Merge branch 'dev' into...

Merge branch 'dev' into 122-ge_s_not_closed-ge_s_multiple_connected_components-due-to-unresolved-triangulatedsurface-x-link

CityDoctorParent/Extensions/CityDoctorGUI/src/main/java/de/hft/stuttgart/citydoctor2/gui/gl/PickingFramebuffer.java

+package de.hft.stuttgart.citydoctor2.gui.gl;
+
+import com.jogamp.opengl.GL;
+import com.jogamp.opengl.GL3;
+import java.nio.ByteBuffer;
+import java.nio.ByteOrder;
+
+/** Off-screen framebuffer that stores picking ids as RGBA8; supports single-pixel readback. */
+public class PickingFramebuffer {
+
+    private int fbo;
+    private int colorTex;
+    private int depthRbo;
+    private int width;
+    private int height;
+    private boolean created;
+
+    public void resize(GL3 gl, int w, int h) {
+        if (w <= 0 || h <= 0 || (w == width && h == height && created)) {
+            return;
+        }
+        dispose(gl);
+        width = w;
+        height = h;
+
+        int[] tmp = new int[1];
+        gl.glGenFramebuffers(1, tmp, 0);
+        fbo = tmp[0];
+        gl.glBindFramebuffer(GL.GL_FRAMEBUFFER, fbo);
+
+        gl.glGenTextures(1, tmp, 0);
+        colorTex = tmp[0];
+        gl.glBindTexture(GL.GL_TEXTURE_2D, colorTex);
+        gl.glTexImage2D(GL.GL_TEXTURE_2D, 0, GL.GL_RGBA8, w, h, 0, GL.GL_RGBA, GL.GL_UNSIGNED_BYTE, null);
+        gl.glTexParameteri(GL.GL_TEXTURE_2D, GL.GL_TEXTURE_MIN_FILTER, GL.GL_NEAREST);
+        gl.glTexParameteri(GL.GL_TEXTURE_2D, GL.GL_TEXTURE_MAG_FILTER, GL.GL_NEAREST);
+        gl.glFramebufferTexture2D(GL.GL_FRAMEBUFFER, GL.GL_COLOR_ATTACHMENT0, GL.GL_TEXTURE_2D, colorTex, 0);
+
+        gl.glGenRenderbuffers(1, tmp, 0);
+        depthRbo = tmp[0];
+        gl.glBindRenderbuffer(GL.GL_RENDERBUFFER, depthRbo);
+        gl.glRenderbufferStorage(GL.GL_RENDERBUFFER, GL.GL_DEPTH_COMPONENT16, w, h);
+        gl.glFramebufferRenderbuffer(GL.GL_FRAMEBUFFER, GL.GL_DEPTH_ATTACHMENT, GL.GL_RENDERBUFFER, depthRbo);
+
+        gl.glBindFramebuffer(GL.GL_FRAMEBUFFER, 0);
+        created = true;
+    }
+
+    public void bind(GL3 gl) {
+        gl.glBindFramebuffer(GL.GL_FRAMEBUFFER, fbo);
+        gl.glViewport(0, 0, width, height);
+    }
+
+    /**
+     * Reads the picking id at canvas pixel (x, y) measured from the top-left. GL's origin is bottom-left,
+     * so the row is flipped.
+     */
+    public int readId(GL3 gl, int x, int y) {
+        if (!created || x < 0 || y < 0 || x >= width || y >= height) {
+            return 0;
+        }
+        ByteBuffer buf = ByteBuffer.allocateDirect(4).order(ByteOrder.nativeOrder());
+        gl.glBindFramebuffer(GL.GL_FRAMEBUFFER, fbo);
+        gl.glReadPixels(x, height - 1 - y, 1, 1, GL.GL_RGBA, GL.GL_UNSIGNED_BYTE, buf);
+        gl.glBindFramebuffer(GL.GL_FRAMEBUFFER, 0);
+        int r = buf.get(0) & 0xFF;
+        int g = buf.get(1) & 0xFF;
+        int b = buf.get(2) & 0xFF;
+        return PickingCodec.decode(r, g, b);
+    }
+
+    public void dispose(GL3 gl) {
+        if (created) {
+            gl.glDeleteFramebuffers(1, new int[]{fbo}, 0);
+            gl.glDeleteTextures(1, new int[]{colorTex}, 0);
+            gl.glDeleteRenderbuffers(1, new int[]{depthRbo}, 0);
+            created = false;
+        }
+    }
+}

CityDoctorParent/Extensions/CityDoctorGUI/src/main/java/de/hft/stuttgart/citydoctor2/gui/gl/SceneBuilder.java

