OpenGL的一個函式，用於指定深度緩衝比較值。
基本介紹
- 中文名：glDepthFunc
- 外文名：glDepthFunc
- 功能：指定用於深度緩衝比較值
- 參數說明：func指定深度緩衝比較函式
名稱,參數,參數取值範圍,錯誤碼,英文解釋,
名稱
glDepthFunc
參數
func：指定深度緩衝比較函式
參數取值範圍
GL_NEVER,GL_LESS,GL_EQUAL,GL_LEQUAL,GL_GREATER,GL_NOTEQUAL,GL_GEQUAL,GL_ALWAYS,預設值GL_LESS。
GL_NEVER,不通過（輸入的深度值不取代參考值）
GL_LESS,如果輸入的深度值小於參考值，則通過
GL_EQUAL,如果輸入的深度值等於參考值，則通過
GL_LEQUAL,如果輸入的深度值小於或等於參考值，則通過
GL_GREATER,如果輸入的深度值大於參考值，則通過
GL_NOTEQUAL,如果輸入的深度值不等於參考值，則通過
GL_GEQUAL,如果輸入的深度值大於或等於參考值，則通過
GL_ALWAYS,總是通過（輸入的深度值取代參考值）
錯誤碼
GL_INVALID_ENUM：參數值不合法。
GL_INVALID_OPERATION：在glBegin和glEnd之間調用。
英文解釋
NAME
glDepthFunc - specify the value used for depth buffer comparisons
C SPECIFICATION
void glDepthFunc( GLenum func )
PARAMETERS
func : Specifies the depth comparison function. Symbolic constants GL_NEVER, GL_LESS, GL_EQUAL, GL_LEQUAL, GL_GREATER, GL_NOTEQUAL, GL_GEQUAL, and GL_ALWAYS are accepted. The default value is GL_LESS.
DESCRIPTION
glDepthFunc specifies the function used to compare each incoming pixel z value with the z value present in the depth buffer. The comparison is performed only if depth testing is enabled. (See "glEnable" and glDisable of GL_DEPTH_TEST.)
func specifies the conditions under which the pixel will be drawn. The comparison functions are as follows:
GL_NEVER : Never passes.
GL_LESS : Passes if the incoming z value is less than the stored z value.
GL_EQUAL : Passes if the incoming z value is equal to the stored z value.
GL_LEQUAL : Passes if the incoming z value is less than or equal to the stored z value.
GL_GREATER :
Passes if the incoming z value is greater than the stored z value.
GL_NOTEQUAL :
Passes if the incoming z value is not equal to the stored z value.
GL_GEQUAL : Passes if the incoming z value is greater than or equal to the stored z value.
GL_ALWAYS : Always passes.
The default value of func is GL_LESS. Initially, depth testing is disabled.
ERRORS
GL_INVALID_ENUM is generated if func is not an accepted value.
GL_INVALID_OPERATION is generated if glDepthFunc is called between a call to glBegin and the corresponding call to glEnd.
ASSOCIATED GETS
glGet with argument GL_DEPTH_FUNC
glIsEnabled with argument GL_DEPTH_TEST
SEE ALSO
"glDepthRange" , "glEnable"
