Trait SCNShadable 

pub unsafe trait SCNShadable: NSObjectProtocol {
    // Provided methods
    unsafe fn program(&self) -> Option<Retained<SCNProgram>>
       where Self: Sized + Message { ... }
    unsafe fn setProgram(&self, program: Option<&SCNProgram>)
       where Self: Sized + Message { ... }
    unsafe fn handleBindingOfSymbol_usingBlock(
        &self,
        symbol: &NSString,
        block: SCNBindingBlock,
    )
       where Self: Sized + Message { ... }
    unsafe fn handleUnbindingOfSymbol_usingBlock(
        &self,
        symbol: &NSString,
        block: SCNBindingBlock,
    )
       where Self: Sized + Message { ... }
    unsafe fn shaderModifiers(
        &self,
    ) -> Option<Retained<NSDictionary<SCNShaderModifierEntryPoint, NSString>>>
       where Self: Sized + Message { ... }
    unsafe fn setShaderModifiers(
        &self,
        shader_modifiers: Option<&NSDictionary<SCNShaderModifierEntryPoint, NSString>>,
    )
       where Self: Sized + Message { ... }
    unsafe fn minimumLanguageVersion(&self) -> Option<Retained<NSNumber>>
       where Self: Sized + Message { ... }
    unsafe fn setMinimumLanguageVersion(
        &self,
        minimum_language_version: Option<&NSNumber>,
    )
       where Self: Sized + Message { ... }
}

Available on crate feature SCNShadable only.

The SCNShadable protocol defines an object that is rendered with shaders.

See also Apple’s documentation

Provided Methods

unsafe fn program(&self) -> Option<Retained<SCNProgram>>

where Self: Sized + Message,

Specifies a custom program used to render the receiver.

When a program is set, it overrides all the rendering parameters such as material settings and shaderModifiers.

unsafe fn setProgram(&self, program: Option<&SCNProgram>)

where Self: Sized + Message,

Setter for program.

unsafe fn handleBindingOfSymbol_usingBlock( &self, symbol: &NSString, block: SCNBindingBlock, )

where Self: Sized + Message,

Available on crate features SCNNode and SCNRenderer and block2 only.

Sets the block to call at render time to bind the value for the specified symbol of the receiver’s SCNProgram. This method has no effect for symbols declared in shader modifiers.

Parameter symbol: The name of the symbol to bind a value for.

Parameter block: The block to call to bind the specified symbol.

This method can only be used with OpenGL and OpenGLES based programs.

Safety

block must be a valid pointer or null.

unsafe fn handleUnbindingOfSymbol_usingBlock( &self, symbol: &NSString, block: SCNBindingBlock, )

where Self: Sized + Message,

Available on crate features SCNNode and SCNRenderer and block2 only.

Sets the block to call at render time to unbind the value for the specified symbol of the receiver’s SCNProgram. This method has no effect for symbols declared in shader modifiers.

Parameter symbol: The name of the symbol to unbind.

Parameter block: The block to call to unbind the specified symbol.

This method can only be used with OpenGL and OpenGLES based programs.

Safety

block must be a valid pointer or null.

unsafe fn shaderModifiers( &self, ) -> Option<Retained<NSDictionary<SCNShaderModifierEntryPoint, NSString>>>

where Self: Sized + Message,

Dictionary of shader modifiers snippets, targeting entry points. The valid keys are the entry points described in the “Shader Modifier Entry Point” constants. The values are the code snippets formatted as described below.

Shader modifiers allow you to inject shader code in the standard shaders of SceneKit. This injection is allowed in few controlled entry points, allowing specific kind of tasks in specific context. Each modifier can operate on specific structures along with access to global uniforms, that could be the standard SceneKit uniforms or its own declared uniforms.

Shader modifiers can be used to tweak SceneKit rendering by adding custom code at the following entry points:

1. vertex (SCNShaderModifierEntryPointGeometry)
2. surface (SCNShaderModifierEntryPointSurface)
3. lighting (SCNShaderModifierEntryPointLightingModel)
4. fragment (SCNShaderModifierEntryPointFragment) See below for a detailed explanation of these entry points and the context they provide.

