Cleaned up UI renderer a little and added color parameter for quads (WIP).

assets/shaders/glsl/ui.frag

@@ -0,0 +1,24 @@
+#version 460
+
+layout(set = 2, binding = 0)
+uniform sampler2D u_texture;
+
+layout(set = 3, binding = 0)
+uniform Parameters
+{
+    vec4 u_color;
+};
+
+layout(location = 0)
+in vec2 i_texCoord;
+
+layout(location = 1)
+in vec4 i_color;
+
+layout(location = 0)
+out vec4 o_color;
+
+void main()
+{
+    o_color = texture(u_texture, i_texCoord) * i_color * u_color;
+}