Isolate the node drawing code into separate files

include/nodes.h

@@ -0,0 +1,35 @@
+#ifndef NODES_H
+#define NODES_H
+
+#include "window.h"
+
+#define MAX_NODES 1024
+
+#define NODE_WIDTH 70
+#define NODE_HEIGHT 20
+
+#define IO_NODE_FILL_COLOUR ((colour_t){.abgr = 0xff2c84b7})
+#define IO_NODE_BORDER_COLOUR ((colour_t){.abgr = 0xff122d5e})
+#define OP_NODE_FILL_COLOUR ((colour_t){.abgr = 0xffad6c3a})
+#define OP_NODE_BORDER_COLOUR ((colour_t){.abgr = 0xff592516})
+
+typedef struct node node_t;
+
+enum comp_ops {
+  COMP_OP_ADD,
+  COMP_OP_SUB,
+  COMP_OP_MUL,
+  COMP_OP_DIV,
+
+  COUNT_COMP_OPS,
+};
+
+struct node {
+  rect_t rect;
+  const char *path;
+};
+
+bool aabb(const node_t *node, i32 x, i32 y);
+void draw_node(const window_t *wnd, const node_t *node);
+
+#endif // !NODES_H