📄 evalcoord.html

📁 计算机图形学～想必是很多人需要的～在此共享一下
💻 HTML
字号:
<HTML><BODY><PRE>     <STRONG>NAME</STRONG>	  <STRONG>glEvalCoord1d,</STRONG> <STRONG>glEvalCoord1f,</STRONG>	<STRONG>glEvalCoord2d,</STRONG> <STRONG>glEvalCoord2f,</STRONG>	  <STRONG>glEvalCoord1dv,</STRONG> <STRONG>glEvalCoord1fv,</STRONG> <STRONG>glEvalCoord2dv,</STRONG>	  <STRONG>glEvalCoord2fv</STRONG> - evaluate enabled one- and two-dimensional	  maps     <STRONG>C</STRONG> <STRONG>SPECIFICATION</STRONG>	  void <STRONG>glEvalCoord1d</STRONG>( GLdouble <EM>u</EM> )	  void <STRONG>glEvalCoord1f</STRONG>( GLfloat <EM>u</EM>	)	  void <STRONG>glEvalCoord2d</STRONG>( GLdouble <EM>u</EM>,			      GLdouble <EM>v</EM> )	  void <STRONG>glEvalCoord2f</STRONG>( GLfloat <EM>u</EM>,			      GLfloat <EM>v</EM>	)     <STRONG>PARAMETERS</STRONG>	  <EM>u</EM>  Specifies a value that is the domain coordinate u to the	     basis function defined in a previous <STRONG>glMap1</STRONG> or <STRONG>glMap2</STRONG>	     command.	  <EM>v</EM>  Specifies a value that is the domain coordinate v to the	     basis function defined in a previous <STRONG>glMap2</STRONG> command.	     This argument is not present in a <STRONG>glEvalCoord1</STRONG> command.     <STRONG>C</STRONG> <STRONG>SPECIFICATION</STRONG>	  void <STRONG>glEvalCoord1dv</STRONG>( const GLdouble *<EM>u</EM> )	  void <STRONG>glEvalCoord1fv</STRONG>( const GLfloat *<EM>u</EM>	)	  void <STRONG>glEvalCoord2dv</STRONG>( const GLdouble *<EM>u</EM> )	  void <STRONG>glEvalCoord2fv</STRONG>( const GLfloat *<EM>u</EM>	)     <STRONG>PARAMETERS</STRONG>	  <EM>u</EM>    Specifies a pointer to an array containing either one	       or two domain coordinates.  The first coordinate	is u.	       The second coordinate is	v, which is present only in	       <STRONG>glEvalCoord2</STRONG> versions.     <STRONG>DESCRIPTION</STRONG>	  <STRONG>glEvalCoord1</STRONG> evaluates enabled one-dimensional maps at	  argument <EM>u</EM>.  <STRONG>glEvalCoord2</STRONG> does the same for two-dimensional	  maps using two domain	values,	<EM>u</EM> and <EM>v</EM>.  To define a map,	  call <STRONG>glMap1</STRONG> and <STRONG>glMap2</STRONG>; to enable and	disable	it, call	  <STRONG>glEnable</STRONG> and <STRONG>glDisable</STRONG>.	  When one of the <STRONG>glEvalCoord</STRONG> commands is issued, all	  currently enabled maps of the	indicated dimension are	  evaluated.  Then, for	each enabled map, it is	as if the	  corresponding	GL command had been issued with	the computed	  value.  That is, if <STRONG>GL_MAP1_INDEX</STRONG> or <STRONG>GL_MAP2_INDEX</STRONG> is	  enabled, a <STRONG>glIndex</STRONG> command is	simulated.  If <STRONG>GL_MAP1_COLOR_4</STRONG>	  or <STRONG>GL_MAP2_COLOR_4</STRONG> is	enabled, a <STRONG>glColor</STRONG> command is	  simulated.  If <STRONG>GL_MAP1_NORMAL</STRONG>	or <STRONG>GL_MAP2_NORMAL</STRONG> is enabled,	  a normal vector is produced, and if any of	  <STRONG>GL_MAP1_TEXTURE_COORD_1</STRONG>, <STRONG>GL_MAP1_TEXTURE_COORD_2</STRONG>,	  <STRONG>GL_MAP1_TEXTURE_COORD_3</STRONG>, <STRONG>GL_MAP1_TEXTURE_COORD_4</STRONG>,	  <STRONG>GL_MAP2_TEXTURE_COORD_1</STRONG>, <STRONG>GL_MAP2_TEXTURE_COORD_2</STRONG>,	  <STRONG>GL_MAP2_TEXTURE_COORD_3</STRONG>, or <STRONG>GL_MAP2_TEXTURE_COORD_4</STRONG> is	  enabled, then	an appropriate <STRONG>glTexCoord</STRONG> command is	  simulated.	  For color, color index, normal, and texture coordinates the	  GL uses evaluated values instead of current values for those	  evaluations that are enabled,	and current values otherwise,	  However, the evaluated values	do not update the current	  values.  