Hi Tom,
Thanks for the suggestion about GLUtils.
I went back & found that the TriangleRenderer.java example had been
updated some time ago to use this method which is as you say is *much*
more efficient (faster) & simpler than using a ByteBuffer and doing
the color conversions.
( It pays to revisit the examples with new sdk releases ! )
Regards Gary
On Jul 3, 11:04 pm, Tom Gibara <m...@tomgibara.com> wrote:
> Also you can use glTexSubImage2D() if only a portion of your bitmap is
> changing. For these sorts of operations android.opengl.GLUtils will be
> *much* more efficient (and simpler) than your current approach of populating
> a ByteBuffer since the native helper methods can access the Bitmap pixel
> data directly.
> Tom
>
> 2009/7/2 Bruce Rees <baree...@gmail.com>
>
>
>
> > Hi All,
>
> > I have a texture-mapped cube based in part on the Kube API demo and
> > the Textured Cube example from anddev.org, It is working fine using
> > bitmaps loaded from R.drawable.. what I need to do now is to make the
> > texture for each face dynamic (using Bitmaps created in code). I'm
> > having trouble understanding how to change the textures on the fly and
> > I'm hoping someone can point me in the right direction..
>
> > This is the code that initially sets a texture:
>
> > gl.glBindTexture(GL10.GL_TEXTURE_2D, texBuf.get(num));
> > Bitmap bmp =
> > BitmapFactory.decodeResource(context.getResources(),
> > id);
> > int pixels[] = new int[TEX_SIZE * TEX_SIZE];
> > bmp.getPixels(pixels, 0, TEX_SIZE, 0, 0, TEX_SIZE,
> > TEX_SIZE);
> > int pix1[] = new int[TEX_SIZE * TEX_SIZE];
> > for (int i = 0; i < TEX_SIZE; i++)
> > {
> > for (int j = 0; j < TEX_SIZE; j++)
> > {
> > //correction of R and B
> > int pix = pixels[i * TEX_SIZE + j];
> > int pb = (pix >> 16) & 0xff;
> > int pr = (pix << 16) & 0x00ff0000;
> > int px1 = (pix & 0xff00ff00) | pr | pb;
> > //correction of rows
> > pix1[(TEX_SIZE - i - 1) * TEX_SIZE + j] =
> > px1;
> > }
> > }
>
> > IntBuffer tbuf = IntBuffer.wrap(pix1);
> > tbuf.position(0);
> > gl.glTexImage2D(GL10.GL_TEXTURE_2D, 0, GL10.GL_RGBA,
> > TEX_SIZE,
> > TEX_SIZE, 0, GL10.GL_RGBA, GL10.GL_UNSIGNED_BYTE, tbuf);
> > gl.glTexParameterx(GL10.GL_TEXTURE_2D,
> > GL10.GL_TEXTURE_MIN_FILTER,
> > GL10.GL_LINEAR);
> > gl.glTexParameterx(GL10.GL_TEXTURE_2D,
> > GL10.GL_TEXTURE_MAG_FILTER,
> > GL10.GL_LINEAR);
>
> > What would I need to change in this code to allow an existing texture
> > to be replaced (eg. a new Bitmap would be passed in instead of loading
> > the resource, but when I try this the texture remains unchanged).
>
> > Thanks!
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