veloren/voxygen/src/mesh/greedy.rs
2022-07-16 11:09:35 +01:00

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use crate::render::{mesh::Quad, ColLightInfo, TerrainVertex, Vertex};
use common_base::{prof_span, span};
use vek::*;
type TodoRect = (
Vec3<i32>,
Vec2<Vec3<u16>>,
guillotiere::Rectangle,
Vec3<i32>,
);
pub struct GreedyConfig<D, FA, FL, FG, FO, FS, FP, FT> {
pub data: D,
/// The minimum position to mesh, in the coordinate system used
/// for queries against the volume.
pub draw_delta: Vec3<i32>,
/// For each dimension i, for faces drawn in planes *parallel* to i,
/// represents the number of voxels considered along dimension i in those
/// planes, starting from `draw_delta`.
pub greedy_size: Vec3<usize>,
/// For each dimension i, represents the number of planes considered
/// *orthogonal* to dimension i, starting from `draw_delta`. This should
/// usually be the same as greedy_size.
///
/// An important exception is during chunk rendering (where vertical faces
/// at chunk boundaries would otherwise be rendered twice, and also
/// force us to use more than 5 bits to represent x and y
/// positions--though there may be a clever way around the latter).
/// Thus, for chunk rendering we set the number of *vertical* planes to
/// one less than the chunk size along the x and y dimensions, but keep
/// the number of *horizontal* planes large enough to cover the whole
/// chunk.
pub greedy_size_cross: Vec3<usize>,
/// Given a position, return the AO information for the voxel at that
/// position (0.0 - 1.0).
pub get_ao: FA,
/// Given a position, return the lighting information for the voxel at that
/// position.
pub get_light: FL,
/// Given a position, return the glow information for the voxel at that
/// position (i.e: additional non-sun light).
pub get_glow: FG,
/// Given a position, return the opacity information for the voxel at that
/// position. Currently, we don't support real translucent lighting, so the
/// value should either be `false` (for opaque blocks) or `true`
/// (otherwise).
pub get_opacity: FO,
/// Given a position and a normal, should we draw the face between the
/// position and position - normal (i.e. the voxel "below" this vertex)?
/// If so, provide its orientation, together with any other meta
/// information required for the mesh that needs to split up faces. For
/// example, terrain faces currently record a bit indicating whether
/// they are exposed to water or not, so we should not merge faces where
/// one is submerged in water and the other is not, even if they
/// otherwise have the same orientation, dimensions, and are
/// next to each other.
pub should_draw: FS,
/// Create an opaque quad (used for only display rendering) from its
/// top-left atlas position, the rectangle's dimensions in (2D) atlas
/// space, a world position, the u and v axes of the rectangle in (3D)
/// world space, the normal facing out frmo the rectangle in world
/// space, and meta information common to every voxel in this rectangle.
pub push_quad: FP,
/// Given a position and the lighting information for a face at that
/// position, return the texel for the face at that position.
pub make_face_texel: FT,
}
/// A suspended greedy mesh, with enough information to recover color data.
///
/// The reason this exists is that greedy meshing is split into two parts.
/// First, the meshing itself needs to be performed; secondly, we generate a
/// texture atlas. We do things in this order to avoid having to copy all the
/// old vertices to the correct location. However, when trying to use the same
/// texture atlas for more than one model, this approach runs into the
/// problem that enough model information needs to be remembered to be able to
/// generate the colors after the function returns, so we box up the actual
/// coloring part as a continuation. When called with a final tile size and
/// vector, the continuation will consume the color data and write it to the
/// vector.
pub type SuspendedMesh<'a> = dyn for<'r> FnOnce(&'r mut ColLightInfo) + 'a;
/// Abstraction over different atlas allocators. Useful to swap out the
/// allocator implementation for specific cases (e.g. sprites).
pub trait AtlasAllocator {
type Config;
/// Creates a new instance of this atlas allocator taking into account the
/// provided max size;
fn with_max_size(max_size: Vec2<u16>, config: Self::Config) -> Self;
/// Allocates a rectangle of the given size.
