Question

I am having problems with my simple 2D OpenGL game.
Its really weird, I get textures to display correctly etc. but when I wanted to create particle effect with simple changing colors, for some reason it displays wrong colors from the buffer. I am using Android’s OpenGL ES 1.1 but its the same with any version of OpenGL that uses VBO’s.

I initialize the screen etc. and red triangle is displayed, but according to my color buffer it should be white, whats wrong?

        GL11 gl11 = (GL11) gl;
        gl11.glLoadIdentity();
        gl11.glClear(GL_COLOR_BUFFER_BIT);
        GLU.gluLookAt(gl, 0f, 0f, -container.getCamera().getScale(), 0f, 0f, 0f, 0f, -1f, 0f);
        gl11.glEnableClientState(GL10.GL_VERTEX_ARRAY);
gl11.glEnableClientState(GL10.GL_COLOR_ARRAY);

        gl11.glTranslatef(container.getCamera().getX(), container.getCamera().getY(), 0.0f);

        container.addParticle(new ColouredParticle(-container.getCamera().getX(), -container.getCamera().getY(), (float)Math.random(), (float)Math.random(), 0f, 5000));

        particleColorBufferPointer = createFloatBuffer(gl11, GL11.GL_ARRAY_BUFFER, new float[] {
                1f, 1f, 1f, 1f,
                1f, 1f, 1f, 1f,
                1f, 1f, 1f, 1f,

        });

        gl11.glBindBuffer(GL11.GL_ARRAY_BUFFER, particleColorBufferPointer);
        gl11.glColorPointer(4, GL10.GL_FLOAT, 0, 0);

        particleVertexBufferPointer = createFloatBuffer(gl11, GL11.GL_ARRAY_BUFFER, new float[]{
                -0.1f, -0.05f,
                0.1f, -0.05f,
                0.0f, 0.05f
        });
        gl11.glBindBuffer(GL11.GL_ARRAY_BUFFER, particleVertexBufferPointer);
        gl11.glVertexPointer(2, GL10.GL_FLOAT, 0, 0);

        gl11.glDrawArrays(GL11.GL_TRIANGLES, 0, 3);

        gl11.glDeleteBuffers(2, new int[]{particleVertexBufferPointer, particleColorBufferPointer}, 0);

        gl11.glDisableClientState(GL10.GL_VERTEX_ARRAY);
        gl11.glDisableClientState(GL10.GL_COLOR_ARRAY);

        int error = gl11.glGetError();
        if(error != GL11.GL_NO_ERROR) {
            Log.v(TAG, "error " + Integer.toHexString(error));
        }

Its just simple hardcoded float array containing the triangle vertices and colors, but for some reason the colors are wrong as I said before, what can possibly go wrong with such small amount of code? the color doesn’t change to anything but black, like it only reads the red value from the buffer. Also it gives absolutely no error at all!

createFloatBuffer method:

private int createFloatBuffer(GL11 gl, int type, float[] data) {
    int[] bufferPointerBuffer = new int[1];
    gl.glGenBuffers(1, bufferPointerBuffer, 0);
    int bufferPointer = bufferPointerBuffer[0];
    gl.glBindBuffer(type, bufferPointer);
    FloatBuffer dataBuffer = createFloatBuffer(data);
    gl.glBufferData(type, data.length * FLOAT_SIZE, dataBuffer, GL_STATIC_DRAW);
    gl.glBindBuffer(type, -1);
    return bufferPointer;
}

Answer 1

Wow.. It all was because I had texture bound and it for some reason tried to draw it even if I had texture coords disabled, I wish i could have just listened when I got told to disable any state thats not needed anymore.. Thanks guys! Problem solved!