Magnum::GL::Shader class

Shader.

See AbstractShaderProgram for usage information.

Compilation error reporting

To help localize shader compilation errors, each addSource() / addFile() call precedes the source with a #line n 1 directive, where n is the source number. Drivers then use the source number to print error location, usually in a form <file>(<line>): or <file>:<line>:.

Source number 0 is a #version directive added in the constructor (unless Version::None is specified). which means the first added source has a number 1.

Performance optimizations

Shader limits and implementation-defined values (such as maxUniformComponents()) are cached, so repeated queries don't result in repeated glGet() calls.

Base classes

class AbstractObject
Base for all OpenGL objects.

Public types

enum class Type: GLenum { Vertex = GL_VERTEX_SHADER, TessellationControl = GL_TESS_CONTROL_SHADER, TessellationEvaluation = GL_TESS_EVALUATION_SHADER, Geometry = GL_GEOMETRY_SHADER, Compute = GL_COMPUTE_SHADER, Fragment = GL_FRAGMENT_SHADER }
Shader type.

Public static functions

static auto maxVertexOutputComponents() -> Int
Max supported component count on vertex shader output.
static auto maxTessellationControlInputComponents() -> Int
Max supported component count of tessellation control shader input vertex.
static auto maxTessellationControlOutputComponents() -> Int
Max supported component count of tessellation control shader output vertex.
static auto maxTessellationControlTotalOutputComponents() -> Int
Max supported component count of all tessellation control shader output vertices combined.
static auto maxTessellationEvaluationInputComponents() -> Int
Max supported component count of tessellation evaluation shader input vertex.
static auto maxTessellationEvaluationOutputComponents() -> Int
Max supported component count of tessellation evaluation shader output vertex.
static auto maxGeometryInputComponents() -> Int
Max supported component count of geometry shader input vertex.
static auto maxGeometryOutputComponents() -> Int
Max supported component count of geometry shader output vertex.
static auto maxGeometryTotalOutputComponents() -> Int
Max supported component count of all geometry shader output vertices combined.
static auto maxFragmentInputComponents() -> Int
Max supported component count on fragment shader input.
static auto maxUniformComponents(Type type) -> Int
Max supported uniform component count in default block.
static auto maxAtomicCounterBuffers(Type type) -> Int
Max supported atomic counter buffer count.
static auto maxCombinedAtomicCounterBuffers() -> Int
Max supported atomic counter buffer count for all stages combined.
static auto maxAtomicCounters(Type type) -> Int
Max supported atomic counter count.
static auto maxCombinedAtomicCounters() -> Int
Max supported atomic counter count for all stages combined.
static auto maxImageUniforms(Type type) -> Int
Max supported image uniform count.
static auto maxCombinedImageUniforms() -> Int
Max supported image uniform count for all stages combined.
static auto maxShaderStorageBlocks(Type type) -> Int
Max supported shader storage block count.
static auto maxCombinedShaderStorageBlocks() -> Int
Max supported shader storage block count for all stages combined.
static auto maxTextureImageUnits(Type type) -> Int
Max supported texture image unit count.
static auto maxCombinedTextureImageUnits() -> Int
Max supported texture image unit count for all stages combined.
static auto maxUniformBlocks(Type type) -> Int
Max supported uniform block count.
static auto maxCombinedUniformBlocks() -> Int
Max supported uniform block count for all stages combined.
static auto maxCombinedUniformComponents(Type type) -> Int
Max supported uniform component count in all blocks combined.
static auto compile(std::initializer_list<Containers::Reference<Shader>> shaders) -> bool deprecated in Git master
Compile multiple shaders simultaneously.
static auto wrap(Type type, GLuint id, ObjectFlags flags = {}) -> Shader new in Git master
Wrap existing OpenGL shader object.

Constructors, destructors, conversion operators

Shader(Version version, Type type) explicit
Constructor.
Shader(NoCreateT) explicit noexcept
Construct without creating the underlying OpenGL object.
Shader(const Shader&) deleted
Copying is not allowed.
Shader(Shader&& other) noexcept
Move constructor.
~Shader()
Destructor.