// TODO: don't use guillotiere type here
fn allocate(&mut self, size: Vec2<u16>) -> Option<guillotiere::Rectangle>;
/// Retrieves the current size of the atlas being allocated from.
fn size(&self) -> Vec2<u16>;
/// Grows the size of the atlas to the provided size.
fn grow(&mut self, new_size: Vec2<u16>);
}
fn guillotiere_size<T: Into<i32>>(size: Vec2<T>) -> guillotiere::Size {
guillotiere::Size::new(size.x.into(), size.y.into())
}
/// Currently used by terrain/particles/figures
pub fn general_config() -> guillotiere::AllocatorOptions {
// TODO: Collect information to see if we can choose a good value here. These
// current values were optimized for sprites, but we are using a
// different allocator for them so different values might be better
// here.
let large_size_threshold = 8; //256.min(min_max_dim / 2 + 1);
let small_size_threshold = 3; //33.min(large_size_threshold / 2 + 1);
guillotiere::AllocatorOptions {
alignment: guillotiere::Size::new(1, 1),
small_size_threshold,
large_size_threshold,
}
}
pub fn sprite_config() -> guillotiere::AllocatorOptions {
// TODO: Collect information to see if we can choose a better value here (these
// values were picked before switching to this tiled implementation). I
// suspect these are still near optimal though.
let large_size_threshold = 8;
let small_size_threshold = 3;
guillotiere::AllocatorOptions {
alignment: guillotiere::Size::new(1, 1),
small_size_threshold,
large_size_threshold,
}
}
impl AtlasAllocator for guillotiere::SimpleAtlasAllocator {
type Config = guillotiere::AllocatorOptions;
fn with_max_size(max_size: Vec2<u16>, config: Self::Config) -> Self {
let size = guillotiere_size(Vec2::new(32, 32)).min(guillotiere_size(max_size));
guillotiere::SimpleAtlasAllocator::with_options(size, &config)
}
/// Allocates a rectangle of the given size.
fn allocate(&mut self, size: Vec2<u16>) -> Option<guillotiere::Rectangle> {
self.allocate(guillotiere_size(size))
}
/// Retrieves the current size of the atlas being allocated from.
fn size(&self) -> Vec2<u16> {
// NOTE: with_max_size / grow take a u16 so the size will never be larger than
// u16::MAX
Vec2::<i32>::from(self.size().to_array()).map(|e| e as u16)
}
/// Grows the size of the atlas to the provided size.
fn grow(&mut self, new_size: Vec2<u16>) { self.grow(guillotiere_size(new_size)) }
}
pub struct GuillotiereTiled {
options: guillotiere::AllocatorOptions,
// Each tile is Self::TILE_SIZE (unless max size is not aligned to this, in which case the
// tiles that reach the max size are truncated below this value).
allocator: guillotiere::SimpleAtlasAllocator,
// offset in tiles
free_tiles: Vec<Vec2<usize>>,
// Total width and height in tiles (in case this isn't a square).
// Not zero
size: Vec2<usize>,
// Offset (in tiles) of current tile being allocated from (others returned `None` on last
// allocation attempt)
current: Option<Vec2<usize>>,
// Efficiency history for filled tiles (total area, used area)
//
// This is useful to examine packing efficiency.
history: Vec<(u32, u32)>,
used_in_current_tile: u32,
}
impl GuillotiereTiled {
// We can potentially further optimize packing by deferring the allocations
// until all rectangles are available for packing. We could also cache this
// for sprites if we get to the point of having the rest of start up times
// fast enough for this to be helpful (e.g. for iterative work).
//
// Tested with sprites:
// 64 1.63s 1.109 packing
// 128 1.65s 1.083 packing
// 256 1.77s 1.070 packing
// 512 2.27s 1.055 packing
// 1024 5.32s 1.045 packing
// 2048 10.49s n/a packing (didn't fill up)
const TILE_SIZE: u16 = 512;
fn next_tile(&mut self) {
if self.current.is_some() {
prof_span!("stats");
let size = self.allocator.size();
// NOTE: TILE_SIZE is small enough that this won't overflow.
