Struct Canvas 

pub struct Canvas { /* private fields */ }

An off-screen render target (framebuffer object) with optional MSAA.

Supports multiple colour attachments, depth/stencil, and MSAA resolve. Created via Canvas::new or GPU::ship_canvas.

Example

use optic_render::handles::{Canvas, CanvasDesc};

let canvas = Canvas::new(&CanvasDesc::default())?;

Implementations

impl Canvas

pub fn new(desc: &CanvasDesc) -> OpticResult<Self>

Creates a new framebuffer from a descriptor.

Validates constraints:

• At least one colour format or depth must be specified
• Stencil requires depth
• depth_compare requires depth_as_texture

pub fn size(&self) -> Size2D

Returns the canvas size.

pub fn color_tex(&self, index: usize) -> OpticResult<&Texture2D>

Returns a reference to the colour texture at the given attachment index.

pub fn depth_tex(&self) -> Option<&Texture2D>

Returns a reference to the depth texture, if present.

pub fn set_size(&mut self, new_size: Size2D) -> OpticResult<()>

Resizes the canvas by recreating the framebuffer with a new size.

pub fn resolve(&self)

Resolves MSAA colour/depth/stencil into the resolve framebuffer.

No-op if the canvas does not use MSAA.

pub fn blit_to_screen(&self, window_size: Size2D)

Blits this canvas into the default framebuffer (screen), scaling to fit.

pub fn set_renderable_area( &self, x: i32, y: i32, size: Size2D, ) -> OpticResult<()>

Sets the viewport scissor within this canvas.

The rectangle must be within the canvas bounds.

pub fn read_pixels(&self, index: usize) -> OpticResult<Vec<u8>>

Reads pixel data from a colour attachment back to the CPU.

pub fn save_to_disk(&self, index: usize, path: &str) -> OpticResult<()>

Saves a colour attachment to an image file on disk.

Supported formats depend on the colour attachment format (8/16/32 bpc, 1–4 channels).

pub fn delete(&mut self)

Deletes all GL resources (FBOs, RBOs, textures).