Public functions

auto operator=(const Shader&) -> Shader& deleted
Copying is not allowed.
auto operator=(Shader&& other) -> Shader& noexcept
Move assignment.
auto id() const -> GLuint
OpenGL shader ID.
auto release() -> GLuint new in Git master
Release the underlying OpenGL object.
auto label() const -> Containers::String
Shader label.
auto setLabel(Containers::StringView label) -> Shader&
Set shader label.
auto type() const -> Type
Shader type.
auto sources() const -> std::vector<std::string>
Shader sources.
auto addSource(std::string source) -> Shader&
Add shader source.
auto addFile(const std::string& filename) -> Shader&
Add shader source file.
auto compile() -> bool
Compile the shader.
void submitCompile() new in Git master
Submit the shader for compilation.
auto checkCompile() -> bool new in Git master
Check shader compilation status and await completion.
auto isCompileFinished() -> bool new in Git master
Whether a submitCompile() operation has finished.

Enum documentation

enum class Magnum::GL::Shader::Type: GLenum

Shader type.

Enumerators
Vertex

Vertex shader

TessellationControl

Tessellation control shader

TessellationEvaluation

Tessellation evaluation shader

Geometry

Geometry shader

Compute

Compute shader

Fragment

Fragment shader

Function documentation

static Int Magnum::GL::Shader::maxVertexOutputComponents()

Max supported component count on vertex shader output.

The result is cached, repeated queries don't result in repeated OpenGL calls. In OpenGL ES 2.0 the four-component vector count is queried and multiplied with 4.

static Int Magnum::GL::Shader::maxTessellationControlInputComponents()

Max supported component count of tessellation control shader input vertex.

The result is cached, repeated queries don't result in repeated OpenGL calls. If neither ARB_tessellation_shader (part of OpenGL 4.0) nor ANDROID_extension_pack_es31a / EXT_tessellation_shader ES extension is available, returns 0.

static Int Magnum::GL::Shader::maxTessellationControlOutputComponents()

Max supported component count of tessellation control shader output vertex.

The result is cached, repeated queries don't result in repeated OpenGL calls. If neither ARB_tessellation_shader (part of OpenGL 4.0) nor ANDROID_extension_pack_es31a / EXT_tessellation_shader (part of OpenGL ES 3.2) is available, returns 0.

static Int Magnum::GL::Shader::maxTessellationControlTotalOutputComponents()

Max supported component count of all tessellation control shader output vertices combined.

The result is cached, repeated queries don't result in repeated OpenGL calls. If neither ARB_tessellation_shader (part of OpenGL 4.0) nor ANDROID_extension_pack_es31a / EXT_tessellation_shader (part of OpenGL ES 3.2) is available, returns 0.

static Int Magnum::GL::Shader::maxTessellationEvaluationInputComponents()

Max supported component count of tessellation evaluation shader input vertex.

The result is cached, repeated queries don't result in repeated OpenGL calls. If neither ARB_tessellation_shader (part of OpenGL 4.0) nor ANDROID_extension_pack_es31a / EXT_tessellation_shader (part of OpenGL ES 3.2) is available, returns 0.

static Int Magnum::GL::Shader::maxTessellationEvaluationOutputComponents()

Max supported component count of tessellation evaluation shader output vertex.

The result is cached, repeated queries don't result in repeated OpenGL calls. If neither ARB_tessellation_shader (part of OpenGL 4.0) nor ANDROID_extension_pack_es31a / EXT_tessellation_shader (part of OpenGL ES 3.2) is available, returns 0.

static Int Magnum::GL::Shader::maxGeometryInputComponents()

Max supported component count of geometry shader input vertex.

The result is cached, repeated queries don't result in repeated OpenGL calls. If neither ARB_geometry_shader4 (part of OpenGL 3.2) nor ANDROID_extension_pack_es31a / EXT_geometry_shader (part of OpenGL ES 3.2) is not available, returns 0.

static Int Magnum::GL::Shader::maxGeometryOutputComponents()

Max supported component count of geometry shader output vertex.

The result is cached, repeated queries don't result in repeated OpenGL calls. If neither ARB_geometry_shader4 (part of OpenGL 3.2) nor ANDROID_extension_pack_es31a / EXT_geometry_shader (part of OpenGL ES 3.2) is not available, returns 0.

static Int Magnum::GL::Shader::maxGeometryTotalOutputComponents()

Max supported component count of all geometry shader output vertices combined.

The result is cached, repeated queries don't result in repeated OpenGL calls. If neither ARB_geometry_shader4 (part of OpenGL 3.2) nor ANDROID_extension_pack_es31a / EXT_geometry_shader (part of OpenGL ES 3.2) is not available, returns 0.

static Int Magnum::GL::Shader::maxFragmentInputComponents()

Max supported component count on fragment shader input.