let area = size.width as u32 * size.height as u32;
let used = self.used_in_current_tile;
self.history.push((area, used));
}
self.current = if let Some(offset) = self.free_tiles.pop() {
self.allocator.reset(
guillotiere_size(Vec2::broadcast(Self::TILE_SIZE)),
&self.options,
);
self.used_in_current_tile = 0;
Some(offset)
} else {
None
};
}
}
impl AtlasAllocator for GuillotiereTiled {
type Config = guillotiere::AllocatorOptions;
fn with_max_size(max_size: Vec2<u16>, config: Self::Config) -> Self {
let size =
guillotiere_size(Vec2::broadcast(Self::TILE_SIZE)).min(guillotiere_size(max_size));
let allocator = guillotiere::SimpleAtlasAllocator::with_options(size, &config);
Self {
options: config,
allocator,
free_tiles: Vec::new(),
size: Vec2::new(1, 1),
current: Some(Vec2::new(0, 0)),
history: Vec::new(),
used_in_current_tile: 0,
}
}
/// Allocates a rectangle of the given size.
fn allocate(&mut self, size: Vec2<u16>) -> Option<guillotiere::Rectangle> {
let size = guillotiere_size(size);
while let Some(current) = self.current {
match self.allocator.allocate(size) {
Some(r) => {
// NOTE: The offset will always be smaller or equal to the `u16`s passed into
// `with_max_size`/`grow` so this won't overflow.
let offset = guillotiere_size(current.map(|e| e as u16 * Self::TILE_SIZE));
let offset_rect = guillotiere::Rectangle {
min: r.min.add_size(&offset),
max: r.max.add_size(&offset),
};
// NOTE: `i32` -> `u32` conversion is fine since these will always be positive.
self.used_in_current_tile += size.width as u32 * size.height as u32;
return Some(offset_rect);
},
None => self.next_tile(),
}
}
None
}
/// Retrieves the current size of the atlas being allocated from.
fn size(&self) -> Vec2<u16> {
// NOTE: The size will always be smaller or equal to the `u16`s passed into
// `with_max_size`/`grow` so this won't overflow.
self.size.map(|e| e as u16 * Self::TILE_SIZE)
}
/// Grows the size of the atlas to the provided size.
fn grow(&mut self, new_size: Vec2<u16>) {
if tracing::enabled!(tracing::Level::TRACE) {
tracing::trace!(
"Tile count: {}",
self.history.len() + self.free_tiles.len() + self.current.is_some() as usize
);
let mut total_area = 0;
let mut total_used = 0;
for (area, used) in self.history.iter() {
total_area += area;
total_used += used;
}
tracing::trace!("Packing ratio: {}", total_area as f32 / total_used as f32);
}
let diff = (new_size - self.size()).map(|e| e.max(0));
// NOTE: Growing only occurs in increments of TILE_SIZE so any remaining size is
// ignored. Max size is not known here so this must truncate instead of rounding
// up.
let diff_tiles = diff.map(|e| usize::from(e) / usize::from(Self::TILE_SIZE));
let old_size = self.size;
self.size += diff_tiles;
// Add new tiles to free tile list
for x in old_size.x..self.size.x {
for y in 0..old_size.y {
self.free_tiles.push(Vec2::new(x, y));
}
}
for y in old_size.y..self.size.y {
for x in 0..self.size.x {
self.free_tiles.push(Vec2::new(x, y));
}
}
if self.current.is_none() {
self.next_tile();
}
}
}
pub type SpriteAtlasAllocator = GuillotiereTiled;
/// Shared state for a greedy mesh, potentially passed along to multiple models.
///
/// For an explanation of why we want this, see `SuspendedMesh`.
pub struct GreedyMesh<'a, Allocator: AtlasAllocator = guillotiere::SimpleAtlasAllocator> {
//atlas: guillotiere::SimpleAtlasAllocator,
atlas: Allocator,
col_lights_size: Vec2<u16>,
max_size: Vec2<u16>,
suspended: Vec<Box<SuspendedMesh<'a>>>,
}
impl<'a, Allocator: AtlasAllocator> GreedyMesh<'a, Allocator> {
/// Construct a new greedy mesher.
///
/// Takes as input the maximum allowable size of the texture atlas used to
/// store the light/color data for this mesh.
///
/// NOTE: It is an error to pass any size > u16::MAX (this is now enforced
/// by the type being `u16`).
///
/// Even aside from the above limitation, this will not necessarily always
/// be the same as the maximum atlas size supported by the hardware.
