I have a based image and some sprites on top of the basd image movieclip... Some of the sprites can be drawn by the user using graphics api in actionscript 3. I can draw things on the sprites but I can't create an eraser like brush that can remove part of the unwanted drawings. I try using Alpha but no it doesn't work
I have googled about it and come up with the solution:
1) Linebitmapstyle... This solution is not the best one coz I my sprites can be moved so if I use linebitmapstyle, it does draw the pixel from the image to the sprite but if the sprite moved the drawn pixel won't change.
2) Masking may not work for me either....
What is the best way of creating the eraser
You may rather want to use a Bitmap to make such things easier to manipulate (unless you need to do scalable vector graphics of course!). To draw shapes you can still use the graphics API to create the shapes.
To do so, instantiate a "dummy" sprite (or another IBitmapDrawable implementation) to create the graphics and then "copy" them to the BitmapData the bitmapData.draw() function. This way you can for instance draw with the option BlendMode.ERASE in order remove the pixels of the shape.
Example (from the top of my mind) :
// creates a bitmap data canvas
var bitmapData:BitmapData = new BitmapData(500, 500);
// creates a bitmap display object to contain the BitmapData
addChild(new Bitmap(bitmapData));
// creates a dummy object to draw and draws a 10px circle
var brush:Sprite = new Sprite(); // note this is not even added to the stage
brush.graphics.beginFill(0xff0000);
brush.graphics.drawCircle(10, 10, 10);
// the matrix will be used to position the "brush strokes" on the canvas
var matrix:Matrix = new Matrix();
// draws a circle in the middle of the canvas
matrix.translate(250, 250);
bitmapData.draw(brush, matrix
// translates the position 5 pixels to the right to slightly erase the previously
// drawn circle creating a half moon
matrix.translate(5, 0);
bitmapData.draw(brush, matrix,null,BlendMode.ERASE);
Related
I am working on API which requires me set up a outer geometry mask on ID2D1Rendertarget such that any draw call after that only draws portion of drawings which lies outside this geometry.
https://msdn.microsoft.com/en-us/library/windows/desktop/dd756675(v=vs.85).aspx explains how can we setup a inner geometry mask on ID2D1Rendertarget such that any draw call after that only draws portion of drawings which lies inside this geometry.I want to implement just opposite of that. Is this possible? Any help is deeply appreciated.
One way to do this is to subtract your geometry from a rectangle that fills the entire render target. Check out the MSDN page on combining geometries. I have a small code example below:
ComPtr<ID2D1PathGeometry> invertedGeometry;
ComPtr<ID2D1RectangleGeometry> rectangleGeometry;
d2dFactory->CreateRectangleGeometry(
{ 0, 0, targetWidth, targetHeight },
&rectangleGeometry
);
ComPtr<ID2D1GeometrySink> geometrySink;
d2dFactory->CreatePathGeometry(&invertedGeometry);
invertedGeometry->Open(&geometrySink);
rectangleGeometry->CombineWithGeometry(
pathGeometry.Get(),
D2D1_COMBINE_MODE_EXCLUDE,
D2D1::Matrix3x2F::Identity(),
geometrySink.Get()
);
geometrySink->Close();
Use the inverted geometry as the geometric mask instead of the original path geometry.
A second way to do this is to rasterize your geometry to a bitmap and use it as an opacity mask. You can flip the colors depending on whether or not you want the inside or outside to mask.
I'm attempting to determine which sprite a mouse is over in an isometric 2D game. I think my best bet is to draw each sprite a different color into a separate renderTarget2D and turn it into a Texture2D at which point I can get the color data from the mouse point and check it against the drawn sprites.
The problem I'm having with that method though is that I can't change the color of the individual sprites to a solid color. If I change the Color in the spriteBatch.Draw call, it only tints the color of the sprite rather than drawing it at a solid color so the data I retrieve from the Texture doesn't help.
Any suggestions or help with drawing those sprites in a solid color?
Don't do it that way. Creating a new render target and copying the data into the memory even for a mere hundred sprites sixty times per sec is far beyond what current systems can handle.
Simply use the Contains method of the Rectangle structure:
var destination = new Rectangle(100, 100, 50, 50);
bool mouseOver = destination.Contains(mouseX, mouseY);
I'm currently developping an old-school game with XNA 4.
My graphics assets are based on 568x320 resolution (16/9 ration), I want to change my window resolution (1136x640 for example) and my graphics are scaled without stretching, that they keep pixel aspect.
How can I reach this ?
You could use a RenderTargetto achieve your goal. It sounds like you don't want to have to render accordingly to every possible screen size, so if your graphics aren't dependant on other graphical features like a mouse, then I would use a RenderTarget and draw all the pixel data to that and afterwards draw it to the actual screen allowing the screen to stretch it.
This technique can be used in other ways too. I use it to draw objects in my game, so I can easily change the rotation and location without having to calculate every sprite for the object.
