Thank you for that elaborate response. Your assumptions were all
correct (and I _did_ do a little too much work when I called
texImage2D, I only really needed to do that once, not every time I
updated the texture).
I now make a Canvas, which I draw my dynamic bitmap to, and just bind
that texture with texImage2D without using texSubImage2D. This works
perfectly, however, I feel a slight lag (although I haven't done any
performance tests on it) when I change the texture, that I didn't
notice before. I am certain my textures are at most 100x100 but
usually smaller on one dimension. As I don't replace the entire
texture, but only a portion of it, texSubImage2D might be the faster
choice - if only it worked. Also, I didn't get any GL errors
(gl.getError()) when using texSubImage2D.
So what's left for me is this:
* Is drawing the image to a canvas using drawBitmap the fastest way to
make a npot texture pot?
* Is texSubImage2D broken, in which case I should report it?
Regards, Mark Gjøl
On Sep 21, 2:32 am, Robert Green <rbgrn....@gmail.com> wrote:
> I'm a little confused by what you're doing.
>
> You're first calling texImage2D, which uploads mImg to vram as your
> texture.
> The very next call you make is texSubImage2D with an offset of 0 and
> 0, which uploads "texture" to vram, overwriting mImg.
>
> I'm assuming that:
>
> 1) mImg is 128x128
> 2) You first upload mImg to allocate a space as big as mImg
> 3) None of your textures are greater than mImg's width or height
>
> I'm going to suggest you change your code to do the following:
>
> 1) Create a bitmap of 128x128 or whatever size is appropriate for
> each dynamic texture, unless you have many different images you want
> to use.
> 2) Draw your texture to that bitmap
> 3) Upload that texture using regular texImage2D (in my tests, it's
> faster for full-size updates than using texSubImage2D).
> 4) If using one "scratchpad" bitmap, just erase it and reuse.
> Remember to .recycle() when done with it.
>
> basically, I suggest that you only upload once to vram and do any pre-
> processing on the client-side using a Bitmap or many Bitmaps depending
> on your app/game. That's how I do it. You can texImage2D the same
> textureId as many times as you like.
>
> Also, I recommend using GL_NICEST for perspective correction when
> dealing with large projected quads. It's not as fast as GL_FASTEST
> but for big triangles, it's the only way to guarantee they won't get
> really weird when cut off at near-Z.
>
> I have "renderer" classes that render game objects for my games. My
> renderers all look like this:
>
> public MyRenderer(GL10 gl) {
> // read geometry from disk resource
> reInit(gl);
>
> }
>
> public void reInit(GL10 gl) {
> // create VBOIds
> // upload VBOs
> // create textureIds
> // upload textures
>
> }
>
> public void draw(GL10 gl, GameObject obj) {
> // bind VBOs and TextureIds
> // transform for obj
> // draw elements
>
> }
>
> so if I wanted a dynamic texture, I'd just add in this:
>
> public void setTexture(GL10 gl, Bitmap texture) {
> // bind to appropriate textureId
> // upload whichTex
>
> }
>
> though I'd never let the main renderer hang on to bitmaps that an
> object render will be drawing - I would be managing that in the object
> renderer, so probably passing a sort of pointer or configuration,
> usually in the form of an int constant, like:
>
> public static final int TEXTURE_HAPPY_FACE = 0;
> public static final int TEXTURE_ANGRY_FACE = 1;
>
> public void setTexture(GL10 gl, int whichTex) {
> // bind to appropriate textureId
> // upload bitmap associated with whichTex
> if (whichTex == TEXTURE_HAPPY_FACE) {
> // upload happy face bitmap that we loadad probably in our
> constructor or somewhere before runtime.
> }
>
> }
>
> I know I'm not solving your exact problem, but I think if you followed
> this, you wouldn't have it anymore.
>
> If you want to stick with what you've got, throw some debug statements
> in there to print out the image size and the texture coordinates so
> you can make sure that it's not just a problem with those. If they
> look exactly right, Just make sure you're not doing something goofy
> like uploading an image that's bigger than the original.
>
> On Sep 20, 4:53 pm, Mark Gjøl <bitflips...@gmail.com> wrote:
>
> > I am developing an application that dynamically changes the texture of
> > an object. The textures I download from the internet and are of fairly
> > random aspect ratios. I apply these textures to a 2^nth texture using
> >GLUtils.texSubImage2D supplying the bitmap containing the texture, and
> > only use the part of the constructed texture that holds the newly
> > applied data.
>
> > This works fine when using textures with a greater width than height.
> > However, when using tall images, I sometimes get images that are
> > skewed. That is, it seems as if the texture is copied to the new
> > texture, but with the width being one off, so each line just one pixel
> > too short.
>
> > This happens consistently when using the same images, however it does
> > not happen for all tall images.
