Add all common parameters to context definition and make gl.getParameter support.

binding/binding.cc

@@ -51,6 +51,7 @@ static napi_value InitBinding(napi_env env, napi_value exports) {
   WebGLDebugRendererInfoExtension::Register(env, exports);
   WebGLDepthTextureExtension::Register(env, exports);
   WebGLLoseContextExtension::Register(env, exports);
+  WebGLDrawBuffersExtension::Register(env, exports);
   WebGLRenderingContext::Register(env, exports);
 
   napi_property_descriptor properties[] = {

binding/egl_context_wrapper.cc

@@ -444,6 +444,12 @@ void EGLContextWrapper::BindProcAddresses() {
   // ANGLE specific
   glRequestExtensionANGLE = reinterpret_cast<PFNGLREQUESTEXTENSIONANGLEPROC>(
       eglGetProcAddress("glRequestExtensionANGLE"));
+
+  // GL ES
+  glGetFloatv =
+      reinterpret_cast<PFNGLGETFLOATVPROC>(eglGetProcAddress("glGetFloatv"));
+  glGetBooleanv = reinterpret_cast<PFNGLGETBOOLEANVPROC>(
+      eglGetProcAddress("glGetBooleanv"));
 }
 
 void EGLContextWrapper::RefreshGLExtensions() {

binding/egl_context_wrapper.h

@@ -233,6 +233,10 @@ class EGLContextWrapper {
   // ANGLE specific
   PFNGLREQUESTEXTENSIONANGLEPROC glRequestExtensionANGLE;
 
+  // GL ES
+  PFNGLGETFLOATVPROC glGetFloatv;
+  PFNGLGETBOOLEANVPROC glGetBooleanv;
+
   // Refreshes extensions list:
   void RefreshGLExtensions();
 

binding/webgl_extensions.cc

@@ -936,4 +936,56 @@ napi_value WebGLLoseContextExtension::RestoreContext(napi_env env,
   return nullptr;
 }
 
+//==============================================================================
+// WebGLDrawBuffersExtension
+
+napi_ref WebGLDrawBuffersExtension::constructor_ref_;
+
+WebGLDrawBuffersExtension::WebGLDrawBuffersExtension(napi_env env)
+    : GLExtensionBase(env) {}
+
+/* static */
+bool WebGLDrawBuffersExtension::IsSupported(
+    EGLContextWrapper* egl_context_wrapper) {
+  IS_EXTENSION_NAME_AVAILABLE("GL_EXT_draw_buffers");
+}
+
+/* static */
+napi_status WebGLDrawBuffersExtension::Register(napi_env env,
+                                                napi_value exports) {
+  napi_status nstatus;
+
+  napi_property_descriptor properties[] = {
+      NapiDefineIntProperty(env, GL_MAX_COLOR_ATTACHMENTS,
+                            "MAX_COLOR_ATTACHMENTS_WEBGL"),
+      NapiDefineIntProperty(env, GL_MAX_DRAW_BUFFERS, "MAX_DRAW_BUFFERS_WEBGL"),
+  };
+
+  napi_value ctor_value;
+  nstatus = napi_define_class(env, "WEBGL_draw_buffers", NAPI_AUTO_LENGTH,
+                              GLExtensionBase::InitStubClass, nullptr,
+                              ARRAY_SIZE(properties), properties, &ctor_value);
+  ENSURE_NAPI_OK_RETVAL(env, nstatus, nstatus);
+
+  nstatus = napi_create_reference(env, ctor_value, 1, &constructor_ref_);
+  ENSURE_NAPI_OK_RETVAL(env, nstatus, nstatus);
+
+  return napi_ok;
+}
+
+/* static */
+napi_status WebGLDrawBuffersExtension::NewInstance(
+    napi_env env, napi_value* instance,
+    EGLContextWrapper* egl_context_wrapper) {
+  ENSURE_EXTENSION_IS_SUPPORTED
+
+  napi_status nstatus = NewInstanceBase(env, constructor_ref_, instance);
+  ENSURE_NAPI_OK_RETVAL(env, nstatus, nstatus);
+
+  egl_context_wrapper->glRequestExtensionANGLE("GL_EXT_draw_buffers");
+  egl_context_wrapper->RefreshGLExtensions();
+
+  return napi_ok;
+}
+
 }  // namespace nodejsgl

binding/webgl_extensions.h

@@ -239,6 +239,16 @@ class WebGLLoseContextExtension : public GLExtensionBase {
   static void Cleanup(napi_env env, void* native, void* hint);
 };
 
+// Provides 'WEBGL_draw_buffers':
+// https://www.khronos.org/registry/webgl/extensions/WEBGL_draw_buffers/
+class WebGLDrawBuffersExtension : public GLExtensionBase {
+  NAPI_BOOTSTRAP_METHODS
+
+ protected:
+  WebGLDrawBuffersExtension(napi_env env);
+  virtual ~WebGLDrawBuffersExtension() {}
+};
+
 }  // namespace nodejsgl
 
 #endif  // NODEJS_GL_WEBGL_EXTENSIONS_H_