Trying to draw textured triangles on device fails, but the emulator works. Why?
- by Dinedal
I have a series of OpenGL-ES calls that properly render a triangle and texture it with alpha blending on the emulator (2.0.1). When I fire up the same code on an actual device (Droid 2.0.1), all I get are white squares.
This suggests to me that the textures aren't loading, but I can't figure out why they aren't loading. All of my textures are 32-bit PNGs with alpha channels, under res/raw so they aren't optimized per the sdk docs.
Here's how I am loading my textures:
private void loadGLTexture(GL10 gl, Context context, int reasource_id, int texture_id)
{
//Get the texture from the Android resource directory
Bitmap bitmap = BitmapFactory.decodeResource(context.getResources(), reasource_id, sBitmapOptions);
//Generate one texture pointer...
gl.glGenTextures(1, textures, texture_id);
//...and bind it to our array
gl.glBindTexture(GL10.GL_TEXTURE_2D, textures[texture_id]);
//Create Nearest Filtered Texture
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);
//Different possible texture parameters, e.g. GL10.GL_CLAMP_TO_EDGE
gl.glTexParameterf(GL10.GL_TEXTURE_2D, GL10.GL_TEXTURE_WRAP_S, GL10.GL_REPEAT);
gl.glTexParameterf(GL10.GL_TEXTURE_2D, GL10.GL_TEXTURE_WRAP_T, GL10.GL_REPEAT);
//Use the Android GLUtils to specify a two-dimensional texture image from our bitmap
GLUtils.texImage2D(GL10.GL_TEXTURE_2D, 0, bitmap, 0);
//Clean up
bitmap.recycle();
}
Here's how I am rendering the texture:
//Clear
gl.glClear(GL10.GL_COLOR_BUFFER_BIT | GL10.GL_DEPTH_BUFFER_BIT);
//Enable vertex buffer
gl.glEnableClientState(GL10.GL_VERTEX_ARRAY);
gl.glEnableClientState(GL10.GL_TEXTURE_COORD_ARRAY);
gl.glVertexPointer(3, GL10.GL_FLOAT, 0, vertexBuffer);
gl.glTexCoordPointer(2, GL10.GL_FLOAT, 0, textureBuffer);
//Push transformation matrix
gl.glPushMatrix();
//Transformation matrices
gl.glTranslatef(x, y, 0.0f);
gl.glScalef(scalefactor, scalefactor, 0.0f);
gl.glColor4f(1.0f,1.0f,1.0f,1.0f);
//Bind the texture
gl.glBindTexture(GL10.GL_TEXTURE_2D, textures[textureid]);
//Draw the vertices as triangles
gl.glDrawElements(GL10.GL_TRIANGLES, indices.length, GL10.GL_UNSIGNED_BYTE, indexBuffer);
//Pop the matrix back to where we left it
gl.glPopMatrix();
//Disable the client state before leaving
gl.glDisableClientState(GL10.GL_VERTEX_ARRAY);
gl.glDisableClientState(GL10.GL_TEXTURE_COORD_ARRAY);
And here are the options I have enabled:
gl.glShadeModel(GL10.GL_SMOOTH); //Enable Smooth Shading
gl.glEnable(GL10.GL_DEPTH_TEST); //Enables Depth Testing
gl.glDepthFunc(GL10.GL_LEQUAL); //The Type Of Depth Testing To Do
gl.glEnable(GL10.GL_TEXTURE_2D);
gl.glEnable(GL10.GL_BLEND);
gl.glBlendFunc(GL10.GL_SRC_ALPHA,GL10.GL_ONE_MINUS_SRC_ALPHA);
Edit: I just tried supplying a BitmapOptions to the BitmapFactory.decodeResource() call, but this doesn't seem to fix the issue, despite manually setting the same preferredconfig, density, and targetdensity.
Edit2: As requested, here is a screenshot of the emulator working. The underlaying triangles are shown with a circle texture rendered onto it, the transparency is working because you can see the black background.
Here is a shot of what the droid does with the exact same code on it:
Edit3:
Here are my BitmapOptions, updated the call above with how I am now calling the BitmapFactory, still the same results as below:
sBitmapOptions.inPreferredConfig = Bitmap.Config.RGB_565;
sBitmapOptions.inDensity = 160;
sBitmapOptions.inTargetDensity = 160;
sBitmapOptions.inScreenDensity = 160;
sBitmapOptions.inDither = false;
sBitmapOptions.inSampleSize = 1;
sBitmapOptions.inScaled = false;
Here are my vertices, texture coords, and indices:
/** The initial vertex definition */
private static final 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
};
/** The initial texture coordinates (u, v) */
private static final float texture[] = {
//Mapping coordinates for the vertices
0.0f, 1.0f,
1.0f, 1.0f,
0.0f, 0.0f,
1.0f, 0.0f
};
/** The initial indices definition */
private static final byte indices[] = {
//Faces definition
0,1,3, 0,3,2
};
Is there anyway to dump the contents of the texture once it's been loaded into OpenGL ES? Maybe I can compare the emulator's loaded texture with the actual device's loaded texture?
I did try with a different texture (the default android icon) and again, it works fine for the emulator but fails to render on the actual phone.
Edit4: Tried switching around when I do texture loading. No luck. Tried using a constant offset of 0 to glGenTextures, no change.
Is there something that I'm using that the emulator supports that the actual phone does not?
Edit5: Per Ryan below, I resized my texture from 200x200 to 256x256, and the issue was NOT resolved.
Edit: As requested, added the calls to glVertexPointer and glTexCoordPointer above. Also, here is the initialization of vertexBuffer, textureBuffer, and indexBuffer:
ByteBuffer byteBuf = ByteBuffer.allocateDirect(vertices.length * 4);
byteBuf.order(ByteOrder.nativeOrder());
vertexBuffer = byteBuf.asFloatBuffer();
vertexBuffer.put(vertices);
vertexBuffer.position(0);
byteBuf = ByteBuffer.allocateDirect(texture.length * 4);
byteBuf.order(ByteOrder.nativeOrder());
textureBuffer = byteBuf.asFloatBuffer();
textureBuffer.put(texture);
textureBuffer.position(0);
indexBuffer = ByteBuffer.allocateDirect(indices.length);
indexBuffer.put(indices);
indexBuffer.position(0);
loadGLTextures(gl, this.context);
