From db056481ae8207e0df2bd84a44920f3e2416c6b3 Mon Sep 17 00:00:00 2001
From: harshiltewari2004 <harshiltewari2004@gmail.com>
Date: Tue, 14 Jul 2026 04:38:17 +0530
Subject: [PATCH] Add mat2 uniform support to WebGL setUniform, fixing silent
 no-op (#8939)

---
 src/webgl/utils.js                            |   4 ++++
 test/unit/visual/cases/webgl.js               |  18 ++++++++++++++++++
 .../mat2 uniforms are uploaded/000.png        | Bin 0 -> 238 bytes
 .../mat2 uniforms are uploaded/metadata.json  |   3 +++
 4 files changed, 25 insertions(+)
 create mode 100644 test/unit/visual/screenshots/WebGL/setUniform/mat2 uniforms are uploaded/000.png
 create mode 100644 test/unit/visual/screenshots/WebGL/setUniform/mat2 uniforms are uploaded/metadata.json

diff --git a/src/webgl/utils.js b/src/webgl/utils.js
index a5742c3f50..2d79b14578 100644
--- a/src/webgl/utils.js
+++ b/src/webgl/utils.js
@@ -222,6 +222,9 @@ export function setWebGLUniformValue(shader, uniform, data, getTexture, gl) {
         gl.uniform1f(location, data);
       }
       break;
+    case gl.FLOAT_MAT2:
+      gl.uniformMatrix2fv(location, false, data);
+      break;
     case gl.FLOAT_MAT3:
       gl.uniformMatrix3fv(location, false, data);
       break;
@@ -360,6 +363,7 @@ export function getWebGLUniformMetadata(shader, gl) {
 
     uniform.isArray =
       uniformInfo.size > 1 ||
+      uniform.type === gl.FLOAT_MAT2 ||
       uniform.type === gl.FLOAT_MAT3 ||
       uniform.type === gl.FLOAT_MAT4 ||
       uniform.type === gl.FLOAT_VEC2 ||
diff --git a/test/unit/visual/cases/webgl.js b/test/unit/visual/cases/webgl.js
index 618078bc81..8edf5523d0 100644
--- a/test/unit/visual/cases/webgl.js
+++ b/test/unit/visual/cases/webgl.js
@@ -1521,6 +1521,24 @@ visualTest('randomGaussian() in a fragment loop averages to the mean', (p5, scre
     });
   });
 
+  visualSuite('setUniform', () => {
+    visualTest('mat2 uniforms are uploaded', (p5, screenshot) => {
+      p5.createCanvas(50, 50, p5.WEBGL);
+      const myShader = p5.createFilterShader(`
+        precision highp float;
+        uniform mat2 uMatrix;
+        void main() {
+          // Diagonal drives red & green: expect (1.0, 0.5, 0.0)
+          gl_FragColor = vec4(uMatrix[0][0], uMatrix[1][1], 0.0, 1.0);
+         }
+      `);
+      p5.background(200);
+      myShader.setUniform('uMatrix', [1.0, 0.0, 0.0, 0.5]);
+      p5.filter(myShader);
+      screenshot();
+    });
+  });
+
   visualSuite('background()', function () {
     visualTest('background(image) works in WEBGL', function (p5, screenshot) {
       p5.createCanvas(50, 50, p5.WEBGL);
diff --git a/test/unit/visual/screenshots/WebGL/setUniform/mat2 uniforms are uploaded/000.png b/test/unit/visual/screenshots/WebGL/setUniform/mat2 uniforms are uploaded/000.png
new file mode 100644
index 0000000000000000000000000000000000000000..e0b865144266120e22c18637d2d4e54bfb5abaf5
GIT binary patch
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literal 0
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diff --git a/test/unit/visual/screenshots/WebGL/setUniform/mat2 uniforms are uploaded/metadata.json b/test/unit/visual/screenshots/WebGL/setUniform/mat2 uniforms are uploaded/metadata.json
new file mode 100644
index 0000000000..2d4bfe30da
--- /dev/null
+++ b/test/unit/visual/screenshots/WebGL/setUniform/mat2 uniforms are uploaded/metadata.json	
@@ -0,0 +1,3 @@
+{
+  "numScreenshots": 1
+}
\ No newline at end of file