Gemara

27a (Rabah): If one fell off a roof in a normal wind, he pays four damages, but is exempt for Boshes (embarrassment).

(Mishnah): One pays for Boshes only if he intended to damage.

(Rabah): If he turned over (in midair to land on the person), he is liable even for Boshes.

(Beraisa): Obviously, "she stuck out her hand" to grab (the private parts of the man fighting her husband)! It says "and grabbed" to teach that intent to damage obligates payment for Boshes, even without intent to embarrass.

86a (Beraisa): If one intended to embarrass a Katan and embarrassed a Gadol, he pays the Gadol what is fitting for a Katan.

This is unlike R. Shimon. He exempts one who intended to embarrass Reuven and embarrassed Shimon!

He learns from murder. R. Shimon exempts one who intended to kill Reuven and killed Shimon - "he waited in ambush for him and rose against him." He is liable only if he intended for his victim.

Also regarding Boshes it says "she sent her hand and grabbed his private parts" - she is liable only if she intended for him.

86b (Mishnah): If a sleeping person embarrassed, he is exempt. If one fell off a roof and damaged and embarrassed, he is liable for damage and exempt for Boshes, unless he intended.

One pays for Boshes only if he intended to damage.

Rishonim

The Rif and Rosh (30b and 8:7) bring the Mishnah. (Their text of the Mishnah learned from "she stuck out her hand and grabbed Mevushav" that one pays for Boshes only if he intended.)

Hagahos Ashri: If one intended to embarrass David and embarrassed Moshe, he is exempt, just like R. Shimon exempts such a case regarding murder.

Nimukei Yosef (11b DH b'Ru'ach): One who can fall in a normal wind is totally negligent. The same applies to one who slept on the roof and fell due to turning over, not due to wind. It is known that people are prone to fall like this. Even though he is negligent, he is exempt for Boshes, for he did not intend to fall. If when falling he turned over to fall on someone, for his own benefit, he is liable for Boshes. Even though he did not intend to embarrass, since he knows that the other will be damaged, it is as if he intended to damage. This is like we say regarding Shabbos, that R. Shimon agrees that a Pesik Reishei (an inevitable consequence) is as if one intended for it.

Rambam (Hilchos Chovel u'Mazik 1:10): One pays for Boshes only if he intended - "she stuck out her hand". One who embarrassed without intent is exempt. Therefore, if one who was sleeping, or similar cases, embarrassed, he is exempt.

Rambam (12): If one fell off a roof in a normal wind, he pays four damages, but not for Boshes. for he is close to Mezid. If he turned over he is liable even for Boshes. Anyone who intends to damage, even if he did not intend to embarrass, pays for Boshes.

Rosh (2:15): If one fell off a roof in an abnormal wind and damaged, he pays Nezek, but not the four damages. If he fell in a normal wind, he pays four damages, for he is close to Mezid. He should not have gone up to a roof without a wall around it, for one can fall from it in a normal wind. He is exempt for Boshes, for he did not intend to embarrass. If he turned over to land on the person for his own benefit, he is liable even for Boshes.

Poskim

Shulchan Aruch (CM 421:1): One pays for Boshes only if he intended to embarrass. One who embarrassed without intent is exempt. Therefore, if a sleeping person embarrassed, he is exempt.

SMA (1): We learn payment for Boshes from "she grabbed Mevushav." Therefore, it must be similar, i.e. with intent.

Rema: Similarly, if David claims that Levi informed on David or stole from him, etc., even though he cannot prove it, he is exempt for he did not intend to embarrass him.

Yam Shel Shlomo (2:39): Rabah taught that if he turned in midair to land on someone, he is liable for Boshes. Rashi and the Tur say that he intended for his own benefit. I didn't see any Ge'onim explain differently. However, the Gemara says 'since he intended to damage, he is liable.' One who intended for his own benefit did not intend to damage! He does not want to harm the person below. He is liable four payments because one may not save himself even through another's money, all the more so through another's body! He does not pay for Boshes. Shogeg close to Mezid pays four damages, but not Boshes, because it is known that he did not intend to shame the victim, so it is not shameful. When he intended to harm him, it is shameful. This is why we exempt one who intended to embarrass David and embarrassed Moshe.

Gra (2): If two were fighting about who owns a particular land, and one of them informed to Nochrim (so they took it), the Rema (388:5) brings two opinions about whether or not one this is considered Moser. One says that Moser is only with intent to make the other lose. Here, he intended to retrieve his own. Damage is different. One is liable for four payments without intent to damage!

Question (Gilyon Maharsha): Above (420:38) we exempt for verbal Boshes, even if he intended to embarrass! In Sa'if 11, we obligate one who damaged just in order to save himself!

Shulchan Aruch (11): If one fell off a roof in a normal wind and injured, he pays the four payments, but is exempt from Boshes. If he fell in an abnormal wind, he pays only Nezek. If he turned over to land on the person for his benefit, he is liable even for Boshes. Anyone who intends to damage, even if he does not intend to embarrass, is liable for Boshes.