Thus, if <STRONG>glVertex</STRONG> commands are interspersed with	  <STRONG>glEvalCoord</STRONG> commands,	the color, normal, and texture	  coordinates associated with the <STRONG>glVertex</STRONG> commands are	not	  affected by the values generated by the <STRONG>glEvalCoord</STRONG>	  commands, but	only by	the most recent	<STRONG>glColor</STRONG>, <STRONG>glIndex</STRONG>,	  <STRONG>glNormal</STRONG>, and	<STRONG>glTexCoord</STRONG> commands.	  No commands are issued for maps that are not enabled.	 If	  more than one	texture	evaluation is enabled for a particular	  dimension (for example, <STRONG>GL_MAP2_TEXTURE_COORD_1</STRONG> and	  <STRONG>GL_MAP2_TEXTURE_COORD_2</STRONG>), then only the evaluation of	the	  map that produces the	larger number of coordinates (in this	  case,	<STRONG>GL_MAP2_TEXTURE_COORD_2</STRONG>) is carried out.	  <STRONG>GL_MAP1_VERTEX_4</STRONG> overrides <STRONG>GL_MAP1_VERTEX_3</STRONG>, and	  <STRONG>GL_MAP2_VERTEX_4</STRONG> overrides <STRONG>GL_MAP2_VERTEX_3</STRONG>, in the same	  manner.  If neither a	three- nor a four-component vertex map	  is enabled for the specified dimension, the <STRONG>glEvalCoord</STRONG>	  command is ignored.	  If you have enabled automatic	normal generation, by calling	  <STRONG>glEnable</STRONG> with	argument <STRONG>GL_AUTO_NORMAL</STRONG>, <STRONG>glEvalCoord2</STRONG>	  generates surface normals analytically, regardless of	the	  contents or enabling of the <STRONG>GL_MAP2_NORMAL</STRONG> map.  Let	      Pp   Pp	  m = -- X --	      Pu   Pv	  Then the generated normal n is	      <STRONG>_</STRONG>	  n=_____	    ||m||	  If automatic normal generation is disabled, the	  corresponding	normal map <STRONG>GL_MAP2_NORMAL</STRONG>, if enabled, is used	  to produce a normal.	If neither automatic normal generation	  nor a	normal map is enabled, no normal is generated for	  <STRONG>glEvalCoord2</STRONG> commands.     <STRONG>ASSOCIATED</STRONG>	<STRONG>GETS</STRONG>	  <STRONG>glIsEnabled</STRONG> with argument <STRONG>GL_MAP1_VERTEX_3</STRONG>	  <STRONG>glIsEnabled</STRONG> with argument <STRONG>GL_MAP1_VERTEX_4</STRONG>	  <STRONG>glIsEnabled</STRONG> with argument <STRONG>GL_MAP1_INDEX</STRONG>	  <STRONG>glIsEnabled</STRONG> with argument <STRONG>GL_MAP1_COLOR_4</STRONG>	  <STRONG>glIsEnabled</STRONG> with argument <STRONG>GL_MAP1_NORMAL</STRONG>	  <STRONG>glIsEnabled</STRONG> with argument <STRONG>GL_MAP1_TEXTURE_COORD_1</STRONG>	  <STRONG>glIsEnabled</STRONG> with argument <STRONG>GL_MAP1_TEXTURE_COORD_2</STRONG>	  <STRONG>glIsEnabled</STRONG> with argument <STRONG>GL_MAP1_TEXTURE_COORD_3</STRONG>	  <STRONG>glIsEnabled</STRONG> with argument <STRONG>GL_MAP1_TEXTURE_COORD_4</STRONG>	  <STRONG>glIsEnabled</STRONG> with argument <STRONG>GL_MAP2_VERTEX_3</STRONG>	  <STRONG>glIsEnabled</STRONG> with argument <STRONG>GL_MAP2_VERTEX_4</STRONG>	  <STRONG>glIsEnabled</STRONG> with argument <STRONG>GL_MAP2_INDEX</STRONG>	  <STRONG>glIsEnabled</STRONG> with argument <STRONG>GL_MAP2_COLOR_4</STRONG>	  <STRONG>glIsEnabled</STRONG> with argument <STRONG>GL_MAP2_NORMAL</STRONG>	  <STRONG>glIsEnabled</STRONG> with argument <STRONG>GL_MAP2_TEXTURE_COORD_1</STRONG>	  <STRONG>glIsEnabled</STRONG> with argument <STRONG>GL_MAP2_TEXTURE_COORD_2</STRONG>	  <STRONG>glIsEnabled</STRONG> with argument <STRONG>GL_MAP2_TEXTURE_COORD_3</STRONG>	  <STRONG>glIsEnabled</STRONG> with argument <STRONG>GL_MAP2_TEXTURE_COORD_4</STRONG>	  <STRONG>glIsEnabled</STRONG> with argument <STRONG>GL_AUTO_NORMAL</STRONG>	  <STRONG>glGetMap</STRONG>     <STRONG>SEE</STRONG> <STRONG>ALSO</STRONG>	  <STRONG>glBegin</STRONG>, <STRONG>glColor</STRONG>, <STRONG>glEnable</STRONG>, <STRONG>glEvalMesh</STRONG>, <STRONG>glEvalPoint</STRONG>,	  <STRONG>glIndex</STRONG>, <STRONG>glMap1</STRONG>, <STRONG>glMap2</STRONG>, <STRONG>glMapGrid</STRONG>, <STRONG>glNormal</STRONG>,	<STRONG>glTexCoord</STRONG>,	  <STRONG>glVertex</STRONG></PRE></BODY></HTML>
⌨️ 快捷键说明

复制代码 Ctrl + C
搜索代码 Ctrl + F
全屏模式 F11
切换主题 Ctrl + Shift + D
显示快捷键 ?
增大字号 Ctrl + =
减小字号 Ctrl + -