Shader modifiers can be written in either GLSL or the Metal Shading Language. Metal shaders won’t run on iOS 8 and macOS 10.10 or earlier.

The structure of a shader modifier is:

GLSL | uniform float myGrayAmount = 3.0; // Custom GLSL uniforms declarations are of the form [uniform type uniformName [= defaultValue]] | | // Optional global function definitions (for Metal: references to uniforms in global functions are not supported). | float mySin(float t) { | return sin(t); | } | | [#pragma transparent | opaque] | [#pragma body] | | // the shader modifier code snippet itself | vec3 myColor = myGrayAmount; | _output.color.rgb += myColor;

Metal Shading Language | #pragma arguments | float myGrayAmount; // Custom Metal uniforms declarations require a #pragma and are of the form [type name] | | #pragma declaration | // Optional global function definitions (for Metal: references to uniforms in global functions are not supported). | float mySin(float t) { | return sin(t); | } | | [#pragma transparent | opaque] | [#pragma body] | | // the shader modifier code snippet itself | float3 myColor = myGrayAmount; | _output.color.rgb += myColor;

The #pragma body directive Is only needed if you declared functions that must not be included in the shader code itself.

The #pragma transparent directive Forces the rendering to be blended using the following equation: _output.color.rgb + (1 - _output.color.a) * dst.rgb; where dst represents the current fragment color. The rgb components must be premultiplied.

The #pragma opaque directive Forces the rendering to be opaque. It then ignores the alpha component of the fragment.

When using Metal, you can also transfer varying values from the vertex shader (geometry shader modifier) to the fragment shader (surface and/or fragment shader modifier):

1. Start by declaring the varying values in at least one of the shader modifiers:

Metal Shading Language | #pragma varyings | half3 myVec;

2. Then write the varying values from the vertex shader (geometry shader modifier):

Metal Shading Language | #pragma body | out.myVec = _geometry.normal.xyz * 0.5h + 0.5h;

3. Finally read the varying values from the fragment shader (surface and/or fragment shader modifier):

Metal Shading Language | _output.color.rgb = saturate(in.myVec);

SceneKit declares the following built-in uniforms:

GLSL | Metal Shading Language | ––––––––––––––––––––––┼—————————————————––┤ float u_time | float scn_frame.time | The current time, in seconds vec2 u_inverseResolution | float2 scn_frame.inverseResolution | 1.0 / screen size ––––––––––––––––––––––┼—————————————————––┤ mat4 u_viewTransform | float4x4 scn_frame.viewTransform | See SCNViewTransform mat4 u_inverseViewTransform | float4x4 scn_frame.inverseViewTransform | mat4 u_projectionTransform | float4x4 scn_frame.projectionTransform | See SCNProjectionTransform mat4 u_inverseProjectionTransform | float4x4 scn_frame.inverseProjectionTransform | ––––––––––––––––––––––┼—————————————————––┤ mat4 u_normalTransform | float4x4 scn_node.normalTransform | See SCNNormalTransform mat4 u_modelTransform | float4x4 scn_node.modelTransform | See SCNModelTransform mat4 u_inverseModelTransform | float4x4 scn_node.inverseModelTransform | mat4 u_modelViewTransform | float4x4 scn_node.modelViewTransform | See SCNModelViewTransform mat4 u_inverseModelViewTransform | float4x4 scn_node.inverseModelViewTransform | mat4 u_modelViewProjectionTransform | float4x4 scn_node.modelViewProjectionTransform | See SCNModelViewProjectionTransform mat4 u_inverseModelViewProjectionTransform | float4x4 scn_node.inverseModelViewProjectionTransform | ––––––––––––––––––––––┼—————————————————––┤ mat2x3 u_boundingBox; | float2x3 scn_node.boundingBox | The bounding box of the current geometry, in model space, u_boundingBox[0].xyz and u_boundingBox[1].xyz being respectively the minimum and maximum corner of the box. mat2x3 u_worldBoundingBox; | float2x3 scn_node.worldBoundingBox | The bounding box of the current geometry, in world space.

When writing shaders using the Metal Shading Language a complete description of the type of the scn_frame variable (SCNSceneBuffer) can be found in the <SceneKit /scn_metal> header file. The type of the scn_node variable is generated at compile time and there’s no corresponding header file in the framework.

