Add support for creating Vulkan window surfaces.

examples/vulkan/resources/shader.frag

@@ -0,0 +1,16 @@
+#version 450
+#extension GL_ARB_separate_shader_objects : enable
+
+layout(binding = 1) uniform sampler2D texSampler;
+
+layout(location = 0) in vec4 fragColor;
+layout(location = 1) in vec2 fragTexCoord;
+
+layout(location = 0) out vec4 outColor;
+
+void main() {
+    outColor = fragColor * texture(texSampler, fragTexCoord);
+
+    if (outColor.a < 0.5)
+        discard;
+}