update

2024/08/raylib_cgo_demo.md

@@ -0,0 +1,96 @@
+
+#cgo
+
+#wasm
+
+[They Made a Sequel to C - YouTube](https://www.youtube.com/watch?v=Qzw1m7PweXs&t=9s)
+
+[# Go Wiki: cgo](https://go.dev/wiki/cgo)  
+[# Go Wiki: WebAssembly](https://go.dev/wiki/WebAssembly)
+
+**[raylib_go_demo](https://github.com/Ysoding/raylib_go_demo)**
+
+## CGo
+
+```sh
+go build -x
+
+WORK=/tmp/go-build1176050387
+cd /home/ultraman/Desktop/workspace/raylib_go_demo
+git status --porcelain
+cd /home/ultraman/Desktop/workspace/raylib_go_demo
+git -c log.showsignature=false show -s --format=%H:%ct
+mkdir -p $WORK/b001/
+cd /home/ultraman/Desktop/workspace/raylib_go_demo
+TERM='dumb' CGO_LDFLAGS='"-L./raylib-5.0_linux_amd64/lib" "-lraylib" "-lm"' /home/ultraman/go/pkg/mod/golang.org/[email protected]/pkg/tool/linux_amd64/cgo -objdir $WORK/b001/ -importpath github.com/Ysoding/raylib_go_demo -- -I $WORK/b001/ -I./raylib-5.0_linux_amd64/src ./main.go
+# github.com/Ysoding/raylib_go_demo
+./main.go:18:2: could not determine kind of name for C.CloseWindow
+./main.go:17:2: could not determine kind of name for C.InitWindow
+./main.go:15:8: could not determine kind of name for C.free
+```
+
+相对路径使用方法不对，没找到方法，只看到设置一个$SRCDIR，暂时用绝对  
+[How to use a relative path for LDFLAGS in golang](https://stackoverflow.com/questions/28037827/how-to-use-a-relative-path-for-ldflags-in-golang)
+
+```go
+/*
+#cgo CFLAGS: -I/home/ultraman/Desktop/workspace/raylib_go_demo/raylib-5.0_linux_amd64/include
+#cgo LDFLAGS: -L/home/ultraman/Desktop/workspace/raylib_go_demo/raylib-5.0_linux_amd64/lib -lraylib -lm
+#include "raylib.h"
+*/
+import "C"
+```
+
+```sh
+ü/Desktop/workspace/raylib_go_demo (master ✘)✭ ᐅ go build
+ü/Desktop/workspace/raylib_go_demo (master ✘)✭ ᐅ ldd raylib_go_demo 
+  linux-vdso.so.1 (0x00007ffcb29ce000)
+  libraylib.so.500 => not found
+  libc.so.6 => /lib/x86_64-linux-gnu/libc.so.6 (0x000074b23c600000)
+  /lib64/ld-linux-x86-64.so.2 (0x000074b23c875000)
+```
+
+指定动态链接库（shared libraries）的搜索路径。
+
+```sh
+export LD_LIBRARY_PATH=$LD_LIBRARY_PATH:/home/ultraman/Desktop/workspace/raylib_go_demo/raylib-5.0_linux_amd64/lib
+
+ldd raylib_go_demo
+  linux-vdso.so.1 (0x00007ffffcf41000)
+  libraylib.so.500 => /home/ultraman/Desktop/workspace/raylib_go_demo/raylib-5.0_linux_amd64/lib/libraylib.so.500 (0x000073bcc9000000)
+  libc.so.6 => /lib/x86_64-linux-gnu/libc.so.6 (0x000073bcc8c00000)
+  libm.so.6 => /lib/x86_64-linux-gnu/libm.so.6 (0x000073bcc8f19000)
+  libpthread.so.0 => /lib/x86_64-linux-gnu/libpthread.so.0 (0x000073bcc92fb000)
+  libdl.so.2 => /lib/x86_64-linux-gnu/libdl.so.2 (0x000073bcc92f6000)
+  /lib64/ld-linux-x86-64.so.2 (0x000073bcc9314000)
+```
+
+> 目录下有.so和.a优化，上面方法优先使用了.so
+
+也可以直接放到build根目录
+
+```go
+/*
+#cgo CFLAGS: -I.
+#cgo LDFLAGS: -L. -lraylib -lm
+#include "raylib.h"
+*/
+```
+
+由于raylib.h里面用到了`libm.a`，所以go build时找不到这个库，可以以cgo LDFLAGS加上 `-lm`
+
+```sh
+Desktop/workspace/raylib_go_demo (master ✘)✭ ᐅ go build # github.com/Ysoding/raylib_go_demo /home/ultraman/go/pkg/mod/golang.org/[email protected]/pkg/tool/linux_amd64/link: running gcc failed: exit status 1 /usr/bin/ld: /home/ultraman/Desktop/workspace/raylib_go_demo/libraylib.a(rcore.o): in function érgVector2Distance': rcore.c:(.text+0x6d3b): undefined reference to ésqrtf' /usr/bin/ld: /home/ultraman/Desktop/workspace/raylib_go_demo/libraylib.a(rcore.o): in function érlRotatef': rcore.c:(.text+0xbb16): undefined reference to ésincosf' /usr/bin/ld: rcore.c:(.text+0xbd88): undefined reference to ésqrtf' /usr/bin/ld: /home/ultraman/Desktop/workspace/raylib_go_demo/libraylib.a(rcore.o): in function érlGenTextureMipmaps': rcore.c:(.text+0xe31b): undefined reference to élog' /usr/bin/ld: /home/ultraman/Desktop/workspace/raylib_go_demo/libraylib.a(rcore.o): in function éFloatEquals': rcore.c:(.text+0x11a0d): undefined reference to éfmaxf' /usr/bin/ld: rcore.c:(.text+0x11a1d): undefined reference to éfmaxf' /usr/bin/ld: /home/ultraman/Desktop/workspace/raylib_go_demo/libraylib.a(rcore.o): in function éVector2Length': rcore.c:(.text+0x11b8c): undefined reference to ésqrtf' /usr/bin/ld: 
+```
+
+在go里的的init object时用到了` C.GetScreenWidth()`但是 init在main之前调用，则窗口还没有初始化，得出的值是0。
+
+## WASM
+
+[CGO library build to JS WASM file](https://stackoverflow.com/questions/54946214/cgo-library-build-to-js-wasm-file)  
+[# build: support emscripten compiler for cgo on wasm](https://github.com/golang/go/issues/55351)  
+cgo没有办法直接编译成wasm。  
+
+将raylib c代码编译 使用[Emscripten: An LLVM-to-WebAssembly Compiler](https://github.com/emscripten-core/emscripten)  
+
+然后在用go调用raylib wasm模块，在通过go build成wasm？ ？？(是不是多此一举)

README.md

@@ -4,6 +4,7 @@ The best thing to do is have fun.
 - [Hobby Projects](/hobby_projects.md)
 
 - **2024-08**
+  - [Raylib CGo Demo](/2024/08/raylib_cgo_demo.md)
   - [Vscode/ssh配置远程服务器图形化](/2024/08/vscode_ssh_graph_configure.md)
   - [Ros2环境搭建](/2024/08/ros2_dev_environment.md)
 - **2024-07**