I'm trying to draw transparent textures (text) in my app. Strangely, it works on the newest Nexus 7 and on my second generation Moto X but on the original Nexus 7 the textures are just black. I've got blending enabled and the texture is 512x512 so it's not a power-of-two issue. I'm also just using GL10 which should be supported on everything, right? Any reasons the textures wouldn't work on just this device?
gl.glEnable(GL10.GL_BLEND);
gl.glBlendFunc(GL10.GL_SRC_ALPHA, GL10.GL_ONE_MINUS_SRC_ALPHA);
gl.glEnable(GL10.GL_TEXTURE_2D);
// text drawn here
gl.glDisable(GL10.GL_TEXTURE_2D);
gl.glDisable(GL10.GL_BLEND);
And here's the texture initialization, where I load the texture atlas:
public void loadGlyphs(GL10 gl, Context context) {
Bitmap bitmap = BitmapFactory.decodeResource(context.getResources(), R.drawable.text_bitmap);
gl.glGenTextures(1, textures, 0);
gl.glBindTexture(GL10.GL_TEXTURE_2D, textures[0]);
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);
GLUtils.texImage2D(GL10.GL_TEXTURE_2D, 0, bitmap, 0);
bitmap.recycle();
}
Top shows what happens on the old Nexus 7. The bottom picture is a Moto X.
Edit: Here's a complete example. No transparency, doesn't draw anything on the old Nexus 7. If I get rid of the texture stuff it draws the square in white like it should.
MainActivity.java
import android.app.Activity;
import android.opengl.GLSurfaceView;
import android.os.Bundle;
public class MainActivity extends Activity {
private GLSurfaceView glView;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
glView = new TestView(this);
setContentView(glView);
}
@Override
protected void onPause() {
super.onPause();
glView.onPause();
}
@Override
protected void onResume() {
super.onResume();
glView.onResume();
}
}
TestView.java
import android.content.Context;
import android.opengl.GLSurfaceView;
public class TestView extends GLSurfaceView {
private TestRenderer renderer;
public TestView(Context context) {
super(context);
renderer = new TestRenderer(context);
setRenderer(renderer);
}
}
TestRenderer.java
import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.opengl.GLSurfaceView;
import android.opengl.GLU;
import android.opengl.GLUtils;
import java.nio.ByteBuffer;
import java.nio.ByteOrder;
import java.nio.FloatBuffer;
import javax.microedition.khronos.egl.EGLConfig;
import javax.microedition.khronos.opengles.GL10;
public class TestRenderer implements GLSurfaceView.Renderer {
private FloatBuffer floatBuffer;
private FloatBuffer textureBuffer;
private Context context;
private int[] textures;
public TestRenderer(Context context) {
this.context = context;
textures = new int[1];
}
public void onSurfaceCreated(GL10 gl, EGLConfig config) {
floatBuffer = ByteBuffer.allocateDirect(4 * 2 * 4).order(ByteOrder.nativeOrder()).asFloatBuffer();
floatBuffer.put(-0.5f);
floatBuffer.put(-0.5f);
floatBuffer.put(-0.5f);
floatBuffer.put(0.5f);
floatBuffer.put(0.5f);
floatBuffer.put(-0.5f);
floatBuffer.put(0.5f);
floatBuffer.put(0.5f);
floatBuffer.rewind();
textureBuffer = ByteBuffer.allocateDirect(4*2*4).order(ByteOrder.nativeOrder()).asFloatBuffer();
textureBuffer.put(0);
textureBuffer.put(1);
textureBuffer.put(0);
textureBuffer.put(0);
textureBuffer.put(1);
textureBuffer.put(1);
textureBuffer.put(1);
textureBuffer.put(0);
textureBuffer.rewind();
Bitmap bitmap = BitmapFactory.decodeResource(context.getResources(), R.drawable.test);
gl.glGenTextures(1, textures, 0);
gl.glBindTexture(GL10.GL_TEXTURE_2D, textures[0]);
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);
GLUtils.texImage2D(GL10.GL_TEXTURE_2D, 0, bitmap, 0);
bitmap.recycle();
}
public void onSurfaceChanged(GL10 gl, int w, int h) {
gl.glMatrixMode(GL10.GL_PROJECTION);
gl.glLoadIdentity();
GLU.gluPerspective(gl, 45.0f, (float) w / (float) h, 0.1f, 100.0f);
gl.glMatrixMode(GL10.GL_MODELVIEW);
gl.glLoadIdentity();
}
public void onDrawFrame(GL10 gl) {
gl.glLoadIdentity();
gl.glClearColor(0.0f, 0.0f, 0.0f, 1.0f);
gl.glClear(GL10.GL_COLOR_BUFFER_BIT);
gl.glTranslatef(0.0f, 0.0f, -5.0f);
gl.glColor4f(1.0f, 1.0f, 1.0f, 1.0f);
gl.glEnable(GL10.GL_TEXTURE_2D);
gl.glEnableClientState(GL10.GL_VERTEX_ARRAY);
gl.glEnableClientState(GL10.GL_TEXTURE_COORD_ARRAY);
gl.glFrontFace(GL10.GL_CW);
gl.glVertexPointer(2, GL10.GL_FLOAT, 0, floatBuffer);
gl.glTexCoordPointer(2, GL10.GL_FLOAT, 0, textureBuffer);
gl.glDrawArrays(GL10.GL_TRIANGLE_STRIP, 0, 4);
gl.glDisableClientState(GL10.GL_TEXTURE_COORD_ARRAY);
gl.glDisableClientState(GL10.GL_VERTEX_ARRAY);
gl.glDisable(GL10.GL_TEXTURE_2D);
}
}
Edit: Here's an example I found online. If I disable GL_TEXTURE_2D I get a white square. If I enable GL_TEXTURE_2D I get nothing.
