fix: Windows build for sam3_image/sam3_video + close CI gap

.github/workflows/ci.yml

@@ -30,7 +30,7 @@ jobs:
 
           - name: Windows (MSVC)
             os: windows-latest
-            cmake_args: "-DGGML_METAL=OFF -DSAM3_METAL=OFF -A x64"
+            cmake_args: "-DGGML_METAL=OFF -DSAM3_METAL=OFF -A x64 -DCMAKE_TOOLCHAIN_FILE=C:/vcpkg/scripts/buildsystems/vcpkg.cmake -DVCPKG_TARGET_TRIPLET=x64-windows"
             build_args: "--config Release"
 
     steps:
@@ -47,6 +47,11 @@ jobs:
         if: runner.os == 'macOS'
         run: brew install ninja
 
+      - name: Install SDL2 (Windows)
+        if: runner.os == 'Windows'
+        shell: pwsh
+        run: vcpkg install sdl2:x64-windows
+
       - name: ccache
         uses: hendrikmuhs/ccache-action@v1
         with:
@@ -64,7 +69,7 @@ jobs:
       - name: Build
         run: cmake --build build ${{ matrix.build_args }} --parallel
 
-      - name: Verify library
+      - name: Verify build artifacts
         shell: bash
         run: |
           if [ -f build/libsam3.a ]; then
@@ -77,3 +82,14 @@ jobs:
             echo "ERROR: sam3 library not found"
             exit 1
           fi
+
+          if [ "$RUNNER_OS" = "Windows" ]; then
+            for exe in sam3_image.exe sam3_video.exe; do
+              if [ -f "build/examples/Release/$exe" ]; then
+                echo "Found build/examples/Release/$exe"
+              else
+                echo "ERROR: $exe not built (GUI examples were silently skipped — likely SDL2 not found)"
+                exit 1
+              fi
+            done
+          fi

examples/main_image.cpp

@@ -14,20 +14,14 @@
 
 #include "sam3.h"
 
+#define SDL_MAIN_HANDLED
 #include <SDL.h>
+#include <SDL_opengl.h>
+
 #include <imgui.h>
 #include <imgui_impl_sdl2.h>
 #include <imgui_impl_opengl3.h>
 
-#ifdef __APPLE__
-#ifndef GL_SILENCE_DEPRECATION
-#define GL_SILENCE_DEPRECATION
-#endif
-#include <OpenGL/gl3.h>
-#else
-#include <GL/gl.h>
-#endif
-
 #include <algorithm>
 #include <cmath>
 #include <cstdio>

examples/main_video.cpp

@@ -13,20 +13,14 @@
 
 #include "sam3.h"
 
+#define SDL_MAIN_HANDLED
 #include <SDL.h>
+#include <SDL_opengl.h>
+
 #include <imgui.h>
 #include <imgui_impl_sdl2.h>
 #include <imgui_impl_opengl3.h>
 
-#ifdef __APPLE__
-#ifndef GL_SILENCE_DEPRECATION
-#define GL_SILENCE_DEPRECATION
-#endif
-#include <OpenGL/gl3.h>
-#else
-#include <GL/gl.h>
-#endif
-
 #include <algorithm>
 #include <cstdio>
 #include <cstring>

examples/third-party/CMakeLists.txt

@@ -1,5 +1,23 @@
-# ImGui library with SDL2 + OpenGL3 backend
-set(IMGUI_DIR ${CMAKE_CURRENT_SOURCE_DIR}/imgui)
+# ImGui library with SDL2 + OpenGL3 backend.
+#
+# ImGui is not vendored. Prefer a local checkout at examples/third-party/imgui
+# (useful for offline builds); otherwise fetch it at configure time via
+# FetchContent, pinned to a known-good tag.
+if(EXISTS "${CMAKE_CURRENT_SOURCE_DIR}/imgui/imgui.cpp")
+    set(IMGUI_DIR ${CMAKE_CURRENT_SOURCE_DIR}/imgui)
+    message(STATUS "Using local ImGui checkout at ${IMGUI_DIR}")
+else()
+    include(FetchContent)
+    FetchContent_Declare(
+        imgui
+        GIT_REPOSITORY https://github.com/ocornut/imgui.git
+        GIT_TAG        v1.91.8
+        GIT_SHALLOW    TRUE
+    )
+    FetchContent_MakeAvailable(imgui)
+    set(IMGUI_DIR ${imgui_SOURCE_DIR})
+    message(STATUS "Fetched ImGui v1.91.8 into ${IMGUI_DIR}")
+endif()
 