Example:
void PreDraw()
// You need your graphics device to render to
GraphicsDevice graphicsDevice = Settings.GlobalGraphicsDevice;
// You need a spritebatch to begin/end a draw call
SpriteBatch spriteBatch = Settings.GlobalSpriteBatch;
// Tell the graphics device where to draw too
graphicsDevice.SetRenderTarget(renderTarget);
// Clear the buffer with transparent so the image is transparent
graphicsDevice.Clear(Color.Transparent);
spriteBatch.Begin();
flameAnimation.Draw(spriteBatch);
spriteBatch.Draw(gunTextureToDraw, new Vector2(100, 0), Color.White);
if (!base.CurrentPowerUpLevel.Equals(PowerUpLevels.None)) {
powerUpAnimation.Draw(spriteBatch);
}
// DRAWS THE IMAGE TO THE RENDERTARGET
spriteBatch.Draw(shipSpriteSheet, new Rectangle(105,0, (int)Size.X, (int)Size.Y), shipRectangleToDraw, Color.White);
spriteBatch.End();
// Let the graphics device know you are done and return to drawing according to its dimensions
graphicsDevice.SetRenderTarget(null);
// utilize your render target
finishedShip = renderTarget;
}
Remember, in your case, you would initialize your RenderTarget with dimensions of 568x320 and draw according to that and not worry about any other possible sizes. Once you give the RenderTarget to the spritebatch to draw to the screen, it will "stretch" the image for you!
EDIT:
Sorry, I skimmed through the question and missed that you don't want to "stretch" your result. This could be achieved by drawing the final RenderTarget to your specified dimensions according to the graphics device.
Oh Gosh !!!! I've got it ! Just give SamplerState.PointClamp at your spriteBatch.Begin methods to keep that cool pixel visuel effet <3
spriteBatch.Begin(SpriteSortMode.Immediate,
BlendState.AlphaBlend,
SamplerState.PointClamp,
null,
null,
null,
cam.getTransformation(this.GraphicsDevice));
Take for example I draw a circle at (10,10) then on the next frame another at (20,20). the circle at (10,10) is no longer visible.
I am not calling graphicsdevice.clear.
is there a way to make the previously drawn graphics not be cleared?
I am drawing these into a seconary rendertarget so I can use it as a background.
Any Ideas?
When you initialize the RenderTarget2D you need to use RenderTargetUsage.PreserveContents.
// Disregard the arguments up to RenderTargetUsage
RenderTarget2D r = new RenderTarget2D(GraphicsDevice,
graphics.PreferredBackBufferWidth,
graphics.PreferredBackBufferHeight,
false,
RenderTargetUsage.PreserveContents);
I'm just starting game development and I thought a game like Tank wars or Worms would be nice.
The hardest part I can think of so far is making the terrain destructible and I want to know how it's done before doing the easy parts.
I thought that explosion could have a mask texture which could be scaled for different weapons. Then using that mask I should make underlying terrain transparent (and optionally draw a dark border).
(source: mikakolari.fi)
How do I achieve that?
Do I have to change the alpha value pixel by pixel or can I use some kind of masking technique? Drawing a blue circle on top of the terrain isn't an option.
I have versions 3.1 and 4.0 of XNA.
This tutorial is what you are searching:
http://www.riemers.net/eng/Tutorials/XNA/Csharp/series2d.php
Capter 20: Adding explosion craters
In short:
You have 2 textures: 1 Color Texture (visible), 1 Collision Texture (invisible)
You substract the explosion image from your collision texture.
To get the dark border: expand the explosion texture and darken the color in this area.
Now you generate a new Color Texture (old color - collison = new color).
This is a difficult question to answer - because there are many ways you could do it. And there are pros and cons to each method. I'll just give an overview:
As an overall design, you need to keep track of: the original texture, the "darkness" applied, and the "transparency" applied. One thing I can say almost for sure is you want to "accumulate" the results of the explosions somewhere - what you don't want to be doing is maintaining a list of all explosions that have ever happened.
So you have surfaces for texture, darkness and transparency. You could probably merge darkness and transparency into a single surface with a single channel that stores "normal", "dark" (or a level of darkness) and "transparent".
Because you probably don't want the dark rings to get progressively darker where they intersect, when you apply an explosion to your darkness layer with the max function (Math.Max in C#).
To produce your final texture you could just write from the darkness/transparency texture to your original texture or a copy of it (you only need to update the area that each explosion touches).
Or you could use a pixel shader to combine them - the details of which are beyond the scope of this question. (Also a pixel shader won't work on XNA 4.0 on Windows Phone 7.)
You should Make a new Texure2D with the Color of desired pixels.Alpha = 0.
Color[] bits = new Color[Texture.Width * Texture.Height];
Texture.GetData(bits);
foreach(Vector2D pixel in overlapedArea)
{
int x = (int)(pixel.X);
int y = (int)(pixel.Y);
bits[x + y * texture.Width] = Color.FromNonPremultiplied(0,0,0,0));
}
Texture2D newTexture = new Texture2D(texture.GraphicsDevice, texture.Width, texture.Height);
newTexture.SetData(bits);
Now replace the new Texture2D with the Last Texture and you're good to go!
For more code about Collision, or changing texture pixels color go to this page for codes:
http://www.codeproject.com/Articles/328894/XNA-Sprite-Class-with-useful-methods