TARGET_EXEC := sim

BUILD_DIR := ./build
SRC_DIR := ./src
INC_DIR := ./include
SHADER_DIR := ./kernels
SHADER_EXT := 'cl'

# Find all the C and C++ files we want to compile
SRCS := $(shell find $(SRC_DIR) -name '*.cpp')
GLSLS := $(shell find $(SHADER_DIR) -name '*.cl')

# Prepends BUILD_DIR and appends .o to every src file
OBJS := $(SRCS:%=$(BUILD_DIR)/%.o)
spirvs := $(glsls:%.$(shader_ext)=$(build_dir)/%.sphv)

# String substitution (suffix version without %).
DEPS := $(OBJS:.o=.d)

# Every folder in ./include will need to be passed to GCC so that it can find header files
INC_DIRS := $(shell find $(INC_DIR) -type d)
# Add a prefix to INC_DIRS. So moduleA would become -ImoduleA. GCC understands this -I flag
INC_FLAGS := $(addprefix -I,$(INC_DIRS))

LIBS := OpenCL

LDFLAGS := $(addprefix -l,$(LIBS))

# The -MMD and -MP flags together generate Makefiles for us! we use c++ 26
CPPFLAGS := -Wall -Wextra $(INC_FLAGS) -L/libs -MMD -MP -std=c++20

#set flags for kernel compiling
GPU_VENDOR := glxinfo | grep -E "OpenGL vendor | OpenGL renderer" | cut -d" " -f4
ARCH := uname -m
ifeq ($(GPU_VENDOR),"AMD")
	CLFLAGS := --target=amdgcn-amd-amdhsa -mcpu=gfx900
else ifeq ($(GPU_VENDOR),"NVIDIA")
	CLFLAGS := --target=nvtpx64-unkown-unkown
else ifeq ($(ARCH), "x86_64")
	CLFLAGS := --target=spirv64
else
	CLFLAGS := --target=spirv32
endif

CXX := clang -v

# The final build step.
$(BUILD_DIR)/$(TARGET_EXEC): $(OBJS)
	$(CXX) $(OBJS) -o $@ $(LDFLAGS)

# Build step for C++ source
$(BUILD_DIR)/%.cpp.o: %.cpp $(SPIRVS)
	mkdir -p $(dir $@)
	$(CXX) $(CPPFLAGS) $(CXXFLAGS) -c $< -o $@ $(LDFLAGS)

#build the shaders
$(BUILD_DIR)/%.spv: %.cl
	mkdir -p $(dir $@)
	$(CXX) $(CLFLAGS) -c $< -o $@

run: $(BUILD_DIR)/$(TARGET_EXEC)
	./$(BUILD_DIR)/$(TARGET_EXEC)