diff --git a/app/internal/gl/gl_js.go b/app/internal/gl/gl_js.go
index ffb18316..bc16cbf3 100644
--- a/app/internal/gl/gl_js.go
+++ b/app/internal/gl/gl_js.go
@@ -21,16 +21,16 @@ type Functions struct {
 func (f *Functions) Init(version int) error {
 	if version < 2 {
 		f.EXT_disjoint_timer_query = f.getExtension("EXT_disjoint_timer_query")
-		if f.getExtension("OES_texture_half_float") == js.Null() && f.getExtension("OES_texture_float") == js.Null() {
+		if f.getExtension("OES_texture_half_float").IsNull() && f.getExtension("OES_texture_float").IsNull() {
 			return errors.New("gl: no support for neither OES_texture_half_float nor OES_texture_float")
 		}
-		if f.getExtension("EXT_sRGB") == js.Null() {
+		if f.getExtension("EXT_sRGB").IsNull() {
 			return errors.New("gl: EXT_sRGB not supported")
 		}
 	} else {
 		// WebGL2 extensions.
 		f.EXT_disjoint_timer_query_webgl2 = f.getExtension("EXT_disjoint_timer_query_webgl2")
-		if f.getExtension("EXT_color_buffer_half_float") == js.Null() && f.getExtension("EXT_color_buffer_float") == js.Null() {
+		if f.getExtension("EXT_color_buffer_half_float").IsNull() && f.getExtension("EXT_color_buffer_float").IsNull() {
 			return errors.New("gl: no support for neither EXT_color_buffer_half_float nor EXT_color_buffer_float")
 		}
 	}
@@ -48,7 +48,7 @@ func (f *Functions) AttachShader(p Program, s Shader) {
 	f.Ctx.Call("attachShader", js.Value(p), js.Value(s))
 }
 func (f *Functions) BeginQuery(target Enum, query Query) {
-	if f.EXT_disjoint_timer_query_webgl2 != js.Null() {
+	if !f.EXT_disjoint_timer_query_webgl2.IsNull() {
 		f.Ctx.Call("beginQuery", int(target), js.Value(query))
 	} else {
 		f.EXT_disjoint_timer_query.Call("beginQueryEXT", int(target), js.Value(query))
@@ -124,7 +124,7 @@ func (f *Functions) DeleteProgram(p Program) {
 	f.Ctx.Call("deleteProgram", js.Value(p))
 }
 func (f *Functions) DeleteQuery(query Query) {
-	if f.EXT_disjoint_timer_query_webgl2 != js.Null() {
+	if !f.EXT_disjoint_timer_query_webgl2.IsNull() {
 		f.Ctx.Call("deleteQuery", js.Value(query))
 	} else {
 		f.EXT_disjoint_timer_query.Call("deleteQueryEXT", js.Value(query))
@@ -164,7 +164,7 @@ func (f *Functions) EnableVertexAttribArray(a Attrib) {
 	f.Ctx.Call("enableVertexAttribArray", int(a))
 }
 func (f *Functions) EndQuery(target Enum) {
-	if f.EXT_disjoint_timer_query_webgl2 != js.Null() {
+	if !f.EXT_disjoint_timer_query_webgl2.IsNull() {
 		f.Ctx.Call("endQuery", int(target))
 	} else {
 		f.EXT_disjoint_timer_query.Call("endQueryEXT", int(target))
@@ -201,7 +201,7 @@ func (f *Functions) GetProgramInfoLog(p Program) string {
 	return f.Ctx.Call("getProgramInfoLog", js.Value(p)).String()
 }
 func (f *Functions) GetQueryObjectuiv(query Query, pname Enum) uint {
-	if f.EXT_disjoint_timer_query_webgl2 != js.Null() {
+	if !f.EXT_disjoint_timer_query_webgl2.IsNull() {
 		return uint(paramVal(f.Ctx.Call("getQueryParameter", js.Value(query), int(pname))))
 	} else {
 		return uint(paramVal(f.EXT_disjoint_timer_query.Call("getQueryObjectEXT", js.Value(query), int(pname))))
@@ -231,8 +231,8 @@ func (f *Functions) GetUniformLocation(p Program, name string) Uniform {
 }
 func (f *Functions) InvalidateFramebuffer(target, attachment Enum) {
 	fn := f.Ctx.Get("invalidateFramebuffer")
-	if fn != js.Undefined() {
-		if f.int32Buf == (js.Value{}) {
+	if !fn.IsUndefined() {
+		if f.int32Buf.IsUndefined() {
 			f.int32Buf = js.Global().Get("Int32Array").New(1)
 		}
 		f.int32Buf.SetIndex(0, int32(attachment))
@@ -306,7 +306,7 @@ func (f *Functions) resizeByteBuffer(n int) {
 	if n == 0 {
 		return
 	}
-	if f.byteBuf != (js.Value{}) && f.byteBuf.Length() >= n {
+	if !f.byteBuf.IsUndefined() && f.byteBuf.Length() >= n {
 		return
 	}
 	f.byteBuf = js.Global().Get("Uint8Array").New(n)
diff --git a/app/internal/gl/types.go b/app/internal/gl/types.go
index 2f007ca2..291001fa 100644
--- a/app/internal/gl/types.go
+++ b/app/internal/gl/types.go
@@ -17,3 +17,19 @@ type (
 func (u Uniform) Valid() bool {
 	return u.V != -1
 }
+
+func (p Program) Valid() bool {
+	return p.V != 0
+}
+
+func (s Shader) Valid() bool {
+	return s.V != 0
+}
+
+func (t Texture) Valid() bool {
+	return t.V != 0
+}
+
+func (t Texture) Equal(t2 Texture) bool {
+	return t == t2
+}
diff --git a/app/internal/gl/types_js.go b/app/internal/gl/types_js.go
index 61be5608..8f0419a8 100644
--- a/app/internal/gl/types_js.go
+++ b/app/internal/gl/types_js.go
@@ -16,6 +16,22 @@ type (
 	Object       js.Value
 )
 
