Textures

The GlTexture object

The GlTexture object will generate and allocate an OpenGL texture. The texture can then be used to read from it, render into it, attach to a framebuffer object and much more.

By default, the GlTexture is created with the GLES11Ext.GL_TEXTURE_EXTERNAL_OES texture target. This means that it is suitable for using it as the output of a SurfaceTexture:

val texture = GlTexture()
val surfaceTexture = SurfaceTexture(texture.id)
// Anytime the surface texture is passed new data, its contents are put into our GlTexture
// For example, we can receive the stream of video frames:
videoPlayer.setOutputSurface(surfaceTexture)
videoPlayer.play()

However, different targets can be specified within the texture constructor. When using GLES20.GL_TEXTURE_2D, you will probably want to use the constructor that accepts a width and height so that the buffer is actually allocated.

To render texture contents, just use a GlTextureProgram and pass the texture to it. See the programs page for details.

The GlFramebuffer object

The GlFramebuffer object will generate an OpenGL framebuffer object. You can attach textures to it by using GlFramebuffer.attach(), like so:

val texture = GlTexture()
val fbo = GlFramebuffer()
fbo.attach(texture, GLES20.GL_COLOR_ATTACHMENT0)

The attached textures will now receive the framebuffer contents.