Documentation
¶
Overview ¶
Package glsl provides a GLSL (OpenGL Shading Language) backend for naga.
This package generates GLSL source code from naga's IR representation. It supports multiple GLSL versions for different target platforms:
- GLSL ES 3.00: WebGL 2.0, Mobile OpenGL ES 3.0
- GLSL 3.30 Core: Desktop OpenGL 3.3+
- GLSL ES 3.10: Android 5.0+ with compute shaders
- GLSL 4.30 Core: Desktop OpenGL 4.3+ with compute shaders
Basic Usage ¶
source, info, err := glsl.Compile(module, glsl.Options{
LangVersion: glsl.Version330,
})
Texture/Sampler Handling ¶
WGSL separates textures and samplers, but GLSL combines them. The backend automatically generates combined sampler uniforms for texture-sampler pairs used together.
Reserved Words ¶
GLSL has over 500 reserved words (including future reserved). The backend automatically escapes conflicting identifier names by prefixing them with an underscore.
Index ¶
Constants ¶
This section is empty.
Variables ¶
var ( // Desktop OpenGL versions Version330 = Version{Major: 3, Minor: 30, ES: false} // OpenGL 3.3 Core Version400 = Version{Major: 4, Minor: 0, ES: false} // OpenGL 4.0 Version410 = Version{Major: 4, Minor: 10, ES: false} // OpenGL 4.1 Version420 = Version{Major: 4, Minor: 20, ES: false} // OpenGL 4.2 Version430 = Version{Major: 4, Minor: 30, ES: false} // OpenGL 4.3 (compute shaders) Version450 = Version{Major: 4, Minor: 50, ES: false} // OpenGL 4.5 Version460 = Version{Major: 4, Minor: 60, ES: false} // OpenGL 4.6 // OpenGL ES / WebGL versions VersionES300 = Version{Major: 3, Minor: 0, ES: true} // ES 3.0 / WebGL 2.0 VersionES310 = Version{Major: 3, Minor: 10, ES: true} // ES 3.1 (compute shaders) VersionES320 = Version{Major: 3, Minor: 20, ES: true} // ES 3.2 )
Common GLSL versions.
Functions ¶
This section is empty.
Types ¶
type BindingMapKey ¶
BindingMapKey identifies a resource binding for the BindingMap.
type BoundsCheckPolicies ¶
type BoundsCheckPolicies struct {
// ImageLoad controls bounds checking for image load operations.
ImageLoad BoundsCheckPolicy
// ImageStore controls bounds checking for image store operations.
ImageStore BoundsCheckPolicy
}
BoundsCheckPolicies holds per-resource-type bounds check policies.
type BoundsCheckPolicy ¶
type BoundsCheckPolicy uint8
BoundsCheckPolicy controls how out-of-bounds resource accesses are handled.
const ( // BoundsCheckUnchecked performs no bounds checking. BoundsCheckUnchecked BoundsCheckPolicy = iota // BoundsCheckRestrict clamps indices to valid range. BoundsCheckRestrict // BoundsCheckReadZeroSkipWrite returns zero for reads, skips writes. BoundsCheckReadZeroSkipWrite )
Bounds check policy constants.
type Options ¶
type Options struct {
// LangVersion is the target GLSL version.
// Defaults to Version330 if zero.
LangVersion Version
// EntryPoint specifies which entry point to compile.
// If empty, the first entry point is compiled.
EntryPoint string
// SamplerBindingBase adds offset to sampler binding indices.
SamplerBindingBase uint32
// TextureBindingBase adds offset to texture binding indices.
TextureBindingBase uint32
// UniformBindingBase adds offset to uniform buffer binding indices.
UniformBindingBase uint32
// StorageBindingBase adds offset to storage buffer binding indices.
StorageBindingBase uint32
// WriterFlags control output formatting.
WriterFlags WriterFlags
// ForceHighPrecision forces highp precision for all float types (ES only).
// If false, uses default precision qualifiers.
ForceHighPrecision bool
// BoundsCheckPolicies controls bounds checking for resource accesses.
BoundsCheckPolicies BoundsCheckPolicies
// BindingMap maps resource bindings to flat GL binding indices.
// When set, layout(binding = N) qualifiers are emitted.
BindingMap map[BindingMapKey]uint8
// PipelineConstants provides values for pipeline-overridable constants.
// Keys are either "@id(N)" numeric IDs as strings or override names.
// Values are float64 (NaN means "not set, use default").
