docs: add new alignment option to docs

docs/source/getting_started.rst

@@ -27,6 +27,13 @@ Alignment is Required:
 **vec4** and **mat4** requires 16 byte alignment because vec4 and mat4 operations are
 vectorized by SIMD instructions (SSE/AVX).
 
+**UPDATE:**
+  By starting v0.4.5 cglm provides an option to disable alignment requirement, it is enabled as default 
+
+  | Check :doc:`opt` page for more details
+
+  Also alignment is disabled for older msvc verisons as default. Now alignment only is required in Visual Studio 2017 version 15.6+ if CGLM_ALL_UNALIGNED macro is not defined.
+
 Allocations:
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 *cglm* doesn't alloc any memory on heap. So it doesn't provide any allocator.

docs/source/index.rst

@@ -40,6 +40,7 @@ Also currently only **float** type is supported for most operations.
    getting_started
    opengl
    api
+   opt
    troubleshooting
 
 Indices and tables

docs/source/opt.rst

@@ -0,0 +1,36 @@
+.. default-domain:: C
+
+Options
+===============================================================================
+
+A few options are provided via macros.
+
+Alignment
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+As default, cglm requires types to be aligned. Alignment requirements:
+
+vec3:   8 byte
+vec4:   16 byte
+mat4:   16 byte
+versor: 16 byte
+
+By starting **v0.4.5** cglm provides an option to disable alignment requirement.
+To enable this option define **CGLM_ALL_UNALIGNED** macro before all headers.
+You can define it in Xcode, Visual Studio (or other IDEs) or you can also prefer
+to define it in build system. If you use pre-compiled verisons then you
+have to compile cglm with **CGLM_ALL_UNALIGNED** macro.
+
+**VERY VERY IMPORTANT:** If you use cglm in multiple projects and
+ those projects are depends on each other, then
+
+ | *ALWAYS* or *NEVER USE* **CGLM_ALL_UNALIGNED** macro in linked projects
+
+ if you do not know what you are doing. Because a cglm header included
+ via 'project A' may force types to be aligned and another cglm header
+ included via 'project B' may not require alignment. In this case
+ cglm functions will read from and write to **INVALID MEMORY LOCATIONs**.
+
+ ALWAYS USE SAME CONFIGURATION / OPTION for **cglm** if you have multiple projects.
+
+ For instance if you set CGLM_ALL_UNALIGNED in a project then set it in other projects too

docs/source/troubleshooting.rst

@@ -43,6 +43,9 @@ you may do it yourself.
 
 **This MSVC issue is still in TODOs.**
 
+**UPDATE:** By starting v0.4.5 cglm provides an option to disable alignment requirement.
+Also alignment is disabled for older msvc verisons as default. Now alignment only is required in Visual Studio 2017 version 15.6+ if CGLM_ALL_UNALIGNED macro is defined.
+
 Crashes, Invalid Memory Access:
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 

include/cglm/types.h

@@ -9,10 +9,10 @@
 #define cglm_types_h
 
 #if defined(_MSC_VER)
-#if _MSC_VER < 1913     /* Visual Studio 2017 version 15.6 */
-#  define CGLM_ALL_UNALIGNED
 /* do not use alignment for older visual studio versions */
-#  define CGLM_ALIGN(X) /* __declspec(align(X))            */
+#if _MSC_VER < 1913 /*  Visual Studio 2017 version 15.6  */
+#  define CGLM_ALL_UNALIGNED
+#  define CGLM_ALIGN(X) /* no alignment */
 #else
 #  define CGLM_ALIGN(X) __declspec(align(X))
 #endif