/// For instance, since we want to reserve 4 bits for a bone index for
/// figures in their shadow vertex, the atlas parameter for figures has
/// to have at least 2 bits of the normal; thus, it can only take up at
/// most 30 bits total, meaning we are restricted to "only" at most 2^15
/// × 2^15 atlases even if the hardware supports larger ones.
pub fn new(max_size: Vec2<u16>, config: Allocator::Config) -> Self {
span!(_guard, "new", "GreedyMesh::new");
let min_max_dim = max_size.reduce_min();
assert!(
min_max_dim >= 4,
"min_max_dim={:?} >= 4 ({:?}",
min_max_dim,
max_size
);
let atlas = Allocator::with_max_size(max_size, config);
let col_lights_size = Vec2::new(1, 1);
Self {
atlas,
col_lights_size,
max_size,
suspended: Vec::new(),
}
}
/// Perform greedy meshing on a model, separately producing "pure" model
/// data (the opaque mesh, together with atlas positions connecting
/// each rectangle with texture information), and raw light and color
/// data ready to be used as a texture (accessible with `finalize`).
/// Texture data built up within the same greedy mesh will be inserted
/// into the same atlas, which can be used to group texture data for
/// things like figures that are the result of meshing multiple models.
///
/// Returns an estimate of the bounds of the current meshed model.
///
/// For more information on the config parameter, see [GreedyConfig].
pub fn push<M: PartialEq, D: 'a, FA, FL, FG, FO, FS, FP, FT>(
&mut self,
config: GreedyConfig<D, FA, FL, FG, FO, FS, FP, FT>,
) where
FA: for<'r> FnMut(&'r mut D, Vec3<i32>) -> f32 + 'a,
FL: for<'r> FnMut(&'r mut D, Vec3<i32>) -> f32 + 'a,
FG: for<'r> FnMut(&'r mut D, Vec3<i32>) -> f32 + 'a,
FO: for<'r> FnMut(&'r mut D, Vec3<i32>) -> bool + 'a,
FS: for<'r> FnMut(&'r mut D, Vec3<i32>, Vec3<i32>, Vec2<Vec3<i32>>) -> Option<(bool, M)>,
FP: FnMut(Vec2<u16>, Vec2<Vec2<u16>>, Vec3<f32>, Vec2<Vec3<f32>>, Vec3<f32>, &M),
FT: for<'r> FnMut(&'r mut D, Vec3<i32>, u8, u8, bool) -> [u8; 4] + 'a,
{
span!(_guard, "push", "GreedyMesh::push");
let cont = greedy_mesh(
&mut self.atlas,
&mut self.col_lights_size,
self.max_size,
config,
);
self.suspended.push(cont);
}
/// Finalize the mesh, producing texture color data for the whole model.
///
/// By delaying finalization until the contents of the whole texture atlas
/// are known, we can perform just a single allocation to construct a
/// precisely fitting atlas. This will also let us (in the future)
/// suspend meshing partway through in order to meet frame budget, and
/// potentially use a single staged upload to the GPU.
///
/// Returns the ColLightsInfo corresponding to the constructed atlas.
pub fn finalize(self) -> ColLightInfo {
span!(_guard, "finalize", "GreedyMesh::finalize");
let cur_size = self.col_lights_size;
let col_lights = vec![
TerrainVertex::make_col_light(254, 0, Rgb::broadcast(254), true);
cur_size.x as usize * cur_size.y as usize
];
let mut col_lights_info = (col_lights, cur_size);
self.suspended.into_iter().for_each(|cont| {
cont(&mut col_lights_info);
});
col_lights_info
}
pub fn max_size(&self) -> Vec2<u16> { self.max_size }
}
fn greedy_mesh<'a, M: PartialEq, D: 'a, FA, FL, FG, FO, FS, FP, FT, Allocator: AtlasAllocator>(
atlas: &mut Allocator,
col_lights_size: &mut Vec2<u16>,
max_size: Vec2<u16>,
GreedyConfig {
mut data,
draw_delta,
greedy_size,
greedy_size_cross,
get_ao,
get_light,
get_glow,
get_opacity,
mut should_draw,
mut push_quad,
make_face_texel,
}: GreedyConfig<D, FA, FL, FG, FO, FS, FP, FT>,
) -> Box<SuspendedMesh<'a>>
where
FA: for<'r> FnMut(&'r mut D, Vec3<i32>) -> f32 + 'a,
FL: for<'r> FnMut(&'r mut D, Vec3<i32>) -> f32 + 'a,
FG: for<'r> FnMut(&'r mut D, Vec3<i32>) -> f32 + 'a,
FO: for<'r> FnMut(&'r mut D, Vec3<i32>) -> bool + 'a,
FS: for<'r> FnMut(&'r mut D, Vec3<i32>, Vec3<i32>, Vec2<Vec3<i32>>) -> Option<(bool, M)>,
FP: FnMut(Vec2<u16>, Vec2<Vec2<u16>>, Vec3<f32>, Vec2<Vec3<f32>>, Vec3<f32>, &M),
FT: for<'r> FnMut(&'r mut D, Vec3<i32>, u8, u8, bool) -> [u8; 4] + 'a,
{
span!(_guard, "greedy_mesh");
// TODO: Collect information to see if we can choose a good value here.
