# Beginner question about vertex arrays in OpenGL

Is there a special order in which vertices are entered into a vertex array? Currently I'm drawing single textures like this:

glBindTexture(GL_TEXTURE_2D, texName);
glVertexPointer(2, GL_FLOAT, 0, vertices);
glTexCoordPointer(2, GL_FLOAT, 0, coordinates);
glDrawArrays(GL_TRIANGLE_STRIP, 0, 4);


where vertices has four "xy pairs". This is working fine.

As a test I doubled the sizes of the vertices and coordinates arrays and changed the last line above to:

glDrawArrays(GL_TRIANGLE_STRIP, 0, 8);


since vertices now contains eight "xy pairs". I do see two textures (the second is intentionally offset from the first). However the textures are now distorted. I've tried passing GL_TRIANGLES to glDrawArrays instead of GL_TRIANGLE_STRIP but this doesn't work either. I'm so new to OpenGL that I thought it's best to just ask here :-)

Cheers!

• Define distorted? Are you trying to draw two separate quads on the screen and seeing triangles from the first to the second quad due to the tri-stripping? – Roger Perkins Jan 12 '11 at 17:51
• Thanks for the response. Yes I'm trying to draw two separate quads. I've read a bit more and it sounds like I should use GL_TRIANGLES instead of GL_TRIANGLE_STRIPS. When I use GL_TRIANGLES the distortion I see looks kinda like the first star is being folded over on itself while the second star is kinda stretched "out of the screen" (my game is 2D btw). – MrDatabase Jan 12 '11 at 17:58