pinhole camera ray map like vanilla (vertical fov 70, horizontal from aspect, pixel centres, no roll) instead of yaw/pitch corner rotation that squashed photos vertically by cos 35, shared buildRayMap in test tools, camera projection test scenes

src/main/java/eu/mhsl/minecraft/pixelpics/render/render/DefaultScreenRenderer.java

@@ -24,7 +24,6 @@ import eu.mhsl.minecraft.pixelpics.render.snapshot.SnapshotBuilder;
 import eu.mhsl.minecraft.pixelpics.render.snapshot.WorldSnapshot;
 import eu.mhsl.minecraft.pixelpics.render.tint.BiomeTintProvider;
 import eu.mhsl.minecraft.pixelpics.render.util.ColorUtil;
-import eu.mhsl.minecraft.pixelpics.render.util.MathUtil;
 import java.awt.image.BufferedImage;
 import java.awt.image.DataBufferInt;
 import java.util.ArrayList;
@@ -46,10 +45,11 @@ import org.bukkit.util.Vector;
  */
 public class DefaultScreenRenderer implements Renderer {
 
-    /** Horizontal half field-of-view; the vertical half is derived from the output aspect ratio. */
-    private static final double H_FOV_HALF_RAD = Math.toRadians(35);
-
-    private static final Vector BASE_VEC = new Vector(1, 0, 0);
+    /**
+     * Vertical field of view in degrees (vanilla's default FOV option, which is vertical too); the
+     * horizontal FOV follows from the image aspect ratio. Square photos: 70° both ways.
+     */
+    public static final double V_FOV_DEG = 70;
 
     private static final double MAX_DISTANCE = 256;
     private static final int REFLECTION_DEPTH = 4;
@@ -203,45 +203,36 @@ public class DefaultScreenRenderer implements Renderer {
         }
     }
 
-    private List<Vector> buildRayMap(Location eyeLocation, int width, int height) {
-        Vector lineDirection = eyeLocation.getDirection();
+    /**
+     * Pinhole camera like vanilla's projection: the rays go through a flat image plane one unit in front
+     * of the eye, {@code ray = forward + u·tan(fovX/2)·right + v·tan(fovY/2)·up} with u, v ∈ [-1, 1] at
+     * the pixel centres, row 0 = top. The vertical FOV is fixed ({@link #V_FOV_DEG}, like vanilla's
+     * default 70°), the horizontal one follows from the aspect ratio ({@code tan(fovX/2) = tan(fovY/2)·w/h}),
+     * so one pixel covers the same angle (at the centre) both ways and squares stay square. Right/up come
+     * from the yaw/pitch of {@code eye} (no roll), so looking straight up or down keeps the yaw orientation.
+     */
+    public static List<Vector> buildRayMap(Location eye, int width, int height) {
+        double yaw = Math.toRadians(eye.getYaw());
+        Vector forward = eye.getDirection();
+        // Player's right in Minecraft's coordinates (yaw 0 = south/+Z → right = west/−X).
+        Vector right = new Vector(-Math.cos(yaw), 0, -Math.sin(yaw));
+        Vector up = right.getCrossProduct(forward).normalize();
 
-        double x = lineDirection.getX();
-        double y = lineDirection.getY();
-        double z = lineDirection.getZ();
-
-        double angleYaw = Math.atan2(z, x);
-        double anglePitch = Math.atan2(y, Math.sqrt(x * x + z * z));
-
-        // Derive the vertical half-FOV from the horizontal one so square output is not distorted.
-        double yawHalf = H_FOV_HALF_RAD;
-        double pitchHalf = Math.atan(Math.tan(yawHalf) * ((double) height / width));
-
-        Vector lowerLeftCorner = MathUtil.doubleYawPitchRotation(BASE_VEC, -yawHalf, -pitchHalf, angleYaw, anglePitch);
-        Vector upperLeftCorner = MathUtil.doubleYawPitchRotation(BASE_VEC, -yawHalf, pitchHalf, angleYaw, anglePitch);
-        Vector lowerRightCorner = MathUtil.doubleYawPitchRotation(BASE_VEC, yawHalf, -pitchHalf, angleYaw, anglePitch);
-        Vector upperRightCorner = MathUtil.doubleYawPitchRotation(BASE_VEC, yawHalf, pitchHalf, angleYaw, anglePitch);
+        double tanY = Math.tan(Math.toRadians(V_FOV_DEG) / 2);
+        double tanX = tanY * width / height;
 
