From a03269603a4641257877fd72185fef7700a77e73 Mon Sep 17 00:00:00 2001
From: Tony Garnock-Jones <tonyg@leastfixedpoint.com>
Date: Tue, 10 Jan 2023 22:04:38 +0100
Subject: [PATCH] CSG

---
 protocols/schemas/shapes.prs | 11 ++--
 scene/lobby.pr               | 29 +++++++++--
 scene/other.pr               | 13 +++++
 src/shapes.ts                | 99 +++++++++++++++++++++++++++---------
 4 files changed, 120 insertions(+), 32 deletions(-)

diff --git a/protocols/schemas/shapes.prs b/protocols/schemas/shapes.prs
index 25eec13..65c0460 100644
--- a/protocols/schemas/shapes.prs
+++ b/protocols/schemas/shapes.prs
@@ -42,10 +42,13 @@ Touchable = <touchable @shape Shape> .
 CSG = <csg @expr CSGExpr> .
 
 CSGExpr =
-/ <mesh @shape Shape>
-/ <subtract @base CSGExpr @more [CSGExpr ...]>
-/ <union @shapes [CSGExpr ...]>
-/ <intersect @shapes [CSGExpr ...]>
+/ <mesh @shape Mesh>
+/ <scale @v Vector3 @shape CSGExpr>
+/ <move @v Vector3 @shape CSGExpr>
+/ <rotate @v Vector3 @shape CSGExpr>
+/ <subtract [@base CSGExpr @more CSGExpr ...]>
+/ <union [@base CSGExpr @more CSGExpr ...]>
+/ <intersect [@base CSGExpr @more CSGExpr ...]>
 / <invert @shape CSGExpr>
 .
 
diff --git a/scene/lobby.pr b/scene/lobby.pr
index f871f4f..95961cb 100644
--- a/scene/lobby.pr
+++ b/scene/lobby.pr
@@ -66,7 +66,28 @@
      <color 0.5 0.5 0.0
       <box>>>>>>>
 
-<sprite "house"
- <scale <v 10.0 4.0 15.0>
-  <floor
-   <move <v 1.5 0.5 -0.5> <box>>>>>
+<sprite "x"
+ <move <v 10.0 1.6 -5.0>
+  <texture ["textures/oak-herringbone-5e80fb40b00c9-1200.jpg"
+            <v 1.0 3.0 1.0>
+            <v 0.0 0.0 0.0>]
+   <csg
+    <subtract [
+      <move <v 0.0 0.0 0.5> <scale <v 1.1 3.1 1.1> <mesh <box>>>>
+      <move <v 0.0 0.0 0.5> <scale <v 1.0 3.0 1.0> <mesh <box>>>>
+    ]>
+   >
+  >>>
+
+<sprite "y"
+ <move <v 12.0 0.75 -5.0>
+  <texture ["textures/oak-herringbone-5e80fb40b00c9-1200.jpg"
+            <v 1.0 1.0 1.0>
+            <v 0.0 0.0 0.0>]
+   <csg
+    <intersect [
+      <scale <v 0.5 1.0 0.5> <mesh <box>>>
+      <mesh <sphere>>
+    ]>
+   >
+  >>>
diff --git a/scene/other.pr b/scene/other.pr
index d62339b..06b5332 100644
--- a/scene/other.pr
+++ b/scene/other.pr
@@ -17,3 +17,16 @@
       <touchable <move <v 0.0 0.5 0.0> <plane>>>>>
     <scale <v 1.0 2.11 0.1> <move <v 0.0 0.5 0.6> <box>>>
   ]>>>
+
+<sprite "x"
+ <move <v 0.0 0.0 10.0>
+  <texture ["textures/oak-herringbone-5e80fb40b00c9-1200.jpg"
+            <v 1.0 3.0 1.0>
+            <v 0.0 0.0 0.0>]
+   <csg
+    <subtract [
+      <move <v 0.0 0.0 0.5> <scale <v 1.1 3.1 1.1> <mesh <box>>>>
+      <move <v 0.0 0.0 0.5> <scale <v 1.0 3.0 1.0> <mesh <box>>>>
+    ]>
+   >
+  >>>
diff --git a/src/shapes.ts b/src/shapes.ts
index 79430af..a449b34 100644
--- a/src/shapes.ts
+++ b/src/shapes.ts
@@ -4,6 +4,7 @@ import {
     CSG,
     HemisphericLight,
     Material,
+    Matrix,
     Mesh,
     MeshBuilder,
     Node,
@@ -177,32 +178,22 @@ function releaseTexture(entry: CachedTexture) {
     }
 }
 
