From 6930e28e2f5c64205a95cdf40ef6da0697463599 Mon Sep 17 00:00:00 2001
From: Dave Pagurek <davepagurek@gmail.com>
Date: Wed, 22 Oct 2025 10:17:22 -0400
Subject: [PATCH] Fix bugs in buildGeometry

---
 src/webgl/3d_primitives.js       |  8 ++++----
 src/webgl/p5.RendererGL.js       |  6 +++++-
 test/unit/webgl/p5.RendererGL.js | 27 +++++++++++++++++++++++++++
 3 files changed, 36 insertions(+), 5 deletions(-)

diff --git a/src/webgl/3d_primitives.js b/src/webgl/3d_primitives.js
index cc07f71f78..57c4b3921b 100644
--- a/src/webgl/3d_primitives.js
+++ b/src/webgl/3d_primitives.js
@@ -1726,7 +1726,7 @@ function primitives3D(p5, fn){
 
       this.states.setValue('uModelMatrix', mult);
 
-      this._drawGeometry(this.geometryBufferCache.getGeometryByID(gid));
+      this.model(this.geometryBufferCache.getGeometryByID(gid));
     } finally {
       this.states.setValue('uModelMatrix', uModelMatrix);
     }
@@ -1858,7 +1858,7 @@ function primitives3D(p5, fn){
       this.states.uModelMatrix.translate([x, y, 0]);
       this.states.uModelMatrix.scale(width, height, 1);
 
-      this._drawGeometry(this.geometryBufferCache.getGeometryByID(gid));
+      this.model(this.geometryBufferCache.getGeometryByID(gid));
     } finally {
       this.states.setValue('uModelMatrix', uModelMatrix);
     }
@@ -1919,7 +1919,7 @@ function primitives3D(p5, fn){
         this.states.uModelMatrix.translate([x, y, 0]);
         this.states.uModelMatrix.scale(width, height, 1);
 
-        this._drawGeometry(this.geometryBufferCache.getGeometryByID(gid));
+        this.model(this.geometryBufferCache.getGeometryByID(gid));
       } finally {
         this.states.setValue('uModelMatrix', uModelMatrix);
       }
@@ -2069,7 +2069,7 @@ function primitives3D(p5, fn){
       quadGeom.gid = gid;
       this.geometryBufferCache.ensureCached(quadGeom);
     }
-    this._drawGeometry(this.geometryBufferCache.getGeometryByID(gid));
+    this.model(this.geometryBufferCache.getGeometryByID(gid));
     return this;
   };
 
diff --git a/src/webgl/p5.RendererGL.js b/src/webgl/p5.RendererGL.js
index 3705bed131..5ff988c3ec 100644
--- a/src/webgl/p5.RendererGL.js
+++ b/src/webgl/p5.RendererGL.js
@@ -511,7 +511,11 @@ class RendererGL extends Renderer {
       );
     }
     const geometry = this.geometryBuilder.finish();
-    this.fill(this.geometryBuilder.prevFillColor);
+    if (this.geometryBuilder.prevFillColor) {
+      this.fill(this.geometryBuilder.prevFillColor);
+    } else {
+      this.noFill();
+    }
     this.geometryBuilder = undefined;
     return geometry;
   }
diff --git a/test/unit/webgl/p5.RendererGL.js b/test/unit/webgl/p5.RendererGL.js
index 7b84728695..2e651e1644 100644
--- a/test/unit/webgl/p5.RendererGL.js
+++ b/test/unit/webgl/p5.RendererGL.js
@@ -2950,4 +2950,31 @@ suite('p5.RendererGL', function() {
       myp5.checkPMatrix();
     });
   });
+
+  suite('buildGeometry', function() {
+    test('captures geometry without drawing', function() {
+      myp5.createCanvas(10, 10, myp5.WEBGL);
+      myp5.background(255, 0, 0);
+      const geom = myp5.buildGeometry(() => myp5.circle(0, 0, 5));
+      expect(geom.vertices.length).toBeGreaterThan(0);
+      expect(myp5.get(5, 5)).toEqual([255, 0, 0, 255]);
+    });
+
+    test('returns fill state back to a previous color', function() {
+      myp5.createCanvas(10, 10, myp5.WEBGL);
+      myp5.background(255, 0, 0);
+      myp5.fill(0, 255, 0);
+      const geom = myp5.buildGeometry(() => myp5.circle(0, 0, 10));
+      myp5.model(geom);
+      expect(myp5.get(5, 5)).toEqual([0, 255, 0, 255]);
+    });
+    test('returns fill state back to no fill', function() {
+      myp5.createCanvas(10, 10, myp5.WEBGL);
+      myp5.background(255, 0, 0);
+      myp5.noFill();
+      const geom = myp5.buildGeometry(() => myp5.circle(0, 0, 10));
+      myp5.model(geom);
+      expect(myp5.get(5, 5)).toEqual([255, 0, 0, 255]);
+    });
+  });
 });