         List<Vector> rayMap = new ArrayList<>(width * height);
-
-        Vector leftFraction = upperLeftCorner.clone().subtract(lowerLeftCorner).multiply(1.0 / (height - 1));
-        Vector rightFraction =
-                upperRightCorner.clone().subtract(lowerRightCorner).multiply(1.0 / (height - 1));
-
-        for (int pitch = 0; pitch < height; pitch++) {
-            Vector leftPitch =
-                    upperLeftCorner.clone().subtract(leftFraction.clone().multiply(pitch));
-            Vector rightPitch =
-                    upperRightCorner.clone().subtract(rightFraction.clone().multiply(pitch));
-            Vector yawFraction = rightPitch.clone().subtract(leftPitch).multiply(1.0 / (width - 1));
-
-            for (int yaw = 0; yaw < width; yaw++) {
-                Vector ray =
-                        leftPitch.clone().add(yawFraction.clone().multiply(yaw)).normalize();
-                rayMap.add(ray);
+        for (int row = 0; row < height; row++) {
+            double v = (1 - 2 * (row + 0.5) / height) * tanY;
+            for (int col = 0; col < width; col++) {
+                double u = (2 * (col + 0.5) / width - 1) * tanX;
+                rayMap.add(new Vector(
+                                forward.getX() + u * right.getX() + v * up.getX(),
+                                forward.getY() + u * right.getY() + v * up.getY(),
+                                forward.getZ() + u * right.getZ() + v * up.getZ())
+                        .normalize());
             }
         }
-
         return rayMap;
     }
 }

src/main/java/eu/mhsl/minecraft/pixelpics/render/util/MathUtil.java

@@ -7,28 +7,6 @@ public class MathUtil {
 
     private MathUtil() {}
 
-    private static Vector yawPitchRotation(Vector base, double angleYaw, double anglePitch) {
-        double oldX = base.getX();
-        double oldY = base.getY();
-        double oldZ = base.getZ();
-
-        double sinOne = Math.sin(angleYaw);
-        double sinTwo = Math.sin(anglePitch);
-        double cosOne = Math.cos(angleYaw);
-        double cosTwo = Math.cos(anglePitch);
-
-        double newX = oldX * cosOne * cosTwo - oldY * cosOne * sinTwo - oldZ * sinOne;
-        double newY = oldX * sinTwo + oldY * cosTwo;
-        double newZ = oldX * sinOne * cosTwo - oldY * sinOne * sinTwo + oldZ * cosOne;
-
-        return new Vector(newX, newY, newZ);
-    }
-
-    public static Vector doubleYawPitchRotation(
-            Vector base, double firstYaw, double firstPitch, double secondYaw, double secondPitch) {
-        return yawPitchRotation(yawPitchRotation(base, firstYaw, firstPitch), secondYaw, secondPitch);
-    }
-
     /** Reflects {@code direction} across the plane with the given (unit) {@code normal}. */
     public static Vector reflectVector(Vector direction, Vector normal) {
         return direction.clone().subtract(normal.clone().multiply(2 * direction.dot(normal)));

tools/BlockEntityTestRender.java

@@ -6,7 +6,6 @@ import eu.mhsl.minecraft.pixelpics.render.render.*;
 import eu.mhsl.minecraft.pixelpics.render.sky.SkyContext;
 import eu.mhsl.minecraft.pixelpics.render.snapshot.WorldSnapshot;
 import eu.mhsl.minecraft.pixelpics.render.tint.BiomeTintProvider;
-import eu.mhsl.minecraft.pixelpics.render.util.MathUtil;
 import org.bukkit.Location;
 import org.bukkit.Material;
 import org.bukkit.block.data.BlockData;
@@ -25,8 +24,7 @@ import java.util.logging.Logger;
 public class BlockEntityTestRender {
 
     static final String ROOT = "/home/elias/Dokumente/mcTestServer/plugins/PixelPics";
-    static final double H_FOV_HALF = Math.toRadians(35);
-    static final Vector BASE = new Vector(1, 0, 0);
+    static final double V_FOV_HALF = Math.toRadians(eu.mhsl.minecraft.pixelpics.render.render.DefaultScreenRenderer.V_FOV_DEG / 2);
     static final int SSAA = 3;
     static final int TW = 220, TH = 240;
 