+package de.hft.stuttgart.citydoctor2.gui.gl;
+
+import de.hft.stuttgart.citydoctor2.datastructure.BoundarySurfaceType;
+import de.hft.stuttgart.citydoctor2.datastructure.CityDoctorModel;
+import de.hft.stuttgart.citydoctor2.datastructure.CityObject;
+import de.hft.stuttgart.citydoctor2.datastructure.Geometry;
+import de.hft.stuttgart.citydoctor2.datastructure.Lod;
+import de.hft.stuttgart.citydoctor2.datastructure.Polygon;
+import de.hft.stuttgart.citydoctor2.math.Triangle3d;
+import de.hft.stuttgart.citydoctor2.math.Vector3d;
+import de.hft.stuttgart.citydoctor2.tesselation.TesselatedPolygon;
+import de.hft.stuttgart.citydoctor2.utils.visitors.CityObjectCollector;
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.List;
+import java.util.stream.Stream;
+import javafx.scene.paint.Color;
+
+/**
+ * Builds {@link SceneData} from model polygons: tesselate, bake shade colour, assign picking ids,
+ * accumulate vertices and per-triangle metadata, recentre by the bounding-box centre.
+ * Intended to run on a worker thread.
+ */
+public final class SceneBuilder {
+
+    private SceneBuilder() {}
+
+    public static SceneData fromPolygons(Collection<? extends Polygon> polygons, Color baseColor) {
+        return build(polygons, baseColor, Lod.LOD2.ordinal(), false);
+    }
+
+    /** General entry: caller supplies polygons already chosen, plus their lod/roof attributes. */
+    public static SceneData build(Collection<? extends Polygon> polygons, Color baseColor,
+                                  int lod, boolean roof) {
+        Vector3d center = findCenter(polygons);
+        MeshAccumulator acc = new MeshAccumulator(center);
+        PickRegistry registry = new PickRegistry();
+        List<TriangleMeta> metas = new ArrayList<>();
+        int triangleIndex = 0;
+
+        for (Polygon p : polygons) {
+            Color base = chooseBase(p, baseColor);
+            Color shaded = ShadeColor.shade(p.calculateNormalNormalized(), base);
+            float r = (float) shaded.getRed();
+            float g = (float) shaded.getGreen();
+            float b = (float) shaded.getBlue();
+            int id = registry.register(p);
+
+            TesselatedPolygon tp = p.tesselate();
+            for (Triangle3d t : tp.getTriangles()) {
+                acc.addTriangle(t, id, r, g, b);
+                metas.add(new TriangleMeta(triangleIndex++, p, lod, roof));
+            }
+        }
+
+        double[] centerArr = {center.getX(), center.getY(), center.getZ()};
+        return new SceneData(acc.positions(), acc.colors(), acc.ids(), metas, registry, centerArr);
+    }
+
+    /**
+     * Builds ALL features of the model into a single {@link SceneData} with one shared center,
+     * one {@link PickRegistry} and continuous triangle indices. Filtering by LOD/roof happens later
+     * via the index set, not at build time. Replicates the per-feature base colours of the legacy
+     * {@code TriangulatedGeometry.of(model, filters)}.
+     */
+    public static SceneData fromModel(CityDoctorModel model) {
+        Vector3d center = findCenterOfModel(model);
+        MeshAccumulator acc = new MeshAccumulator(center);
+        PickRegistry registry = new PickRegistry();
+        List<TriangleMeta> metas = new ArrayList<>();
+        int[] triangleIndex = {0};
+
+        appendFeatures(model.getBuildings(), Color.WHITE, acc, registry, metas, triangleIndex);
+        appendFeatures(model.getBridges(), Color.LIGHTSTEELBLUE, acc, registry, metas, triangleIndex);
+        appendFeatures(model.getTunnels(), Color.SLATEGRAY, acc, registry, metas, triangleIndex);
+        appendFeatures(model.getLand(), Color.TAN, acc, registry, metas, triangleIndex);
+        appendFeatures(model.getTransportation(), Color.DIMGRAY, acc, registry, metas, triangleIndex);
+        appendFeatures(model.getVegetation(), Color.LIGHTGREEN, acc, registry, metas, triangleIndex);
+        appendFeatures(model.getWater(), Color.LIGHTSKYBLUE, acc, registry, metas, triangleIndex);
+        appendFeatures(model.getCityFurniture(), Color.BLUEVIOLET, acc, registry, metas, triangleIndex);
+        appendFeatures(model.getOtherCityObjects(), Color.BLACK, acc, registry, metas, triangleIndex);
+
+        double[] centerArr = {center.getX(), center.getY(), center.getZ()};
+        return new SceneData(acc.positions(), acc.colors(), acc.ids(), metas, registry, centerArr);
+    }
+
