̾??¶

gluPerspective - Ʃ???ͱƹ????????ꤹ??

????¶

void gluPerspective( GLdouble fovy,

	GLdouble aspect,
	GLdouble zNear,
	GLdouble zFar )

??????¶

fovy

y ?????λ????Ѥ????ꤹ?롣 ñ?̤??ٿ??Ǥ??롣

aspect

?????ڥ??????????ꤹ?롣 ?????ͤ? x ?????λ??????????롣 ?????ڥ??????? x (??)?? y (?⤵)?????Ǥ??롣

zNear

?????ȡ??????˶ᤤ¦?Υ????åԥ???ʿ?̤ε?Υ?????ꤹ??(???????Ǥ???)??

zFar

?????ȡ?????????????¦?Υ????åԥ???ʿ?̤ε?Υ?????ꤹ??(???????Ǥ???)??

????¶

gluPerspective ?ϡ??????ѿ???(viewing frustum)??????ɺ?ɸ?? ???Ф??ƻ??ꤹ?롣 $\mathrm{aspect}=2.0$ means ????Ū?ˤϡ?gluPerspective ?ǻ??ꤹ?륢???ڥ??????ϡ? ???????б??????ӥ塼?ݡ??ȤΥ????ڥ???????Ʊ???ˤʤ??٤??Ǥ??롣 ?㤨?? "aspect" ~=~ 2.0 $?ʤ??С???\neg ?Ԥ?<i></i>\mathrm{<i>x</i>}<i></i>?????\lambda ????Ѥ?<i></i>\mathrm{<i>y</i>}<i></i>?????\lambda ????Ѥ?2?ܤˤʤ롣..?ӥ塼?ݡ??Ȥ??????⤵??2?ܤʤ??С????????Ĥळ?Ȥʤ??ӥ塼?ݡ?????ɽ???????롣.P..<b></b>\mathrm{<b>gluPerspective</b>}<b></b>?????ä??????ˤϡ????ߤ\iota ??󤬳ݤ??????롣??????<b></b>\mathrm{<b>gluPerspective</b>}<b></b>?????ä???????????????<b></b>\mathrm{<b>glMultMatrix</b>}<b></b>???ƤӽФ?????????Ʊ?ͤ?ư???Ǥ??롣..?軻???Ԥ??{\rm T}ǤϤʤ???Ʃ???ͱƹ????򸽺ߤ\iota ??󥹥??å??˥????ɤ????ˤϡ?<b></b>\mathrm{<b>gluPerspective</b>}<b></b>??????<b></b>\mathrm{<b>glLoadIdentity</b>}<b></b>???ƤӽФ??Ƥ??????ȡ?.P.<i></i>\mathrm{<i>f</i>}<i></i>??.\mathrm{sp}.\mathrm{ce}.\mathrm{EQ}f=\mathrm{cotangent}\left(\frac{\mathrm{fovy}}{2}\right)$ ?Τ褦???????????Ƥ??????硢 ???????????????ϼ??Τ褦?ˤʤ?:

$\left(\begin{array}{cccc}\frac{f}{\mathrm{aspect}}& 0& 0& 0\\ 0& f& 0& 0\\ 0& 0& \frac{\mathrm{zFar}+\mathrm{zNear}}{\mathrm{zNear}-\mathrm{zFar}}& \frac{2*\mathrm{zFar}*\mathrm{zNear}}{\mathrm{zNear}-\mathrm{zFar}}\\ 0& 0& -1& 0\end{array}\right)$

????¶

?ǥץ??Хåե??????٤ϡ?zNear ?????? zFar ?˻??ꤷ?? ?ͤαƶ????????롣 zNear ???Ф??? zFar ????Ψ???礭???ۤɡ? ?ߤ??˶ᤤ???̤??ǥץ??Хåե??????̤????ݤθ?Ψ?ϰ????ʤäƤ????? ?⤷

$r=\frac{\mathrm{zFar}}{\mathrm{zNear}}$

?ʤ??С? ${\log }_{2}r$ bits of depth buffer precision are lost. ?ǥץ??Хåե??????٤Ϥ??????? ${\log }_{2}r$ ?ӥåȼ??????롣 $r$ approaches infinity as zNear approaches 0, zNear ?? 0 ?˶??դ??Ƥ????? $r$ ??̵?????˶??դ??Ƥ??????ᡢ zNear ?? 0 ?????ꤷ?ƤϤʤ??ʤ???

??Ϣ????¶

glFrustum, glLoadIdentity, glMultMatrix, gluOrtho2D