add option to build a recent version of assimp

fixes bug on fedora 33 where the default assimp version doesn't support
glTF2

Makefile

@@ -1,6 +1,10 @@
 
+SHELL = /bin/sh
 CXX = g++
-CXXFLAGS = -std=c++11 -g -ggdb3 -Wall -Iinclude -I/usr/include/SDL2 -Iext/stb_libs
+CXXFLAGS = -std=c++11 -g -ggdb3 -Wall \
+	-Iinclude \
+	-I/usr/include/SDL2 \
+	-Iext/stb_libs
 EXAMPLEDIR = examples
 OBJDIR = build
 SRCDIR = src
@@ -9,14 +13,33 @@ LIBNAME = libTangerine.a
 RENDER_SOURCES = $(wildcard $(SRCDIR)/*.cpp)
 RENDER_OBJECTS = $(patsubst $(SRCDIR)/%.cpp, $(OBJDIR)/%.o, $(RENDER_SOURCES))
 
+ASSIMP_DIR=ext/assimp
+
+ifeq ($(USE_INTERNAL_ASSIMP), y)
+$(info using internal assimp)
+CXXFLAGS += -I$(ASSIMP_DIR)/include
+endif
 
 all: mkdirs $(LIBNAME) examples
 .PHONY: all
 
 -include $(OBJDIR)/*.d
 
+# NOTE: target to automatically build a current release of assimp. Fixes
+# 	issue on Fedora where the default assimp version doesn't support glTF2
+build_assimp:
+	if [ ! -d $(ASSIMP_DIR) ]; then	\
+		git clone -n "https://github.com/assimp/assimp" $(ASSIMP_DIR); \
+		cd $(ASSIMP_DIR); \
+		git checkout -q v5.0.1; \
+	fi
+
+	cmake -S $(ASSIMP_DIR) -B $(ASSIMP_DIR)
+	$(MAKE) -C $(ASSIMP_DIR)
+.PHONY: build_assimp
+
 mkdirs:
-	mkdir -p $(OBJDIR)
+	@mkdir -p $(OBJDIR)
 .PHONY: mkdirs
 
 $(LIBNAME): $(RENDER_OBJECTS)
@@ -26,7 +49,7 @@ $(RENDER_OBJECTS): $(OBJDIR)/%.o : $(SRCDIR)/%.cpp
 	$(CXX) $(CXXFLAGS) -c -MMD $< -o $@
 
 examples: $(LIBNAME)
-	$(MAKE) -C $(EXAMPLEDIR)
+	ASSIMP_DIR=$(ASSIMP_DIR) $(MAKE) -C $(EXAMPLEDIR)
 .PHONY: examples
 
 clean:

README.txt

@@ -15,8 +15,37 @@ TODO:
 	add a function to update camera transforms only once per frame, per shader
 
 Dependencies:
-	assimp
+	assimp >= 5.0.0
 	glew
 	glm
 	SDL2
 	stb_image
+
+Build Instructions:
+	install dependencies:
+		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
+			$ sudo dnf install glew-devel glm-devel catch-devel SDL2-devel \
+				gcc-c++ make cmake
+	checkout, and initialize submodules: (stb_image)
+		$ git submodule init
+		$ git submodule update
+	(optional) checkout large files for running examples:
+		(NOTE: https://git-lfs.github.com/)
+		$ git lfs pull
+	build:
+		$ make
+
+		NOTE: if build fails with errors from assimp or mesh.cpp, you can build
+			a recent version of assimp first. 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/bin ./assimp_loading
+

examples/Makefile

@@ -1,4 +1,5 @@
 
+SHELL = /bin/sh
 CXX = g++
 CXXFLAGS = -std=c++11 -g -ggdb3 -Wall -I../include -I/usr/include/SDL2
 LDFLAGS = -lSDL2 -lGLEW -lGL -lassimp
@@ -6,6 +7,11 @@ OBJDIR = build
 LIB = ../build/libTangerine.a
 BINDIR = bin
 
+ifeq ($(USE_INTERNAL_ASSIMP), y)
+CXXFLAGS += -I../$(ASSIMP_DIR)/include
+LDFLAGS = -lSDL2 -lGLEW -lGL -L../$(ASSIMP_DIR)/bin -lassimp
+endif
+
 
 all: mkdirs \
 	$(OBJDIR)/hello_world.o \

src/renderer.cpp

@@ -201,10 +201,9 @@ initContext(SDL_Handles* handles)
 		return false;
 	}
 
-	if (SDL_GL_SetSwapInterval(1) != 0) {	// vsync
+	// TODO: this doesn't work inside VM with QXL graphics
+	if (SDL_GL_SetSwapInterval(1) != 0)	// vsync
 		LOG(Error) << "SDL Errors: " << SDL_GetError() << "\n";
-		return false;
-	}
 
 	return true;
 }