+    private static void appendFeatures(Stream<? extends CityObject> cos, Color color,
+                                       MeshAccumulator acc, PickRegistry registry,
+                                       List<TriangleMeta> metas, int[] triangleIndex) {
+        CityObjectCollector collector = new CityObjectCollector();
+        cos.forEach(cityObject -> cityObject.accept(collector));
+        for (CityObject co : collector.getCityObjects()) {
+            for (Geometry geom : co.getGeometries()) {
+                int lod = geom.getLod() == null ? Lod.LOD2.ordinal() : geom.getLod().ordinal();
+                for (Polygon p : geom.getPolygons()) {
+                    if (p.isLink()) {
+                        continue;
+                    }
+                    boolean roof = p.getPartOfSurface() != null
+                            && p.getPartOfSurface().getType() == BoundarySurfaceType.ROOF;
+                    appendPolygon(p, color, lod, roof, acc, registry, metas, triangleIndex);
+                }
+            }
+        }
+    }
+
+    private static void appendPolygon(Polygon p, Color baseColor, int lod, boolean roof,
+                                      MeshAccumulator acc, PickRegistry registry,
+                                      List<TriangleMeta> metas, int[] triangleIndex) {
+        Color base = chooseBase(p, baseColor);
+        Color shaded = ShadeColor.shade(p.calculateNormalNormalized(), base);
+        float r = (float) shaded.getRed();
+        float g = (float) shaded.getGreen();
+        float b = (float) shaded.getBlue();
+        int id = registry.register(p);
+
+        TesselatedPolygon tp = p.tesselate();
+        for (Triangle3d t : tp.getTriangles()) {
+            acc.addTriangle(t, id, r, g, b);
+            metas.add(new TriangleMeta(triangleIndex[0]++, p, lod, roof));
+        }
+    }
+
+    private static Vector3d findCenterOfModel(CityDoctorModel model) {
+        double xMin = Double.MAX_VALUE, yMin = Double.MAX_VALUE, zMin = Double.MAX_VALUE;
+        double xMax = -Double.MAX_VALUE, yMax = -Double.MAX_VALUE, zMax = -Double.MAX_VALUE;
+        boolean any = false;
+        for (CityObject co : model.createFeatureStream().toList()) {
+            CityObjectCollector collector = new CityObjectCollector();
+            co.accept(collector);
+            for (CityObject inner : collector.getCityObjects()) {
+                for (Geometry geom : inner.getGeometries()) {
+                    for (Polygon p : geom.getPolygons()) {
+                        if (p.isLink()) {
+                            continue;
+                        }
+                        for (Vector3d v : p.getExteriorRing().getVertices()) {
+                            xMin = Math.min(xMin, v.getX()); xMax = Math.max(xMax, v.getX());
+                            yMin = Math.min(yMin, v.getY()); yMax = Math.max(yMax, v.getY());
+                            zMin = Math.min(zMin, v.getZ()); zMax = Math.max(zMax, v.getZ());
+                            any = true;
+                        }
+                    }
+                }
+            }
+        }
+        if (!any) {
+            return new Vector3d(0, 0, 0);
+        }
+        return new Vector3d((xMax - xMin) / 2 + xMin, (yMax - yMin) / 2 + yMin, (zMax - zMin) / 2 + zMin);
+    }
+
+    private static Color chooseBase(Polygon p, Color fallback) {
+        Color rc = p.getRenderColor();
+        if (rc != null && !rc.equals(Color.WHITE)) {
+            return rc;
+        }
+        return fallback;
+    }
+
+    private static Vector3d findCenter(Collection<? extends Polygon> polygons) {
+        double xMin = Double.MAX_VALUE, yMin = Double.MAX_VALUE, zMin = Double.MAX_VALUE;
+        double xMax = -Double.MAX_VALUE, yMax = -Double.MAX_VALUE, zMax = -Double.MAX_VALUE;
+        for (Polygon p : polygons) {
+            for (Vector3d v : p.getExteriorRing().getVertices()) {
+                xMin = Math.min(xMin, v.getX()); xMax = Math.max(xMax, v.getX());
+                yMin = Math.min(yMin, v.getY()); yMax = Math.max(yMax, v.getY());
+                zMin = Math.min(zMin, v.getZ()); zMax = Math.max(zMax, v.getZ());
+            }
+        }
+        if (xMin > xMax) {
+            return new Vector3d(0, 0, 0);
+        }
+        return new Vector3d((xMax - xMin) / 2 + xMin, (yMax - yMin) / 2 + yMin, (zMax - zMin) / 2 + zMin);
+    }
+}

