_DEPTH_TEST);
+		for (var texture : guiTextures) {
+			glActiveTexture(GL_TEXTURE0);
+			Matrix4f transform = new Matrix4f()
+					.translate(texture.getPosition().x, texture.getPosition().y, 0)
+					.scale(texture.getScale().x, texture.getScale().y, 1);
+			float[] transformData = new float[16];
+			transform.get(transformData);
+			glUniformMatrix4fv(transformUniformLocation, false, transformData);
+			glBindTexture(GL_TEXTURE_2D, texture.getTextureId());
+			glDrawArrays(GL_TRIANGLE_STRIP, 0, vertexCount);
+		}
+		glDisable(GL_BLEND);
+		glEnable(GL_DEPTH_TEST);
+		glDisableVertexAttribArray(0);
+		glBindVertexArray(0);
+	}
+
+	public void free() {
+		for (var tex : guiTextures) tex.free();
+		glDeleteBuffers(vboId);
+		glDeleteVertexArrays(vaoId);
+		shaderProgram.free();
+	}
+}

client/src/main/java/nl/andrewl/aos2_client/render/gui/GUITexture.java

@@ -0,0 +1,52 @@
+package nl.andrewl.aos2_client.render.gui;
+
+import nl.andrewl.aos_core.ImageUtils;
+import org.joml.Vector2f;
+import org.joml.Vector3f;
+
+import javax.imageio.ImageIO;
+import java.awt.image.BufferedImage;
+import java.io.IOException;
+
+import static org.lwjgl.opengl.GL46.*;
+
+public class GUITexture {
+	private final int textureId;
+	private final int width;
+	private final int height;
+	private final Vector2f position = new Vector2f(0, 0);
+	private final Vector2f scale = new Vector2f(1, 1);
+
+	public GUITexture(String location) throws IOException {
+		try (var in = GUITexture.class.getClassLoader().getResourceAsStream(location)) {
+			if (in == null) throw new IOException("Couldn't load texture image from " + location);
+			BufferedImage img = ImageIO.read(in);
+			width = img.getWidth();
+			height = img.getHeight();
+
+			textureId = glGenTextures();
+			glBindTexture(GL_TEXTURE_2D, textureId);
+			glPixelStorei(GL_UNPACK_ALIGNMENT, textureId);
+			glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
+			glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
+			var buf = ImageUtils.decodePng(img);
+			glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, width, height, 0, GL_RGBA, GL_UNSIGNED_BYTE, buf);
+		}
+	}
+
+	public int getTextureId() {
+		return textureId;
+	}
+
+	public Vector2f getPosition() {
+		return position;
+	}
+
+	public Vector2f getScale() {
+		return scale;
+	}
+
+	public void free() {
+		glDeleteTextures(textureId);
+	}
+}

client/src/main/java/nl/andrewl/aos2_client/render/gui/font/Character.java

@@ -1,4 +1,4 @@
-package nl.andrewl.aos2_client.render.font;
+package nl.andrewl.aos2_client.render.gui.font;
 
 /**
  * Simple data structure class holding information about a certain glyph in the

client/src/main/java/nl/andrewl/aos2_client/render/gui/font/FontRenderer.java

@@ -1,4 +1,4 @@
-package nl.andrewl.aos2_client.render.font;
+package nl.andrewl.aos2_client.render.gui.font;
 
 import nl.andrewl.aos2_client.render.ShaderProgram;
 

client/src/main/java/nl/andrewl/aos2_client/render/gui/font/FontType.java

@@ -1,4 +1,4 @@
-package nl.andrewl.aos2_client.render.font;
+package nl.andrewl.aos2_client.render.gui.font;
 
 import java.io.File;
 

client/src/main/java/nl/andrewl/aos2_client/render/gui/font/GUIText.java

@@ -1,10 +1,7 @@
-package nl.andrewl.aos2_client.render.font;
+package nl.andrewl.aos2_client.render.gui.font;
 