@@ -271,7 +269,7 @@ public class BlockEntityTestRender {
         double cx = (min[0] + max[0]) / 2, cy = (min[1] + max[1]) / 2, cz = (min[2] + max[2]) / 2;
         double ext = 0.5;
         for (int a = 0; a < 3; a++) ext = Math.max(ext, max[a] - min[a]);
-        double dist = ext / (2 * Math.tan(H_FOV_HALF)) * 1.4 + 0.6;
+        double dist = ext / (2 * Math.tan(V_FOV_HALF)) * 1.4 + 0.6;
 
         Vector center = new Vector(cx, cy, cz);
         Vector cam = new Vector(cx - dist, cy + dist * 0.45, cz - dist * 0.35);
@@ -300,7 +298,7 @@ public class BlockEntityTestRender {
         double cx = (min[0] + max[0]) / 2, cy = (min[1] + max[1]) / 2, cz = (min[2] + max[2]) / 2;
         double ext = 0.5;
         for (int a = 0; a < 3; a++) ext = Math.max(ext, max[a] - min[a]);
-        double dist = ext / (2 * Math.tan(H_FOV_HALF)) * 1.4 + 0.6;
+        double dist = ext / (2 * Math.tan(V_FOV_HALF)) * 1.4 + 0.6;
         // View from the front side (along +facing) so the picture is visible, not the back.
         DecorationState.Facing f = states.get(0).facing();
         double fx = f.axis() == 0 ? f.sign() : 0, fy = f.axis() == 1 ? f.sign() : 0, fz = f.axis() == 2 ? f.sign() : 0;
@@ -328,24 +326,6 @@ public class BlockEntityTestRender {
     }
 
     static List<Vector> buildRayMap(Location eye, int width, int height) {
-        Vector dir = eye.getDirection();
-        double angleYaw = Math.atan2(dir.getZ(), dir.getX());
-        double anglePitch = Math.atan2(dir.getY(), Math.sqrt(dir.getX() * dir.getX() + dir.getZ() * dir.getZ()));
-        double yawHalf = H_FOV_HALF;
-        double pitchHalf = Math.atan(Math.tan(yawHalf) * ((double) height / width));
-        Vector ll = MathUtil.doubleYawPitchRotation(BASE, -yawHalf, -pitchHalf, angleYaw, anglePitch);
-        Vector ul = MathUtil.doubleYawPitchRotation(BASE, -yawHalf, pitchHalf, angleYaw, anglePitch);
-        Vector lr = MathUtil.doubleYawPitchRotation(BASE, yawHalf, -pitchHalf, angleYaw, anglePitch);
-        Vector ur = MathUtil.doubleYawPitchRotation(BASE, yawHalf, pitchHalf, angleYaw, anglePitch);
-        List<Vector> rayMap = new ArrayList<>(width * height);
-        Vector leftFrac = ul.clone().subtract(ll).multiply(1.0 / (height - 1));
-        Vector rightFrac = ur.clone().subtract(lr).multiply(1.0 / (height - 1));
-        for (int pitch = 0; pitch < height; pitch++) {
-            Vector leftPitch = ul.clone().subtract(leftFrac.clone().multiply(pitch));
-            Vector rightPitch = ur.clone().subtract(rightFrac.clone().multiply(pitch));
-            Vector yawFrac = rightPitch.clone().subtract(leftPitch).multiply(1.0 / (width - 1));
-            for (int yaw = 0; yaw < width; yaw++) rayMap.add(leftPitch.clone().add(yawFrac.clone().multiply(yaw)).normalize());
-        }
-        return rayMap;
+        return eu.mhsl.minecraft.pixelpics.render.render.DefaultScreenRenderer.buildRayMap(eye, width, height);
     }
 }

tools/EntityTestRender.java

@@ -4,7 +4,6 @@ import eu.mhsl.minecraft.pixelpics.render.render.*;
 import eu.mhsl.minecraft.pixelpics.render.sky.SkyContext;
 import eu.mhsl.minecraft.pixelpics.render.snapshot.WorldSnapshot;
 import eu.mhsl.minecraft.pixelpics.render.tint.BiomeTintProvider;
-import eu.mhsl.minecraft.pixelpics.render.util.MathUtil;
 import org.bukkit.Location;
 import org.bukkit.Material;
 import org.bukkit.block.data.BlockData;
@@ -23,8 +22,7 @@ import java.util.logging.Logger;
 public class EntityTestRender {
 
     static final String ROOT = "/home/elias/Dokumente/mcTestServer/plugins/PixelPics";
-    static final double H_FOV_HALF = Math.toRadians(35);
-    static final Vector BASE = new Vector(1, 0, 0);
+    static final double V_FOV_HALF = Math.toRadians(eu.mhsl.minecraft.pixelpics.render.render.DefaultScreenRenderer.V_FOV_DEG / 2);
     static final int SSAA = 3;
     static final int TW = 200, TH = 230; // per-view tile size
 
