First Release

.gitmodules

@@ -1,9 +1,6 @@
-[submodule "src/opencv"]
-	path = src/opencv
-	url = https://github.com/sfe-SparkFro/opencv.git
-[submodule "src/ulab"]
-	path = src/ulab
+[submodule "opencv"]
+	path = opencv
+	url = https://github.com/opencv/opencv.git
+[submodule "ulab"]
+	path = ulab
 	url = https://github.com/v923z/micropython-ulab.git
-[submodule "micropython"]
-	path = micropython
-	url = https://github.com/sparkfun/micropython.git

Makefile

@@ -1,20 +1,16 @@
-# Set Pico SDK flags to create our own malloc wrapper and enable exceptions
-CMAKE_ARGS += -DSKIP_PICO_MALLOC=1 -DPICO_CXX_ENABLE_EXCEPTIONS=1
+ifndef PLATFORM
+$(error PLATFORM not specified. Use 'make PLATFORM=rp2350' or similar.)
+endif
 
-# Get current directory
-CURRENT_DIR = $(shell pwd)
+TOOLCHAIN_FILE = platforms/${PLATFORM}.toolchain.cmake
 
-# Set the MicroPython user C module path to the OpenCV module
-MAKE_ARGS = USER_C_MODULES="$(CURRENT_DIR)/src/opencv_upy.cmake"
+# TODO: For some reason, specifying this in the toolchain file doesn't work
+CMAKE_ARGS += -DBUILD_LIST=core,imgproc,imgcodecs
 
-# Build MicroPython with the OpenCV module
+# Generic build
 all:
-	@cd micropython/ports/rp2 && export CMAKE_ARGS="$(CMAKE_ARGS)" && make -f Makefile $(MAKEFLAGS) $(MAKE_ARGS)
+	cd opencv && mkdir -p build && cmake -S . -B build -DPICO_BUILD_DOCS=0 -DCMAKE_TOOLCHAIN_FILE=../${TOOLCHAIN_FILE} ${CMAKE_ARGS} && make -C build -f Makefile $(MAKEFLAGS) $(MAKE_ARGS)
 
-# Clean the MicroPython build
+# Clean the OpenCV build
 clean:
-	@cd micropython/ports/rp2 && make -f Makefile $(MAKEFLAGS) clean
-
-# Load the MicroPython submodules
-submodules:
-	@cd micropython/ports/rp2 && make -f Makefile $(MAKEFLAGS) submodules
+	cd opencv && rm -rf build

src/opencv_upy.cmake → micropython_opencv.cmake

@@ -1,14 +1,26 @@
+#-------------------------------------------------------------------------------
+# SPDX-License-Identifier: MIT
+# 
+# Copyright (c) 2025 SparkFun Electronics
+#-------------------------------------------------------------------------------
+# opencv_upy.cmake
+# 
+# CMake file for the MicroPython port of OpenCV.
+#-------------------------------------------------------------------------------
+
 # Create an INTERFACE library for our CPP module.
 add_library(usermod_cv2 INTERFACE)
 
 # Add our source files to the library.
 target_sources(usermod_cv2 INTERFACE
-    ${CMAKE_CURRENT_LIST_DIR}/alloc.c
-    ${CMAKE_CURRENT_LIST_DIR}/convert.cpp
-    ${CMAKE_CURRENT_LIST_DIR}/core.cpp
-    ${CMAKE_CURRENT_LIST_DIR}/imgproc.cpp
-    ${CMAKE_CURRENT_LIST_DIR}/numpy.cpp
-    ${CMAKE_CURRENT_LIST_DIR}/opencv_upy.c
+    ${CMAKE_CURRENT_LIST_DIR}/src/alloc.c
+    ${CMAKE_CURRENT_LIST_DIR}/src/convert.cpp
+    ${CMAKE_CURRENT_LIST_DIR}/src/core.cpp
+    ${CMAKE_CURRENT_LIST_DIR}/src/highgui.cpp
+    ${CMAKE_CURRENT_LIST_DIR}/src/imgcodecs.cpp
+    ${CMAKE_CURRENT_LIST_DIR}/src/imgproc.cpp
+    ${CMAKE_CURRENT_LIST_DIR}/src/numpy.cpp
+    ${CMAKE_CURRENT_LIST_DIR}/src/opencv_upy.c
 )
 
