Add ktx

ktx/tests/loadtests/appfwSDL/VulkanAppSDL/shaders/textoverlay.frag

@@ -0,0 +1,16 @@
+// Copyright 2017-2020 Mark Callow
+// SPDX-License-Identifier: Apache-2.0
+
+#version 450 core
+
+layout (location = 0) in vec2 inUV;
+
+layout (binding = 0) uniform sampler2D samplerFont;
+
+layout (location = 0) out vec4 outFragColor;
+
+void main(void)
+{
+	float color = texture(samplerFont, inUV).r;
+	outFragColor = vec4(vec3(color), 1.0);
+}