first build attempt

shaders/phosphor.vert

@@ -0,0 +1,15 @@
+/*
+ * MIT License
+ * Author: Mark Allyn
+ *
+ * phosphor.vert — vertex shader for the phosphor display pass.
+ * Renders a fullscreen quad; the fragment shader clips to the
+ * scope circle and maps the phosphor FBO to P7 colours.
+ */
+#version 330 core
+
+layout(location = 0) in vec2 aPos;  // clip-space quad [-1,+1]^2
+
+void main() {
+    gl_Position = vec4(aPos, 0.0, 1.0);
+}