What is the difference between glClient *** gl ***?

Question

I study GLES. There are many paired functions, such as glClientActiveTexture/ glActiveTexture. What is the difference between the two? (Especially in case glClientActiveTexture)

Answer 1

From openGL documentation :

• glActiveTexture glActiveTexture determines which texture units will follow the state states of the texture.
• glClientActiveTexture selects the client state parameters of the vertex array that should be changed using glTexCoordPointer.

, glClientActiveTexture glTexCoordPointer ( ). , glActiveTexture glTexCoord ( ( OpenGL ES (AFAIK)).

Answer 2

Kenji, ( , OpenGL ES).

, ( ).

• : (, GL_TEXTURE_2D). glActiveTexture
• : . (, 2D). glBindTexture.
• : , ( , ) (, ), . //, glGenTextures, ( ) glBindTexture .

: , .

2D- (), 2D-, - 2D- 2D . glActiveTexture , glBindTexture, glBindTexture , , .

, , , texcoords. - OpenGL/GLSL, texcoords /, texcoords . , texcoord . , , - , glClientActiveTexture. , , , glActiveTexture , , gl_MultiTexCoord ( ) texcoords, glTexCoordPointer.

glActiveTexture , glClientActiveTexture - texcoord. API- , , :

• glActiveTexture , , glBindTexture. glMultiTexCoord, glTexCoord glTexCoordPointer, texcoords, .
• glClientActiveTexture , , , glTexCoordPointer. glBindTexture, , texcoords.
  • glMultiTexCoord, DSA glTexCoord, 0 (GL_TEXTURE0). glTexCoordPointer , , glTexCoordPointer glVertexAttribPointer, glClientActiveTexture. , glClientActiveTexture , , glWhateverPointer.
• glActiveTexture + glBindTexture all . glClientActiveTexture + glTexCoordPointer, DrawArrays/DrawElements glVertexAttribPointer.

OpenGL . :

• ( glBegin/glEnd) GLSL, 130 , glMultiTexCoord texcoords.
• glBindVertexArray glBindBuffer + glDrawArrays/glDrawElements, , glVertexPointer, glNormalPointer, glTexCoordPointer .., .
• glBindVertexArray + glDrawArrays/glDrawElements, , glVertexAttribPointer, .

API 2D-, ( ):

• :

  • init
  • draw
  • shutdown

• DrawElements, VertexAttribPointer:

  • init
  • draw
  • shutdown
  • ( , )
  • ( , )

• DrawElements VertexAttribPointer:

  • init
  • draw
  • shutdown

.

• glMultiTexCoord 0,0,0,1. glMultiTexCoord2f == s, t, 0,1
• GL_TEXTURE0 + i, i.
• GL_TEXTURE0 + i, 0 - GL_MAX_TEXTURE_COORDS -1.
• GL_MAX_TEXTURE_COORDS , 80 OpenGL 4.0.
• glMultiTexCoord OpenGL 1.3+ ARB_multitexture
• glActiveTexture glBindTexture glBegin glEnd. , .