Enum dx::platform::core::SnippetHook

#[non_exhaustive]
pub enum SnippetHook {
    Vertex,
    VertexTransform,
    VertexGlobals,
    PointSize,
    Fragment,
    FragmentGlobals,
    TextureCoordTransform,
    LayerFragment,
    TextureLookup,
}

Location within a Pipeline

SnippetHook is used to specify a location within a Pipeline where the code of the snippet should be used when it is attached to a pipeline.

SnippetHook::VertexGlobals

Adds a shader snippet at the beginning of the global section of the shader for the vertex processing. Any declarations here can be shared with all other snippets that are attached to a vertex hook. Only the ‘declarations’ string is used and the other strings are ignored.

SnippetHook::FragmentGlobals

Adds a shader snippet at the beginning of the global section of the shader for the fragment processing. Any declarations here can be shared with all other snippets that are attached to a fragment hook. Only the ‘declarations’ string is used and the other strings are ignored.

SnippetHook::Vertex

Adds a shader snippet that will hook on to the vertex processing stage of the pipeline. This gives a chance for the application to modify the vertex attributes generated by the shader. Typically the snippet will modify color_out or position_out builtins.

The ‘declarations’ string in snippet will be inserted in the global scope of the shader. Use this to declare any uniforms, attributes or functions that the snippet requires.

The ‘pre’ string in snippet will be inserted at the top of the main fn before any vertex processing is done.

The ‘replace’ string in snippet will be used instead of the generated vertex processing if it is present. This can be used if the application wants to provide a complete vertex shader and doesn’t need the generated output from .

The ‘post’ string in snippet will be inserted after all of the standard vertex processing is done. This can be used to modify the outputs.

SnippetHook::VertexTransform

Adds a shader snippet that will hook on to the vertex transform stage. Typically the snippet will use the modelview_matrix, projection_matrix and modelview_projection_matrix matrices and the position_in attribute. The hook must write to position_out. The default processing for this hook will multiply position_in by the combined modelview-projection matrix and store it on position_out.

The ‘declarations’ string in snippet will be inserted in the global scope of the shader. Use this to declare any uniforms, attributes or functions that the snippet requires.

The ‘pre’ string in snippet will be inserted at the top of the main fn before the vertex transform is done.

The ‘replace’ string in snippet will be used instead of the generated vertex transform if it is present.

The ‘post’ string in snippet will be inserted after all of the standard vertex transformation is done. This can be used to modify the position_out in addition to the default processing.

SnippetHook::PointSize

Adds a shader snippet that will hook on to the point size calculation step within the vertex shader stage. The snippet should write to the builtin point_size_out with the new point size. The snippet can either read point_size_in directly and write a new value or first read an existing value in point_size_out that would be set by a previous snippet. Note that this hook is only used if Pipeline::set_per_vertex_point_size is enabled on the pipeline.

The ‘declarations’ string in snippet will be inserted in the global scope of the shader. Use this to declare any uniforms, attributes or functions that the snippet requires.

The ‘pre’ string in snippet will be inserted just before calculating the point size.

The ‘replace’ string in snippet will be used instead of the generated point size calculation if it is present.

The ‘post’ string in snippet will be inserted after the standard point size calculation is done. This can be used to modify point_size_out in addition to the default processing.

SnippetHook::Fragment

Adds a shader snippet that will hook on to the fragment processing stage of the pipeline. This gives a chance for the application to modify the fragment color generated by the shader. Typically the snippet will modify color_out.

The ‘declarations’ string in snippet will be inserted in the global scope of the shader. Use this to declare any uniforms, attributes or functions that the snippet requires.

The ‘pre’ string in snippet will be inserted at the top of the main fn before any fragment processing is done.

The ‘replace’ string in snippet will be used instead of the generated fragment processing if it is present. This can be used if the application wants to provide a complete fragment shader and doesn’t need the generated output from .

The ‘post’ string in snippet will be inserted after all of the standard fragment processing is done. At this point the generated value for the rest of the pipeline state will already be in color_out so the application can modify the result by altering this variable.

SnippetHook::TextureCoordTransform

Adds a shader snippet that will hook on to the texture coordinate transformation of a particular layer. This can be used to replace the processing for a layer or to modify the results.

Within the snippet code for this hook there are two extra variables. The first is a mat4 called matrix which represents the user matrix for this layer. The second is called tex_coord and represents the incoming and outgoing texture coordinate. On entry to the hook, tex_coord contains the value of the corresponding texture coordinate attribute for this layer. The hook is expected to modify this variable. The output will be passed as a varying to the fragment processing stage. The default code will just multiply matrix by tex_coord and store the result in tex_coord.

The ‘declarations’ string in snippet will be inserted in the global scope of the shader. Use this to declare any uniforms, attributes or functions that the snippet requires.

The ‘pre’ string in snippet will be inserted just before the fragment processing for this layer. At this point tex_coord still contains the value of the texture coordinate attribute.

