From 8f7bf116aab8a40cd417b859422b2c8ce507085f Mon Sep 17 00:00:00 2001
From: a dinosaur <dino@a-dinosaur.com>
Date: Wed, 28 Jun 2023 06:43:46 +1000
Subject: [PATCH] old backend selector

---
 CMakeLists.txt     | 27 +++++++--------------------
 src/CMakeLists.txt | 24 ++++++++++++------------
 2 files changed, 19 insertions(+), 32 deletions(-)

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 5ed3bb5..3463421 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -2,25 +2,12 @@ cmake_minimum_required(VERSION 3.3 FATAL_ERROR)
 project(padlab C)
 set(TARGET padlab)
 
-option(USE_METAL "use Metal for drawing" ${APPLE})
-if (USE_METAL)
-	option(USE_OPENGL "Use OpenGL for drawing (WIP)" OFF)
-	option(USE_OPENGL_LEGACY "Use legacy OpenGL for drawing" OFF)
-	if (USE_OPENGL)
-		message(FATAL_ERROR "USE_METAL and USE_OPENGL are both ON but only one backend can be used at a time, turn one OFF and regenerate. (or delete cache and try again)")
-	elseif (USE_OPENGL_LEGACY)
-		message(FATAL_ERROR "USE_METAL and USE_OPENGL_LEGACY are both ON but only one backend can be used at a time, turn one OFF and regenerate. (or delete cache and try again)")
-	endif()
-else()
-	option(USE_OPENGL "Use OpenGL for drawing (WIP)" OFF)
-	if (USE_OPENGL)
-		option(USE_OPENGL_LEGACY "Use legacy OpenGL for drawing" OFF)
-		if (USE_OPENGL_LEGACY)
-			message(FATAL_ERROR "USE_OPENGL and USE_OPENGL_LEGACY are both ON but only one backend can be used at a time, turn one OFF and regenerate. (or delete cache and try again)")
-		endif()
-	else()
-		option(USE_OPENGL_LEGACY "Use legacy OpenGL for drawing" ON)
-	endif()
+set(GFX_BACKEND "OPENGL_LEGACY" CACHE STRING "Graphics API to render with: \"SDL\", \"OPENGL_LEGACY\" 1.1 compatibility profile, \"OPENGL\" 3.3 core profile (WIP), \"METAL\"")
+
+set(GL_BACKENDS OPENGL_LEGACY OPENGL)
+set(BACKENDS SDL ${GL_BACKENDS} METAL)
+if (NOT GFX_BACKEND IN_LIST BACKENDS)
+	message(FATAL_ERROR "\"${GFX_BACKEND}\" is not a valid graphics backend, GFX_BACKEND may be one of: ${BACKENDS}")
 endif()
 
 list(APPEND CMAKE_MODULE_PATH "${CMAKE_SOURCE_DIR}/cmake")
@@ -33,7 +20,7 @@ elseif (MSVC)
 endif()
 
 find_package(SDL2 REQUIRED)
-if (USE_OPENGL OR USE_OPENGL_LEGACY)
+if (GFX_BACKEND IN_LIST GL_BACKENDS)
 	if (NOT DEFINED OpenGL_GL_PREFERENCE)
 		set(OpenGL_GL_PREFERENCE "GLVND")
 	endif()
diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
index 707698c..9ff02ce 100644
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -2,15 +2,15 @@ set(SOURCES
 	maths.h
 	draw.h
 	draw_common.c
-	$<$<NOT:$<OR:$<BOOL:${USE_METAL}>,$<BOOL:${USE_OPENGL}>,$<BOOL:${USE_OPENGL_LEGACY}>>>:draw.c>
-	$<$<BOOL:${USE_METAL}>:draw_metal.m metal_shader_types.h>
-	$<$<BOOL:${USE_OPENGL}>:draw_opengl_core.c>
-	$<$<BOOL:${USE_OPENGL_LEGACY}>:draw_opengl.c>
+	$<$<NOT:$<OR:$<STREQUAL:${GFX_BACKEND},OPENGL>,$<STREQUAL:${GFX_BACKEND},OPENGL_LEGACY>,$<STREQUAL:${GFX_BACKEND},METAL>>>:draw.c>
+	$<$<STREQUAL:${GFX_BACKEND},METAL>:draw_metal.m metal_shader_types.h>
+	$<$<STREQUAL:${GFX_BACKEND},OPENGL>:draw_opengl_core.c>
+	$<$<STREQUAL:${GFX_BACKEND},OPENGL_LEGACY>:draw_opengl.c>
 	stick.h
 	stick.c
 	analogue.c)
 
