Fix noErase() breaking in WebGL

Author: davepagurek

src/webgl/material.js

@@ -3683,9 +3683,7 @@ function material(p5, fn){
         );
         break;
     }
-    if (!this._isErasing) {
-      this._cachedBlendMode = this.states.curBlendMode;
-    }
+    this._cachedBlendMode = this.states.curBlendMode;
   };
 
   RendererGL.prototype.shader = function(s) {

src/webgl/p5.RendererGL.js

@@ -1329,6 +1329,7 @@ class RendererGL extends Renderer {
       // Restore blend mode
       this.states.curBlendMode = this.preEraseBlend;
       this.blendMode(this.preEraseBlend);
+      console.log(this.preEraseBlend, this._cachedBlendMode)
       // Ensure that _applyBlendMode() sets preEraseBlend back to the original blend mode
       this._isErasing = false;
       this._applyBlendMode();

test/unit/visual/cases/webgl.js

@@ -533,4 +533,33 @@ visualSuite('WebGL', function() {
       screenshot();
     });
   });
+
+  visualSuite('erase()', () => {
+    visualTest('on the main canvas', (p5, screenshot) => {
+      p5.createCanvas(50, 50, p5.WEBGL);
+      p5.background(0);
+      p5.fill('red');
+      p5.rect(-20, -20, 40, 40);
+      p5.erase();
+      p5.circle(0, 0, 10);
+      p5.noErase();
+      screenshot();
+    });
+
+    visualTest('on a framebuffer', (p5, screenshot) => {
+      p5.createCanvas(50, 50, p5.WEBGL);
+      p5.background(0);
+      const fbo = p5.createFramebuffer();
+      fbo.begin();
+      p5.fill('red');
+      p5.rect(-20, -20, 40, 40);
+      p5.erase();
+      p5.circle(0, 0, 10);
+      p5.noErase();
+      fbo.end();
+      p5.imageMode(p5.CENTER);
+      p5.image(fbo, 0, 0);
+      screenshot();
+    });
+  });
 });

test/unit/visual/screenshots/WebGL/erase()/on a framebuffer/000.png

@@ -0,0 +1,3 @@
+{
+  "numScreenshots": 1
+}

test/unit/visual/screenshots/WebGL/erase()/on a framebuffer/metadata.json

@@ -0,0 +1,3 @@
+{
+  "numScreenshots": 1
+}