let mut todo_rects = Vec::with_capacity(1024);
// x (u = y, v = z)
greedy_mesh_cross_section(
Vec3::new(greedy_size.y, greedy_size.z, greedy_size_cross.x),
|pos| {
should_draw(
&mut data,
draw_delta + Vec3::new(pos.z, pos.x, pos.y),
Vec3::unit_x(),
Vec2::new(Vec3::unit_y(), Vec3::unit_z()),
)
},
|pos, dim, &(faces_forward, ref meta)| {
let pos = Vec3::new(pos.z, pos.x, pos.y);
let uv = Vec2::new(Vec3::unit_y(), Vec3::unit_z());
let norm = Vec3::unit_x();
let atlas_pos = add_to_atlas(
atlas,
&mut todo_rects,
pos,
uv,
dim,
norm,
faces_forward,
max_size,
col_lights_size,
);
create_quad_greedy(
pos,
dim,
uv,
norm,
faces_forward,
meta,
atlas_pos,
|atlas_pos, dim, pos, draw_dim, norm, meta| {
push_quad(atlas_pos, dim, pos, draw_dim, norm, meta)
},
);
},
);
// y (u = z, v = x)
greedy_mesh_cross_section(
Vec3::new(greedy_size.z, greedy_size.x, greedy_size_cross.y),
|pos| {
should_draw(
&mut data,
draw_delta + Vec3::new(pos.y, pos.z, pos.x),
Vec3::unit_y(),
Vec2::new(Vec3::unit_z(), Vec3::unit_x()),
)
},
|pos, dim, &(faces_forward, ref meta)| {
let pos = Vec3::new(pos.y, pos.z, pos.x);
let uv = Vec2::new(Vec3::unit_z(), Vec3::unit_x());
let norm = Vec3::unit_y();
let atlas_pos = add_to_atlas(
atlas,
&mut todo_rects,
pos,
uv,
dim,
norm,
faces_forward,
max_size,
col_lights_size,
);
create_quad_greedy(
pos,
dim,
uv,
norm,
faces_forward,
meta,
atlas_pos,
|atlas_pos, dim, pos, draw_dim, norm, meta| {
push_quad(atlas_pos, dim, pos, draw_dim, norm, meta)
},
);
},
);
// z (u = x, v = y)
greedy_mesh_cross_section(
Vec3::new(greedy_size.x, greedy_size.y, greedy_size_cross.z),
|pos| {
should_draw(
&mut data,
draw_delta + Vec3::new(pos.x, pos.y, pos.z),
Vec3::unit_z(),
Vec2::new(Vec3::unit_x(), Vec3::unit_y()),
)
},
|pos, dim, &(faces_forward, ref meta)| {
let pos = Vec3::new(pos.x, pos.y, pos.z);
let uv = Vec2::new(Vec3::unit_x(), Vec3::unit_y());
let norm = Vec3::unit_z();
let atlas_pos = add_to_atlas(
atlas,
&mut todo_rects,
pos,
uv,
dim,
norm,
faces_forward,
max_size,
col_lights_size,
);
create_quad_greedy(
pos,
dim,
uv,
norm,
faces_forward,
meta,
atlas_pos,
|atlas_pos, dim, pos, draw_dim, norm, meta| {
push_quad(atlas_pos, dim, pos, draw_dim, norm, meta)
},
);
},
);
Box::new(move |col_lights_info| {
let mut data = data;
draw_col_lights(
col_lights_info,
&mut data,
todo_rects,
draw_delta,
get_ao,
get_light,
get_glow,
get_opacity,
make_face_texel,
);
})
}
/// Greedy meshing a single cross-section.