 # Add the src directory as an include directory.
@@ -21,16 +33,16 @@ target_link_libraries(usermod INTERFACE usermod_cv2)
 
 # OpenCV creates some global variables on the heap. These get created before
 # the GC is initialized, so we need to allocate some space for them on the C
-# heap. 10kB seems sufficient. TODO: See if we can get away with less.
-set(MICROPY_C_HEAP_SIZE 10240)
+# heap. 64kB seems sufficient.
+set(MICROPY_C_HEAP_SIZE 65536)
 
 # Makes m_tracked_calloc() and m_tracked_free() available. These track pointers
 # in a linked list to ensure the GC does not free them. Needed for some OpenCV
 # functions
 set(MICROPY_TRACKED_ALLOC 1)
 
-# Set ULAB max number of dimensions to 4 (default is 2). TODO: See if 4 is
-# actually needed, or if we can get away with 2.
+# Set ULAB max number of dimensions to 4 (default is 2), which is needed for
+# some OpenCV functions
 target_compile_definitions(usermod INTERFACE ULAB_MAX_DIMS=4)
 
 # Include ULAB
@@ -48,3 +60,8 @@ target_link_libraries(usermod INTERFACE "-Wl,--wrap,malloc")
 target_link_libraries(usermod INTERFACE "-Wl,--wrap,free")
 target_link_libraries(usermod INTERFACE "-Wl,--wrap,calloc")
 target_link_libraries(usermod INTERFACE "-Wl,--wrap,realloc")
+
+# __NEWLIB__ is not defined for some reason, which causes a conflicting
+# definition of uint here:
+# https://github.com/opencv/opencv/blob/9cdd525bc59b34a3db8f6db905216c5398ca93d6/modules/core/include/opencv2/core/hal/interface.h#L35-L39
+target_compile_definitions(usermod INTERFACE -D__NEWLIB__)

platforms/common.cmake

@@ -0,0 +1,46 @@
+# Derived from:
+# https://github.com/joachimBurket/esp32-opencv/blob/master/esp32/doc/detailed_build_procedure.md
+set(CMAKE_BUILD_TYPE Release)
+set(BUILD_SHARED_LIBS OFF)
+set(CV_DISABLE_OPTIMIZATION OFF)
+set(WITH_IPP OFF)
+set(WITH_TBB OFF)
+set(WITH_OPENMP OFF)
+set(WITH_PTHREADS_PF OFF)
+set(WITH_QUIRC OFF)
+set(WITH_1394 OFF)
+set(WITH_CUDA OFF)
+set(WITH_OPENCL OFF)
+set(WITH_OPENCLAMDFFT OFF)
+set(WITH_OPENCLAMDBLAS OFF)
+set(WITH_VA_INTEL OFF)
+set(WITH_EIGEN OFF)
+set(WITH_GSTREAMER OFF)
+set(WITH_GTK OFF)
+set(WITH_JASPER OFF)
+set(WITH_JPEG OFF)
+set(WITH_OPENJPEG OFF)
+set(WITH_WEBP OFF)
+set(BUILD_ZLIB ON)
+set(BUILD_PNG ON)
+set(WITH_TIFF OFF)
+set(WITH_V4L OFF)
+set(WITH_LAPACK OFF)
+set(WITH_ITT OFF)
+set(WITH_PROTOBUF OFF)
+set(WITH_IMGCODEC_HDR OFF)
+set(WITH_IMGCODEC_SUNRASTER OFF)
+set(WITH_IMGCODEC_PXM OFF)
+set(WITH_IMGCODEC_PFM OFF)
+# TODO: For some reason, specifying this in the toolchain file doesn't work
+# set(BUILD_LIST core,imgproc,imgcodecs)
+set(BUILD_JAVA OFF)
+set(BUILD_opencv_python OFF)
+set(BUILD_opencv_java OFF)
+set(BUILD_opencv_apps OFF)
+set(BUILD_PACKAGE OFF)
+set(BUILD_PERF_TESTS OFF)
+set(BUILD_TESTS OFF)
+set(CV_ENABLE_INTRINSICS OFF)
+set(CV_TRACE OFF)
+set(OPENCV_ENABLE_MEMALIGN OFF)