CityDoctorParent/Extensions/CityDoctorGUI/src/main/java/de/hft/stuttgart/citydoctor2/gui/gl/SceneData.java

+package de.hft.stuttgart.citydoctor2.gui.gl;
+
+import java.util.List;
+
+/** Immutable CPU-side result of building the scene; uploaded to the GPU by the GL layer. */
+public class SceneData {
+
+    private final float[] positions;
+    private final float[] colors;
+    private final int[] ids;
+    private final List<TriangleMeta> triangleMetas;
+    private final PickRegistry pickRegistry;
+    private final double[] center;
+
+    public SceneData(float[] positions, float[] colors, int[] ids,
+                     List<TriangleMeta> triangleMetas, PickRegistry pickRegistry, double[] center) {
+        this.positions = positions;
+        this.colors = colors;
+        this.ids = ids;
+        this.triangleMetas = triangleMetas;
+        this.pickRegistry = pickRegistry;
+        this.center = center;
+    }
+
+    public float[] positions() { return positions; }
+    public float[] colors() { return colors; }
+    public int[] ids() { return ids; }
+    public List<TriangleMeta> triangleMetas() { return triangleMetas; }
+    public PickRegistry pickRegistry() { return pickRegistry; }
+    public double[] center() { return center; }
+    public int triangleCount() { return triangleMetas.size(); }
+}

CityDoctorParent/Extensions/CityDoctorGUI/src/main/java/de/hft/stuttgart/citydoctor2/gui/gl/ShadeColor.java

+package de.hft.stuttgart.citydoctor2.gui.gl;
+
+import de.hft.stuttgart.citydoctor2.math.UnitVector3d;
+import de.hft.stuttgart.citydoctor2.math.Vector3d;
+import javafx.scene.paint.Color;
+
+/**
+ * Computes the surface-differentiation shade used by the legacy renderer: brightness derived from the
+ * angle between the polygon normal and a fixed axis. Not physical lighting; only makes adjacent faces
+ * distinguishable. Ported from {@code TriangulatedGeometry.calculateMaterial}.
+ */
+public final class ShadeColor {
+
+    private static final UnitVector3d AXIS = new Vector3d(19, 0.8, 1.5).normalize();
+
+    private ShadeColor() {}
+
+    public static Color shade(Vector3d normal, Color base) {
+        double cos = normal.dot(AXIS);
+        // clamp to acos domain; raw dot can drift slightly outside [-1,1] for near-parallel normals
+        cos = Math.max(-1.0, Math.min(1.0, cos));
+        double brightness = Math.acos(cos) / Math.PI * 0.6 + 0.3; // -> [0.3, 0.9]
+        return base.deriveColor(0, 1.0, brightness, 1.0);
+    }
+}

CityDoctorParent/Extensions/CityDoctorGUI/src/main/java/de/hft/stuttgart/citydoctor2/gui/gl/ShaderProgram.java