If a ‘replace’ string is given then this will be used instead of the default fragment processing for this layer. The snippet can modify tex_coord or leave it as is to apply no transformation.

The ‘post’ string in snippet will be inserted just after the transformation. At this point tex_coord will contain the results of the transformation but it can be further modified by the snippet.

SnippetHook::LayerFragment

Adds a shader snippet that will hook on to the fragment processing of a particular layer. This can be used to replace the processing for a layer or to modify the results.

Within the snippet code for this hook there is an extra vec4 variable called ‘layer’. This contains the resulting color that will be used for the layer. This can be modified in the ‘post’ section or it the default processing can be replaced entirely using the ‘replace’ section.

The ‘declarations’ string in snippet will be inserted in the global scope of the shader. Use this to declare any uniforms, attributes or functions that the snippet requires.

The ‘pre’ string in snippet will be inserted just before the fragment processing for this layer.

If a ‘replace’ string is given then this will be used instead of the default fragment processing for this layer. The snippet must write to the ‘layer’ variable in that case.

The ‘post’ string in snippet will be inserted just after the fragment processing for the layer. The results can be modified by changing the value of the ‘layer’ variable.

SnippetHook::TextureLookup

Adds a shader snippet that will hook on to the texture lookup part of a given layer. This gives a chance for the application to modify the coordinates that will be used for the texture lookup or to alter the returned texel.

Within the snippet code for this hook there are three extra variables available. ‘sampler’ is a sampler object representing the sampler for the layer where the snippet is attached. ‘tex_coord’ is a vec4 which contains the texture coordinates that will be used for the texture lookup. This can be modified. ‘texel’ will contain the result of the texture lookup. This can also be modified.

The ‘declarations’ string in snippet will be inserted in the global scope of the shader. Use this to declare any uniforms, attributes or functions that the snippet requires.

The ‘pre’ string in snippet will be inserted at the top of the main fn before any fragment processing is done. This is a good place to modify the tex_coord variable.

If a ‘replace’ string is given then this will be used instead of a the default texture lookup. The snippet would typically use its own sampler in this case.

The ‘post’ string in snippet will be inserted after texture lookup has been preformed. Here the snippet can modify the texel variable to alter the returned texel.

Variants (Non-exhaustive)

Non-exhaustive enums could have additional variants added in future. Therefore, when matching against variants of non-exhaustive enums, an extra wildcard arm must be added to account for any future variants.

Vertex

A hook for the entire vertex processing stage of the pipeline.

VertexTransform

A hook for the vertex transformation.

VertexGlobals

A hook for declaring global data that can be shared with all other snippets that are on a vertex hook.

PointSize

A hook for manipulating the point size of a vertex. This is only used if Pipeline::set_per_vertex_point_size is enabled on the pipeline.

Fragment

A hook for the entire fragment processing stage of the pipeline.

FragmentGlobals

A hook for declaring global data wthat can be shared with all other snippets that are on a fragment hook.

TextureCoordTransform

A hook for applying the layer matrix to a texture coordinate for a layer.

LayerFragment

A hook for the fragment processing of a particular layer.

TextureLookup

A hook for the texture lookup stage of a given layer in a pipeline.

Trait Implementations

impl Clone for SnippetHook

fn clone(&self) -> SnippetHook

Returns a copy of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for SnippetHook

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Display for SnippetHook

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Hash for SnippetHook

fn hash<__H: Hasher>(&self, state: &mut __H)

Feeds this value into the given Hasher.

fn hash_slice<H>(data: &[Self], state: &mut H) where
    H: Hasher, 

Feeds a slice of this type into the given Hasher.

impl Ord for SnippetHook

fn cmp(&self, other: &SnippetHook) -> Ordering

This method returns an Ordering between self and other.

fn max(self, other: Self) -> Self

Compares and returns the maximum of two values.

fn min(self, other: Self) -> Self

Compares and returns the minimum of two values.

fn clamp(self, min: Self, max: Self) -> Self

Restrict a value to a certain interval.

impl PartialEq<SnippetHook> for SnippetHook

fn eq(&self, other: &SnippetHook) -> bool

This method tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

This method tests for !=.

impl PartialOrd<SnippetHook> for SnippetHook

fn partial_cmp(&self, other: &SnippetHook) -> Option<Ordering>

This method returns an ordering between self and other values if one exists.

fn lt(&self, other: &Rhs) -> bool

This method tests less than (for self and other) and is used by the < operator.

fn le(&self, other: &Rhs) -> bool

This method tests less than or equal to (for self and other) and is used by the <= operator.

fn gt(&self, other: &Rhs) -> bool

This method tests greater than (for self and other) and is used by the > operator.

fn ge(&self, other: &Rhs) -> bool

This method tests greater than or equal to (for self and other) and is used by the >= operator.

impl Copy for SnippetHook

impl Eq for SnippetHook

impl StructuralEq for SnippetHook

impl StructuralPartialEq for SnippetHook