how to use glVertexPointer

Started by lanhaiou, Aug 05 2012 08:32 AM

glVertexPointer

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#1 lanhaiou Members - Reputation: 101

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Posted 05 August 2012 - 08:32 AM

Hi,
I am pretty new to OPENGL, and could any one help me ? thanks !!

I have a texture which contains number of tiles (each tile is part of this texture).
now I want to draw all the tiles in one draw call : glDrawElements(), (every tile's vertex coordination is different).
something like:

glVertexPointer(); //set the vertex array,
glTexCoordPointer(); //set the coordinations of the tile in texture.
glDrawElements();

do I have to call glTexCoordPointer() to set the coordinations for every tile ? that will be 3 times call of above code if I want to draw 3 tiles.
is there any efficient way to handle that ?

thank you very much !!

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#2 V-man Members - Reputation: 785

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Posted 05 August 2012 - 06:27 PM

You can put your data in one large array and just setup the pointers once. One call to glVertexPointer and one to glTexCoordPointer.
A more efficient way would be to move up to GL 1.5 and start using VBO so that your vertices will be in video memory rather than local RAM.

Sig: http://glhlib.sourceforge.net
an open source GLU replacement library. Much more modern than GLU.
float matrix[16], inverse_matrix[16];
glhLoadIdentityf2(matrix);
glhTranslatef2(matrix, 0.0, 0.0, 5.0);
glhRotateAboutXf2(matrix, angleInRadians);
glhScalef2(matrix, 1.0, 1.0, -1.0);
glhQuickInvertMatrixf2(matrix, inverse_matrix);
glUniformMatrix4fv(uniformLocation1, 1, FALSE, matrix);
glUniformMatrix4fv(uniformLocation2, 1, FALSE, inverse_matrix);

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