Converting draw calls to Texture2D in raylib

I want to apply some shader effects to a couple of draw calls using raylib, but I haven't found ways of implementing shaders without a texture.

I was wondering if I could refactor the function below to work as a Texture2D, and if so, how could I go about doing that?

void drawBoard(Color lineColor, Color boardColor){  ClearBackground(Color(boardColor));  DrawRectangleV( (Vector2){294, 100}, (Vector2){7, 600}, Color(lineColor));  DrawRectangleV( (Vector2){494, 100}, (Vector2){7, 600}, Color(lineColor));  DrawRectangle(100, 294, 600, 7, Color(lineColor));  DrawRectangle(100, 494, 600, 7, Color(lineColor));}