update Makefile and build instructions

Makefile

@@ -19,6 +19,7 @@ ASSIMP_DIR=ext/assimp
 
 ifeq ($(USE_INTERNAL_ASSIMP), y)
 CXXFLAGS += -I$(ASSIMP_DIR)/include
+ASSIMP_LIB := $(ASSIMP_DIR)/build/code/libassimp.a
 BUILD_ASSIMP_TARGET := build_assimp
 endif
 
@@ -35,8 +36,13 @@ build_assimp:
 		git checkout -q v5.0.1; \
 	fi
 
-	cmake -S $(ASSIMP_DIR) -B $(ASSIMP_DIR)
-	$(MAKE) -C $(ASSIMP_DIR)
+	cmake -S $(ASSIMP_DIR) -B $(ASSIMP_DIR)/build \
+		-DBUILD_SHARED_LIBS=OFF \
+		-DASSIMP_BUILD_TOOLS=OFF -DASSIMP_BUILD_TESTS=OFF \
+		-DASSIMP_BUILD_ALL_EXPORTERS_BY_DEFAULT=OFF \
+		-DASSIMP_BUILD_ALL_IMPORTERS_BY_DEFAULT=OFF \
+		-DASSIMP_BUILD_GLTF_IMPORTER=ON ./
+	$(MAKE) -C $(ASSIMP_DIR)/build
 .PHONY: build_assimp
 
 mkdirs:

README

@@ -26,8 +26,7 @@ Build Instructions:
 		Arch)
 			$ sudo pacman -S assimp glew glm sd2 catch2 gcc make
 		Fedora)
-			NOTE: Fedora (33) ships with assimp v3.3.1 which doesn't support
-				glTF2: https://en.wikipedia.org/wiki/GlTF
+			NOTE: Fedora (33) see note below about building assimp
 			$ sudo dnf install glew-devel glm-devel catch-devel SDL2-devel \
 				gcc-c++ make cmake
 	checkout, and initialize submodules: (stb_image)
@@ -39,13 +38,11 @@ Build Instructions:
 	build:
 		$ make
 
+	examples will be in examples/bin
+
 		NOTE: if build fails with errors from assimp or mesh.cpp, you can build
-			a recent version of assimp first. Requires cmake
+			a recent version of assimp that supports glTF2
+			https://en.wikipedia.org/wiki/GlTF. Requires cmake
 
 			$ make build_assimp && USE_INTERNAL_ASSIMP=y make
 
-			to run examples without installing assimp as a system library:
-
-			$ cd examples/bin
-			$ LD_LIBRARY_PATH=../../ext/assimp/lib ./assimp_loading
-

examples/Makefile

@@ -9,8 +9,8 @@ BINDIR = bin
 
 ifeq ($(USE_INTERNAL_ASSIMP), y)
 CXXFLAGS += -I../$(ASSIMP_DIR)/include
-LDFLAGS = -lSDL2 -lGLEW -lGL \
-		  -L../$(ASSIMP_DIR)/bin -L../$(ASSIMP_DIR)/lib -lassimp
+LDFLAGS = -lSDL2 -lGLEW -lGL
+ASSIMP_LIB := ../$(ASSIMP_DIR)/build/code/libassimp.a
 endif
 
 
@@ -28,15 +28,15 @@ mkdirs:
 
 $(OBJDIR)/hello_world.o: $(LIB)
 	$(CXX) $(CXXFLAGS) -c -MMD hello_world/main.cpp -o $@
-	$(CXX) -o $(BINDIR)/hello_world $(LDFLAGS) $@ $(LIB)
+	$(CXX) -o $(BINDIR)/hello_world $(LDFLAGS) $@ $(LIB) $(ASSIMP_LIB)
 
 $(OBJDIR)/assimp_loading.o: $(LIB)
 	$(CXX) $(CXXFLAGS) -c -MMD assimp_loading/main.cpp -o $@
-	$(CXX) -o $(BINDIR)/assimp_loading $(LDFLAGS) $@ $(LIB)
+	$(CXX) -o $(BINDIR)/assimp_loading $(LDFLAGS) $@ $(LIB) $(ASSIMP_LIB)
 
 $(OBJDIR)/simple_mesh.o: $(LIB)
 	$(CXX) $(CXXFLAGS) -c -MMD simple_mesh/main.cpp -o $@
-	$(CXX) -o $(BINDIR)/simple_mesh $(LDFLAGS) $@ $(LIB)
+	$(CXX) -o $(BINDIR)/simple_mesh $(LDFLAGS) $@ $(LIB) $(ASSIMP_LIB)
 
 clean:
 	rm -rf $(OBJDIR)/* bin/*