From 2a041305e91545c4483f56ed77ebd6d0f755f038 Mon Sep 17 00:00:00 2001
From: Vladimir Mandic <mandic00@live.com>
Date: Wed, 13 Jan 2021 09:35:31 -0500
Subject: [PATCH] added humangl custom backend

---
 demo/browser.js     |  3 ++-
 src/human.js        | 10 +++----
 src/tfjs/backend.js | 64 +++++++++++++++++++++++++++++++++------------
 wiki                |  2 +-
 4 files changed, 56 insertions(+), 23 deletions(-)

diff --git a/demo/browser.js b/demo/browser.js
index 7e829a1e..3d53b3f4 100644
--- a/demo/browser.js
+++ b/demo/browser.js
@@ -3,10 +3,11 @@ import draw from './draw.js';
 import Menu from './menu.js';
 import GLBench from './gl-bench.js';
 
-const userConfig = {}; // add any user configuration overrides
+const userConfig = { backend: 'humangl' }; // add any user configuration overrides
 
 /*
 const userConfig = {
+  backend: 'humangl',
   face: { enabled: false, iris: { enabled: false } },
   body: { enabled: false },
   hand: { enabled: false },
diff --git a/src/human.js b/src/human.js
index 64284c09..eaed2ecf 100644
--- a/src/human.js
+++ b/src/human.js
@@ -182,12 +182,12 @@ class Human {
         if (!simd) log('warning: wasm simd support is not enabled');
       }
 
-      if (this.config.backend === 'humangl') {
-        log('registering humangl backend');
-        backend.register();
+      if (this.config.backend === 'humangl') backend.register();
+      try {
+        await tf.setBackend(this.config.backend);
+      } catch (err) {
+        log('error: cannot set backend:', this.config.backend, err);
       }
-
-      await tf.setBackend(this.config.backend);
       tf.enableProdMode();
       /* debug mode is really too mcuh
       tf.enableDebugMode();
diff --git a/src/tfjs/backend.js b/src/tfjs/backend.js
index f9919043..704b9d68 100644
--- a/src/tfjs/backend.js
+++ b/src/tfjs/backend.js
@@ -1,9 +1,11 @@
+import { log } from '../log.js';
 import * as tf from '../../dist/tfjs.esm.js';
 
 export const config = {
   name: 'humangl',
   priority: 99,
   canvas: null,
+  gl: null,
   width: 1024,
   height: 1024,
   webGLattr: { // https://www.khronos.org/registry/webgl/specs/latest/1.0/#5.2
@@ -20,21 +22,51 @@ export const config = {
 
 export function register() {
   if (!tf.findBackend(config.name)) {
-    // @ts-ignore
-    config.canvas = (typeof OffscreenCanvas !== 'undefined') ? new OffscreenCanvas(config.width, config.height) : document.createElement('canvas');
-    // @ts-ignore
-    const gl = config.canvas.getContext('webgl2', config.webGLattr);
-    tf.setWebGLContext(2, gl);
-    const ctx = new tf.GPGPUContext(gl);
-    tf.registerBackend(config.name, () => new tf.MathBackendWebGL(ctx), config.priority);
-    const kernels = tf.getKernelsForBackend('webgl');
-    kernels.forEach((kernelConfig) => {
-      const newKernelConfig = { ...kernelConfig, backendName: config.name };
-      tf.registerKernel(newKernelConfig);
-    });
-    tf.ENV.set('WEBGL_VERSION', 2);
-    tf.ENV.set('WEBGL_MAX_TEXTURE_SIZE', gl.getParameter(gl.MAX_TEXTURE_SIZE));
-    tf.ENV.set('WEBGL_FORCE_F16_TEXTURES', true);
-    tf.ENV.set('WEBGL_PACK_DEPTHWISECONV', true);
+    log('backend registration:', config.name);
+    try {
+      config.canvas = (typeof OffscreenCanvas !== 'undefined') ? new OffscreenCanvas(config.width, config.height) : document.createElement('canvas');
+    } catch (err) {
+      log('error: cannot create canvas:', err);
+      return;
+    }
+    try {
+      config.gl = config.canvas.getContext('webgl2', config.webGLattr);
+    } catch (err) {
+      log('error: cannot get WebGL2 context:', err);
+      return;
+    }
+    try {
+      tf.setWebGLContext(2, config.gl);
+    } catch (err) {
+      log('error: cannot set WebGL2 context:', err);
+      return;
+    }
+    try {
+      const ctx = new tf.GPGPUContext(config.gl);
+      tf.registerBackend(config.name, () => new tf.MathBackendWebGL(ctx), config.priority);
+    } catch (err) {
+      log('error: cannot register WebGL backend:', err);
+      return;
+    }
+    try {
+      const kernels = tf.getKernelsForBackend('webgl');
+      kernels.forEach((kernelConfig) => {
+        const newKernelConfig = { ...kernelConfig, backendName: config.name };
+        tf.registerKernel(newKernelConfig);
+      });
+    } catch (err) {
+      log('error: cannot update WebGL backend registration:', err);
+      return;
+    }
+    try {
+      tf.ENV.set('WEBGL_VERSION', 2);
+      tf.ENV.set('WEBGL_MAX_TEXTURE_SIZE', config.gl.getParameter(config.gl.MAX_TEXTURE_SIZE));
+      tf.ENV.set('WEBGL_FORCE_F16_TEXTURES', true);
+      tf.ENV.set('WEBGL_PACK_DEPTHWISECONV', true);
+    } catch (err) {
+      log('error: cannot set WebGL backend flags:', err);
+      return;
+    }
+    log('backend registered:', config.name);
   }
 }
diff --git a/wiki b/wiki
index 0ce580ce..c83eeeb1 160000
--- a/wiki
+++ b/wiki
@@ -1 +1 @@
-Subproject commit 0ce580ced2bdf5f2f231dfae6c3d3f90053af6f6
+Subproject commit c83eeeb158f2183d963500d9a767f04851497d2f