Struct SKShader

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#[repr(C)]
pub struct SKShader { /* private fields */ }

Available on crate feature SKShader only.

Expand description

Apple’s documentation

Implementations§

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impl SKShader

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pub unsafe fn initWithSource( this: Allocated<Self>, source: &NSString, ) -> Retained<Self>

Create a custom shader with source code.

Parameter source: the source code for the custom fragment shader.

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pub unsafe fn initWithSource_uniforms( this: Allocated<Self>, source: &NSString, uniforms: &NSArray<SKUniform>, ) -> Retained<Self>

Available on crate feature SKUniform only.

Create a custom shader with source code and uniforms.

Parameter source: the source code for the custom fragment shader.

Parameter uniforms: the array of uniforms supplied to this shader

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pub unsafe fn shader() -> Retained<Self>

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pub unsafe fn shaderWithSource(source: &NSString) -> Retained<Self>

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pub unsafe fn shaderWithSource_uniforms( source: &NSString, uniforms: &NSArray<SKUniform>, ) -> Retained<Self>

Available on crate feature SKUniform only.

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pub unsafe fn shaderWithFileNamed(name: &NSString) -> Retained<Self>

Loads a shader source file named ‘name’ from the main bundle. This is simpler yet functionally equivalent to the following code

[SKShader shaderWithSource:[NSString stringWithContentsOfFile:[[NSBundle mainBundle] pathForResource:name ofType: “ fsh“] encoding:NSUTF8StringEncoding error:NULL]];

The encoding is assumed to be NSUTF8StringEncoding.

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pub unsafe fn source(&self) -> Option<Retained<NSString>>

Shader source must define the ‘main’ method of the fragment shader

Your shader must assign a premultipled fragment value to ‘gl_FragColor’

The following implicit uniforms are available:

sampler2D u_texture (the primary texuture attached the the sprite)

The following varyings are available:

vec2 v_tex_coord (normalized texture coordiantes for the primary texture)
vec4 v_color_mix (premultiplied color value based on color & alpha)

The following functions are available:

vec4 SKDefaultShading() (returns the fragment value that would have been output if no shader was used)

Sample shader source that produces the same result are SpriteKit’s normal rendering:

“void main() { gl_FragColor = SKDefaultShading(); }”

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pub unsafe fn setSource(&self, source: Option<&NSString>)

Setter for source.

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pub unsafe fn uniforms(&self) -> Retained<NSArray<SKUniform>>

Available on crate feature SKUniform only.

You may define additional uniforms to be used in your shader here. There is no need to declare them in you source, just use them by name.

All uniforms declared must be used within the source.

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pub unsafe fn setUniforms(&self, uniforms: &NSArray<SKUniform>)

Available on crate feature SKUniform only.

Setter for uniforms.

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pub unsafe fn addUniform(&self, uniform: &SKUniform)

Available on crate feature SKUniform only.

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pub unsafe fn uniformNamed( &self, name: &NSString, ) -> Option<Retained<SKUniform>>

Available on crate feature SKUniform only.

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pub unsafe fn removeUniformNamed(&self, name: &NSString)

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pub unsafe fn attributes(&self) -> Retained<NSArray<SKAttribute>>

Available on crate feature SKAttribute only.

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pub unsafe fn setAttributes(&self, attributes: &NSArray<SKAttribute>)

Available on crate feature SKAttribute only.

Setter for attributes.

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impl SKShader

Methods declared on superclass NSObject.

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pub unsafe fn init(this: Allocated<Self>) -> Retained<Self>

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pub unsafe fn new() -> Retained<Self>

Methods from Deref<Target = NSObject>§

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pub fn doesNotRecognizeSelector(&self, sel: Sel) -> !

Handle messages the object doesn’t recognize.

See Apple’s documentation for details.

Methods from Deref<Target = AnyObject>§

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pub fn class(&self) -> &'static AnyClass

Dynamically find the class of this object.

§Example

Check that an instance of NSObject has the precise class NSObject.

use objc2::ClassType;
use objc2::runtime::NSObject;

let obj = NSObject::new();
assert_eq!(obj.class(), NSObject::class());

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pub unsafe fn get_ivar<T>(&self, name: &str) -> &T
where T: Encode,

👎Deprecated: this is difficult to use correctly, use Ivar::load instead.

Use Ivar::load instead.

§Safety

The object must have an instance variable with the given name, and it must be of type T.

See Ivar::load_ptr for details surrounding this.

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pub fn downcast_ref<T>(&self) -> Option<&T>
where T: DowncastTarget,

Attempt to downcast the object to a class of type T.

This is the reference-variant. Use Retained::downcast if you want to convert a retained object to another type.

§Mutable classes

Some classes have immutable and mutable variants, such as NSString and NSMutableString.

When some Objective-C API signature says it gives you an immutable class, it generally expects you to not mutate that, even though it may technically be mutable “under the hood”.

So using this method to convert a NSString to a NSMutableString, while not unsound, is generally frowned upon unless you created the string yourself, or the API explicitly documents the string to be mutable.

See Apple’s documentation on mutability and on isKindOfClass: for more details.

§Generic classes

Objective-C generics are called “lightweight generics”, and that’s because they aren’t exposed in the runtime. This makes it impossible to safely downcast to generic collections, so this is disallowed by this method.

You can, however, safely downcast to generic collections where all the type-parameters are AnyObject.

§Panics

This works internally by calling isKindOfClass:. That means that the object must have the instance method of that name, and an exception will be thrown (if CoreFoundation is linked) or the process will abort if that is not the case. In the vast majority of cases, you don’t need to worry about this, since both root objects NSObject and NSProxy implement this method.

§Examples

Cast an NSString back and forth from NSObject.

use objc2::rc::Retained;
use objc2_foundation::{NSObject, NSString};

let obj: Retained<NSObject> = NSString::new().into_super();
let string = obj.downcast_ref::<NSString>().unwrap();
// Or with `downcast`, if we do not need the object afterwards
let string = obj.downcast::<NSString>().unwrap();

Try (and fail) to cast an NSObject to an NSString.

use objc2_foundation::{NSObject, NSString};

let obj = NSObject::new();
assert!(obj.downcast_ref::<NSString>().is_none());

Try to cast to an array of strings.

use objc2_foundation::{NSArray, NSObject, NSString};

let arr = NSArray::from_retained_slice(&[NSObject::new()]);
// This is invalid and doesn't type check.
let arr = arr.downcast_ref::<NSArray<NSString>>();

This fails to compile, since it would require enumerating over the array to ensure that each element is of the desired type, which is a performance pitfall.

Downcast when processing each element instead.

use objc2_foundation::{NSArray, NSObject, NSString};

let arr = NSArray::from_retained_slice(&[NSObject::new()]);

for elem in arr {
    if let Some(data) = elem.downcast_ref::<NSString>() {
        // handle `data`
    }
}