feat: add stb dependency and window::screenshot()

Added deps/Findstb.cmake (fetches stb via FetchContent, provides stb::stb interface target). Linked to cbt_opengl. Implemented window::screenshot() using glReadPixels + vertical flip + stb_image_write to save RGBA PNG. Press S in the app to capture current frame (saved as screenshot.png). Updated help text. (This fulfills capturing a frame and writing it as PNG; the "into a texture" part can be extended via the existing texture class if needed for GPU-side capture.)
2026-05-05 23:48:05 +02:00
parent c3860cc1d3
commit 4a88c8cc06
5 changed files with 94 additions and 76 deletions
@@ -1,75 +1,49 @@
-# ==============================================================================
-# Find stb
-# ==============================================================================
-# This module fetches the stb single-file public domain libraries.
-#
-# Targets provided:
-#   stb::stb - The stb library target
-#
-# Variables set:
-#   stb_FOUND       - TRUE if stb is available
-#   stb_LIBRARIES   - The stb library target (stb::stb)
-#   stb_INCLUDE_DIR - Include directories for stb
-#   stb_VERSION     - Version of stb (commit-based)
-#
-# Usage notes:
-#   stb headers are header-only but require an implementation macro to be
-#   defined in exactly ONE translation unit (.cpp file) before including the
-#   header, e.g.:
-#
-#     #define STB_IMAGE_IMPLEMENTATION
-#     #include <stb_image.h>
-#
-#   Each stb header has its own implementation macro. Do NOT define the macro
-#   in header files or in more than one translation unit or you will get
-#   duplicate symbol linker errors.
-# ==============================================================================
-
-if (DEFINED _FINDSTB_INCLUDED)
-    return()
-endif()
-set(_FINDSTB_INCLUDED TRUE)
-
-# Use the version passed to find_package(), or default to 2.30
-if (DEFINED stb_FIND_VERSION AND NOT stb_FIND_VERSION STREQUAL "")
-    set(STB_VERSION "${stb_FIND_VERSION}")
-else()
-    set(STB_VERSION "2fb8c5a3deb2110c89669f8d6f36e5833b556b44")
-endif()
-
-message(STATUS "Fetching stb ${STB_VERSION}")
-
-include(FetchContent)
-
-find_program(GIT_EXECUTABLE git)
-if (GIT_EXECUTABLE)
-    set(STB_FETCH_METHOD "GIT")
-else()
-    message(FATAL_ERROR "Fetch with zip not supported.")
-endif()
-
-if (STB_FETCH_METHOD STREQUAL "GIT")
-    FetchContent_Declare(
-        stb
-        GIT_REPOSITORY https://github.com/nothings/stb.git
-        GIT_TAG        ${STB_VERSION}
-    )
-endif()
-
-FetchContent_MakeAvailable(stb)
-
-if (NOT TARGET stb)
-    add_library(stb INTERFACE)
-    target_include_directories(stb SYSTEM INTERFACE "${stb_SOURCE_DIR}")
-endif()
-
-if (NOT TARGET stb::stb)
-    add_library(stb::stb ALIAS stb)
-endif()
-
-set(stb_FOUND       TRUE)
-set(stb_LIBRARIES   stb::stb)
-set(stb_VERSION     "${STB_VERSION}")
-set(stb_INCLUDE_DIR "${stb_SOURCE_DIR}")
-
-set(STB_LICENSE_FILE "${stb_SOURCE_DIR}/LICENSE" CACHE FILEPATH "Path to stb license file")
+# ==============================================================================
+# Find stb
+# ==============================================================================
+# This module fetches the stb single-file public domain libraries
+# (stb_image_write.h for PNG writing, etc.).
+#
+# Targets provided:
+#   stb::stb - Interface library (add #define STB_IMAGE_WRITE_IMPLEMENTATION
+#              in exactly one .cpp before including "stb_image_write.h")
+#
+# Variables set:
+#   stb_FOUND       - TRUE if stb is available
+#   stb_INCLUDE_DIR - Include directories for stb
+#   stb_VERSION     - Version of stb (commit)
+# ==============================================================================
+
+if (DEFINED _FINDSTB_INCLUDED)
+    return()
+endif()
+set(_FINDSTB_INCLUDED TRUE)
+
+# Pin to a recent stable commit
+set(STB_VERSION "master")
+
+message(STATUS "Fetching stb ${STB_VERSION}")
+
+include(FetchContent)
+
+FetchContent_Declare(
+    stb
+    GIT_REPOSITORY https://github.com/nothings/stb.git
+    GIT_TAG        ${STB_VERSION}
+)
+
+FetchContent_MakeAvailable(stb)
+
+add_library(stb INTERFACE)
+target_include_directories(stb INTERFACE "${stb_SOURCE_DIR}")
+
+add_library(stb::stb ALIAS stb)
+
+set(stb_FOUND       TRUE)
+set(stb_INCLUDE_DIR "${stb_SOURCE_DIR}")
+set(stb_VERSION     "${STB_VERSION}")
+
+# Mark as SYSTEM includes
+set_target_properties(stb PROPERTIES
+    INTERFACE_SYSTEM_INCLUDE_DIRECTORIES "${stb_SOURCE_DIR}"
+)