Method updateRadial

core/2d/ProgressTimer.cpp:341–486

Update does the work of mapping the texture onto the triangles It now doesn't occur the cost of free/alloc data every update cycle. It also only changes the percentage point but no other points if they have not been modified. It now deals with flipped texture. If you run into this problem, just use the sprite property and enable the methods flipX, flipY.

//    sprite property and enable the methods flipX, flipY.
///
void ProgressTimer::updateRadial()
{
    if (!_sprite)
    {
        return;
    }
    float alpha = _percentage / 100.f;

    float angle = 2.f * ((float)M_PI) * (_reverseDirection ? alpha : 1.0f - alpha);

    //    We find the vector to do a hit detection based on the percentage
    //    We know the first vector is the one @ 12 o'clock (top,mid) so we rotate
    //    from that by the progress angle around the _midpoint pivot
    Vec2 topMid(_midpoint.x, 1.f);
    Vec2 percentagePt = topMid.rotateByAngle(_midpoint, angle);

    int index = 0;
    Vec2 hit;

    if (alpha == 0.f)
    {
        //    More efficient since we don't always need to check intersection
        //    If the alpha is zero then the hit point is top mid and the index is 0.
        hit   = topMid;
        index = 0;
    }
    else if (alpha == 1.f)
    {
        //    More efficient since we don't always need to check intersection
        //    If the alpha is one then the hit point is top mid and the index is 4.
        hit   = topMid;
        index = 4;
    }
    else
    {
        //    We run a for loop checking the edges of the texture to find the
        //    intersection point
        //    We loop through five points since the top is split in half

        float min_t = FLT_MAX;

        for (int i = 0; i <= kProgressTextureCoordsCount; ++i)
        {
            int pIndex = (i + (kProgressTextureCoordsCount - 1)) % kProgressTextureCoordsCount;

            Vec2 edgePtA = boundaryTexCoord(i % kProgressTextureCoordsCount);
            Vec2 edgePtB = boundaryTexCoord(pIndex);

            //    Remember that the top edge is split in half for the 12 o'clock position
            //    Let's deal with that here by finding the correct endpoints
            if (i == 0)
            {
                edgePtB = edgePtA.lerp(edgePtB, 1 - _midpoint.x);
            }
            else if (i == 4)
            {
                edgePtA = edgePtA.lerp(edgePtB, 1 - _midpoint.x);
            }