The result is cached, repeated queries don't result in repeated OpenGL calls. In OpenGL ES 2.0 the four-component vector count is queried and multiplied with 4.

static Int Magnum::GL::Shader::maxUniformComponents(Type type)

Max supported uniform component count in default block.

The result is cached, repeated queries don't result in repeated OpenGL calls. If particular shader stage is not available, returns 0. In OpenGL ES 2.0 the four-component vector count is queried and multiplied with 4.

static Int Magnum::GL::Shader::maxAtomicCounterBuffers(Type type)

Max supported atomic counter buffer count.

The result is cached, repeated queries don't result in repeated OpenGL calls. If neither extension ARB_shader_atomic_counters (part of OpenGL 4.2) nor OpenGL ES 3.1 is available or if particular shader stage is not available, returns 0.

static Int Magnum::GL::Shader::maxCombinedAtomicCounterBuffers()

Max supported atomic counter buffer count for all stages combined.

The result is cached, repeated queries don't result in repeated OpenGL calls. If neither extension ARB_shader_atomic_counters (part of OpenGL 4.2) nor OpenGL ES 3.1 is available, returns 0.

static Int Magnum::GL::Shader::maxAtomicCounters(Type type)

Max supported atomic counter count.

The result is cached, repeated queries don't result in repeated OpenGL calls. If neither extension ARB_shader_atomic_counters (part of OpenGL 4.2) nor OpenGL ES 3.1 is available or if particular shader stage is not available, returns 0.

static Int Magnum::GL::Shader::maxCombinedAtomicCounters()

Max supported atomic counter count for all stages combined.

The result is cached, repeated queries don't result in repeated OpenGL calls. If neither extension ARB_shader_atomic_counters (part of OpenGL 4.2) nor OpenGL ES 3.1 is available, returns 0.

static Int Magnum::GL::Shader::maxImageUniforms(Type type)

Max supported image uniform count.

The result is cached, repeated queries don't result in repeated OpenGL calls. If neither extension ARB_shader_image_load_store (part of OpenGL 4.2) nor OpenGL ES 3.1 is available or if particular shader stage is not available, returns 0.

static Int Magnum::GL::Shader::maxCombinedImageUniforms()

Max supported image uniform count for all stages combined.

The result is cached, repeated queries don't result in repeated OpenGL calls. If neither extension ARB_shader_image_load_store (part of OpenGL 4.2) nor OpenGL ES 3.1 is available, returns 0.

static Int Magnum::GL::Shader::maxShaderStorageBlocks(Type type)

Max supported shader storage block count.

The result is cached, repeated queries don't result in repeated OpenGL calls. If neither extension ARB_shader_storage_buffer_object (part of OpenGL 4.3) nor OpenGL ES 3.1 is available or if particular shader stage is not available, returns 0.

static Int Magnum::GL::Shader::maxCombinedShaderStorageBlocks()

Max supported shader storage block count for all stages combined.

The result is cached, repeated queries don't result in repeated OpenGL calls. If neither extension ARB_shader_storage_buffer_object (part of OpenGL 4.3) nor OpenGL ES 3.1 is available, returns 0.

static Int Magnum::GL::Shader::maxTextureImageUnits(Type type)

Max supported texture image unit count.

The result is cached, repeated queries don't result in repeated OpenGL calls. If particular shader stage is not available, returns 0.

static Int Magnum::GL::Shader::maxCombinedTextureImageUnits()

Max supported texture image unit count for all stages combined.

The result is cached, repeated queries don't result in repeated OpenGL calls.

static Int Magnum::GL::Shader::maxUniformBlocks(Type type)

Max supported uniform block count.

The result is cached, repeated queries don't result in repeated OpenGL calls. If extension ARB_uniform_buffer_objects (part of OpenGL 3.1) or particular shader stage is not available, returns 0.

static Int Magnum::GL::Shader::maxCombinedUniformBlocks()

Max supported uniform block count for all stages combined.

The result is cached, repeated queries don't result in repeated OpenGL calls. If extension ARB_uniform_buffer_objects (part of OpenGL 3.1) is not available, returns 0.

static Int Magnum::GL::Shader::maxCombinedUniformComponents(Type type)

Max supported uniform component count in all blocks combined.

The result is cached, repeated queries don't result in repeated OpenGL calls. If extension ARB_uniform_buffer_objects (part of OpenGL 3.1) or particular shader stage is not available, returns 0.

static bool Magnum::GL::Shader::compile(std::initializer_list<Containers::Reference<Shader>> shaders)

Compile multiple shaders simultaneously.

