How to draw two or more rectangles in OpenGL ES 1.x

[axfo]

Hi!

I am new in OpenGL. Just started to play with drawing triangles and rectangles.
When I want to draw one rectangle I have to define 4 vertices.
Then I call:

glVertexPointer(2, GL_FLOAT, 0, squareVertices);
glColorPointer(4, GL_UNSIGNED_BYTE, 0, squareColors);

glDrawArrays(GL_TRIANGLE_STRIP, 0, 4);

Everything is working and I can see the results in the simulator.

But how to draw to two or more separate rectangles which don't touch each other with one call to glDrawArrays?
Is it possible? When I add next vertices to the array and increment the count
it does not work.

Cheers
axfo

[warmi]

Originally Posted by axfo

Hi!

I am new in OpenGL. Just started to play with drawing triangles and rectangles.
When I want to draw one rectangle I have to define 4 vertices.
Then I call:

glVertexPointer(2, GL_FLOAT, 0, squareVertices);
glColorPointer(4, GL_UNSIGNED_BYTE, 0, squareColors);

glDrawArrays(GL_TRIANGLE_STRIP, 0, 4);

Everything is working and I can see the results in the simulator.

But how to draw to two or more separate rectangles which don't touch each other with one call to glDrawArrays?
Is it possible? When I add next vertices to the array and increment the count
it does not work.

Cheers
axfo

Use indices.

Your vertex array describes vertices ( points) while your index array would describe their relationships ( essentially triangles)

[axfo]

Originally Posted by warmi

Use indices.

Your vertex array describes vertices ( points) while your index array would describe their relationships ( essentially triangles)

Thanks a lot.
Just did it and works fine.
Instead of glDrawArrays I used glDrawElements.

One more question?
Is it possible to mix drawing rectangles with drawing textures in one function call?

Cheers
AF

[martiin59]

Originally Posted by axfo

Thanks a lot.
Just did it and works fine.
Instead of glDrawArrays I used glDrawElements.

One more question?
Is it possible to mix drawing rectangles with drawing textures in one function call?

Cheers
AF

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