>
> > Code for applying the texture:
>
> > public void setTexture(GL10 gl, Bitmap texture) {
> > int height = texture.getHeight();
> > int width = texture.getWidth();
> > float heightRatio = ((float)height) / 128;
> > float widthRatio = ((float)width) / 128;
> > maspect = width / (float)height;
> > int[] textures = new int[1];
> > gl.glGenTextures(1, textures, 0);
> > mTextureID = textures[0];
> > gl.glBindTexture(GL10.GL_TEXTURE_2D, mTextureID);
>
> > gl.glTexParameterf(GL10.GL_TEXTURE_2D,
> > GL10.GL_TEXTURE_MIN_FILTER,
> > GL10.GL_NEAREST);
> > gl.glTexParameterf(GL10.GL_TEXTURE_2D,
> > GL10.GL_TEXTURE_MAG_FILTER,
> > GL10.GL_LINEAR);
>
> > gl.glTexParameterf(GL10.GL_TEXTURE_2D, GL10.GL_TEXTURE_WRAP_S,
> > GL10.GL_CLAMP_TO_EDGE);
> > gl.glTexParameterf(GL10.GL_TEXTURE_2D, GL10.GL_TEXTURE_WRAP_T,
> > GL10.GL_CLAMP_TO_EDGE);
>
> > gl.glTexEnvf(GL10.GL_TEXTURE_ENV, GL10.GL_TEXTURE_ENV_MODE,
> > GL10.GL_BLEND);
>
> > GLUtils.texImage2D(GL10.GL_TEXTURE_2D, 0, mImg, 0);
> > GLUtils.texSubImage2D(GL10.GL_TEXTURE_2D, 0, 0, 0, texture);
>
> > Buffer texBuf = ByteBuffer.allocateDirect(texture.getRowBytes
> > () * height);
> > texture.copyPixelsToBuffer(texBuf);
>
> > ByteBuffer tbb = ByteBuffer.allocateDirect(VERTS * 2 * 4);
> > tbb.order(ByteOrder.nativeOrder());
> > mTexBuffer = tbb.asFloatBuffer();
>
> > float tex[] = {
> > 0.0f, 0.0f,
> > 0.0f, heightRatio,
> > widthRatio, 0.0f,
> > widthRatio, heightRatio,
> > };
> > mTexBuffer.put(tex);
> > mTexBuffer.position(0);
>
> > }
>
> > Code for drawing it to screen:
>
> > public void draw(GL10 gl, long offset){
> > if(maspect < 1.25f){
> > szX = maspect;
> > szY = 1;
> > }else{
> > szX = 1.25f;
> > szY = 1 / maspect * 1.25f;
> > }
>
> > gl.glTexEnvx(GL10.GL_TEXTURE_ENV, GL10.GL_TEXTURE_ENV_MODE,
> > GL10.GL_REPLACE);
> > gl.glActiveTexture(GL10.GL_TEXTURE0);
> > gl.glBindTexture(GL10.GL_TEXTURE_2D, mTextureID);
> > gl.glFrontFace(GL10.GL_CCW);
> > gl.glVertexPointer(3, GL10.GL_FIXED, 0, mVertexBuffer);
> > gl.glEnable(GL10.GL_TEXTURE_2D);
> > gl.glTexCoordPointer(2, GL10.GL_FLOAT, 0, mTexBuffer);
>
> > gl.glTexParameterf(GL10.GL_TEXTURE_2D,
> > GL10.GL_TEXTURE_MIN_FILTER,GL10.GL_NEAREST);
> > gl.glTexParameterf
> > (GL10.GL_TEXTURE_2D,GL10.GL_TEXTURE_MAG_FILTER,GL10.GL_LINEAR);
> > gl.glTexParameterf(GL10.GL_TEXTURE_2D,
> > GL10.GL_TEXTURE_WRAP_S,GL10.GL_CLAMP_TO_EDGE);
> > gl.glTexParameterf(GL10.GL_TEXTURE_2D,
> > GL10.GL_TEXTURE_WRAP_T,GL10.GL_CLAMP_TO_EDGE);
>
> > gl.glPushMatrix();
>
> > gl.glTranslatef(x, y, z);
> > gl.glScalef(szX, szY, 1);
> > gl.glDrawElements(GL10.GL_TRIANGLE_STRIP, 4,
> > GL10.GL_UNSIGNED_BYTE,
> > mIndexBuffer);
>
> > gl.glPopMatrix();
>
> > }
>
> > This is really bugging me, so any help would be great!
--~--~---------~--~----~------------~-------~--~----~
You received this message because you are subscribed to the Google
Groups "Android Developers" group.
To post to this group, send email to android-developers@googlegroups.com
To unsubscribe from this group, send email to
android-developers+unsubscr...@googlegroups.com
For more options, visit this group at
http://groups.google.com/group/android-developers?hl=en
-~----------~----~----~----~------~----~------~--~---
