easy-gl › Sampler

Sampler

A Sampler Object decouples texture sampling parameters (filtering, wrap mode, LOD bias) from the texture itself. Bind a Sampler to a texture unit to override the texture's own sampling parameters. Requires OpenGL 3.3+.

Why use sampler objects?

Reuse the same sampling settings across multiple textures without duplicating parameters.
Swap filtering modes at draw time without touching the texture state.
Useful for atlases where different draw calls need different wrap modes on the same texture.

Factory helpers

Pre-built samplers for common configurations:

auto linearClamp  = easygl::Sampler::create_linear_clamp();   // linear filter, clamp to edge
auto nearestClamp = easygl::Sampler::create_nearest_clamp();  // nearest filter, clamp to edge
auto linearRepeat = easygl::Sampler::create_linear_repeat();  // linear filter, repeat wrap
auto mipLinear    = easygl::Sampler::create_mipmap_linear();  // trilinear mipmap, repeat wrap

Creating a trilinear sampler

easygl::Sampler trilinear;
trilinear.create();
trilinear.set_parameter(easygl::SamplerParameter::MinFilter,
    static_cast<int>(easygl::TextureMinFilter::LinearMipmapLinear));
trilinear.set_parameter(easygl::SamplerParameter::MagFilter,
    static_cast<int>(easygl::TextureMagFilter::Linear));
trilinear.set_parameter(easygl::SamplerParameter::WrapS,
    static_cast<int>(easygl::TextureWrapMode::Repeat));
trilinear.set_parameter(easygl::SamplerParameter::WrapT,
    static_cast<int>(easygl::TextureWrapMode::Repeat));

Creating a shadow-comparison sampler

easygl::Sampler shadowSampler;
shadowSampler.create();
shadowSampler.set_parameter(easygl::SamplerParameter::CompareMode,
    static_cast<int>(easygl::TextureCompareMode::CompareRefToTexture));
shadowSampler.set_parameter(easygl::SamplerParameter::CompareFunc,
    static_cast<int>(easygl::CompareFunc::Lequal));
shadowSampler.set_parameter(easygl::SamplerParameter::MinFilter,
    static_cast<int>(easygl::TextureMinFilter::Linear));
shadowSampler.set_parameter(easygl::SamplerParameter::WrapS,
    static_cast<int>(easygl::TextureWrapMode::ClampToEdge));
shadowSampler.set_parameter(easygl::SamplerParameter::WrapT,
    static_cast<int>(easygl::TextureWrapMode::ClampToEdge));

Binding at render time

shadowTex.active_bind(easygl::TextureUnit::Texture3,
                        easygl::TextureTarget::Texture2D);
shadowSampler.bind(3); // unit index as integer

// Unbind later:
easygl::Sampler::unbind(3);

Method reference

Method	Description
`create()`	Allocate GL sampler handle.
`destroy()`	Free handle. Noexcept.
`bind(unit)`	Bind sampler to texture unit index.
`unbind(unit) [static]`	Bind sampler 0 to unit.
`set_parameter(pname, int)`	Set an integer sampler parameter.
`set_parameter(pname, float)`	Set a float sampler parameter (e.g. LOD bias).
`create_linear_clamp() [static]`	Linear filter, clamp-to-edge wrap.
`create_nearest_clamp() [static]`	Nearest filter, clamp-to-edge wrap.
`create_linear_repeat() [static]`	Linear filter, repeat wrap.
`create_mipmap_linear() [static]`	Trilinear mipmap, repeat wrap.
`is_created()`	True if GL handle allocated.
`native_handle()`	Raw GL integer ID.
`reset_handle_no_gl()`	Context-loss recovery.