public APNGHelper(Game game, string pngFile)
{
this.game = game;
var image = new APNG(pngFile);
numPlays = (int)image.acTLChunk.NumPlays;
baseFrame = new APNGFrame(game, image.DefaultImage);
if (image.IsSimplePNG)
{
CurrentFrame = baseFrame.FrameTexture;
}
else
{
numPlays = (int)image.acTLChunk.NumPlays;
foreach (Frame frame in image.Frames)
{
frameList.Add(new APNGFrame(this.game, frame));
}
sb = new SpriteBatch(this.game.GraphicsDevice);
RenderEachFrame();
CurrentFrame = renderedTextureList[0];
}
}
public APNGHelper(Game game, string pngFile)
{
this.game = game;
var image = new APNG(pngFile);
numPlays = (int)image.acTLChunk.NumPlays;
baseFrame = new APNGFrame(game, image.DefaultImage);
if (image.IsSimplePNG)
{
CurrentFrame = baseFrame.FrameTexture;
}
else
{
numPlays = (int)image.acTLChunk.NumPlays;
foreach (Frame frame in image.Frames)
{
frameList.Add(new APNGFrame(this.game, frame));
}
sb = new SpriteBatch(this.game.GraphicsDevice);
RenderEachFrame();
CurrentFrame = renderedTextureList[0];
}
}
private void RenderEachFrame()
{
for (int crtIndex = 0; crtIndex < frameList.Count; crtIndex++)
{
var currentTexture = new RenderTarget2D(
game.GraphicsDevice,
baseFrame.Width,
baseFrame.Height);
game.GraphicsDevice.SetRenderTarget(currentTexture);
game.GraphicsDevice.Clear(Color.Transparent);
// if this is the first frame, just draw.
if (crtIndex == 0)
{
goto LABEL_DRAW_NEW_FRAME;
}
// Restore previous texture
sb.Begin();
sb.Draw(renderedTextureList[crtIndex - 1], Vector2.Zero, Color.White);
sb.End();
APNGFrame crtFrame = frameList[crtIndex - 1];
switch (crtFrame.DisposeOp)
{
// Do nothing.
case DisposeOps.APNGDisposeOpNone:
break;
// Set current Rectangle to transparent.
case DisposeOps.APNGDisposeOpBackground:
LABEL_APNG_DISPOSE_OP_BACKGROUND:
var t2 = new Texture2D(game.GraphicsDevice, 1, 1);
sb.Begin(SpriteSortMode.Deferred, BlendState.Opaque);
sb.Draw(
t2,
new Rectangle(crtFrame.X, crtFrame.Y, crtFrame.Width, crtFrame.Height),
Color.White);
sb.End();
break;
// Rollback to previous frame.
case DisposeOps.APNGDisposeOpPrevious:
// If the first `fcTL` chunk uses a `dispose_op` of APNG_DISPOSE_OP_PREVIOUS
// it should be treated as APNG_DISPOSE_OP_BACKGROUND.
if (crtIndex - 1 == 0)
{
goto LABEL_APNG_DISPOSE_OP_BACKGROUND;
}
APNGFrame prevFrame = frameList[crtIndex - 2];
sb.Begin(SpriteSortMode.Deferred, BlendState.Opaque);
sb.Draw(
prevFrame.FrameTexture,
new Rectangle(crtFrame.X, crtFrame.Y, crtFrame.Width, crtFrame.Height),
new Rectangle(crtFrame.X, crtFrame.Y, crtFrame.Width, crtFrame.Height),
Color.White);
sb.End();
break;
}
LABEL_DRAW_NEW_FRAME:
// Now let's look at the new frame.
if (crtIndex == 0)
{
crtFrame = frameList[0];
}
else
{
crtFrame = crtIndex < frameList.Count
? frameList[crtIndex]
: frameList[0];
}
switch (crtFrame.BlendOp)
{
// Do not apply alpha
case BlendOps.APNGBlendOpSource:
sb.Begin(SpriteSortMode.Deferred, BlendState.Opaque);
sb.Draw(
crtFrame.FrameTexture,
new Rectangle(crtFrame.X, crtFrame.Y, crtFrame.Width, crtFrame.Height),
Color.White);
sb.End();
break;
// Apply alpha
case BlendOps.APNGBlendOpOver:
sb.Begin();
sb.Draw(
crtFrame.FrameTexture,
new Rectangle(crtFrame.X, crtFrame.Y, crtFrame.Width, crtFrame.Height),
Color.White);
sb.End();
break;
}
renderedTextureList.Add(currentTexture);
}
// Okay it's all over now
game.GraphicsDevice.SetRenderTarget(null);
}
