From 8d50947e46bf843816d5e9d34e2a7cc6ddf8177a Mon Sep 17 00:00:00 2001
From: Edwin Jakobs <edwin@rndr.studio>
Date: Fri, 27 Sep 2024 23:29:09 +0200
Subject: [PATCH] [orx-mesh] Add bounds properties

---
 .../kotlin/IndexedPolygonExtensions.kt        | 32 +++++++++++++++++++
 .../commonMain/kotlin/MeshDataExtensions.kt   |  9 +++++-
 2 files changed, 40 insertions(+), 1 deletion(-)

diff --git a/orx-mesh/src/commonMain/kotlin/IndexedPolygonExtensions.kt b/orx-mesh/src/commonMain/kotlin/IndexedPolygonExtensions.kt
index cd8461a1..87536c7b 100644
--- a/orx-mesh/src/commonMain/kotlin/IndexedPolygonExtensions.kt
+++ b/orx-mesh/src/commonMain/kotlin/IndexedPolygonExtensions.kt
@@ -2,6 +2,9 @@ package org.openrndr.extra.mesh
 
 import org.openrndr.math.LinearType
 import org.openrndr.math.Vector3
+import org.openrndr.shape.Box
+import kotlin.math.max
+import kotlin.math.min
 
 internal fun <T : LinearType<T>> bc(barycentric: Vector3, items: List<T>): T {
     return (items[0] * barycentric.x) + (items[1] * barycentric.y) + (items[2] * barycentric.z)
@@ -30,4 +33,33 @@ fun IIndexedPolygon.point(vertexData: VertexData, barycentric: Vector3): Point {
         if (tangents.isNotEmpty()) bc(barycentric, tangents) else null,
         if (bitangents.isNotEmpty()) bc(barycentric, bitangents) else null
     )
+}
+
+/**
+ * Evaluate position bounds
+ */
+fun List<IIndexedPolygon>.bounds(vertexData: IVertexData): Box {
+    if (isEmpty()) {
+        return Box.EMPTY
+    } else {
+        var px = Double.NEGATIVE_INFINITY
+        var py = Double.NEGATIVE_INFINITY
+        var pz = Double.NEGATIVE_INFINITY
+        var nx = Double.POSITIVE_INFINITY
+        var ny = Double.POSITIVE_INFINITY
+        var nz = Double.POSITIVE_INFINITY
+
+        for (p in this) {
+            for (i in p.positions) {
+                val v = vertexData.positions[i]
+                px = max(px, v.x)
+                py = max(py, v.y)
+                pz = max(pz, v.z)
+                nx = min(nx, v.x)
+                ny = min(ny, v.y)
+                nz = min(nz, v.z)
+            }
+        }
+        return Box(nx, ny, nz, px - nx, py - ny, pz - nz)
+    }
 }
\ No newline at end of file
diff --git a/orx-mesh/src/commonMain/kotlin/MeshDataExtensions.kt b/orx-mesh/src/commonMain/kotlin/MeshDataExtensions.kt
index b93f9585..140edf1f 100644
--- a/orx-mesh/src/commonMain/kotlin/MeshDataExtensions.kt
+++ b/orx-mesh/src/commonMain/kotlin/MeshDataExtensions.kt
@@ -3,6 +3,7 @@ package org.openrndr.extra.mesh
 import org.openrndr.color.ColorRGBa
 import org.openrndr.draw.*
 import org.openrndr.math.*
+import org.openrndr.shape.Box
 
 /**
  * The [VertexFormat] for a [VertexBuffer] with positions, normals and texture coordinates.
@@ -225,4 +226,10 @@ fun IMeshData.weld(
         }
     )
     return MeshData(reindexedVertexData, reindexedPolygons)
-}
\ No newline at end of file
+}
+
+/**
+ * Evaluate mesh bounds
+ */
+val IMeshData.bounds: Box
+    get() = polygons.bounds(vertexData)
\ No newline at end of file