Backend: OpenGL3: Amend b0c18166 fix cases where glGetString(GL_VERSION) returns NULL. (#6154, #4445, #3530)

backends/imgui_impl_opengl3.cpp

@@ -14,6 +14,7 @@
 
 // CHANGELOG
 // (minor and older changes stripped away, please see git history for details)
+//  2023-03-15: OpenGL: Fixed GL loader crash when GL_VERSION returns NULL. (#6154, #4445, #3530)
 //  2023-03-06: OpenGL: Fixed restoration of a potentially deleted OpenGL program, by calling glIsProgram(). (#6220, #6224)
 //  2022-11-09: OpenGL: Reverted use of glBufferSubData(), too many corruptions issues + old issues seemingly can't be reproed with Intel drivers nowadays (revert 2021-12-15 and 2022-05-23 changes).
 //  2022-10-11: Using 'nullptr' instead of 'NULL' as per our switch to C++11.

backends/imgui_impl_opengl3_loader.h

@@ -118,7 +118,7 @@ extern "C" {
 ** included as <GL/glcorearb.h>.
 **
 ** glcorearb.h includes only APIs in the latest OpenGL core profile
-** implementation together with APIs in newer ARB extensions which 
+** implementation together with APIs in newer ARB extensions which
 ** can be supported by the core profile. It does not, and never will
 ** include functionality removed from the core profile, such as
 ** fixed-function vertex and fragment processing.
@@ -692,8 +692,8 @@ static int parse_version(void)
     if (version.major == 0 && version.minor == 0)
     {
         // Query GL_VERSION in desktop GL 2.x, the string will start with "<major>.<minor>"
-        const char* gl_version = (const char*)glGetString(GL_VERSION);
+        if (const char* gl_version = (const char*)glGetString(GL_VERSION))
-        sscanf(gl_version, "%d.%d", &version.major, &version.minor);
+            sscanf(gl_version, "%d.%d", &version.major, &version.minor);
     }
     if (version.major < 2)
         return GL3W_ERROR_OPENGL_VERSION;

docs/CHANGELOG.txt

@@ -39,6 +39,7 @@ Breaking Changes:
 
 Other changes:
 
+- Backends: OpenGL3: Fixed GL loader crash when GL_VERSION returns NULL. (#6154, #4445, #3530)
 
 
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