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//! Resource manager to allocate and switch between render targets.
use crate::context::Context;
/// The target to every rendering call.
pub enum RenderTarget {
/// The screen (main surface).
Screen,
/// An off-screen buffer.
Offscreen(Box<OffscreenBuffers>),
}
/// wgpu resources for an off-screen render target.
pub struct OffscreenBuffers {
/// The color texture to render to.
pub color_texture: wgpu::Texture,
/// The color texture view.
pub color_view: wgpu::TextureView,
/// The depth texture.
pub depth_texture: wgpu::Texture,
/// The depth texture view.
pub depth_view: wgpu::TextureView,
/// The sampler for the color texture (for post-processing).
pub sampler: wgpu::Sampler,
/// Width of the render target.
pub width: u32,
/// Height of the render target.
pub height: u32,
}
impl RenderTarget {
/// Returns the color texture view for off-screen rendering.
///
/// Returns `None` if this is the screen target.
pub fn color_view(&self) -> Option<&wgpu::TextureView> {
match self {
RenderTarget::Screen => None,
RenderTarget::Offscreen(o) => Some(&o.color_view),
}
}
/// Returns the depth texture view for off-screen rendering.
///
/// Returns `None` if this is the screen target.
pub fn depth_view(&self) -> Option<&wgpu::TextureView> {
match self {
RenderTarget::Screen => None,
RenderTarget::Offscreen(o) => Some(&o.depth_view),
}
}
/// Returns the color texture for off-screen rendering.
///
/// Returns `None` if this is the screen target.
pub fn color_texture(&self) -> Option<&wgpu::Texture> {
match self {
RenderTarget::Screen => None,
RenderTarget::Offscreen(o) => Some(&o.color_texture),
}
}
/// Returns the sampler for the color texture.
///
/// Returns `None` if this is the screen target.
pub fn sampler(&self) -> Option<&wgpu::Sampler> {
match self {
RenderTarget::Screen => None,
RenderTarget::Offscreen(o) => Some(&o.sampler),
}
}
/// Resizes this render target.
pub fn resize(&mut self, width: u32, height: u32, surface_format: wgpu::TextureFormat) {
match self {
RenderTarget::Screen => {
// Screen resizing is handled by the canvas/surface
}
RenderTarget::Offscreen(o) => {
if o.width != width || o.height != height {
// Recreate textures with new size
**o = OffscreenBuffers::new(width, height, surface_format, true);
}
}
}
}
}
impl OffscreenBuffers {
/// Creates new off-screen buffers with the specified dimensions.
pub fn new(
width: u32,
height: u32,
format: wgpu::TextureFormat,
create_depth_texture: bool,
) -> Self {
let ctxt = Context::get();
// Ensure minimum dimensions of 1x1 to avoid wgpu validation errors
let width = width.max(1);
let height = height.max(1);
// Create color texture
let color_texture = ctxt.create_texture(&wgpu::TextureDescriptor {
label: Some("offscreen_color_texture"),
size: wgpu::Extent3d {
width,
height,
depth_or_array_layers: 1,
},
mip_level_count: 1,
sample_count: 1,
dimension: wgpu::TextureDimension::D2,
format,
usage: wgpu::TextureUsages::RENDER_ATTACHMENT
| wgpu::TextureUsages::TEXTURE_BINDING
| wgpu::TextureUsages::COPY_SRC,
view_formats: &[],
});
let color_view = color_texture.create_view(&wgpu::TextureViewDescriptor::default());
// Create depth texture
let depth_format = Context::depth_format();
let depth_texture = ctxt.create_texture(&wgpu::TextureDescriptor {
label: Some("offscreen_depth_texture"),
size: wgpu::Extent3d {
width,
height,
depth_or_array_layers: 1,
},
mip_level_count: 1,
sample_count: 1,
dimension: wgpu::TextureDimension::D2,
format: depth_format,
usage: if create_depth_texture {
wgpu::TextureUsages::RENDER_ATTACHMENT | wgpu::TextureUsages::TEXTURE_BINDING
} else {
wgpu::TextureUsages::RENDER_ATTACHMENT
},
view_formats: &[],
});
let depth_view = depth_texture.create_view(&wgpu::TextureViewDescriptor::default());
// Create sampler for the color texture
let sampler = ctxt.create_sampler(&wgpu::SamplerDescriptor {
label: Some("offscreen_sampler"),
address_mode_u: wgpu::AddressMode::ClampToEdge,
address_mode_v: wgpu::AddressMode::ClampToEdge,
address_mode_w: wgpu::AddressMode::ClampToEdge,
mag_filter: wgpu::FilterMode::Linear,
min_filter: wgpu::FilterMode::Linear,
mipmap_filter: wgpu::MipmapFilterMode::Nearest,
..Default::default()
});
OffscreenBuffers {
color_texture,
color_view,
depth_texture,
depth_view,
sampler,
width,
height,
}
}
}
/// A framebuffer manager. It manages off-screen render targets for post-processing effects.
pub struct FramebufferManager {
/// The surface format for creating compatible textures.
surface_format: wgpu::TextureFormat,
}
impl Default for FramebufferManager {
fn default() -> Self {
Self::new()
}
}
impl FramebufferManager {
/// Creates a new framebuffer manager.
pub fn new() -> FramebufferManager {
let ctxt = Context::get();
FramebufferManager {
surface_format: ctxt.surface_format,
}
}
/// Creates a new render target. A render target is the combination of a color buffer and a
/// depth buffer.
pub fn new_render_target(
&self,
width: u32,
height: u32,
create_depth_texture: bool,
) -> RenderTarget {
RenderTarget::Offscreen(Box::new(OffscreenBuffers::new(
width,
height,
self.surface_format,
create_depth_texture,
)))
}
/// Returns the render target associated with the screen.
pub fn screen() -> RenderTarget {
RenderTarget::Screen
}
/// Gets the surface format used by this manager.
pub fn surface_format(&self) -> wgpu::TextureFormat {
self.surface_format
}
}