platforms/include/rp2350_unsafe_cv_xadd.h

@@ -0,0 +1,20 @@
+#ifndef RP2350_UNSAFE_CV_XADD_H
+#define RP2350_UNSAFE_CV_XADD_H
+
+// Fix for https://github.com/raspberrypi/pico-sdk/issues/2505
+// TLDR; OpenCV uses atomic operations for incrementing reference counters by
+// default. However, the Pico SDK does not support atomic operations on data in
+// PSRAM; attempting to do so just causes an infinite loop where the value is
+// incremented forever. The workaround is to use a non-atomic operation by
+// re-defining the `CV_XADD` macro. This is "unsafe" because it's not atomic,
+// but it *should* be fine since we're only using one thread. Also see:
+// https://github.com/opencv/opencv/blob/52bed3cd7890192700b2451e2713c340209ffd79/modules/core/include/opencv2/core/cvdef.h#L697-L723
+static inline int unsafe_cv_xadd(int* addr, int delta)
+{
+    int tmp = *addr;
+    *addr += delta;
+    return tmp;
+}
+#define CV_XADD(addr, delta) unsafe_cv_xadd(addr, delta)
+
+#endif

platforms/include/zephyr_stdint.h

@@ -0,0 +1,79 @@
+/*
+ * Copyright (c) 2019 BayLibre SAS
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#ifndef ZEPHYR_INCLUDE_TOOLCHAIN_STDINT_H_
+#define ZEPHYR_INCLUDE_TOOLCHAIN_STDINT_H_
+
+/*
+ * Some gcc versions and/or configurations as found in the Zephyr SDK
+ * (questionably) define __INT32_TYPE__ and derivatives as a long int
+ * which makes the printf format checker to complain about long vs int
+ * mismatch when %u is given a uint32_t argument, and uint32_t pointers not
+ * being compatible with int pointers. Let's redefine them to follow
+ * common expectations and usage.
+ */
+
+#if __SIZEOF_INT__ != 4
+#error "unexpected int width"
+#endif
+
+#undef __INT32_TYPE__
+#undef __UINT32_TYPE__
+#undef __INT_FAST32_TYPE__
+#undef __UINT_FAST32_TYPE__
+#undef __INT_LEAST32_TYPE__
+#undef __UINT_LEAST32_TYPE__
+#undef __INT64_TYPE__
+#undef __UINT64_TYPE__
+#undef __INT_FAST64_TYPE__
+#undef __UINT_FAST64_TYPE__
+#undef __INT_LEAST64_TYPE__
+#undef __UINT_LEAST64_TYPE__
+
+#define __INT32_TYPE__ int
+#define __UINT32_TYPE__ unsigned int
+#define __INT_FAST32_TYPE__ __INT32_TYPE__
+#define __UINT_FAST32_TYPE__ __UINT32_TYPE__
+#define __INT_LEAST32_TYPE__ __INT32_TYPE__
+#define __UINT_LEAST32_TYPE__ __UINT32_TYPE__
+#define __INT64_TYPE__ long long int
+#define __UINT64_TYPE__ unsigned long long int
+#define __INT_FAST64_TYPE__ __INT64_TYPE__
+#define __UINT_FAST64_TYPE__ __UINT64_TYPE__
+#define __INT_LEAST64_TYPE__ __INT64_TYPE__
+#define __UINT_LEAST64_TYPE__ __UINT64_TYPE__
+
+/*
+ * The confusion also exists with __INTPTR_TYPE__ which is either an int
+ * (even when __INT32_TYPE__ is a long int) or a long int. Let's redefine
+ * it to a long int to get some uniformity. Doing so also makes it compatible
+ * with LP64 (64-bit) targets where a long is always 64-bit wide.
+ */
+
+#if __SIZEOF_POINTER__ != __SIZEOF_LONG__
+#error "unexpected size difference between pointers and long ints"
+#endif
+
+#undef __INTPTR_TYPE__
+#undef __UINTPTR_TYPE__
+#define __INTPTR_TYPE__ long int
+#define __UINTPTR_TYPE__ long unsigned int
+
+/*
+ * Re-define the INTN_C(value) integer constant expression macros to match the
+ * integer types re-defined above.
+ */
+
+#undef __INT32_C
+#undef __UINT32_C
+#undef __INT64_C
+#undef __UINT64_C
+#define __INT32_C(c) c
+#define __UINT32_C(c) c ## U
+#define __INT64_C(c) c ## LL
+#define __UINT64_C(c) c ## ULL
+
+#endif /* ZEPHYR_INCLUDE_TOOLCHAIN_STDINT_H_ */