+package de.hft.stuttgart.citydoctor2.gui.gl;
+
+import com.jogamp.opengl.GL3;
+import java.io.BufferedReader;
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.InputStreamReader;
+import java.io.UncheckedIOException;
+import java.nio.charset.StandardCharsets;
+import java.util.stream.Collectors;
+
+/** Compiles and links a GLSL program from classpath resources next to this class. */
+public class ShaderProgram {
+
+    private final int program;
+
+    public ShaderProgram(GL3 gl, String vertexResource, String fragmentResource) {
+        this(gl, vertexResource, null, fragmentResource);
+    }
+
+    /** Builds a program with an optional geometry stage ({@code geometryResource} may be null). */
+    public ShaderProgram(GL3 gl, String vertexResource, String geometryResource, String fragmentResource) {
+        int vs = compile(gl, GL3.GL_VERTEX_SHADER, read(vertexResource));
+        int gs = geometryResource != null ? compile(gl, GL3.GL_GEOMETRY_SHADER, read(geometryResource)) : 0;
+        int fs = compile(gl, GL3.GL_FRAGMENT_SHADER, read(fragmentResource));
+        program = gl.glCreateProgram();
+        gl.glAttachShader(program, vs);
+        if (gs != 0) {
+            gl.glAttachShader(program, gs);
+        }
+        gl.glAttachShader(program, fs);
+        gl.glLinkProgram(program);
+        checkLink(gl, program);
+        gl.glDeleteShader(vs);
+        if (gs != 0) {
+            gl.glDeleteShader(gs);
+        }
+        gl.glDeleteShader(fs);
+    }
+
+    public void use(GL3 gl) { gl.glUseProgram(program); }
+
+    public int uniform(GL3 gl, String name) { return gl.glGetUniformLocation(program, name); }
+
+    public void dispose(GL3 gl) { gl.glDeleteProgram(program); }
+
+    private static int compile(GL3 gl, int type, String src) {
+        int shader = gl.glCreateShader(type);
+        gl.glShaderSource(shader, 1, new String[]{src}, new int[]{src.length()}, 0);
+        gl.glCompileShader(shader);
+        int[] status = new int[1];
+        gl.glGetShaderiv(shader, GL3.GL_COMPILE_STATUS, status, 0);
+        if (status[0] == 0) {
+            throw new IllegalStateException("Shader compile failed: " + infoLog(gl, shader, true));
+        }
+        return shader;
+    }
+
+    private static void checkLink(GL3 gl, int program) {
+        int[] status = new int[1];
+        gl.glGetProgramiv(program, GL3.GL_LINK_STATUS, status, 0);
+        if (status[0] == 0) {
+            throw new IllegalStateException("Program link failed: " + infoLog(gl, program, false));
+        }
+    }
+
+    private static String infoLog(GL3 gl, int handle, boolean shader) {
+        int[] len = new int[1];
+        if (shader) {
+            gl.glGetShaderiv(handle, GL3.GL_INFO_LOG_LENGTH, len, 0);
+        } else {
+            gl.glGetProgramiv(handle, GL3.GL_INFO_LOG_LENGTH, len, 0);
+        }
+        byte[] log = new byte[Math.max(1, len[0])];
+        if (shader) {
+            gl.glGetShaderInfoLog(handle, log.length, new int[1], 0, log, 0);
+        } else {
+            gl.glGetProgramInfoLog(handle, log.length, new int[1], 0, log, 0);
+        }
+        return new String(log, StandardCharsets.UTF_8);
+    }
+
+    private static String read(String resource) {
+        try (InputStream in = ShaderProgram.class.getResourceAsStream(resource)) {
+            if (in == null) {
+                throw new IllegalStateException("Shader resource not found: " + resource);
+            }
+            try (BufferedReader r = new BufferedReader(new InputStreamReader(in, StandardCharsets.UTF_8))) {
+                return r.lines().collect(Collectors.joining("\n"));
+            }
+        } catch (IOException e) {
+            throw new UncheckedIOException(e);
+        }
+    }
+}

CityDoctorParent/Extensions/CityDoctorGUI/src/main/java/de/hft/stuttgart/citydoctor2/gui/gl/TriangleMeta.java

+package de.hft.stuttgart.citydoctor2.gui.gl;
+
+import de.hft.stuttgart.citydoctor2.datastructure.Polygon;
+
+/**
+ * Metadata for one triangle in the global buffer.
+ * @param triangleIndex index of this triangle (vertices are 3*triangleIndex .. +2)
+ * @param polygon       source polygon (for picking/highlight resolution); may be null in tests
+ * @param lod           LOD ordinal (Lod.ordinal()) of the owning geometry
+ * @param roof          true if the triangle belongs to a ROOF boundary surface
+ */
+public record TriangleMeta(int triangleIndex, Polygon polygon, int lod, boolean roof) {}

CityDoctorParent/Extensions/CityDoctorGUI/src/main/resources/de/hft/stuttgart/citydoctor2/gui/gl/pick.frag

+#version 330 core
+flat in int vId;
+out vec4 fragColor;
+void main() {
+    int id = vId;
+    float r = float( id        & 0xFF) / 255.0;
+    float g = float((id >> 8)  & 0xFF) / 255.0;
+    float b = float((id >> 16) & 0xFF) / 255.0;
+    fragColor = vec4(r, g, b, 1.0);
+}

CityDoctorParent/Extensions/CityDoctorGUI/src/main/resources/de/hft/stuttgart/citydoctor2/gui/gl/pick.vert

+#version 330 core
+layout(location = 0) in vec3 aPos;
+layout(location = 2) in int  aId;
+uniform mat4 uMVP;
+flat out int vId;
+void main() {
+    gl_Position = uMVP * vec4(aPos, 1.0);
+    vId = aId;
+}

CityDoctorParent/Extensions/CityDoctorGUI/src/main/resources/de/hft/stuttgart/citydoctor2/gui/gl/point.frag

+#version 330 core
+in vec2 vQuad;
+in vec3 vColor;
+out vec4 fragColor;
+
+void main() {
+    float r2 = dot(vQuad, vQuad);
+    if (r2 > 1.0) {
+        discard; // outside the sphere's silhouette
+    }
+    fragColor = vec4(vColor, 1.0);
+}

CityDoctorParent/Extensions/CityDoctorGUI/src/main/resources/de/hft/stuttgart/citydoctor2/gui/gl/point.geom

