On May 26, 1996, about 1715 Pacific daylight time, N177JM, a Cessna 177, operated by the owner/pilot, landed hard in Corvallis, Oregon, and was substantially damaged. The private pilot, the sole occupant, was not injured. Visual meteorological conditions prevailed and no flight plan had been filed. The personal flight was conducted under 14 CFR 91. The pilot stated that while he was on "short final" for runway 27 at the Corvallis Municipal Airport, the sun "came from behind a cloud with some glare and visibility problems...." He stated that he "could not tell [the airplane's] height [above the runway] accurately." He stated that he began to flare for landing after he "judged that the dark pavement was just below." The airplane landed hard on the main landing gear and porpoised forward onto the nose gear. The nose gear collapsed and the firewall was substantially damaged. No preimpact mechanical deficiencies were reported.