diff --git a/ui/gl/gl_image.cpp b/ui/gl/gl_image.cpp
index 633d108..3db6653 100644
--- a/ui/gl/gl_image.cpp
+++ b/ui/gl/gl_image.cpp
@@ -155,14 +155,4 @@ TexturedRect Image::texturedRect(
 	};
 }
 
-GLint CurrentSingleComponentFormat() {
-	const auto context = QOpenGLContext::currentContext();
-	Assert(context != nullptr);
-
-	const auto format = context->format();
-	return (format.renderableType() == QSurfaceFormat::OpenGLES)
-		? GL_LUMINANCE
-		: GL_RED;
-}
-
 } // namespace Ui::GL
diff --git a/ui/gl/gl_image.h b/ui/gl/gl_image.h
index fe8fd3e..75c24ec 100644
--- a/ui/gl/gl_image.h
+++ b/ui/gl/gl_image.h
@@ -134,8 +134,6 @@ private:
 
 };
 
-[[nodiscard]] GLint CurrentSingleComponentFormat();
-
 #ifdef Q_OS_WIN
 inline constexpr auto kFormatRGBA = GL_BGRA_EXT;
 inline constexpr auto kSwizzleRedBlue = false;
diff --git a/ui/gl/gl_shader.cpp b/ui/gl/gl_shader.cpp
index 3079a52..2f47edd 100644
--- a/ui/gl/gl_shader.cpp
+++ b/ui/gl/gl_shader.cpp
@@ -89,9 +89,9 @@ uniform sampler2D u_texture;
 uniform sampler2D v_texture;
 )",
 		.body = R"(
-	float y = texture2D(y_texture, v_texcoord).r - 0.0625;
-	float u = texture2D(u_texture, v_texcoord).r - 0.5;
-	float v = texture2D(v_texture, v_texcoord).r - 0.5;
+	float y = texture2D(y_texture, v_texcoord).a - 0.0625;
+	float u = texture2D(u_texture, v_texcoord).a - 0.5;
+	float v = texture2D(v_texture, v_texcoord).a - 0.5;
 	result = vec4(
 		1.164 * y + 1.596 * v,
 		1.164 * y - 0.392 * u - 0.813 * v,