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refactor: add comments and rename variables in chunk.zig

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catangent 2025-04-10 15:56:19 +01:00
parent ed1e0ecb6b
commit 371c3545dd
1 changed files with 48 additions and 43 deletions
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91
src/world/chunk.zig
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@ -28,6 +28,7 @@ const RawQuad = struct {
bottom_left_obscured: bool, bottom_left_obscured: bool,
}; };
// Quad shader metadata. Has to be 128 bytes in size.
const Metadata1 = packed struct { const Metadata1 = packed struct {
ambient_occlusion_1: u32, ambient_occlusion_1: u32,
ambient_occlusion_2: u32, ambient_occlusion_2: u32,
@ -63,23 +64,23 @@ pub const Chunk = struct {
self.a7r.free(self.tiles); self.a7r.free(self.tiles);
} }
// Fetch the tile at (x, y, z), but with potential side effects. If you imagine tiles to be a 3-dimensional array, this would be tiles[x][y][z].
pub fn getTile(self: Chunk, x: u5, y: u5, z: u5) u32 { pub fn getTile(self: Chunk, x: u5, y: u5, z: u5) u32 {
// Fetch the tile at (x, y, z), but with potential side effects. If you imagine tiles to be a 3-dimensional array, this would be tiles[x][y][z].
return self.tiles[@as(u15, x) << 10 | @as(u15, y) << 5 | @as(u15, z)]; return self.tiles[@as(u15, x) << 10 | @as(u15, y) << 5 | @as(u15, z)];
} }
// Set the tile at (x, y, z). If you imagine tiles to be a 3-dimensional array, this would be tiles[x][y][z] = tile.
pub fn setTile(self: Chunk, x: u5, y: u5, z: u5, tile: u32) void { pub fn setTile(self: Chunk, x: u5, y: u5, z: u5, tile: u32) void {
// Set the tile at (x, y, z). If you imagine tiles to be a 3-dimensional array, this would be tiles[x][y][z] = tile.
self.tiles[@as(u15, x) << 10 | @as(u15, y) << 5 | @as(u15, z)] = tile; self.tiles[@as(u15, x) << 10 | @as(u15, y) << 5 | @as(u15, z)] = tile;
} }
// Fetch the tile at (x, y, z) without changin anything. If you imagine tiles to be a 3-dimensional array, this would be tiles[x][y][z].
fn getTileRaw(self: Chunk, x: u5, y: u5, z: u5) u32 { fn getTileRaw(self: Chunk, x: u5, y: u5, z: u5) u32 {
// Fetch the tile at (x, y, z) without changin anything. If you imagine tiles to be a 3-dimensional array, this would be tiles[x][y][z].
return self.tiles[@as(u15, x) << 10 | @as(u15, y) << 5 | @as(u15, z)]; return self.tiles[@as(u15, x) << 10 | @as(u15, y) << 5 | @as(u15, z)];
} }
// This cyclically permutes the x, y, z coordinates at compile time. Useful when iterating over x, y, and z axis.
inline fn getTileRawShifted(self: Chunk, x: u5, y: u5, z: u5, comptime d: comptime_int) u32 { inline fn getTileRawShifted(self: Chunk, x: u5, y: u5, z: u5, comptime d: comptime_int) u32 {
// This cyclicaly permutes the x, y, z coordinates at compile time. Useful when iterating over x, y, and z axis.
if (d % 3 == 0) { if (d % 3 == 0) {
return self.getTileRaw(x, y, z); return self.getTileRaw(x, y, z);
} else if (d % 3 == 1) { } else if (d % 3 == 1) {
@ -89,24 +90,25 @@ pub const Chunk = struct {
} }
} }
fn pack_raw_quad(y: usize, y2: usize, z: usize, z2: usize, sign: comptime_int, d: comptime_int, surface: u32, xf: f32) RawQuad { // Create a raw quad with specified parameters and surface, accounting for dimension and sign. Surface is the block ID.