 import org.joml.Vector2f;
 import org.joml.Vector3f;
-import org.lwjgl.BufferUtils;
-
-import java.nio.FloatBuffer;
 
 import static org.lwjgl.opengl.GL46.*;
 

client/src/main/java/nl/andrewl/aos2_client/render/gui/font/Line.java

@@ -1,4 +1,4 @@
-package nl.andrewl.aos2_client.render.font;
+package nl.andrewl.aos2_client.render.gui.font;
 
 import java.util.ArrayList;
 import java.util.List;

client/src/main/java/nl/andrewl/aos2_client/render/gui/font/MetaFile.java

@@ -1,4 +1,4 @@
-package nl.andrewl.aos2_client.render.font;
+package nl.andrewl.aos2_client.render.gui.font;
 
 import java.io.BufferedReader;
 import java.io.File;

client/src/main/java/nl/andrewl/aos2_client/render/gui/font/TextMesh.java

@@ -1,4 +1,4 @@
-package nl.andrewl.aos2_client.render;
+package nl.andrewl.aos2_client.render.gui.font;
 
 import org.joml.Vector2f;
 import org.lwjgl.BufferUtils;

client/src/main/java/nl/andrewl/aos2_client/render/gui/font/TextMeshCreator.java

@@ -1,4 +1,4 @@
-package nl.andrewl.aos2_client.render.font;
+package nl.andrewl.aos2_client.render.gui.font;
 
 import java.io.File;
 import java.util.ArrayList;

client/src/main/java/nl/andrewl/aos2_client/render/gui/font/TextMeshData.java

@@ -1,4 +1,4 @@
-package nl.andrewl.aos2_client.render.font;
+package nl.andrewl.aos2_client.render.gui.font;
 
 /**
  * Stores the vertex data for all the quads on which a text will be rendered.

client/src/main/java/nl/andrewl/aos2_client/render/gui/font/Word.java

@@ -1,4 +1,4 @@
-package nl.andrewl.aos2_client.render.font;
+package nl.andrewl.aos2_client.render.gui.font;
 
 import java.util.ArrayList;
 import java.util.List;

client/src/main/resources/shader/gui/fragment.glsl

@@ -0,0 +1,10 @@
+#version 460 core
+
+in vec2 texturePosition;
+out vec4 fragmentColor;
+
+uniform sampler2D guiTexture;
+
+void main() {
+    fragmentColor = texture(guiTexture, texturePosition);
+}

client/src/main/resources/shader/gui/vertex.glsl

@@ -0,0 +1,14 @@
+#version 460 core
+
+in vec2 position;
+out vec2 texturePosition;
+
+uniform mat4 transform;
+
+void main() {
+    gl_Position = transform * vec4(position, 0.0, 1.0);
+    texturePosition = vec2(
+        (position.x + 1.0) / 2.0,
+        1 - (position.y + 1.0) / 2.0
+    );
+}

core/src/main/java/nl/andrewl/aos_core/ImageUtils.java

@@ -0,0 +1,28 @@
+package nl.andrewl.aos_core;
+
+import java.awt.image.BufferedImage;
+import java.io.IOException;
+import java.nio.ByteBuffer;
+
+public class ImageUtils {
+	public static ByteBuffer decodePng(BufferedImage image) {
+		int width = image.getWidth();
+		int height = image.getHeight();
+
+		// Load texture contents into a byte buffer
+		ByteBuffer buf = ByteBuffer.allocateDirect(4 * width * height );
+
+		// decode image
+		// ARGB format to -> RGBA
+		for( int h = 0; h < height; h++ )
+			for( int w = 0; w < width; w++ ) {
+				int argb = image.getRGB( w, h );
+				buf.put( (byte) ( 0xFF & ( argb >> 16 ) ) );
+				buf.put( (byte) ( 0xFF & ( argb >> 8 ) ) );
+				buf.put( (byte) ( 0xFF & ( argb ) ) );
+				buf.put( (byte) ( 0xFF & ( argb >> 24 ) ) );
+			}
+		buf.flip();
+		return buf;
+	}
+}