// TODO: See if we can speed a lot of this up using SIMD.
fn greedy_mesh_cross_section<M: PartialEq>(
dims: Vec3<usize>,
// Should we draw a face here (below this vertex)? If so, provide its meta information.
mut draw_face: impl FnMut(Vec3<i32>) -> Option<M>,
// Vertex, width and height, and meta information about the block.
mut push_quads: impl FnMut(Vec3<usize>, Vec2<usize>, &M),
) {
span!(_guard, "greedy_mesh_cross_section");
// mask represents which faces are either set while the other is unset, or unset
// while the other is set.
let mut mask = (0..dims.y * dims.x).map(|_| None).collect::<Vec<_>>();
(0..dims.z + 1).for_each(|d| {
// Compute mask
mask.iter_mut().enumerate().for_each(|(posi, mask)| {
let i = posi % dims.x;
let j = posi / dims.x;
// NOTE: Safe because dims.z actually fits in a u16.
*mask = draw_face(Vec3::new(i as i32, j as i32, d as i32));
});
(0..dims.y).for_each(|j| {
let mut i = 0;
while i < dims.x {
// Compute width (number of set x bits for this row and layer, starting at the
// current minimum column).
if let Some(ori) = &mask[j * dims.x + i] {
let width = 1 + mask[j * dims.x + i + 1..j * dims.x + dims.x]
.iter()
.take_while(move |&mask| mask.as_ref() == Some(ori))
.count();
let max_x = i + width;
// Compute height (number of rows having w set x bits for this layer, starting
// at the current minimum column and row).
let height = 1
+ (j + 1..dims.y)
.take_while(|h| {
mask[h * dims.x + i..h * dims.x + max_x]
.iter()
.all(|mask| mask.as_ref() == Some(ori))
})
.count();
let max_y = j + height;
// Add quad.
push_quads(Vec3::new(i, j, d), Vec2::new(width, height), ori);
// Unset mask bits in drawn region, so we don't try to re-draw them.
(j..max_y).for_each(|l| {
mask[l * dims.x + i..l * dims.x + max_x]
.iter_mut()
.for_each(|mask| {
*mask = None;
});
});
// Update x value.
i = max_x;
} else {
i += 1;
}
}
});
});
}
fn add_to_atlas<Allocator: AtlasAllocator>(
atlas: &mut Allocator,
todo_rects: &mut Vec<TodoRect>,
pos: Vec3<usize>,
uv: Vec2<Vec3<u16>>,
dim: Vec2<usize>,
norm: Vec3<i16>,
faces_forward: bool,
max_size: Vec2<u16>,
cur_size: &mut Vec2<u16>,
) -> guillotiere::Rectangle {
// TODO: Check this conversion.
let atlas_rect = loop {
// NOTE: Conversion to u16 is safe because he x, y, and z dimensions for any
// chunk index must fit in at least an i16 (lower for x and y, probably
// lower for z) and at least x and y are not negative.
let res = atlas.allocate(Vec2::new(dim.x as u16 + 1, dim.y as u16 + 1));
if let Some(atlas_rect) = res {
break atlas_rect;
}
// Allocation failure.
let current_size = atlas.size();
if current_size == max_size {
// NOTE: Currently, if we fail to allocate a terrain chunk in the atlas and we
// have already reached the maximum texture size, we choose to just skip the
// geometry and log a warning, rather than panicking or trying to use a fallback
// technique (e.g. a texture array).
