first build attempt

build/shaders/bloom.frag

@@ -0,0 +1,18 @@
+/*
+ * MIT License
+ * Author: Mark Allyn
+ *
+ * bloom.frag — stub for a future dedicated two-pass Gaussian bloom.
+ * Currently bloom is applied inline in phosphor.frag.
+ * This shader is a pass-through so the CMake target compiles cleanly.
+ */
+#version 330 core
+
+in  vec2 vTexCoord;
+out vec4 fragColor;
+
+uniform sampler2D u_texture;
+
+void main() {
+    fragColor = texture(u_texture, vTexCoord);
+}