-func (u Uniform) Valid() bool {
-	return js.Value(u) != js.Null()
+func (p Program) Valid() bool {
+	return !js.Value(p).IsUndefined() && !js.Value(p).IsNull()
+}
+
+func (s Shader) Valid() bool {
+	return !js.Value(s).IsUndefined() && !js.Value(s).IsNull()
+}
+
+func (u Uniform) Valid() bool {
+	return !js.Value(u).IsUndefined() && !js.Value(u).IsNull()
+}
+
+func (t Texture) Valid() bool {
+	return !js.Value(t).IsUndefined() && !js.Value(t).IsNull()
+}
+
+func (t Texture) Equal(t2 Texture) bool {
+	return js.Value(t).Equal(js.Value(t2))
 }
diff --git a/app/internal/gl/util.go b/app/internal/gl/util.go
index 0e438636..ead9590f 100644
--- a/app/internal/gl/util.go
+++ b/app/internal/gl/util.go
@@ -22,7 +22,7 @@ func CreateProgram(ctx *Functions, vsSrc, fsSrc string, attribs []string) (Progr
 	}
 	defer ctx.DeleteShader(fs)
 	prog := ctx.CreateProgram()
-	if prog == (Program{}) {
+	if !prog.Valid() {
 		return Program{}, errors.New("glCreateProgram failed")
 	}
 	ctx.AttachShader(prog, vs)
@@ -49,7 +49,7 @@ func GetUniformLocation(ctx *Functions, prog Program, name string) Uniform {
 
 func createShader(ctx *Functions, typ Enum, src string) (Shader, error) {
 	sh := ctx.CreateShader(typ)
-	if sh == (Shader{}) {
+	if !sh.Valid() {
 		return Shader{}, errors.New("glCreateShader failed")
 	}
 	ctx.ShaderSource(sh, src)
diff --git a/app/internal/gpu/gpu.go b/app/internal/gpu/gpu.go
index d194630d..05ab150d 100644
--- a/app/internal/gpu/gpu.go
+++ b/app/internal/gpu/gpu.go
@@ -409,7 +409,7 @@ func (g *GPU) setErr(err error) {
 }
 
 func (r *renderer) texHandle(t *texture) gl.Texture {
-	if t.id != (gl.Texture{}) {
+	if t.id.Valid() {
 		return t.id
 	}
 	t.id = createTexture(r.ctx)
@@ -419,7 +419,7 @@ func (r *renderer) texHandle(t *texture) gl.Texture {
 }
 
 func (t *texture) release(ctx *context) {
-	if t.id != (gl.Texture{}) {
+	if t.id.Valid() {
 		ctx.DeleteTexture(t.id)
 	}
 }
@@ -898,7 +898,7 @@ func (r *renderer) drawOps(ops []imageOp) {
 		case clipTypeIntersection:
 			fbo = r.pather.stenciler.intersections.fbos[img.place.Idx]
 		}
-		if coverTex != fbo.tex {
+		if !coverTex.Equal(fbo.tex) {
 			coverTex = fbo.tex
 			r.ctx.ActiveTexture(gl.TEXTURE1)
 			r.ctx.BindTexture(gl.TEXTURE_2D, coverTex)
diff --git a/app/internal/window/gl_js.go b/app/internal/window/gl_js.go
index acb49e27..798ff4ae 100644
--- a/app/internal/window/gl_js.go
+++ b/app/internal/window/gl_js.go
@@ -25,11 +25,11 @@ func newContext(w *window) (*context, error) {
 	}
 	version := 2
 	ctx := w.cnv.Call("getContext", "webgl2", args)
-	if ctx == js.Null() {
+	if ctx.IsNull() {
 		version = 1
 		ctx = w.cnv.Call("getContext", "webgl", args)
 	}
-	if ctx == js.Null() {
+	if ctx.IsNull() {
 		return nil, errors.New("app: webgl is not supported")
 	}
 	f := &gl.Functions{Ctx: ctx}
diff --git a/app/internal/window/os_js.go b/app/internal/window/os_js.go
index 010f7c8a..e537eb96 100644
--- a/app/internal/window/os_js.go
+++ b/app/internal/window/os_js.go
@@ -65,7 +65,7 @@ func NewWindow(win Callbacks, opts *Options) error {
 
 func getContainer(doc js.Value) js.Value {
 	cont := doc.Call("getElementById", "giowindow")
-	if cont != js.Null() {
+	if !cont.IsNull() {
 		return cont
 	}
 	cont = doc.Call("createElement", "DIV")
@@ -252,7 +252,7 @@ func (w *window) touchEvent(typ pointer.Type, e js.Value) {
 func (w *window) touchIDFor(touch js.Value) pointer.ID {
 	id := touch.Get("identifier")
 	for i, id2 := range w.touches {
-		if id2 == id {
+		if id2.Equal(id) {
 			return pointer.ID(i)
 		}
 	}