//
// FIXME: Either make more robust, or explicitly document that limits on texture
// size need to be respected for terrain data (the OpenGL minimum requirement is
// 1024 × 1024, but in practice almost all computers support 4096 × 4096 or
// higher; see
// https://feedback.wildfiregames.com/report/opengl/feature/GL_MAX_TEXTURE_SIZE).
panic!(
"Could not add texture to atlas using simple allocator (pos={:?}, dim={:?});we \
could not fit the whole model into a single texture on this machine
(max texture size={:?}, so we are discarding this rectangle.",
pos, dim, max_size
);
}
// Otherwise, we haven't reached max size yet, so double the size (or reach the
// max texture size) and try again.
let new_size = max_size.map2(current_size, |max, current| {
max.min(current.saturating_mul(2))
});
atlas.grow(new_size);
};
// NOTE: Conversion is correct because our initial max size for the atlas was a
// u16 and we never grew the atlas past the max size, meaning all valid
// coordinates within the atlas also fit into a u16.
*cur_size = Vec2::new(
cur_size.x.max(atlas_rect.max.x as u16),
cur_size.y.max(atlas_rect.max.y as u16),
);
// NOTE: pos can be converted safely from usize to i32 because all legal block
// coordinates in this chunk must fit in an i32 (actually we have the much
// stronger property that this holds across the whole map).
let norm = norm.map(i32::from);
todo_rects.push((
pos.map(|e| e as i32) + if faces_forward { -norm } else { Vec3::zero() },
uv,
atlas_rect,
if faces_forward { norm } else { -norm },
));
atlas_rect
}
/// We deferred actually recording the colors within the rectangles in order to
/// generate a texture of minimal size; we now proceed to create and populate
/// it.
// TODO: Consider using the heavier interface (not the simple one) which seems
// to provide builtin support for what we're doing here.
//
// TODO: See if we can speed this up using SIMD.
fn draw_col_lights<D>(
(col_lights, cur_size): &mut ColLightInfo,
data: &mut D,
todo_rects: Vec<TodoRect>,
draw_delta: Vec3<i32>,
mut get_ao: impl FnMut(&mut D, Vec3<i32>) -> f32,
mut get_light: impl FnMut(&mut D, Vec3<i32>) -> f32,
mut get_glow: impl FnMut(&mut D, Vec3<i32>) -> f32,
mut get_opacity: impl FnMut(&mut D, Vec3<i32>) -> bool,
mut make_face_texel: impl FnMut(&mut D, Vec3<i32>, u8, u8, bool) -> [u8; 4],
) {
todo_rects.into_iter().for_each(|(pos, uv, rect, delta)| {
// NOTE: Conversions are safe because width, height, and offset must be
// non-negative, and because every allocated coordinate in the atlas must be in
// bounds for the original size, max_texture_size, which fit into a u16.
let width = (rect.max.x - rect.min.x) as u16;
let height = (rect.max.y - rect.min.y) as u16;
let left = rect.min.x as u16;
let top = rect.min.y as u16;
let uv = uv.map(|e| e.map(i32::from));
let pos = pos + draw_delta;
(0..height).for_each(|v| {
let start = cur_size.x as usize * usize::from(top + v) + usize::from(left);
(0..width)
.zip(&mut col_lights[start..start + usize::from(width)])
.for_each(|(u, col_light)| {
let pos = pos + uv.x * i32::from(u) + uv.y * i32::from(v);
// TODO: Consider optimizing to take advantage of the fact that this whole
// face should be facing nothing but air (this is not currently true, but
// could be if we used the right AO strategy).
// Each indirect light needs to come in through the direct light.
// Thus, we assign each light a score based on opacity (currently just 0 or
// 1, but it could support translucent lights in the future).
// Thus, indirect_u_opacity and indirect_v_opacity are multiplied by
// direct_opacity, and indirect_uv_opacity is multiplied by
// the maximum of both of u and v's indirect opacities (since there are
// two choices for how to get to the direct surface).
let pos = pos
+ if u + 1 == width { -uv.x } else { Vec3::zero() }
+ if v + 1 == height { -uv.y } else { Vec3::zero() };
let uv = Vec2::new(
if u + 1 == width { -uv.x } else { uv.x },
if v + 1 == height { -uv.y } else { uv.y },
);
let light_pos = pos + delta;
// Currently, we assume that direct_opacity is 1 (if it's 0, you can't see
// the face anyway, since it's blocked by the block directly in front of it).
// TODO: If we add non-0/1 opacities, fix this.