+#version 330 core
+layout(points) in;
+layout(triangle_strip, max_vertices = 4) out;
+
+in vec3 vColorG[];
+
+uniform vec2 uViewport;   // framebuffer size in pixels
+uniform float uPointSize; // sphere diameter in pixels
+
+out vec2 vQuad;           // billboard-local coords in [-1, 1]
+out vec3 vColor;
+
+void main() {
+    vec4 c = gl_in[0].gl_Position;
+    if (c.w <= 0.0) {
+        return; // behind the camera
+    }
+    // half-extent in clip space for a constant on-screen pixel size
+    vec2 h = vec2(uPointSize / uViewport.x, uPointSize / uViewport.y) * c.w;
+    vColor = vColorG[0];
+
+    gl_Position = c + vec4(-h.x, -h.y, 0.0, 0.0); vQuad = vec2(-1.0, -1.0); EmitVertex();
+    gl_Position = c + vec4( h.x, -h.y, 0.0, 0.0); vQuad = vec2( 1.0, -1.0); EmitVertex();
+    gl_Position = c + vec4(-h.x,  h.y, 0.0, 0.0); vQuad = vec2(-1.0,  1.0); EmitVertex();
+    gl_Position = c + vec4( h.x,  h.y, 0.0, 0.0); vQuad = vec2( 1.0,  1.0); EmitVertex();
+    EndPrimitive();
+}

CityDoctorParent/Extensions/CityDoctorGUI/src/main/resources/de/hft/stuttgart/citydoctor2/gui/gl/point.vert

+#version 330 core
+layout(location = 0) in vec3 aPos;
+layout(location = 1) in vec3 aColor;
+uniform mat4 uMVP;
+out vec3 vColorG;
+void main() {
+    gl_Position = uMVP * vec4(aPos, 1.0);
+    vColorG = aColor;
+}

CityDoctorParent/Extensions/CityDoctorGUI/src/main/resources/de/hft/stuttgart/citydoctor2/gui/gl/scene.frag

+#version 330 core
+in vec3 vColor;
+out vec4 fragColor;
+void main() {
+    fragColor = vec4(vColor, 1.0);
+}

CityDoctorParent/Extensions/CityDoctorGUI/src/main/resources/de/hft/stuttgart/citydoctor2/gui/gl/scene.vert

+#version 330 core
+layout(location = 0) in vec3 aPos;
+layout(location = 1) in vec3 aColor;
+uniform mat4 uMVP;
+out vec3 vColor;
+void main() {
+    gl_Position = uMVP * vec4(aPos, 1.0);
+    vColor = aColor;
+}

CityDoctorParent/Extensions/CityDoctorGUI/src/test/java/de/hft/stuttgart/citydoctor2/gui/gl/FloatListTest.java

+package de.hft.stuttgart.citydoctor2.gui.gl;
+
+import static org.junit.Assert.assertArrayEquals;
+import static org.junit.Assert.assertEquals;
+import org.junit.Test;
+
+public class FloatListTest {
+
+    @Test
+    public void growsBeyondInitialCapacityAndPreservesOrder() {
+        FloatList list = new FloatList(2);
+        for (int i = 0; i < 10; i++) {
+            list.add(i);
+        }
+        assertEquals(10, list.size());
+        float[] expected = {0,1,2,3,4,5,6,7,8,9};
+        assertArrayEquals(expected, list.toArray(), 0.0f);
+    }
+
+    @Test
+    public void addThreeAddsAllInOrder() {
+        FloatList list = new FloatList(1);
+        list.add(1f, 2f, 3f);
+        assertArrayEquals(new float[]{1,2,3}, list.toArray(), 0.0f);
+    }
+
+    @Test
+    public void clearResetsSizeAndArray() {
+        FloatList list = new FloatList(4);
+        list.add(1f, 2f, 3f);
+        list.add(4f);
+        list.clear();
+        assertEquals(0, list.size());
+        assertEquals(0, list.toArray().length);
+    }
+}

CityDoctorParent/Extensions/CityDoctorGUI/src/test/java/de/hft/stuttgart/citydoctor2/gui/gl/IndexSetBuilderTest.java

