diff --git a/.circleci/config.yml b/.circleci/config.yml
index dffff08b436fd..520a08d52a8c7 100644
--- a/.circleci/config.yml
+++ b/.circleci/config.yml
@@ -817,6 +817,7 @@ jobs:
             browser64_4gb.test_audio_worklet*
             browser64_4gb.test_emscripten_log
             browser64_4gb.test_clientside_vertex_arrays_es3
+            browser64_4gb.test_emscripten_animate_canvas_element_size*
             "
   test-browser-firefox:
     executor: bionic
diff --git a/src/library_html5_webgl.js b/src/library_html5_webgl.js
index 468fe487c6423..bc1af123e3303 100644
--- a/src/library_html5_webgl.js
+++ b/src/library_html5_webgl.js
@@ -30,12 +30,12 @@ var LibraryHtml5WebGL = {
       HEAP32[a+i] = 0;
     }
 
-    HEAP32[a + ({{{ C_STRUCTS.EmscriptenWebGLContextAttributes.alpha }}}>>2)] =
-    HEAP32[a + ({{{ C_STRUCTS.EmscriptenWebGLContextAttributes.depth }}}>>2)] =
-    HEAP32[a + ({{{ C_STRUCTS.EmscriptenWebGLContextAttributes.antialias }}}>>2)] =
-    HEAP32[a + ({{{ C_STRUCTS.EmscriptenWebGLContextAttributes.premultipliedAlpha }}}>>2)] =
-    HEAP32[a + ({{{ C_STRUCTS.EmscriptenWebGLContextAttributes.majorVersion }}}>>2)] =
-    HEAP32[a + ({{{ C_STRUCTS.EmscriptenWebGLContextAttributes.enableExtensionsByDefault }}}>>2)] = 1;
+    HEAP8[a + ({{{ C_STRUCTS.EmscriptenWebGLContextAttributes.alpha }}})] =
+    HEAP8[a + ({{{ C_STRUCTS.EmscriptenWebGLContextAttributes.depth }}})] =
+    HEAP8[a + ({{{ C_STRUCTS.EmscriptenWebGLContextAttributes.antialias }}})] =
+    HEAP8[a + ({{{ C_STRUCTS.EmscriptenWebGLContextAttributes.premultipliedAlpha }}})] =
+    HEAP8[a + ({{{ C_STRUCTS.EmscriptenWebGLContextAttributes.majorVersion }}})] =
+    HEAP8[a + ({{{ C_STRUCTS.EmscriptenWebGLContextAttributes.enableExtensionsByDefault }}})] = 1;
 
 #if PTHREADS
     // Default context initialization state (user can override):
@@ -80,25 +80,25 @@ var LibraryHtml5WebGL = {
 #if ASSERTIONS
     assert(attributes);
 #endif
-    var a = attributes >> 2;
-    var powerPreference = HEAP32[a + ({{{ C_STRUCTS.EmscriptenWebGLContextAttributes.powerPreference }}}>>2)];
+    var powerPreference = {{{ makeGetValue('attributes', C_STRUCTS.EmscriptenWebGLContextAttributes.powerPreference, 'i32') }}};
     var contextAttributes = {
-      'alpha': !!HEAP32[a + ({{{ C_STRUCTS.EmscriptenWebGLContextAttributes.alpha }}}>>2)],
-      'depth': !!HEAP32[a + ({{{ C_STRUCTS.EmscriptenWebGLContextAttributes.depth }}}>>2)],
-      'stencil': !!HEAP32[a + ({{{ C_STRUCTS.EmscriptenWebGLContextAttributes.stencil }}}>>2)],
-      'antialias': !!HEAP32[a + ({{{ C_STRUCTS.EmscriptenWebGLContextAttributes.antialias }}}>>2)],
-      'premultipliedAlpha': !!HEAP32[a + ({{{ C_STRUCTS.EmscriptenWebGLContextAttributes.premultipliedAlpha }}}>>2)],
-      'preserveDrawingBuffer': !!HEAP32[a + ({{{ C_STRUCTS.EmscriptenWebGLContextAttributes.preserveDrawingBuffer }}}>>2)],
+      'alpha': !!{{{ makeGetValue('attributes', C_STRUCTS.EmscriptenWebGLContextAttributes.alpha, 'i32') }}},
+      'depth': !!{{{ makeGetValue('attributes', C_STRUCTS.EmscriptenWebGLContextAttributes.depth, 'i32') }}},
+      'stencil': !!{{{ makeGetValue('attributes', C_STRUCTS.EmscriptenWebGLContextAttributes.stencil, 'i32') }}},
+      'antialias': !!{{{ makeGetValue('attributes', C_STRUCTS.EmscriptenWebGLContextAttributes.antialias, 'i32') }}},
+      'premultipliedAlpha': !!{{{ makeGetValue('attributes', C_STRUCTS.EmscriptenWebGLContextAttributes.premultipliedAlpha, 'i32') }}},
+      'preserveDrawingBuffer': !!{{{ makeGetValue('attributes', C_STRUCTS.EmscriptenWebGLContextAttributes.preserveDrawingBuffer, 'i32') }}},
       'powerPreference': emscripten_webgl_power_preferences[powerPreference],
-      'failIfMajorPerformanceCaveat': !!HEAP32[a + ({{{ C_STRUCTS.EmscriptenWebGLContextAttributes.failIfMajorPerformanceCaveat }}}>>2)],
+      'failIfMajorPerformanceCaveat': !!{{{ makeGetValue('attributes', C_STRUCTS.EmscriptenWebGLContextAttributes.failIfMajorPerformanceCaveat, 'i32') }}},
       // The following are not predefined WebGL context attributes in the WebGL specification, so the property names can be minified by Closure.
-      majorVersion: HEAP32[a + ({{{ C_STRUCTS.EmscriptenWebGLContextAttributes.majorVersion }}}>>2)],
-      minorVersion: HEAP32[a + ({{{ C_STRUCTS.EmscriptenWebGLContextAttributes.minorVersion }}}>>2)],
-      enableExtensionsByDefault: HEAP32[a + ({{{ C_STRUCTS.EmscriptenWebGLContextAttributes.enableExtensionsByDefault }}}>>2)],
-      explicitSwapControl: HEAP32[a + ({{{ C_STRUCTS.EmscriptenWebGLContextAttributes.explicitSwapControl }}}>>2)],
-      proxyContextToMainThread: HEAP32[a + ({{{ C_STRUCTS.EmscriptenWebGLContextAttributes.proxyContextToMainThread }}}>>2)],
-      renderViaOffscreenBackBuffer: HEAP32[a + ({{{ C_STRUCTS.EmscriptenWebGLContextAttributes.renderViaOffscreenBackBuffer }}}>>2)]
+      majorVersion: {{{ makeGetValue('attributes', C_STRUCTS.EmscriptenWebGLContextAttributes.majorVersion, 'i32') }}},
+      minorVersion: {{{ makeGetValue('attributes', C_STRUCTS.EmscriptenWebGLContextAttributes.minorVersion, 'i32') }}},
+      enableExtensionsByDefault: {{{ makeGetValue('attributes', C_STRUCTS.EmscriptenWebGLContextAttributes.enableExtensionsByDefault, 'i32') }}},
+      explicitSwapControl: {{{ makeGetValue('attributes', C_STRUCTS.EmscriptenWebGLContextAttributes.explicitSwapControl, 'i32') }}},
+      proxyContextToMainThread: {{{ makeGetValue('attributes', C_STRUCTS.EmscriptenWebGLContextAttributes.proxyContextToMainThread, 'i32') }}},
+      renderViaOffscreenBackBuffer: {{{ makeGetValue('attributes', C_STRUCTS.EmscriptenWebGLContextAttributes.renderViaOffscreenBackBuffer, 'i32') }}}
     };
+    err(contextAttributes);
 
