OpenGL ES 16-bit Textures?

Same problem. Have you found a solution for this?

Have a look at the Texture2D class in the Lunar Lander example. It creates textures that don't have alpha with this attribute: kTexture2DPixelFormat_RGB565.

This is the actual GL call:

glTexImage2D(GL TEXTURE2D, 0, GL_RGB, width, height, 0, GL_RGB, GL UNSIGNED_SHORT_5_65, data);

Tom

I have pixel data stored in RGBA, 32 bits per pixel, so I tried to let glTexImage2D convert this to some 16 Bit internal format with:
glTexImage2D(GL TEXTURE2D, 0, GL_RGBA4, width, height, 0, GL_RGBA8, GL UNSIGNEDBYTE, data);
This works with the Mac Version of my app, but not with the iPhone (Simulator) Version.

I haven't tried with glTexImage2D(GL TEXTURE2D, 0, GL_RGB, width, height, 0, GL_RGB, GL UNSIGNED_SHORT_5_65, data);
This means, I'd have to convert the pixel data to 565 before this call. The internal format of GL_RGB would then also be 16 bit (565)?

Message was edited by: charnold

Message was edited by: charnold

You don't need to convert it first from 32-bit to 16-bit. It happens automatically.

Tom

I mean, when I want to use glTexImage2D(GL TEXTURE2D, 0, GL_RGB, width, height, 0, GL_RGB, GL UNSIGNED_SHORT_5_65, data); I'd have to provide the data in 16 bit format.

I wanted to use automatic conversion with glTexImage2D(GL TEXTURE2D, 0, GL_RGBA4, width, height, 0, GL_RGBA8, GL UNSIGNEDBYTE, data); but GL_RGBA4 can't be used in OpenGL ES.

OpenGL ES generally doesn't provide any control over automatic conversions. You can only use unsized internal formats. If you want to load 16bit data, you must provide 16bit data to glTexImage2D.

Ok, this works, thanks!

I'm testing only on the iPhone Simulator at the moment (on a device asap). There is not much performance difference when using 16 or 32 bit textures. And the performance is not very high. My test program renders closed 3D rooms / no lighting / low polycount. With the OpenGL Desktop version, I get >1000 fps, with the iPhone Simulator only <60 fps.
Is there anything wrong? Is this the speed, I can expect on the device? (I know, the Simulator tells not much about the performance on the device, but what is your experience with real time 3D on the Simulator compared to the device?)

I'm just using a (slightly modified) version Texture2D.m of the LunarLander. With that one, you can provide 32-bit data and request a 565 texture format. This works without problems. Now, of course, it's hard to say if the conversion effectively took place. I haven't really checked that.

I don't have a desktop OpenGL program, so I really can't compare, but my experience on a MacMini (with the horrendously bad Intel graphics chip, so YMMV) is that the performance between the iPhone simulator and the actual hardware is somewhat equivalent. When I'm using a low poly count (<15000 polys), the iPhone hardware tends to be a bit faster than the simulator. When the poly counts goes up, the situation goes the opposite way.

It would be nice to hear what others have seen...