@@ -232,7 +230,7 @@ public class EntityTestRender {
         double ext = 0;
         for (int a = 0; a < 3; a++) ext = Math.max(ext, re.aabbMax[a] - re.aabbMin[a]);
         if (ext < 0.5) ext = 0.5;
-        double dist = ext / (2 * Math.tan(H_FOV_HALF)) * 1.25 + 0.4;
+        double dist = ext / (2 * Math.tan(V_FOV_HALF)) * 1.25 + 0.4;
 
         Vector center = new Vector(cx, cy, cz);
         Vector cam = new Vector(cx - dist, cy + dist * 0.42, cz - dist * 0.15);
@@ -293,28 +291,7 @@ public class EntityTestRender {
         return cell;
     }
 
-    // Replicated from DefaultScreenRenderer.buildRayMap.
     static List<Vector> buildRayMap(Location eye, int width, int height) {
-        Vector dir = eye.getDirection();
-        double angleYaw = Math.atan2(dir.getZ(), dir.getX());
-        double anglePitch = Math.atan2(dir.getY(), Math.sqrt(dir.getX() * dir.getX() + dir.getZ() * dir.getZ()));
-        double yawHalf = H_FOV_HALF;
-        double pitchHalf = Math.atan(Math.tan(yawHalf) * ((double) height / width));
-        Vector ll = MathUtil.doubleYawPitchRotation(BASE, -yawHalf, -pitchHalf, angleYaw, anglePitch);
-        Vector ul = MathUtil.doubleYawPitchRotation(BASE, -yawHalf, pitchHalf, angleYaw, anglePitch);
-        Vector lr = MathUtil.doubleYawPitchRotation(BASE, yawHalf, -pitchHalf, angleYaw, anglePitch);
-        Vector ur = MathUtil.doubleYawPitchRotation(BASE, yawHalf, pitchHalf, angleYaw, anglePitch);
-        List<Vector> rayMap = new ArrayList<>(width * height);
-        Vector leftFrac = ul.clone().subtract(ll).multiply(1.0 / (height - 1));
-        Vector rightFrac = ur.clone().subtract(lr).multiply(1.0 / (height - 1));
-        for (int pitch = 0; pitch < height; pitch++) {
-            Vector leftPitch = ul.clone().subtract(leftFrac.clone().multiply(pitch));
-            Vector rightPitch = ur.clone().subtract(rightFrac.clone().multiply(pitch));
-            Vector yawFrac = rightPitch.clone().subtract(leftPitch).multiply(1.0 / (width - 1));
-            for (int yaw = 0; yaw < width; yaw++) {
-                rayMap.add(leftPitch.clone().add(yawFrac.clone().multiply(yaw)).normalize());
-            }
-        }
-        return rayMap;
+        return eu.mhsl.minecraft.pixelpics.render.render.DefaultScreenRenderer.buildRayMap(eye, width, height);
     }
 }

