Module luminance::shader::program
[−]
[src]
Shader programs related types and functions.
A shader Program
is an object representing several operations. It’s a streaming program that
will operate on vertices, vertex patches, primitives and/or fragments.
Note: shader programs don’t have to run on all those objects; they can be ran only on vertices and fragments, for instance.
Creating a shader program is very simple. You need shader Stage
s representing each step of the
processing. Here’s the actual mapping between the shader stage types and the processing unit:
Stage<TessellationControlShader>
: ran on tessellation parameters ;Stage<TessellationEvaluationShader>
: ran on patches ;Stage<VertexShader>
: ran on vertices ;Stage<GeometryShader>
: ran on primitives ;Stage<FragmentShader>
: ran on screen fragments.
You have to provide at least a Stage<VertexShader>
and a Stage<FragmentShader>
. If you
want tessellation processing, you need to provide both a Stage<TessellationControlShader>
and
a Stage<TessellationEvaluationShader>
. If you want primitives processing, you need to add a
Stage<GeometryShader>
.
In order to customize the behavior of your shader programs, you have access to uniforms. For
more details about them, see the documentation for the type Uniform
and Uniformable
. When
creating a new shader program, you have to provide code to declare its uniform interface. The
uniform interface refers to a type of your own that will be kept by the shader program and
exposed to you when you’ll express the need to update its uniforms. That uniform interface is
created via a closure you pass. That closure takes as arguments a ProgramProxy
used to
retrieve Uniform
s from the program being constructed. That pattern, that can be a bit
overwhelming at first, is important to keep things safe and functional. Keep in mind that you
can make the closure fail, so that you can notify a Uniform
lookup failure, for instance.
You can create a Program
with its new
associated function.
Example
// assume we have a vertex shader `vs` and fragment shader `fs` let program = Program::new(None, &vs, None, &fs, |get_uni| { let resolution: Result<Uniform<[f32; 2]>, _> = get_uni("resolution"); let time: Result<Uniform<f32>, _> = get_uni("time"); if let Err(err) = resolution { return Err(err); } let resolution = resolution.unwrap(); if let Err(err) = time { return Err(err); } let time = time.unwrap(); Ok(resolution, time) });
Structs
Program |
A shader program with uniform interface. |
ProgramProxy |
|
Enums
ProgramError |
Traits
HasProgram |
Trait to implement to provide shader program features. |