#3597 Fix crash when RenderDebugGLSession is True

Author: marchcat

indra/llrender/llgl.cpp

@@ -2458,12 +2458,15 @@ void LLGLState::checkStates(GLboolean writeAlpha)
         return;
     }
 
-    GLint src;
-    GLint dst;
-    glGetIntegerv(GL_BLEND_SRC, &src);
-    glGetIntegerv(GL_BLEND_DST, &dst);
-    llassert_always(src == GL_SRC_ALPHA);
-    llassert_always(dst == GL_ONE_MINUS_SRC_ALPHA);
+    GLint srcRGB, dstRGB, srcAlpha, dstAlpha;
+    glGetIntegerv(GL_BLEND_SRC_RGB, &srcRGB);
+    glGetIntegerv(GL_BLEND_DST_RGB, &dstRGB);
+    glGetIntegerv(GL_BLEND_SRC_ALPHA, &srcAlpha);
+    glGetIntegerv(GL_BLEND_DST_ALPHA, &dstAlpha);
+    llassert_always(srcRGB == GL_SRC_ALPHA);
+    llassert_always(srcAlpha == GL_SRC_ALPHA);
+    llassert_always(dstRGB == GL_ONE_MINUS_SRC_ALPHA);
+    llassert_always(dstAlpha == GL_ONE_MINUS_SRC_ALPHA);
 
     // disable for now until usage is consistent
     //GLboolean colorMask[4];