From e6e8b2c9353fc928f46b95aedaef1f025178be30 Mon Sep 17 00:00:00 2001
From: Emmanuel Benoit <tseeker@nocternity.net>
Date: Mon, 2 Oct 2017 10:00:39 +0200
Subject: [PATCH] Build in separate directory

---
 .gitignore |  1 +
 Makefile   | 59 +++++++++++++++++++++++++++++-------------------------
 2 files changed, 33 insertions(+), 27 deletions(-)

diff --git a/.gitignore b/.gitignore
index 07056f0..ffb88be 100644
--- a/.gitignore
+++ b/.gitignore
@@ -6,3 +6,4 @@ imgui.ini
 .*.d
 .vim.local/data/*
 .vim.local/signature
+output/
diff --git a/Makefile b/Makefile
index 02ffc37..ea87301 100644
--- a/Makefile
+++ b/Makefile
@@ -1,38 +1,45 @@
+OUTDIR = output
+
 CXXFLAGS += $(shell sdl2-config --cflags) -std=c++14 -Wall -g
 CFLAGS += $(shell sdl2-config --cflags)
-CPPFLAGS += -I. -Iimgui -Iglm \
+CPPFLAGS += -I. -I$(OUTDIR) -Iimgui -Iglm \
 	    -DREAL_BUILD -DGLM_ENABLE_EXPERIMENTAL
 LIBS += $(shell sdl2-config --libs) -lGL -lGLEW -ldl
 
 FILEDUMPS =
 
-IMGUI = imgui.o imgui_demo.o imgui_draw.o
+IMGUI = imgui.cpp imgui_draw.cpp
 DEMO = \
-	 main.o \
-	 imgui_impl_sdl.o \
+	 main.cc \
+	 imgui_impl_sdl.cc \
 	 \
-	 utilities.o \
-	 texture.o \
-	 rendertarget.o \
-	 programs.o \
+	 utilities.cc \
+	 texture.cc \
+	 rendertarget.cc \
+	 programs.cc \
 	 \
-	 raymarcher.o \
+	 raymarcher.cc \
 	 \
-	 bloom.o \
-	 dof.o \
-	 combine.o \
+	 bloom.cc \
+	 dof.cc \
+	 combine.cc \
 	 \
-	 profiling.o
-
-DEMO_DEPS = $(DEMO:%.o=.%.d)
+	 profiling.cc
 
 
-demo:	$(DEMO) $(IMGUI)
+IMGUI_OBJS = $(addprefix $(OUTDIR)/, $(addsuffix .o, $(basename $(IMGUI))))
+DEMO_OBJS = $(addprefix $(OUTDIR)/, $(addsuffix .o, $(basename $(DEMO))))
+OBJS = $(IMGUI_OBJS) $(DEMO_OBJS)
+PCH=externals.hh.gch
+
+DEMO_DEPS = $(DEMO_OBJS:$(OUTDIR)/%.o=$(OUTDIR)/%.d)
+
+demo:	$(OBJS)
 	$(CXX) $(CXXFLAGS) $(CPPFLAGS) -o demo \
-		$(DEMO) $(IMGUI) $(LIBS)
+		$(OBJS) $(LIBS)
 
 clean:
-	rm -f $(IMGUI) $(DEMO) $(FILEDUMPS) demo externals.hh.gch
+	rm -f $(OBJS) $(FILEDUMPS) demo $(PCH)
 
 fullclean: clean
 	rm -f $(DEMO_DEPS)
@@ -44,20 +51,18 @@ $(FILEDUMPS): fd-%.h: %
 	xxd -i $< $@
 
 
-imgui.o: imgui/imgui.cpp
-	$(CXX) $(CXXFLAGS) $(CPPFLAGS) -c -o $@ $<
+outdir:
+	@if ! [ -d "$(OUTDIR)" ]; then mkdir "$(OUTDIR)"; fi
+.PHONY: outdir
 
-imgui_demo.o: imgui/imgui_demo.cpp
-	$(CXX) $(CXXFLAGS) $(CPPFLAGS) -c -o $@ $<
-
-imgui_draw.o: imgui/imgui_draw.cpp
+$(IMGUI_OBJS): $(OUTDIR)/%.o: imgui/%.cpp | outdir
 	$(CXX) $(CXXFLAGS) $(CPPFLAGS) -c -o $@ $<
 
 -include $(DEMO_DEPS)
 
-$(DEMO): %.o: %.cc externals.hh.gch | $(FILEDUMPS)
+$(DEMO_OBJS): $(OUTDIR)/%.o: %.cc $(PCH) | outdir $(FILEDUMPS)
 	$(CXX) $(CXXFLAGS) $(CPPFLAGS) -c -o $@ $<
-	$(CXX) $(CXXFLAGS) $(CPPFLAGS) -M -MF $(@:%.o=.%.d) -MT $@ $<
+	$(CXX) $(CXXFLAGS) $(CPPFLAGS) -M -MF $(@:%.o=%.d) -MT $@ $<
 
-externals.hh.gch: externals.hh
+$(PCH): externals.hh
 	$(CXX) $(CXXFLAGS) $(CPPFLAGS) -c -o $@ $<