crude legacy GL backend w/ anti aliasing

CMakeLists.txt

@@ -2,15 +2,26 @@ cmake_minimum_required(VERSION 3.1 FATAL_ERROR)
 project(padlab C)
 set(CMAKE_C_STANDARD 99)
 set(TARGET padlab)
+
+find_package(SDL2 REQUIRED)
+find_package(OpenGL)
+
 set(SOURCES
 	maths.h
-	draw.c  draw.h
+	draw.h
 	stick.c stick.h
 	analogue.c)
 
-find_package(SDL2 REQUIRED)
+if (OPENGL_FOUND)
+	list(APPEND SOURCES draw_opengl.c)
+else()
+	list(APPEND SOURCES draw.c)
+endif()
 
 add_executable(${TARGET} ${SOURCES})
 target_link_libraries(${TARGET} SDL2::SDL2 m)
+if (OPENGL_FOUND)
+	target_link_libraries(${TARGET} OpenGL::GL)
+endif()
 target_compile_options(${TARGET} PRIVATE
 	-Wall -Wextra -pedantic -Wno-unused-parameter)