Calls submitCompile() on all shaders first, then checkCompile(). Returns false if compilation of any shader failed, true if everything succeeded.

static Shader Magnum::GL::Shader::wrap(Type type, GLuint id, ObjectFlags flags = {}) new in Git master

Wrap existing OpenGL shader object.

Parameters
type Shader type
id OpenGL shader ID
flags Object creation flags

The id is expected to be of an existing OpenGL shader object. Unlike a shader created using a constructor, the OpenGL object is by default not deleted on destruction, use flags for different behavior.

Magnum::GL::Shader::Shader(Version version, Type type) explicit

Constructor.

Parameters
version Target version
type Shader type

Creates empty OpenGL shader and adds #version directive corresponding to version parameter at the beginning. If Version::None is specified, (not) adding the #version directive is left to the user.

Magnum::GL::Shader::Shader(NoCreateT) explicit noexcept

Construct without creating the underlying OpenGL object.

The constructed instance is equivalent to moved-from state. Useful in cases where you will overwrite the instance later anyway. Move another object over it to make it useful.

This function can be safely used for constructing (and later destructing) objects even without any OpenGL context being active. However note that this is a low-level and a potentially dangerous API, see the documentation of NoCreate for alternatives.

Magnum::GL::Shader::~Shader()

Destructor.

Deletes associated OpenGL shader.

GLuint Magnum::GL::Shader::release() new in Git master

Release the underlying OpenGL object.

Releases ownership of the OpenGL shader object and returns its ID so it's not deleted on destruction. The internal state is then equivalent to a moved-from state.

Containers::String Magnum::GL::Shader::label() const

Shader label.

The result is not cached, repeated queries will result in repeated OpenGL calls. If OpenGL 4.3 / OpenGL ES 3.2 is not supported and neither KHR_debug (covered also by ANDROID_extension_pack_es31a) nor EXT_debug_label desktop or ES extension is available, this function returns empty string.

Shader& Magnum::GL::Shader::setLabel(Containers::StringView label)

Set shader label.

Returns Reference to self (for method chaining)

Default is empty string. If OpenGL 4.3 / OpenGL ES 3.2 is not supported and neither KHR_debug (covered also by ANDROID_extension_pack_es31a) nor EXT_debug_label desktop or ES extension is available, this function does nothing.

Shader& Magnum::GL::Shader::addSource(std::string source)

Add shader source.

Parameters
source String with shader source
Returns Reference to self (for method chaining)

Adds given source to source list, preceded with a #line n 1 directive for improved compilation error reporting.

Shader& Magnum::GL::Shader::addFile(const std::string& filename)

Add shader source file.

Parameters
filename Name of source file to read from
Returns Reference to self (for method chaining)

The file must exist and must be readable. Calls addSource() with the contents.

bool Magnum::GL::Shader::compile()

Compile the shader.

Calls submitCompile(), immediately followed by checkCompile(), passing back its return value. See documentation of those two functions for details.

void Magnum::GL::Shader::submitCompile() new in Git master

Submit the shader for compilation.

You can call isCompileFinished() or checkCompile() after, but it's recommended to instead immediately call AbstractShaderProgram::attachShader() and submitLink(), then optionally continue with isLinkFinished() and pass all input shaders to checkLink() on the final program — if compilation would fail, subsequent linking will as well, and checkLink() will print the compilation error if linking failed due to that. See Asynchronous shader compilation and linking for more information.

bool Magnum::GL::Shader::checkCompile() new in Git master

Check shader compilation status and await completion.

Has to be called only if submitCompile() was called before. It's however recommended to instead immediately call AbstractShaderProgram::attachShader() and submitLink(), then optionally continue with isLinkFinished() and pass all input shaders to checkLink() on the final program — if compilation would fail, subsequent linking will as well, and checkLink() will print the compilation error if linking failed due to that. See Asynchronous shader compilation and linking for more information.

bool Magnum::GL::Shader::isCompileFinished() new in Git master

Whether a submitCompile() operation has finished.

Has to be called only if submitCompile() was called before, and before checkCompile(). If returns false, a subsequent checkCompile() call will block until the compilation is finished. If KHR_parallel_shader_compile is not available, the function always returns true — i.e., as if the compilation was done synchronously.

It's however recommended to wait only for the final link to finish, and not for particular compilations — i.e., right after submitCompile() continue with AbstractShaderProgram::attachShader() and submitLink(), and then check with isLinkFinished() on the final program. See Asynchronous shader compilation and linking for more information.

Debug& operator<<(Debug& debug, Shader::Type value)

Debug output operator.