MainActivity public class MainActivity extends Activity {
private GLSurfaceView glSurfaceView;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
requestWindowFeature(Window.FEATURE_NO_TITLE);
getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN,
WindowManager.LayoutParams.FLAG_FULLSCREEN);
glSurfaceView = new GLSurfaceView(this);
glSurfaceView.setRenderer(new GlRenderer(this));
setContentView(glSurfaceView);
}
@Override
protected void onResume() {
super.onResume();
glSurfaceView.onResume();
}
@Override
protected void onPause() {
super.onPause();
glSurfaceView.onPause();
}
}
GlRenderer
public class GlRenderer implements Renderer {
private Square square;
private Context context;
public GlRenderer(Context context) {
this.context = context;
this.square = new Square();
}
@Override
public void onDrawFrame(GL10 gl) {
gl.glClear(GL10.GL_COLOR_BUFFER_BIT | GL10.GL_DEPTH_BUFFER_BIT);
gl.glLoadIdentity();
gl.glTranslatef(0.0f, 0.0f, -5.0f);
square.draw(gl);
}
@Override
public void onSurfaceChanged(GL10 gl, int width, int height) {
if(height == 0) {
height = 1;
}
gl.glViewport(0, 0, width, height);
gl.glMatrixMode(GL10.GL_PROJECTION);
gl.glLoadIdentity();
GLU.gluPerspective(gl, 45.0f, (float)width / (float)height, 0.1f, 100.0f);
gl.glMatrixMode(GL10.GL_MODELVIEW);
gl.glLoadIdentity();
}
@Override
public void onSurfaceCreated(GL10 gl, EGLConfig config) {
square.loadGLTexture(gl, this.context);
gl.glEnable(GL10.GL_TEXTURE_2D);
gl.glShadeModel(GL10.GL_SMOOTH);
gl.glClearColor(0.0f, 0.0f, 0.0f, 0.5f);
gl.glClearDepthf(1.0f);
gl.glEnable(GL10.GL_DEPTH_TEST);
gl.glDepthFunc(GL10.GL_LEQUAL);
gl.glHint(GL10.GL_PERSPECTIVE_CORRECTION_HINT, GL10.GL_NICEST);
}
}
Square
public class Square {
private FloatBuffer vertexBuffer;
private float vertices[] = {
-1.0f, -1.0f, 0.0f,
-1.0f, 1.0f, 0.0f,
1.0f, -1.0f, 0.0f,
1.0f, 1.0f, 0.0f
};
private FloatBuffer textureBuffer;
private float texture[] = {
0.0f, 1.0f,
0.0f, 0.0f,
1.0f, 1.0f,
1.0f, 0.0f
};
private int[] textures = new int[1];
public Square() {
ByteBuffer byteBuffer = ByteBuffer.allocateDirect(vertices.length * 4);
byteBuffer.order(ByteOrder.nativeOrder());
vertexBuffer = byteBuffer.asFloatBuffer();
vertexBuffer.put(vertices);
vertexBuffer.position(0);
byteBuffer = ByteBuffer.allocateDirect(texture.length * 4);
byteBuffer.order(ByteOrder.nativeOrder());
textureBuffer = byteBuffer.asFloatBuffer();
textureBuffer.put(texture);
textureBuffer.position(0);
}
public void loadGLTexture(GL10 gl, Context context) {
Bitmap bitmap = BitmapFactory.decodeResource(context.getResources(),
R.drawable.test);
gl.glGenTextures(1, textures, 0);
gl.glBindTexture(GL10.GL_TEXTURE_2D, textures[0]);
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);
GLUtils.texImage2D(GL10.GL_TEXTURE_2D, 0, bitmap, 0);
bitmap.recycle();
}
public void draw(GL10 gl) {
gl.glBindTexture(GL10.GL_TEXTURE_2D, textures[0]);
gl.glEnableClientState(GL10.GL_VERTEX_ARRAY);
gl.glEnableClientState(GL10.GL_TEXTURE_COORD_ARRAY);
gl.glFrontFace(GL10.GL_CW);
gl.glVertexPointer(3, GL10.GL_FLOAT, 0, vertexBuffer);
gl.glTexCoordPointer(2, GL10.GL_FLOAT, 0, textureBuffer);
gl.glDrawArrays(GL10.GL_TRIANGLE_STRIP, 0, vertices.length / 3);
gl.glDisableClientState(GL10.GL_VERTEX_ARRAY);
gl.glDisableClientState(GL10.GL_TEXTURE_COORD_ARRAY);
}
}
After much troubleshooting, I was able to solve the problem on both devices (and presumably all devices) by adding texture wrapping as so:
I'm not sure why this was necessary for two devices but not the other two, though.