// bottom-left block
let direct_u_opacity = get_opacity(data, light_pos - uv.x);
// top-right block
let direct_v_opacity = get_opacity(data, light_pos - uv.y);
// NOTE: Since we only support 0/1 opacities currently, we assume
// direct_opacity is 1, and the light value will be zero anyway for objects
// with opacity 0, we only "multiply" by indirect_uv_opacity for now (since
// it's the only one that could be 0 even if its light value is not).
// However, "spiritually" these light values are all being multiplied by
// their opacities.
let darkness = (
// Light from the bottom-right-front block to this vertex always
// appears on this face, since it's the block this face is facing (so
// it can't be blocked by anything).
get_light(data, light_pos)
+ get_light(data, light_pos - uv.x)
+ get_light(data, light_pos - uv.y)
+ if direct_u_opacity || direct_v_opacity {
get_light(data, light_pos - uv.x - uv.y)
} else {
0.0
}
) / 4.0;
let ao = (get_ao(data, light_pos)
+ get_ao(data, light_pos - uv.x)
+ get_ao(data, light_pos - uv.y)
+ if direct_u_opacity || direct_v_opacity {
get_ao(data, light_pos - uv.x - uv.y)
} else {
0.0
})
/ 4.0;
let glowiness = (get_glow(data, light_pos)
+ get_glow(data, light_pos - uv.x)
+ get_glow(data, light_pos - uv.y)
+ if direct_u_opacity || direct_v_opacity {
get_glow(data, light_pos - uv.x - uv.y)
} else {
0.0
})
/ 4.0;
let light = (darkness * 31.5) as u8;
let glow = (glowiness * 31.5) as u8;
let ao = ao > 0.7;
*col_light = make_face_texel(data, pos, light, glow, ao);
});
});
});
}
/// Precondition: when this function is called, atlas_pos should reflect an
/// actual valid position in a texture atlas (meaning it should fit into a u16).
// TODO: See if we can speed a lot of this up using SIMD.
fn create_quad_greedy<M>(
origin: Vec3<usize>,
dim: Vec2<usize>,
uv: Vec2<Vec3<u16>>,
norm: Vec3<i16>,
faces_forward: bool,
meta: &M,
atlas_pos: guillotiere::Rectangle,
mut push_quad: impl FnMut(Vec2<u16>, Vec2<Vec2<u16>>, Vec3<f32>, Vec2<Vec3<f32>>, Vec3<f32>, &M),
) {
let origin = origin.map(|e| e as f32);
// NOTE: Conversion to f32 safe by function precondition (u16 can losslessly
// cast to f32, and dim fits in a u16).
let draw_dim = uv.map2(dim.map(|e| e as f32), |e, f| e.map(f32::from) * f);
let dim = Vec2::new(Vec2::new(dim.x as u16, 0), Vec2::new(0, dim.y as u16));
let (draw_dim, dim, /* uv, */ norm) = if faces_forward {
(draw_dim, dim, norm)
} else {
(
Vec2::new(draw_dim.y, draw_dim.x),
Vec2::new(dim.y, dim.x),
-norm,
)
};
let norm = norm.map(f32::from);
// NOTE: Conversion to u16 safe by function precondition.
let atlas_pos = Vec2::new(atlas_pos.min.x as u16, atlas_pos.min.y as u16);
push_quad(atlas_pos, dim, origin, draw_dim, norm, meta);
}
pub fn create_quad<O: Vertex, M>(
atlas_pos: Vec2<u16>,
dim: Vec2<Vec2<u16>>,
origin: Vec3<f32>,
draw_dim: Vec2<Vec3<f32>>,
norm: Vec3<f32>,
meta: &M,
create_vertex: impl Fn(Vec2<u16>, Vec3<f32>, Vec3<f32>, &M) -> O,
) -> Quad<O> {
Quad::new(
create_vertex(atlas_pos, origin, norm, meta),
create_vertex(atlas_pos + dim.x, origin + draw_dim.x, norm, meta),
create_vertex(
atlas_pos + dim.x + dim.y,
origin + draw_dim.x + draw_dim.y,
norm,
meta,
),
create_vertex(atlas_pos + dim.y, origin + draw_dim.y, norm, meta),
)
}