platforms/rp2350.toolchain.cmake

@@ -0,0 +1,22 @@
+# Define PICO_SDK_PATH in your environment before running this script
+if(NOT DEFINED ENV{PICO_SDK_PATH})
+    message(FATAL_ERROR "PICO_SDK_PATH environment variable is not set. Please define it before running this script.")
+endif()
+
+# Include the RP2350 toolchain file
+include("$ENV{PICO_SDK_PATH}/cmake/preload/toolchains/pico_arm_cortex_m33_gcc.cmake")
+
+# Include the common embedded OpenCV settings
+include("${CMAKE_CURRENT_LIST_DIR}/common.cmake")
+
+# Set RP2350 specific settings
+set(OPENCV_DISABLE_THREAD_SUPPORT ON)
+
+# Fix for https://github.com/raspberrypi/pico-sdk/issues/2505
+set(CMAKE_C_FLAGS_INIT "${CMAKE_C_FLAGS_INIT} -DOPENCV_INCLUDE_PORT_FILE=\\\"${CMAKE_CURRENT_LIST_DIR}/include/rp2350_unsafe_cv_xadd.h\\\"")
+set(CMAKE_CXX_FLAGS_INIT "${CMAKE_CXX_FLAGS_INIT} -DOPENCV_INCLUDE_PORT_FILE=\\\"${CMAKE_CURRENT_LIST_DIR}/include/rp2350_unsafe_cv_xadd.h\\\"")
+
+# Fix for https://github.com/sparkfun/micropython-opencv/issues/31
+# Source: https://docs.zephyrproject.org/4.0.0/doxygen/html/zephyr__stdint_8h_source.html
+set(CMAKE_C_FLAGS_INIT "${CMAKE_C_FLAGS_INIT} -imacros ${CMAKE_CURRENT_LIST_DIR}/include/zephyr_stdint.h")
+set(CMAKE_CXX_FLAGS_INIT "${CMAKE_CXX_FLAGS_INIT} -imacros ${CMAKE_CURRENT_LIST_DIR}/include/zephyr_stdint.h")

src/alloc.c

@@ -1,3 +1,17 @@
+/*
+ *------------------------------------------------------------------------------
+ * SPDX-License-Identifier: MIT
+ * 
+ * Copyright (c) 2025 SparkFun Electronics
+ *------------------------------------------------------------------------------
+ * alloc.c
+ * 
+ * Wrapper functions for malloc(), free(), calloc(), and realloc(). These ensure
+ * memory gets allocated on the C heap before the MicroPython garbage collector
+ * has been initialized, and and in the GC pool afterwards.
+ *------------------------------------------------------------------------------
+ */
+
 // C headers
 #include "py/runtime.h"