I am making a isometric game using Swift and Sprite Kit.
I am rethinking my approach about coloring buildings before they are build.
Like in every game, before user builds an object, he has to move it to the free plot, and by moving it, node will change color from green to red, if the object can or cannot be placed.
Here are some pictures for clarification:
What I am doing right now, as i am prety new in Sprite Kit:
I make one SKNode - parent
I make 3 nodes and add them to a parent node. Those 3 nodes contain regular building image, red building image and green building image.
If building should be colored red, I hode nodes containing green and regular images. if it needs to be green, I hide other two and sme goes for regular.
My main question is this:
Can I have only regular node, with regular image, and somehow overlay it with green or red color (but only overlay non transparent image parts?
I was thinking abut using Pixel Shader but I'm not sure if it's the right tool.
If I cannot do that my next question is: Is this 3 nodes in a parent approach a good one or it's better to change the image of one node, depending if I need to show regular green or red object image?
Related
I have several SKSpriteNodes that need to be semi-transparent when they intersect each other. If I set the node's color alpha = 0.5 this works as desired. But, I don't want the "background" to show through at all. So the nodes should never blend with the background (ie, the root node).
There is probably a simple technique to accomplish this, but I don't know what it is.
Update
Here is an example of what I'm trying to describe with two simple circle nodes. The circle border has alpha=1.0, the insides are alpha=0.5. As shown the circles blend when overlapped, which is what I want. But then of course they also blend with the background, which is not desired. For the portions that are not overlapped, the inside of the circles should look exactly like the borders.
I'm working on a sprite kit game and I'm trying to create a particular silhouette lighting effect whenever objects pass in front of a particular object (in this case a red sun). I want anything in front of it to appear black, and everything else to appear as normal (so if an object is partially in front, only that part should be black).
But I'm not sure how to do it in an efficient way. I've tried playing around with different SKBlendModes but so far haven't had much success. The major challenge seems to be achieving the effect whilst preserving the colour of the sun behind.
I'm not sure if it's possible to achieve this with the existing SKBlendModes, or if something else will be required.
I've attached a diagram to illustrate what I'm going for and an image of the current best fit.
You can create the silhouette effect with an SKCropNode, a mask node, and a background node. An SKCropNode selectively mask pixels of the sprite nodes in its node tree. Here, it will provide the silhouette effect by hiding/revealing portions of a black circle.
First, create the following objects:
A shape node (yellow circle) with its zPosition set to -1
A sprite node (black circle) with the same size as the yellow one
A crop node (SKCropNode) and a mask node (SKNode)
Next,
Add the yellow circle at the center of the scene
Add the black sprite as a child of the crop node
Assign the mask node to the maskNode property of the crop node
Add the crop node at the center of the scene
Since the mask node currently has no children, the black circle will be completely hidden and the entire yellow circle beneath it will be visible. As we add sprites to the mask node, the pixels of the black circle that intersect with the sprite will be unmasked (shown in black), producing the silhouette effect.
All that's left is to add a "presentation" node that will be displayed when the mask node's sprite is outside of the black circle. The presentation node will mirror the mask node's sprite's position and rotation. This should be done in didSimulatePhysics to ensure that the presentation and mask-node sprites are synchronized after the physics and actions have been updated.
But wait...if the presentation node moves over the yellow circle, won't it eclipse the Sun? Not if we set its presentation node's zPosition to -2.
The following shows an implementation of the above:
This problem was interesting to me, so I came up with a simple solution. It's not perfect nor does it scale very well, but the basics fulfill your need I believe and it may point others in the right direction.
I don't use any special SKBlendMode. Instead, I am using a duplicate object for the object which moves in front of the sun. This duplicate object is cropped using an SKCropNode with a duplicate of the sun as the maskNode. So, my node tree is as follows:
SKSpriteNode (sun) (the white sun)
SKSpriteNode (object1) (the rotating purple square with alpha 0.25)
SKCropNode
maskNode: SKSpriteNode (sunDuplicate = [sun copy])
SKSpriteNode (object1duplicate, same size as object1 but with [SKColor blackColor])
Inside the update method, align the duplicate with the original to ensure animation is properly forwarded.
- (void)update:(CFTimeInterval)currentTime {
self.object1duplicate.position = self.object1.position;
self.object1duplicate.zRotation = self.object1.zRotation;
}
As I said, this doesn't scale very well since you'll manually have to add duplicate objects and keep track of them for each object moving in front of the sun object. Perhaps SKShader can be of more elegant use.
I added a background SKSpriteNode as a child to my SKScene. This node itself has some children nodes. Each child has some colored pixels as well as totally transparent pixels. The children nodes are moving across the screen and sometimes intersect each other.
I'd like to make the intersecting colored areas of the children fully transparent as they move so that the background sprite shows through. For the non-intersecting areas of each child, the node should appear as normal. I tried playing around with the blendmode but couldn't get the desired effect. Any ideas how to do this? Or, is there a way to do this outside of SpriteKit?
Thanks
I don't think there are commands to achieve what you want. You can change the the entire texture/image of a sprite, you can change part of a sprite's texture/image appearance by using a filter but you cannot specifically modify part of a sprite's texture/image. To be more specific, a sprite's alpha property applies to the entire sprite and not just part of it.
First of all, what I want to achieve is a shape node filled with two different, distinct colors (not blended), e.g. top part of a circle is white, bottom is black.
From what I've found, my only option is to manually create paths and color them. That's fine with me, but I first need to know the exact paths.
I'm trying to avoid complex calculations, so my question is - is there any way to get a path describing a common area of two overlapping nodes?
A simple example to illustrate the problem: when the circle collides with the black area, the part of the circle which overlaps black rectangle should change colour - how can I get that overlap area's path?
so I'm making a game and pretty much when the player (which is a triangular shaped rocket) hits an object flying at you (a rock) the game ends. I have everything working well but my problem is the rocket is a triangle yet the image view its in is a rectangle. So if the edge of the image view touches the rock the game will end even though the actual rocket didn't touch the object. So basically how can I make the rock image view not recognize the parts of the rocket image view which are empty? Basically a triangular shaped image view.
Thank you for your help. Let me know if you need more info or want to see the code I have for them to collide.
You analytically present the triangle with 3 points and a rock with a center and radius then find and implement an algorithm checking a hit test between those 2 shapes. Or draw the two shapes onto some graphics context using an appropriate blending and check for overlapping pixels (for instance draw one as red and another as green and look if a pixel that is both red and green exists) you could actually do that with 2 image views having those colors and .5f alpha added on the 3rd invisible view but you would need to get the image from the view and then iterate through all the pixels. In any of the cases do this check only after the corresponding view frames overlap.