Question

OK so here is the code, it runs great, I just don’t see a texture. I see A White Square exactly the size I specified, just not the texture.

    public class MeshRect {

MyRect rect;
final int VERTEX_SIZE = (2 + 4 + 2) * 4;
FloatBuffer vertices;
ShortBuffer indices;
long MyID;

public MeshRect(MyRect rect, long ID) {
    super();
    this.rect = rect;
    MyID = ID;

    Assemble();

}

private void Assemble() {
    ByteBuffer byteBuffer = ByteBuffer.allocateDirect(4 * VERTEX_SIZE);
    byteBuffer.order(ByteOrder.nativeOrder());
    vertices = byteBuffer.asFloatBuffer();

    float x1 = (float) rect.BottomLeftCorner.x;
    float x2 = (float) rect.BottomRightCorner.x;
    float x3 = (float) rect.TopRightCorner.x;
    float x4 = (float) rect.TopLeftCorner.x;

    float y1 = (float) rect.BottomLeftCorner.y;
    float y2 = (float) rect.BottomRightCorner.y;
    float y3 = (float) rect.TopRightCorner.y;
    float y4 = (float) rect.TopLeftCorner.y;

    vertices.put(new float[] { x1, y1, 1, 1, 1, 1, 0.0f, 1.0f,
                                x2, y2, 1, 1, 1, 1, 1.0f, 1.0f,
                                x3, y3, 1, 1, 1, 1, 1.0f, 0.0f,
                                x4, y4, 1, 1, 1, 1, 0.0f, 0.0f });
                            //  x   y   r  g  b  A   u|s  v|t
    vertices.flip();

    byteBuffer = ByteBuffer.allocateDirect(6 * 2);
    byteBuffer.order(ByteOrder.nativeOrder());
    indices = byteBuffer.asShortBuffer();
    indices.put(new short[] { 0, 1, 2,
                                2, 3, 0 });
    indices.flip();
}

public FloatBuffer getVertices() {
    return vertices;
}

public ShortBuffer getIndices() {
    return indices;
}


public long getMyID() {
    return MyID;
}

public void Draw(int primitiveType, GL10 gl) {
    int numVertices = 6;

    //set vertex array
    gl.glEnableClientState(GL10.GL_VERTEX_ARRAY);
    vertices.position(0);
    gl.glVertexPointer(2, GL10.GL_FLOAT, VERTEX_SIZE, vertices);

    //set color
    gl.glEnableClientState(GL10.GL_COLOR_ARRAY);
    vertices.position(2);
    gl.glColorPointer(4, GL10.GL_FLOAT, VERTEX_SIZE, vertices);

    // set texture coords
    gl.glEnableClientState(GL10.GL_TEXTURE_COORD_ARRAY);
    vertices.position(6);
    gl.glTexCoordPointer(2, GL10.GL_FLOAT, VERTEX_SIZE, vertices);

    //set indices
    indices.position(0);
    gl.glDrawElements(primitiveType, numVertices, GL10.GL_UNSIGNED_SHORT, indices);

    //reset
    gl.glDisableClientState(GL10.GL_TEXTURE_COORD_ARRAY);
    gl.glDisableClientState(GL10.GL_COLOR_ARRAY);

}

}

and the render

    public void Render(GL10 gl, long deltaTime) {
    //render all
    Log.d("Game", "Render");

    gl.glViewport(0, 0, Screen.SCREEN_WIDTH, Screen.SCREEN_HEIGHT);
    gl.glClear(GL10.GL_COLOR_BUFFER_BIT);
    gl.glMatrixMode(GL10.GL_PROJECTION);
    gl.glLoadIdentity();
    gl.glOrthof(0, Screen.WIDTH_SCALE, 0, Screen.HEIGHT_SCALE, 1, -1);

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

    /**
     * so psuedo would look something like this
     * 
     * *.Update();
     * gl.glEnable(GL10.GL_TEXTURE_2D);
     * Textures.BindTexture(*.getCurrentTextureFileID);
     * MeshRects.draw((*.getMyRect) ,GL10.GL_TRIANGLES, gl);
     * 
     * update();
     * bind texture;
     * draw rect;
     */

    ball.Update(deltaTime);
    gl.glEnable(GL10.GL_TEXTURE_2D);
    texture.bind(gl);
    MeshRect mRect = new MeshRect(ball.getMyRect(), 1);
    mRect.Draw(GL10.GL_TRIANGLES, gl);

}

and the texture bind method

    public void bind(GL10 gl) {
    Log.d("Texture", "Bind");
    gl.glBindTexture(GL10.GL_TEXTURE_2D, TextureID);
}

I cant help but think I am missing something. This is my first dive into the world of OPEN GL, and this all this I created today from reading and testing code from all over the internet. There was no easy set resource on how to, so I have been making my own 2D engine as I learn so that I can re-use it for a long time to come.

Answer 1

I don’t see any texture setup code.

Where is glTexImage2D? Also I don’t see calls to set up filtering etc.

Here is a snippet that sets up texture (it’s in C, but you need something similar):

    GLubyte tex[] = {255, 0, 0, 255, 0, 255, 0, 255, 0, 255, 0, 255, 255, 0, 0, 255};
    glActiveTexture(GL_TEXTURE0);
    glGenTextures(1, &texId);
    glBindTexture(GL_TEXTURE_2D, texId);
    glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_MIN_FILTER,GL_LINEAR);
    glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_MAG_FILTER,GL_LINEAR);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
    glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, 2, 2, 0, GL_RGBA, GL_UNSIGNED_BYTE, tex);
    glBindTexture(GL_TEXTURE_2D, 0);