+package de.hft.stuttgart.citydoctor2.gui.gl;
+
+import static org.junit.Assert.assertArrayEquals;
+import java.util.Arrays;
+import java.util.List;
+import java.util.function.Predicate;
+import org.junit.Test;
+
+public class IndexSetBuilderTest {
+
+    @Test
+    public void includesOnlyTrianglesMatchingThePredicate() {
+        List<TriangleMeta> metas = Arrays.asList(
+                new TriangleMeta(0, null, 1, false),
+                new TriangleMeta(1, null, 2, false),
+                new TriangleMeta(2, null, 1, false));
+        Predicate<TriangleMeta> onlyGroup1 = m -> m.lod() == 1;
+        int[] indices = IndexSetBuilder.build(metas, onlyGroup1);
+        assertArrayEquals(new int[]{0, 1, 2, 6, 7, 8}, indices);
+    }
+
+    @Test
+    public void emptyWhenNothingMatches() {
+        List<TriangleMeta> metas = Arrays.asList(new TriangleMeta(0, null, 1, false));
+        int[] indices = IndexSetBuilder.build(metas, m -> false);
+        assertArrayEquals(new int[]{}, indices);
+    }
+}

CityDoctorParent/Extensions/CityDoctorGUI/src/test/java/de/hft/stuttgart/citydoctor2/gui/gl/Mat4Test.java

+package de.hft.stuttgart.citydoctor2.gui.gl;
+
+import static org.junit.Assert.assertArrayEquals;
+import static org.junit.Assert.assertEquals;
+import org.junit.Test;
+
+public class Mat4Test {
+
+    @Test
+    public void identityTimesVectorIsUnchanged() {
+        float[] v = Mat4.transform(Mat4.identity(), 2, 3, 4, 1);
+        assertArrayEquals(new float[]{2, 3, 4, 1}, v, 1e-6f);
+    }
+
+    @Test
+    public void translationMovesPoint() {
+        float[] m = Mat4.translation(5, -2, 1);
+        float[] v = Mat4.transform(m, 1, 1, 1, 1);
+        assertArrayEquals(new float[]{6, -1, 2, 1}, v, 1e-6f);
+    }
+
+    @Test
+    public void multiplyIsIdentityNeutral() {
+        float[] t = Mat4.translation(1, 2, 3);
+        assertArrayEquals(t, Mat4.multiply(Mat4.identity(), t), 1e-6f);
+        assertArrayEquals(t, Mat4.multiply(t, Mat4.identity()), 1e-6f);
+    }
+
+    @Test
+    public void rotationZ90MapsXAxisToYAxis() {
+        float[] m = Mat4.rotationZ((float) (Math.PI / 2));
+        float[] v = Mat4.transform(m, 1, 0, 0, 1);
+        assertEquals(0f, v[0], 1e-6f);
+        assertEquals(1f, v[1], 1e-6f);
+    }
+
+    @Test
+    public void perspectiveHasExpectedDiagonalStructure() {
+        float[] p = Mat4.perspective((float) Math.toRadians(60), 1.0f, 1f, 100f);
+        float f = (float) (1.0 / Math.tan(Math.toRadians(60) / 2));
+        assertEquals(f, p[0], 1e-5f);
+        assertEquals(f, p[5], 1e-5f);
+        assertEquals(-1f, p[11], 1e-6f);
+    }
+}

CityDoctorParent/Extensions/CityDoctorGUI/src/test/java/de/hft/stuttgart/citydoctor2/gui/gl/MeshAccumulatorTest.java

+package de.hft.stuttgart.citydoctor2.gui.gl;
+
+import static org.junit.Assert.assertArrayEquals;
+import static org.junit.Assert.assertEquals;
+import de.hft.stuttgart.citydoctor2.math.Triangle3d;
+import de.hft.stuttgart.citydoctor2.math.Vector3d;
+import org.junit.Test;
+
+public class MeshAccumulatorTest {
+
+    @Test
+    public void emitsNineFloatsAndThreeIdsPerTriangleRecentered() {
+        MeshAccumulator acc = new MeshAccumulator(new Vector3d(1, 0, 0));
+        Triangle3d t = new Triangle3d(
+                new Vector3d(1, 0, 0), new Vector3d(2, 0, 0), new Vector3d(1, 1, 0));
+        acc.addTriangle(t, 7, 0.5f, 0.25f, 0.125f);
+
+        assertEquals(3, acc.vertexCount());
+        assertArrayEquals(new float[]{0,0,0, 1,0,0, 0,1,0}, acc.positions(), 1e-6f);
+        assertArrayEquals(new float[]{0.5f,0.25f,0.125f, 0.5f,0.25f,0.125f, 0.5f,0.25f,0.125f},
+                acc.colors(), 1e-6f);
+        assertArrayEquals(new int[]{7, 7, 7}, acc.ids());
+    }
+
+    @Test
+    public void accumulatesMultipleTriangles() {
+        MeshAccumulator acc = new MeshAccumulator(new Vector3d(0, 0, 0));
+        Triangle3d t = new Triangle3d(
+                new Vector3d(0, 0, 0), new Vector3d(1, 0, 0), new Vector3d(0, 1, 0));
+        acc.addTriangle(t, 1, 1, 1, 1);
+        acc.addTriangle(t, 2, 0, 0, 0);
+        assertEquals(6, acc.vertexCount());
+        assertEquals(18, acc.positions().length);
+        assertArrayEquals(new int[]{1, 1, 1, 2, 2, 2}, acc.ids());
+    }
+}