tools/edgecase-plugin/pptest/PPTest.java

@@ -136,6 +136,15 @@ public class PPTest extends JavaPlugin {
         scenes.put("frames_side", new Scene("frames_side", this::frames, -1.5, 3.2, -1.0, 4.5, 2.6, 3.6));
         scenes.put("frames_dirs_ne", new Scene("frames_dirs_ne", this::framesDirs, 16, 7.5, -4, 8, 4, 3.5));
         scenes.put("frames_dirs_sw", new Scene("frames_dirs_sw", this::framesDirs, 0, 1.2, 10, 8, 4, 3.5));
+        // Camera projection (pinhole, vertical FOV 70): frontal checkerboard wall / item-frame map (squares must be
+        // square, same size everywhere), ceiling straight up, floor straight down at yaw 30, oblique wall with
+        // stripes (edges must stay straight, the vertical stripe through the view centre vertical). *_sq = 384x384.
+        scenes.put("cam_checker_sq", new Scene("cam_checker_sq", this::camChecker, 5.5, 5.5, 1, 5.5, 5.5, 6));
+        scenes.put("cam_checker", new Scene("cam_checker", this::camChecker, 5.5, 5.5, 1, 5.5, 5.5, 6));
+        scenes.put("cam_frame_sq", new Scene("cam_frame_sq", this::camFrame, 5.5, 5.5, 3, 5.5, 5.5, 6));
+        scenes.put("cam_up_sq", new Scene("cam_up_sq", this::camChecker, 5.5, 6, 0.5, 5.5, 11, 0.5));
+        scenes.put("cam_down_sq", new Scene("cam_down_sq", this::camChecker, 5.5, 4, 0.5, 5.4995, 0, 0.500866));
+        scenes.put("cam_oblique", new Scene("cam_oblique", this::camStripes, 2, 11, 1.5, 5.5, 5.5, 6));
         // Performance (entity BVH): a 15x18 animal farm (270 mobs, randomizeData=false, fixed body yaw) and 300
         // item displays from a seeded RNG -> deterministic, pixel-diffable; the render time is logged.
         scenes.put("perf_farm", new Scene("perf_farm", this::perfFarm, -6, 9, -13, 4, 0, 0));
@@ -274,7 +283,7 @@ public class PPTest extends JavaPlugin {
         Location eye = o.clone().add(sc.camX, sc.camY, sc.camZ);
         Vector look = o.clone().add(sc.lookX, sc.lookY, sc.lookZ).toVector().subtract(eye.toVector());
         eye.setDirection(look);
-        RenderJob job = r.prepare(eye, sc.name.startsWith("proj_") || sc.name.startsWith("rf_") || sc.name.startsWith("frames") ? new Resolution(960, 640) : new Resolution(480, 320), null);
+        RenderJob job = r.prepare(eye, sc.name.endsWith("_sq") ? new Resolution(384, 384) : sc.name.startsWith("proj_") || sc.name.startsWith("rf_") || sc.name.startsWith("frames") ? new Resolution(960, 640) : new Resolution(480, 320), null);
         if (sc.name.equals("dbg")) {
             try {
                 java.lang.reflect.Field f = DefaultScreenRenderer.class.getDeclaredField("objectBaker");
@@ -1253,6 +1262,36 @@ public class PPTest extends JavaPlugin {
         }
     }
 
+    /** Black/white concrete checkerboard: wall z=6 (x -6..17, y 0..11), ceiling y=11 and floor y=-1. */
+    private void camChecker(Location o) {
+        for (int a = -6; a < 18; a++)
+            for (int b = 0; b < 12; b++) {
+                Material m = ((a + b) & 1) == 0 ? Material.WHITE_CONCRETE : Material.BLACK_CONCRETE;
+                w.getBlockAt(o.getBlockX() + a, o.getBlockY() + b, o.getBlockZ() + 6).setType(m, false);
+            }
+        for (int a = -6; a < 18; a++)
+            for (int c = -12; c < 6; c++) {
+                Material m = ((a + c) & 1) == 0 ? Material.WHITE_CONCRETE : Material.BLACK_CONCRETE;
+                w.getBlockAt(o.getBlockX() + a, o.getBlockY() + 11, o.getBlockZ() + c).setType(m, false);
+                w.getBlockAt(o.getBlockX() + a, o.getBlockY() - 1, o.getBlockZ() + c).setType(m, false);
+            }
+    }
+
+    /** Black wall z=6 with one item frame (synthetic map, 1x1 block) facing north at cell (5,5,5). */
+    private void camFrame(Location o) {
+        for (int a = -6; a < 18; a++)
+            for (int b = 0; b < 12; b++) w.getBlockAt(o.getBlockX() + a, o.getBlockY() + b, o.getBlockZ() + 6).setType(Material.BLACK_CONCRETE, false);
+        frame(o, 5, 5, 5, BlockFace.NORTH, false, synthMap(), 0, true);
+    }
+
+    /** Black wall z=6 with a white vertical stripe (x=5) and a white horizontal stripe (y=5). */
+    private void camStripes(Location o) {
+        for (int a = -6; a < 18; a++)
+            for (int b = 0; b < 12; b++)
+                w.getBlockAt(o.getBlockX() + a, o.getBlockY() + b, o.getBlockZ() + 6)
+                        .setType(a == 5 || b == 5 ? Material.WHITE_CONCRETE : Material.BLACK_CONCRETE, false);
+    }
+
     private ItemFrame frame(Location o, int x, int y, int z, BlockFace face, boolean glow, ItemStack item, int rot, boolean visible) {
         Location l = o.clone().add(x + 0.5, y + 0.5, z + 0.5);
         Class<? extends ItemFrame> c = glow ? GlowItemFrame.class : ItemFrame.class;