drm: WIP format_selection heuristic

Author: Drakulix

src/backend/drm/format_selection.rs

@@ -0,0 +1,40 @@
+use drm::control::{connector, crtc, Mode};
+use drm_fourcc::{DrmFormat, DrmFourcc, DrmModifier};
+
+use crate::backend::allocator::Allocator;
+
+use super::{exporter::ExportFramebuffer, DrmDevice, DrmSurface};
+
+pub struct SurfaceDefinition<'a> {
+    pub crtc: crtc::Handle,
+    pub mode: &'a Mode,
+    pub connectors: &'a [connector::Handle],
+}
+
+pub fn select_formats<'a, A: Allocator, F: ExportFramebuffer<A::Buffer>>(
+    device: &DrmDevice,
+    allocator: &mut A,
+    framebuffer_exporter: &F,
+    surfaces: impl IntoIterator<Item = SurfaceDefinition<'a>>,
+    color_formats: impl IntoIterator<Item = DrmFourcc>,
+    renderer_formats: impl IntoIterator<Item = DrmFormat>,
+) -> Vec<SurfaceFormat<'a>> {
+    let surfaces = surfaces.into_iter();
+    let color_formats = color_formats.into_iter().collect::<Vec<_>>();
+    let mut surface_formats: Vec<SurfaceFormat<'a>> = Vec::with_capacity(surfaces.size_hint().0);
+
+    // TODO: Okay, so the idea is that we first check if we have a legacy device or atomic
+    // In case we have a legacy device we just search for supported formats and test them accepting it might just flicker like hell...
+    // For atomic issue test commits with:
+    // - All planes except the primaries for the supplied surfaces disabled
+    // - All crtc disabled except the passed ones
+    // - Format by format...with some limit and then just use Invalid
+
+    todo!("Implement the actual format selection...")
+}
+
+pub struct SurfaceFormat<'a> {
+    pub surface: &'a DrmSurface,
+    pub code: DrmFourcc,
+    pub modifiers: Vec<DrmModifier>,
+}

src/backend/drm/mod.rs

@@ -76,9 +76,10 @@ pub(crate) mod device;
 #[cfg(feature = "backend_drm")]
 pub mod dumb;
 mod error;
+pub mod exporter;
+pub mod format_selection;
 #[cfg(feature = "backend_gbm")]
 pub mod gbm;
-pub mod exporter;
 pub mod output;
 
 mod surface;