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.

Creating a trilinear sampler

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

Creating a shadow-comparison sampler

easygl::Sampler shadowSampler;
shadowSampler.create();
shadowSampler.set_parameter(easygl::TextureParameter::CompareMode,
    static_cast<int>(easygl::TextureCompareMode::CompareRefToTexture));
shadowSampler.set_parameter(easygl::TextureParameter::CompareFunc,
    static_cast<int>(easygl::CompareFunc::Lequal));
shadowSampler.set_parameter(easygl::TextureParameter::MinFilter,
    static_cast<int>(easygl::TextureMinFilter::Linear));
shadowSampler.set_parameter(easygl::TextureParameter::WrapS,
    static_cast<int>(easygl::TextureWrapMode::ClampToEdge));
shadowSampler.set_parameter(easygl::TextureParameter::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).
`is_created()`	True if GL handle allocated.
`native_handle()`	Raw GL integer ID.
`reset_handle_no_gl()`	Context-loss recovery.