Question

Here is my GL init code:

    gl.glEnable(GL10.GL_TEXTURE_2D);
    gl.glShadeModel(GL10.GL_SMOOTH);

    gl.glEnable(GL10.GL_BLEND);
    gl.glBlendFunc(GL10.GL_SRC_ALPHA, GL10.GL_ONE_MINUS_SRC_ALPHA);

    gl.glDisable(GL10.GL_DEPTH_TEST);
    gl.glMatrixMode(GL10.GL_PROJECTION);
    gl.glLoadIdentity();

    gl.glViewport(0, 0, width, height);

    float left = 0;
    float right = width;
    float top = height;
    float bottom = 0;
    gl.glOrthof(left, right, top, bottom, -1, 1);

    gl.glMatrixMode(GL10.GL_MODELVIEW);
    gl.glLoadIdentity();

    textures.put("ball", new Texture(gl, BitmapFactory.decodeResource(context.getResources(), R.drawable.ball)));

And here is my Texture class

public class Texture
{
int[] texture = new int[1];

static int real_width = 0;
static int real_height = 0;

Texture(GL10 gl, Bitmap bmp)
{
    real_width = bmp.getWidth();
    real_height = bmp.getHeight();

    gl.glGenTextures(1, texture, 0);

    gl.glTexParameterf(GL10.GL_TEXTURE_2D, GL10.GL_TEXTURE_MAG_FILTER, GL10.GL_NEAREST);
    gl.glTexParameterf(GL10.GL_TEXTURE_2D, GL10.GL_TEXTURE_MIN_FILTER, GL10.GL_NEAREST);

    GLUtils.texImage2D(GL10.GL_TEXTURE_2D, 0, bmp, 0);
    bmp.recycle();

    int error = gl.glGetError();
    if (error != GL10.GL_NO_ERROR)
    { 
        Log.e("ROLL", "GL Texture Load Error: " + GLU.gluErrorString(error));
    }
}

public void draw(GL10 gl, float x, float y)
{
    draw(gl, x, y, real_width, real_height);
}

public void draw(GL10 gl, float x, float y, float w, float h)
{
    gl.glEnableClientState(GL10.GL_TEXTURE_COORD_ARRAY);
    gl.glEnableClientState(GL10.GL_VERTEX_ARRAY);

    float[] vertices = { x + w, y + h, x, y + h, x, y, x + w, y };
    float[] textureCoords = { 1, 1, 0, 1, 0, 0, 1, 0 };

    ByteBuffer byteBuf = ByteBuffer.allocateDirect(vertices.length * 4);
    byteBuf.order(ByteOrder.nativeOrder());
    FloatBuffer vertexBuffer = byteBuf.asFloatBuffer();
    vertexBuffer.put(vertices);
    vertexBuffer.position(0);

    byteBuf = ByteBuffer.allocateDirect(textureCoords.length * 4);
    byteBuf.order(ByteOrder.nativeOrder());
    FloatBuffer textureBuffer = byteBuf.asFloatBuffer();
    textureBuffer.put(textureCoords);
    textureBuffer.position(0);

    gl.glBindTexture(GL10.GL_TEXTURE_2D, texture[0]);

    gl.glVertexPointer(2, GL10.GL_FLOAT, 0, vertexBuffer);
    gl.glTexCoordPointer(2, GL10.GL_FLOAT, 0, textureBuffer);

    gl.glDrawArrays(GL10.GL_TRIANGLE_FAN, 0, 4);

    gl.glDisableClientState(GL10.GL_VERTEX_ARRAY);
    gl.glDisableClientState(GL10.GL_TEXTURE_COORD_ARRAY);

}
}

The problem I get is where nothing is drawn but a white box in the correct shape and position of where the texture should be.

The image is size 50×50 and I thought it would be due to the power of 2 thing, but this problem also occurs on the emulator.

Also, I do get an error in the log and it says: “GL Texture Load Error: invalid value”, but I do not know what that means.

Finally, I draw the texture like this:

gl.glClearColor(0.0f, 0.0f, 0.0f, 1.0f);
gl.glClear(GL10.GL_COLOR_BUFFER_BIT);

textures.get("ball").draw(gl, 10, 10);

Answer 1

From glTexImage2D:

• GL_INVALID_VALUE is generated if internalFormat is not 1, 2, 3, 4, or
  one of the accepted resolution and format symbolic constants.
• GL_INVALID_VALUE is generated if width or height is less than 0 or
  greater than 2 + GL_MAX_TEXTURE_SIZE.
• GL_INVALID_VALUE is generated if non-power-of-two textures are not
  supported and the width or height cannot be represented as 2k + 2
  border for some integer value of k.
• GL_INVALID_VALUE is generated if border is not 0 or 1.

I assume that internal format would be wrong. What about trying to specify it for your own. More documentation about GLUtils you can find there.

But as first i see you haven’t bind texture before loading it to GL.

gl.glGenTextures(1, texture, 0);
gl.glBindTexture(GL10.GL_TEXTURE_2D, texture[0]); 

gl.glTexParameterf(GL10.GL_TEXTURE_2D, GL10.GL_TEXTURE_MAG_FILTER, GL10.GL_NEAREST);
gl.glTexParameterf(GL10.GL_TEXTURE_2D, GL10.GL_TEXTURE_MIN_FILTER, GL10.GL_NEAREST);

GLUtils.texImage2D(GL10.GL_TEXTURE_2D, 0, bmp, 0);
bmp.recycle();