 add_library(imgui-sdl2 STATIC
     ${IMGUI_DIR}/imgui.cpp
@@ -26,8 +44,9 @@ else()
     target_link_libraries(imgui-sdl2 PUBLIC OpenGL::GL)
 endif()
 
+# On non-Apple, leave IMGUI_IMPL_OPENGL_LOADER_* undefined so imgui uses its
+# bundled imgl3w loader (required for GL 3+ on MSVC where opengl32.lib only
+# exports GL 1.1 symbols).
 if(APPLE)
     target_compile_definitions(imgui-sdl2 PUBLIC GL_SILENCE_DEPRECATION)
-else()
-    target_compile_definitions(imgui-sdl2 PUBLIC IMGUI_IMPL_OPENGL_LOADER_CUSTOM)
 endif()

sam3.cpp

@@ -23,8 +23,12 @@
 #define popen  _popen
 #define pclose _pclose
 #define mkdir(path, mode) _mkdir(path)
+#define SAM3_NULL_DEV   "NUL"
+#define SAM3_POPEN_READ "rb"
 #else
 #include <sys/stat.h>
+#define SAM3_NULL_DEV   "/dev/null"
+#define SAM3_POPEN_READ "r"
 #endif
 
 /* C++ standard library */
@@ -12289,16 +12293,16 @@ sam3_image sam3_decode_video_frame(const std::string& video_path, int frame_inde
     snprintf(cmd, sizeof(cmd),
              "ffmpeg -nostdin -loglevel error -i \"%s\" "
              "-vf \"select=eq(n\\,%d)\" -vsync vfr -frames:v 1 "
-             "-f rawvideo -pix_fmt rgb24 pipe:1 2>/dev/null",
-             video_path.c_str(), frame_index);
+             "-f rawvideo -pix_fmt rgb24 pipe:1 2>%s",
+             video_path.c_str(), frame_index, SAM3_NULL_DEV);
 
     // First, get dimensions
     char info_cmd[1024];
     snprintf(info_cmd, sizeof(info_cmd),
              "ffprobe -v error -select_streams v:0 "
-             "-show_entries stream=width,height -of csv=p=0 \"%s\" 2>/dev/null",
-             video_path.c_str());
-    FILE* fp = popen(info_cmd, "r");
+             "-show_entries stream=width,height -of csv=p=0 \"%s\" 2>%s",
+             video_path.c_str(), SAM3_NULL_DEV);
+    FILE* fp = popen(info_cmd, SAM3_POPEN_READ);
     if (!fp) return img;
     int w = 0, h = 0;
     if (fscanf(fp, "%d,%d", &w, &h) != 2) {
@@ -12312,7 +12316,7 @@ sam3_image sam3_decode_video_frame(const std::string& video_path, int frame_inde
     img.channels = 3;
     img.data.resize(w * h * 3);
 
-    fp = popen(cmd, "r");
+    fp = popen(cmd, SAM3_POPEN_READ);
     if (!fp) {
         img.data.clear();
         return img;
@@ -12333,9 +12337,9 @@ sam3_video_info sam3_get_video_info(const std::string& video_path) {
     snprintf(cmd, sizeof(cmd),
              "ffprobe -v error -select_streams v:0 "
              "-show_entries stream=width,height,r_frame_rate,nb_frames "
-             "-of csv=p=0 \"%s\" 2>/dev/null",
-             video_path.c_str());
-    FILE* fp = popen(cmd, "r");
+             "-of csv=p=0 \"%s\" 2>%s",
+             video_path.c_str(), SAM3_NULL_DEV);
+    FILE* fp = popen(cmd, SAM3_POPEN_READ);
     if (!fp) return info;
 
     int w = 0, h = 0, num = 0, den = 1, nf = 0;