+ if (!swrast->TexelBuffer) {
+#ifdef _OPENMP
+ const GLint maxThreads = omp_get_max_threads();
+
+ /* TexelBuffer memory allocation needs to be done in a critical section
+ * as this code runs in a parallel loop.
+ * When entering the section, first check if TexelBuffer has been
+ * initialized already by another thread while this thread was waiting.
+ */
+ #pragma omp critical
+ if (!swrast->TexelBuffer) {
+#else
+ const GLint maxThreads = 1;
+#endif
+
+ /* TexelBuffer is also global and normally shared by all SWspan
+ * instances; when running with multiple threads, create one per
+ * thread.
+ */
+ swrast->TexelBuffer =
+ malloc(ctx->Const.Program[MESA_SHADER_FRAGMENT].MaxTextureImageUnits * maxThreads *
+ SWRAST_MAX_WIDTH * 4 * sizeof(GLfloat));
+#ifdef _OPENMP
+ } /* critical section */
+#endif
+
+ if (!swrast->TexelBuffer) {
+ _mesa_error(ctx, GL_OUT_OF_MEMORY, "texture_combine");
+ return;
+ }
+ }
+
+ primary_rgba = malloc(span->end * 4 * sizeof(GLfloat));
+
+ if (!primary_rgba) {
+ _mesa_error(ctx, GL_OUT_OF_MEMORY, "texture_span");
+ return;
+ }
+
+ ASSERT(span->end <= SWRAST_MAX_WIDTH);