super basic UI constraint and alignment system with a super basic "game framework"

shaders/ui.vert

@@ -0,0 +1,11 @@
+#version 330 core
+layout (location = 0) in vec3 aPos;
+layout (location = 1) in vec2 aTexCoords;
+out vec2 texCoords;
+
+uniform mat4 projection;
+
+void main() {
+  gl_Position = projection * vec4(aPos, 1.0f);
+  texCoords = aTexCoords;
+}