-if (USE_METAL)
+if (GFX_BACKEND STREQUAL "METAL")
 	find_library(METAL Metal REQUIRED)
 	find_library(FOUNDATION Foundation REQUIRED)
 	find_library(QUARTZCORE QuartzCore REQUIRED)
@@ -19,7 +19,7 @@ if (USE_METAL)
 	include(BinHelper)
 	bin2h_compile(OUTPUT metalShader.h BIN ${CMAKE_CURRENT_BINARY_DIR}/shader.metallib)
 	list(APPEND SOURCES ${CMAKE_CURRENT_BINARY_DIR}/metalShader.h)
-elseif (USE_OPENGL)
+elseif (GFX_BACKEND STREQUAL "OPENGL")
 	include(GL3WHelper)
 	add_gl3w(gl3w)
 	include(BinHelper)
@@ -29,16 +29,16 @@ endif()
 
 add_executable(${TARGET} ${SOURCES})
 target_include_directories(${TARGET} PRIVATE
-	$<$<OR:$<BOOL:${USE_METAL}>,$<BOOL:${USE_OPENGL}>>:${CMAKE_CURRENT_BINARY_DIR}>)
+	$<$<OR:$<STREQUAL:${GFX_BACKEND},OPENGL>,$<STREQUAL:${GFX_BACKEND},METAL>>:${CMAKE_CURRENT_BINARY_DIR}>)
 target_link_libraries(${TARGET}
 	$<$<PLATFORM_ID:Windows>:SDL2::SDL2main>
 	SDL2::SDL2
-	$<$<BOOL:${USE_METAL}>:${METAL} ${QUARTZCORE} ${FOUNDATION}>
-	$<$<OR:$<BOOL:${USE_OPENGL}>,$<BOOL:${USE_OPENGL_LEGACY}>>:OpenGL::GL>
-	$<$<BOOL:${USE_OPENGL}>:gl3w>
+	$<$<STREQUAL:${GFX_BACKEND},METAL>:${METAL} ${QUARTZCORE} ${FOUNDATION}>
+	$<$<OR:$<STREQUAL:${GFX_BACKEND},OPENGL>,$<STREQUAL:${GFX_BACKEND},OPENGL_LEGACY>>:OpenGL::GL>
+	$<$<STREQUAL:${GFX_BACKEND},OPENGL>:gl3w>
 	$<$<BOOL:${GNU}>:m>)
 target_compile_options(${TARGET} PRIVATE
 	$<$<BOOL:${GNU}>:-Wall -Wextra -pedantic -Wno-unused-parameter>)
 target_compile_definitions(${TARGET} PRIVATE
-	$<$<BOOL:${USE_METAL}>:USE_METAL>
-	$<$<OR:$<BOOL:${USE_OPENGL}>,$<BOOL:${USE_OPENGL_LEGACY}>>:USE_OPENGL>)
+	$<$<STREQUAL:${GFX_BACKEND},METAL>:USE_METAL>
+	$<$<OR:$<STREQUAL:${GFX_BACKEND},OPENGL>,$<STREQUAL:${GFX_BACKEND},OPENGL_LEGACY>>:USE_OPENGL>)