In addition to these built-in uniforms, it is possible to use custom uniforms:

The SCNGeometry and SCNMaterial classes are key-value coding compliant classes, which means that you can set values for arbitrary keys. Even if the key myAmplitude is not a declared property of the class, you can still set a value for it. Declaring a myAmplitude uniform in the shader modifier makes SceneKit observe the reveiver’s myAmplitude key. Any change to that key will make SceneKit bind the uniform with the new value.

The following GLSL and Metal Shading Language types (and their Objective-C counterparts) can be used to declare (and bind) custom uniforms:

GLSL | Metal Shading Language | Objective-C | ————┼————————┼—————————————┤ int | int | NSNumber, NSInteger, int | float | float | NSNumber, CGFloat, float, double | vec2 | float2 | CGPoint | vec3 | float3 | SCNVector3 | vec4 | float4 | SCNVector4 | mat4, mat44 | float4x4 | SCNMatrix4 | sampler2D | texture2d | SCNMaterialProperty | samplerCube | texturecube | SCNMaterialProperty (with a cube map) |

•       | device const T*        | MTLBuffer                             | Feature introduced in macOS 10.13, iOS 11.0 and tvOS 11.0

•       | struct {...}           | NSData                                | The entire struct can be set using NSData but it is also possible to set individual members using the member's name as a key and a value compatible with the member's type

Common scalar types wrapped into a NSValue are also supported.

The following prefixes are reserved by SceneKit and should not be used in custom names:

1. u_
2. a_
3. v_

Custom uniforms can be animated using explicit animations.

unsafe fn setShaderModifiers( &self, shader_modifiers: Option<&NSDictionary<SCNShaderModifierEntryPoint, NSString>>, )

where Self: Sized + Message,

Setter for shaderModifiers.

This is copied when set.

unsafe fn minimumLanguageVersion(&self) -> Option<Retained<NSNumber>>

where Self: Sized + Message,

The minimum language version required to interpret the shadable source code (wrapped MTLLanguageVersion). Defaults to nil.

By default SceneKit does not use the most recent language version in order to reduce compilation times. If set to nil the shadable source code is assumed to compile with any language version greater than or equal to Metal 2.0.

unsafe fn setMinimumLanguageVersion( &self, minimum_language_version: Option<&NSNumber>, )

where Self: Sized + Message,

Setter for minimumLanguageVersion.

Trait Implementations

impl ProtocolType for dyn SCNShadable

const NAME: &'static str = "SCNShadable"

The name of the Objective-C protocol that this type represents.

fn protocol() -> Option<&'static AnyProtocol>

Get a reference to the Objective-C protocol object that this type represents.

impl<T> ImplementedBy<T> for dyn SCNShadable

where T: ?Sized + Message + SCNShadable,

Implementations on Foreign Types

impl<T> SCNShadable for ProtocolObject<T>

where T: ?Sized + SCNShadable,

Implementors

impl SCNShadable for SCNBox

Available on crate feature SCNParametricGeometry only.

impl SCNShadable for SCNCapsule

Available on crate feature SCNParametricGeometry only.

impl SCNShadable for SCNCone

Available on crate feature SCNParametricGeometry only.

impl SCNShadable for SCNCylinder

Available on crate feature SCNParametricGeometry only.

impl SCNShadable for SCNFloor

Available on crate feature SCNParametricGeometry only.

impl SCNShadable for SCNGeometry

Available on crate feature SCNGeometry only.

impl SCNShadable for SCNMaterial

Available on crate feature SCNMaterial only.

impl SCNShadable for SCNPlane

Available on crate feature SCNParametricGeometry only.

impl SCNShadable for SCNPyramid

Available on crate feature SCNParametricGeometry only.

impl SCNShadable for SCNShape

Available on crate feature SCNParametricGeometry only.

impl SCNShadable for SCNSphere

Available on crate feature SCNParametricGeometry only.

impl SCNShadable for SCNText

Available on crate feature SCNParametricGeometry only.

impl SCNShadable for SCNTorus

Available on crate feature SCNParametricGeometry only.

impl SCNShadable for SCNTube

Available on crate feature SCNParametricGeometry only.