Struct GlRenderState 

pub struct GlRenderState {
    pub depth: GlDepthState,
    pub blend: GlBlendState,
    pub cull: GlCullState,
    pub color_mask: GlColorMask,
    pub scissor: Option<GlScissor>,
    pub viewport: GlViewport,
}

The whole fixed-function state of one draw, as a single Copy value.

The point of bundling these six fields into one struct is that it can be diffed field by field against the state currently bound, so WebGl2Backend::apply_state issues a GL call only for what actually changed. A renderer that calls enable, depthFunc, depthMask, blendFunc, blendEquation, cullFace, frontFace, colorMask, scissor, and viewport unconditionally pays for a dozen redundant calls per draw, each one a validation check inside the driver.

Fields

depth: GlDepthState

The depth-test state.

blend: GlBlendState

The blend state.

cull: GlCullState

The culling and winding state.

color_mask: GlColorMask

Which channels the fragment stage may write.

scissor: Option<GlScissor>

The scissor rectangle, or None when scissoring is off.

viewport: GlViewport

The viewport rectangle.

Implementations

impl GlRenderState

Implements default construction for the fixed-function state shadow.

pub fn from_init(init: GlRenderStateInit) -> Self

Builds a render state from explicit field values.

context_defaults covers only the state a freshly created GL context happens to be in. Anything else – a depth-tested draw, a scissored viewport, a masked render target – has to be assembled field by field to reach apply_state, which without this is impossible from outside the crate.

Arguments

• GlRenderStateInit - The six fixed-function fields.

Returns

• GlRenderState - The assembled state.

pub fn context_defaults(width: i32, height: i32) -> GlRenderState

Builds the state a freshly created WebGL 2 context is actually in.

Every value here is one the driver has already set up, not a zero placeholder, and that is the point: seeding the diffing shadow with the real defaults means the first WebGl2Backend::apply_state emits only the calls that genuinely differ from what the driver already did, rather than a dozen redundant re-assertions. Getting a single default wrong would instead leave one field permanently un-applied, because the diff would consider it unchanged forever.

Depth test off, depth write on, LEQUAL once enabled; blending off; culling off with counter-clockwise front faces; all four color channels writable; scissor off; viewport covering the given size.

Arguments

• i32 - The viewport width in pixels.
• i32 - The viewport height in pixels.

Returns

• GlRenderState - The state a new context starts in.

impl GlRenderState

pub fn get_depth(&self) -> &GlDepthState

pub fn get_blend(&self) -> &GlBlendState

pub fn get_cull(&self) -> &GlCullState

pub fn get_color_mask(&self) -> &GlColorMask

pub fn get_scissor(&self) -> Option<GlScissor>

pub fn try_get_scissor(&self) -> Option<GlScissor>

pub fn get_viewport(&self) -> &GlViewport

Trait Implementations

impl Clone for GlRenderState

fn clone(&self) -> Self

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Copy for GlRenderState

impl Debug for GlRenderState

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl PartialEq for GlRenderState

fn eq(&self, other: &Self) -> bool

Equality operator ==.

fn ne(&self, other: &Rhs) -> bool

Inequality operator !=.

impl StructuralPartialEq for GlRenderState