// If provided, overrides are resolved before compilation.
PipelineConstants ir.PipelineConstants
}
Options configures GLSL code generation.
func DefaultOptions ¶
func DefaultOptions() Options
DefaultOptions returns sensible default options for GLSL generation.
type TextureMapping ¶
type TextureMapping struct {
// TextureBinding is the (group, binding) of the texture global variable.
TextureBinding ir.ResourceBinding
// SamplerBinding is the (group, binding) of the associated sampler, if any.
// Nil for storage images which have no sampler.
SamplerBinding *ir.ResourceBinding
}
TextureMapping describes a combined texture-sampler pair generated by the GLSL backend.
In GLSL, separate texture2D + sampler become a single sampler2D uniform. The combined uniform uses the texture's binding. The GLES HAL needs to know which sampler is associated with which texture to bind the GL sampler object to the correct texture unit (not the sampler's own WGSL binding).
type TranslationInfo ¶
type TranslationInfo struct {
// EntryPointNames maps original entry point names to generated GLSL names.
EntryPointNames map[string]string
// UsedExtensions lists GLSL extensions required by the shader.
UsedExtensions []string
// RequiredVersion is the minimum GLSL version needed for this shader.
// May be higher than the requested version if features require it.
RequiredVersion Version
// TextureSamplerPairs lists the combined texture-sampler pairs generated.
// Each entry is "textureName_samplerName".
TextureSamplerPairs []string
// TextureMappings maps combined sampler2D uniform names to their texture
// and sampler source bindings. Used by GLES HAL to build SamplerBindMap
// (bind GL sampler to texture's unit, not sampler's own binding).
TextureMappings map[string]TextureMapping
// Uniforms lists uniform/storage buffer blocks with their GLSL block
// names and source bindings. Used by GLES HAL for runtime binding
// fallback on GL < 4.2. Matches Rust naga ReflectionInfo.uniforms.
Uniforms []UniformInfo
}
TranslationInfo contains metadata about the translation.
type UniformInfo ¶
type UniformInfo struct {
// BlockName is the GLSL block name (e.g., "Uniforms_block_0Vertex").
// Used with glGetUniformBlockIndex (uniform buffers) or
// glGetShaderStorageBlockIndex (storage buffers).
BlockName string
// Binding is the source (group, binding) from the IR.
Binding ir.ResourceBinding
// IsStorage is true for storage buffers (SSBO), false for uniform buffers (UBO).
IsStorage bool
}
UniformInfo describes a GLSL uniform or storage buffer block for reflection. Used by the HAL runtime binding fallback on GL < 4.2 where layout(binding=N) is unavailable and bindings must be assigned after linking via GL calls. Matches Rust naga ReflectionInfo.uniforms.
type Version ¶
Version represents a GLSL version.
func (Version) SupportsCompute ¶
SupportsCompute returns true if this version supports compute shaders.
func (Version) SupportsExplicitLocations ¶
SupportsExplicitLocations returns true if explicit layout locations for bindings are supported (layout(binding=N) qualifiers). Desktop GLSL 420+, ES 310+. Matches Rust naga Version::supports_explicit_locations.
func (Version) SupportsStorageBuffers ¶
SupportsStorageBuffers returns true if this version supports storage buffers.
func (Version) VersionNumber ¶
VersionNumber returns just the numeric version (e.g., "330", "300").
type WriterFlags ¶
type WriterFlags uint32
WriterFlags control output formatting.
const ( // WriterFlagNone uses default settings. WriterFlagNone WriterFlags = 0 // WriterFlagExplicitTypes forces explicit type annotations. WriterFlagExplicitTypes WriterFlags = 1 << iota // WriterFlagDebugInfo adds source comments for debugging. WriterFlagDebugInfo // WriterFlagMinify removes unnecessary whitespace. WriterFlagMinify // WriterFlagAdjustCoordinateSpace adds gl_Position coordinate adjustment // at the end of vertex shaders to convert from Vulkan/WebGPU conventions // (Y-down, Z in [0,1]) to OpenGL conventions (Y-up, Z in [-1,1]). WriterFlagAdjustCoordinateSpace // WriterFlagForcePointSize emits gl_PointSize = 1.0 in vertex shaders. // Required for WebGL compatibility. WriterFlagForcePointSize // WriterFlagTextureShadowLod enables GL_EXT_texture_shadow_lod extension // for sampling cube/array shadow textures with explicit LOD. WriterFlagTextureShadowLod )
Writer flag constants.