+export function buildMesh(name: string, scene: Scene | null, meshSpec: Shapes.Mesh): Mesh {
+    switch (meshSpec._variant) {
+        case "Sphere": return MeshBuilder.CreateSphere(name, {}, scene);
+        case "Box": return MeshBuilder.CreateBox(name, {}, scene);
+        case "Ground": {
+            const v = v2(meshSpec.value.size);
+            return MeshBuilder.CreateGround(name, { width: v.x, height: v.y }, scene ?? void 0);
+        }
+        case "Plane": return MeshBuilder.CreatePlane(name, {}, scene);
+    }
+}
+
 export function build(name: string, scene: Scene, shape: Shapes.Shape, customize: MeshCustomizer): ShapeTree {
     switch (shape._variant) {
         case "Mesh": {
-            const mesh = shape.value;
-            let t: ShapeTree<Mesh>;
-            switch (mesh._variant) {
-                case "Sphere":
-                    t = new ShapeTree<Mesh>(scene, shape, MeshBuilder.CreateSphere(name, {}, scene));
-                    break;
-                case "Box":
-                    t = new ShapeTree<Mesh>(scene, shape, MeshBuilder.CreateBox(name, {}, scene));
-                    break;
-
-                case "Ground": {
-                    const v = v2(mesh.value.size);
-                    t = new ShapeTree(
-                        scene,
-                        shape,
-                        MeshBuilder.CreateGround(name, { width: v.x, height: v.y }, scene));
-                    break;
-                }
-
-                case "Plane":
-                    t = new ShapeTree<Mesh>(scene, shape, MeshBuilder.CreatePlane(name, {}, scene));
-                    break;
-            }
+            const t = new ShapeTree<Mesh>(scene, shape, buildMesh(name, scene, shape.value));
             applyCustomizer(t, customize);
             return t;
         }
@@ -307,7 +298,10 @@ export function build(name: string, scene: Scene, shape: Shapes.Shape, customize
             });
 
         case "CSG": {
-            throw new Error("unimplemented");
+            const t = new ShapeTree<Mesh>(
+                scene, shape, buildCSG(shape.value.expr).toMesh(name, null, scene));
+            applyCustomizer(t, customize);
+            return t;
         }
 
         case "Skybox": {
@@ -331,6 +325,63 @@ export function build(name: string, scene: Scene, shape: Shapes.Shape, customize
     }
 }
 
+function emptyCSG(): CSG {
+    const c = new CSG();
+    c.matrix = Matrix.Identity();
+    c.position = Vector3.Zero();
+    c.rotation = Vector3.Zero();
+    c.scaling = Vector3.Zero();
+    c.rotationQuaternion = null;
+    return c;
+}
+
+export function buildCSG(expr: Shapes.CSGExpr): CSG {
+    function walk(expr: Shapes.CSGExpr, matrix: Matrix): CSG {
+        switch (expr._variant) {
+            case "mesh": {
+                const mesh = buildMesh("", null, expr.shape);
+                mesh.freezeWorldMatrix(matrix, true);
+                mesh.unfreezeWorldMatrix();
+                const c = CSG.FromMesh(mesh);
+                mesh.dispose();
+                return c;
+            }
+            case "scale":
+                return walk(expr.shape, matrix.multiply(
+                    Matrix.Scaling(expr.v.x, expr.v.y, expr.v.z)));
+            case "move":
+                return walk(expr.shape, matrix.multiply(
+                    Matrix.Translation(expr.v.x, expr.v.y, expr.v.z)));
+            case "rotate":
+                return walk(expr.shape, matrix.multiply(
+                    Matrix.RotationYawPitchRoll(expr.v.y * 2 * Math.PI,
+                                                expr.v.x * 2 * Math.PI,
+                                                expr.v.z * 2 * Math.PI)));
+            case "subtract": {
+                let c = walk(expr.base, matrix);
+                expr.more.forEach(d => c.subtractInPlace(walk(d, matrix)));
+                return c;
+            }
+            case "union": {
+                let c = walk(expr.base, matrix);
+                expr.more.forEach(d => c.unionInPlace(walk(d, matrix)));
+                return c;
+            }
+            case "intersect": {
+                let c = walk(expr.base, matrix);
+                expr.more.forEach(d => c.intersectInPlace(walk(d, matrix)));
+                return c;
+            }
+            case "invert": {
+                let c = walk(expr.shape, matrix);
+                c.inverseInPlace();
+                return c;
+            }
+        }
+    }
+    return walk(expr, Matrix.Identity());
+}
+
 export const builder: { [key: string]: (... args: any[]) => Shapes.Shape } = {
     sphere: () => Shapes.Shape.Mesh(Shapes.Mesh.Sphere(Shapes.Sphere())),
     box: () => Shapes.Shape.Mesh(Shapes.Mesh.Box(Shapes.Box())),