Spectrum analyzer update (#5160)

* advanced config: expose hidden constants to user screen
* advanced config: add support for FFT window overlapping
* waterfall: display at native resolution on high-DPI screens
* waterfall: add cursor and improve label density
* FFT: fix normalization so that 0 dBFS matches full-scale sinewave
* FFT: decouple data acquisition from processing and display
* FFT: separate lock for reallocation (to avoid some needless waiting)
* moved ranges and other constants to a separate file
* debug: better performance measurements
* minor fixes
* build the ringbuffer library as part of LMMS core

src/3rdparty/CMakeLists.txt

@@ -10,3 +10,22 @@ ENDIF()
 
 ADD_SUBDIRECTORY(rpmalloc)
 ADD_SUBDIRECTORY(weakjack)
+
+# The lockless ring buffer library is compiled as part of the core
+SET(RINGBUFFER_DIR "${CMAKE_SOURCE_DIR}/src/3rdparty/ringbuffer/")
+SET(RINGBUFFER_DIR ${RINGBUFFER_DIR} PARENT_SCOPE)
+# Create a dummy ringbuffer_export.h, since ringbuffer is not compiled as a library
+FILE(WRITE ${CMAKE_BINARY_DIR}/src/ringbuffer_export.h
+	"#include \"${CMAKE_BINARY_DIR}/src/lmms_export.h\"\n
+	#define RINGBUFFER_EXPORT LMMS_EXPORT")
+# Enable MLOCK support for ringbuffer if available
+INCLUDE(CheckIncludeFiles)
+CHECK_INCLUDE_FILES(sys/mman.h HAVE_SYS_MMAN)
+IF(HAVE_SYS_MMAN)
+    SET(USE_MLOCK ON)
+ELSE()
+    SET(USE_MLOCK OFF)
+ENDIF()
+# Generate ringbuffer configuration headers
+CONFIGURE_FILE(${RINGBUFFER_DIR}/src/ringbuffer-config.h.in  ${CMAKE_BINARY_DIR}/src/ringbuffer-config.h)
+CONFIGURE_FILE(${RINGBUFFER_DIR}/src/ringbuffer-version.h.in ${CMAKE_BINARY_DIR}/src/ringbuffer-version.h)

src/CMakeLists.txt

@@ -27,6 +27,7 @@ INCLUDE_DIRECTORIES(
 	"${CMAKE_BINARY_DIR}/include"
 	"${CMAKE_SOURCE_DIR}"
 	"${CMAKE_SOURCE_DIR}/include"
+	"${RINGBUFFER_DIR}/include"
 )
 
 IF(WIN32 AND MSVC)
@@ -89,6 +90,8 @@ IF(NOT ("${LAME_INCLUDE_DIRS}" STREQUAL ""))
 	INCLUDE_DIRECTORIES("${LAME_INCLUDE_DIRS}")
 ENDIF()
 
+LIST(APPEND LMMS_SRCS "${RINGBUFFER_DIR}/src/lib/ringbuffer.cpp")
+
 # Use libraries in non-standard directories (e.g., another version of Qt)
 IF(LMMS_BUILD_LINUX)
 	LINK_LIBRARIES(-Wl,--enable-new-dtags)

src/core/CMakeLists.txt

@@ -1,5 +1,6 @@
 set(LMMS_SRCS
 	${LMMS_SRCS}
+
 	core/AutomatableModel.cpp
 	core/AutomationPattern.cpp
 	core/BandLimitedWave.cpp

src/core/fft_helpers.cpp

@@ -66,6 +66,7 @@ int normalize(const float *abs_spectrum, float *norm_spectrum, unsigned int bin_
 	if (abs_spectrum == NULL || norm_spectrum == NULL) {return -1;}
 	if (bin_count == 0 || block_size == 0) {return -1;}
 
+	block_size /= 2;
 	for (i = 0; i < bin_count; i++)
 	{
 		norm_spectrum[i] = abs_spectrum[i] / block_size;