     var canvas = findCanvasEventTarget(target);
 
diff --git a/test/float_tex.cpp b/test/float_tex.cpp
index 6c14f5168cf3a..f0e426bd9d2b7 100644
--- a/test/float_tex.cpp
+++ b/test/float_tex.cpp
@@ -9,10 +9,9 @@
 #include <cmath>
 #include <iostream>
 #include <vector>
-extern "C" {
 #include <GL/gl.h>
 #include <GL/glut.h>
-}
+
 static const char vertex_shader[] =
         "#ifdef GL_ES\n"
         "precision lowp float;\n"
@@ -44,6 +43,7 @@ static const char fragment_shader[] =
         "}\n"
         "if ( dst > 0.5) discard;\n"
         "}";
+
 struct NodeInfo { //structure that we want to transmit to our shaders
     float x;
     float y;
@@ -55,8 +55,9 @@ GLuint nodeSamplerLocation; //shader sampler address
 GLuint indicesAttributeLocation; //shader attribute address
 GLuint indicesVBO; //Vertex Buffer Object Id;
 const int nbNodes = 512;
-NodeInfo * data = new NodeInfo[nbNodes]; //our data that will be transmitted using float texture.
+NodeInfo data[nbNodes]; //our data that will be transmitted using float texture.
 double alpha = 0; //use to make a simple funny effect;
+
 static void updateFloatTexture() {
     int count = 0;
     for (float x=0; x < nbNodes; ++x ) {
@@ -79,7 +80,9 @@ static void updateFloatTexture() {
     glBindTexture(GL_TEXTURE_2D, 0);
     alpha -= 0.001;
 }
+
 static void glut_draw_callback(void) {
+    printf("glut_draw_callback\n");
     glDisable(GL_CULL_FACE);
     glDisable(GL_DEPTH_TEST);
     glEnable(GL_BLEND);
@@ -96,6 +99,7 @@ static void glut_draw_callback(void) {
     glDrawArrays(GL_POINTS, 0, nbNodes);
     glutSwapBuffers();
 }
+
 GLuint createShader(const char source[], int type) {
     GLint status;
     char msg[512];
@@ -110,6 +114,7 @@ GLuint createShader(const char source[], int type) {
     assert(status == GL_TRUE);
     return shader;
 }
+
 static void gl_init(void) {
     GLuint program = glCreateProgram();
     glAttachShader(program, createShader(vertex_shader  , GL_VERTEX_SHADER));
@@ -145,6 +150,7 @@ static void gl_init(void) {
     glEnable(GL_POINT_SPRITE);
 #endif
 }
+
 int main(int argc, char *argv[]) {
     glutInit(&argc, argv);
     glutInitWindowSize(640, 480);
@@ -153,6 +159,7 @@ int main(int argc, char *argv[]) {
     /* Set up glut callback functions */
     glutDisplayFunc(glut_draw_callback      );
     gl_init();
+    printf("done setup\n");
     glutMainLoop();
     return 0;
 }