CityDoctorParent/Extensions/CityDoctorGUI/src/test/java/de/hft/stuttgart/citydoctor2/gui/gl/OrbitCameraTest.java

+package de.hft.stuttgart.citydoctor2.gui.gl;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertTrue;
+import org.junit.Test;
+
+public class OrbitCameraTest {
+
+    private static float[] ndc(OrbitCamera cam, float x, float y, float z) {
+        float[] clip = Mat4.transform(cam.viewProjection(), x, y, z, 1);
+        return new float[]{clip[0] / clip[3], clip[1] / clip[3], clip[2] / clip[3]};
+    }
+
+    @Test
+    public void focusPointProjectsToScreenCentre() {
+        OrbitCamera cam = new OrbitCamera();
+        cam.setAspect(1.0f);
+        cam.zoomOutForBoundingBox(50.0);
+        float[] p = ndc(cam, 0, 0, 0);
+        assertEquals(0f, p[0], 1e-4f);
+        assertEquals(0f, p[1], 1e-4f);
+        assertTrue("origin in front of camera (within clip)", p[2] > -1f && p[2] < 1f);
+    }
+
+    @Test
+    public void zoomingKeepsFocusCentredButChangesDepth() {
+        OrbitCamera cam = new OrbitCamera();
+        cam.setAspect(1.0f);
+        cam.zoomOutForBoundingBox(50.0);
+        float depthBefore = ndc(cam, 0, 0, 0)[2];
+        cam.zoom(1.5);
+        float[] p = ndc(cam, 0, 0, 0);
+        assertEquals(0f, p[0], 1e-4f);
+        assertEquals(0f, p[1], 1e-4f);
+        assertTrue("depth changes when zooming", Math.abs(p[2] - depthBefore) > 1e-4f);
+    }
+
+    @Test
+    public void resetRestoresInitialDistanceAndAngles() {
+        OrbitCamera cam = new OrbitCamera();
+        cam.setAspect(1.0f);
+        cam.orbit(40, 25);
+        cam.pan(10, -5);
+        cam.zoom(2.0);
+        cam.reset();
+        float[] before = cam.viewProjection();
+        OrbitCamera fresh = new OrbitCamera();
+        fresh.setAspect(1.0f);
+        org.junit.Assert.assertArrayEquals(fresh.viewProjection(), before, 1e-5f);
+    }
+}

CityDoctorParent/Extensions/CityDoctorGUI/src/test/java/de/hft/stuttgart/citydoctor2/gui/gl/PickRegistryTest.java

+package de.hft.stuttgart.citydoctor2.gui.gl;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertNull;
+import org.junit.Test;
+
+public class PickRegistryTest {
+
+    @Test
+    public void assignsSequentialNonZeroIdsAndResolvesThem() {
+        PickRegistry reg = new PickRegistry();
+        Object a = "a";
+        Object b = "b";
+        int idA = reg.register(a);
+        int idB = reg.register(b);
+        assertEquals(1, idA);
+        assertEquals(2, idB);
+        assertEquals(a, reg.resolve(idA));
+        assertEquals(b, reg.resolve(idB));
+    }
+
+    @Test
+    public void resolvesBackgroundAndOutOfRangeToNull() {
+        PickRegistry reg = new PickRegistry();
+        reg.register("a");
+        assertNull(reg.resolve(0));
+        assertNull(reg.resolve(99));
+    }
+}

CityDoctorParent/Extensions/CityDoctorGUI/src/test/java/de/hft/stuttgart/citydoctor2/gui/gl/PickingCodecTest.java

+package de.hft.stuttgart.citydoctor2.gui.gl;
+
+import static org.junit.Assert.assertEquals;
+import org.junit.Test;
+
+public class PickingCodecTest {
+
+    @Test
+    public void roundTripsIdsThroughRgbBytes() {
+        int[] ids = {1, 255, 256, 65535, 65536, 16777215};
+        for (int id : ids) {
+            int r = PickingCodec.red(id);
+            int g = PickingCodec.green(id);
+            int b = PickingCodec.blue(id);
+            assertEquals(id, PickingCodec.decode(r, g, b));
+        }
+    }
+
+    @Test
+    public void blackDecodesToZeroBackground() {
+        assertEquals(0, PickingCodec.decode(0, 0, 0));
+    }
+}