OpenGL2: Fix rendering when r_hdr = 0 and r_floatLightmap = 1

code/renderergl2/tr_extensions.c

@@ -725,4 +725,7 @@ void GLimp_InitExtraExtensions()
 	{
 		ri.Printf(PRINT_ALL, result[2], extension);
 	}
+
+	// use float lightmaps?
+	glRefConfig.floatLightmap = (glRefConfig.textureFloat && glRefConfig.halfFloatPixel && r_floatLightmap->integer && r_hdr->integer);
 }