const ymin: f32 = @as(f32, @floatFromInt(y)) - 0.5; fn pack_raw_quad(x: f32, y_start: usize, y_end: usize, z_start: usize, z_end: usize, sign: comptime_int, d: comptime_int, surface: u32) RawQuad {
const ymax: f32 = @as(f32, @floatFromInt(y2)) + 0.5; const ymin: f32 = @as(f32, @floatFromInt(y_start)) - 0.5;
const zmin: f32 = @as(f32, @floatFromInt(z)) - 0.5; const ymax: f32 = @as(f32, @floatFromInt(y_end)) - 0.5;
const zmax: f32 = @as(f32, @floatFromInt(z2)) + 0.5; const zmin: f32 = @as(f32, @floatFromInt(z_start)) - 0.5;
const zmax: f32 = @as(f32, @floatFromInt(z_end)) - 0.5;
const yleft: f32 = if (sign == 1) ymin else ymax; const yleft: f32 = if (sign == 1) ymin else ymax;
const yright: f32 = if (sign == 1) ymax else ymin; const yright: f32 = if (sign == 1) ymax else ymin;
const zleft: f32 = if (sign == 1) zmin else zmax; const zleft: f32 = if (sign == 1) zmin else zmax;
const zright: f32 = if (sign == 1) zmax else zmin; const zright: f32 = if (sign == 1) zmax else zmin;
var raw_quad: RawQuad = undefined; var raw_quad: RawQuad = undefined;
switch (d) { switch (d) {
0 => { 0 => { // X direction
raw_quad = .{ raw_quad = .{
.tile = surface, .tile = surface,
.top_left = v3.new(xf + 0.5 * sign, ymax, zright), .top_left = v3.new(x + 0.5 * sign, ymax, zright),
.top_right = v3.new(xf + 0.5 * sign, ymax, zleft), .top_right = v3.new(x + 0.5 * sign, ymax, zleft),
.bottom_left = v3.new(xf + 0.5 * sign, ymin, zright), .bottom_left = v3.new(x + 0.5 * sign, ymin, zright),
.bottom_right = v3.new(xf + 0.5 * sign, ymin, zleft), .bottom_right = v3.new(x + 0.5 * sign, ymin, zleft),
.normal = v3.new(sign, 0, 0), .normal = v3.new(sign, 0, 0),
.width = zmax - zmin, .width = zmax - zmin,
.height = ymax - ymin, .height = ymax - ymin,
@ -121,13 +123,13 @@ pub const Chunk = struct {
.bottom_left_obscured = false, .bottom_left_obscured = false,
}; };
}, },
1 => { 1 => { // Y direction
raw_quad = .{ raw_quad = .{
.tile = surface, .tile = surface,
.bottom_left = v3.new(yleft, zmin, xf + 0.5 * sign), .bottom_left = v3.new(yleft, zmin, x + 0.5 * sign),
.top_left = v3.new(yleft, zmax, xf + 0.5 * sign), .top_left = v3.new(yleft, zmax, x + 0.5 * sign),
.bottom_right = v3.new(yright, zmin, xf + 0.5 * sign), .bottom_right = v3.new(yright, zmin, x + 0.5 * sign),
.top_right = v3.new(yright, zmax, xf + 0.5 * sign), .top_right = v3.new(yright, zmax, x + 0.5 * sign),
.normal = v3.new(0, 0, sign), .normal = v3.new(0, 0, sign),
.height = zmax - zmin, .height = zmax - zmin,
.width = ymax - ymin, .width = ymax - ymin,
@ -142,13 +144,13 @@ pub const Chunk = struct {
.bottom_left_obscured = false, .bottom_left_obscured = false,
}; };
}, },
2 => { 2 => { // Z direction
raw_quad = .{ raw_quad = .{
.tile = surface, .tile = surface,
.top_left = v3.new(zleft, xf + 0.5 * sign, ymin), .top_left = v3.new(zleft, x + 0.5 * sign, ymin),
.top_right = v3.new(zright, xf + 0.5 * sign, ymin), .top_right = v3.new(zright, x + 0.5 * sign, ymin),
.bottom_left = v3.new(zleft, xf + 0.5 * sign, ymax), .bottom_left = v3.new(zleft, x + 0.5 * sign, ymax),
.bottom_right = v3.new(zright, xf + 0.5 * sign, ymax), .bottom_right = v3.new(zright, x + 0.5 * sign, ymax),
.normal = v3.new(0, sign, 0), .normal = v3.new(0, sign, 0),
.width = zmax - zmin, .width = zmax - zmin,
.height = ymax - ymin, .height = ymax - ymin,
@ -168,44 +170,47 @@ pub const Chunk = struct {
return raw_quad; return raw_quad;
} }
// Create mesh of a chunk. tile_rows and tile_columns are the dimensions of the tiles.png file, in terms of individual tile textures.
pub fn createMesh(chunk: Chunk, tile_rows: u32, tile_columns: u32) !raylib.Mesh { pub fn createMesh(chunk: Chunk, tile_rows: u32, tile_columns: u32) !raylib.Mesh {
var raw_quads = try std.ArrayList(RawQuad).initCapacity(chunk.a7r, 4096); var raw_quads = try std.ArrayList(RawQuad).initCapacity(chunk.a7r, 4096);
defer raw_quads.deinit(); defer raw_quads.deinit();
// Begin scanning the chunk for block surfaces to make raw quads. // Begin scanning the chunk for tile surfaces to make raw quads.
inline for (0..3) |d| { // For each of the 3 dimensions, inline for (0..3) |d| { // Iterate over the 3 dimensions, X, Y and Z.
for (0..32) |raw_x| { for (0..32) |raw_x| {
const x: u5 = @intCast(raw_x); const x: u5 = @intCast(raw_x);
// Create surface arrays for the +x side of the layer and the -x side.
var positive_tile_surfaces: [32][32]u32 = .{.{0} ** 32} ** 32; var positive_tile_surfaces: [32][32]u32 = .{.{0} ** 32} ** 32;
var negative_tile_surfaces: [32][32]u32 = .{.{0} ** 32} ** 32; var negative_tile_surfaces: [32][32]u32 = .{.{0} ** 32} ** 32;
for (0..32) |raw_y| for (0..32) |raw_z| { for (0..32) |raw_y| for (0..32) |raw_z| {
const y: u5 = @intCast(raw_y); const y: u5 = @intCast(raw_y);
const z: u5 = @intCast(raw_z); const z: u5 = @intCast(raw_z);
const tile: u32 = chunk.getTileRawShifted(x, y, z, d); const tile: u32 = chunk.getTileRawShifted(x, y, z, d);
if (tile == 0) continue; if (tile == 0) continue; // If air, there is no surface.
// If either at the edge of the chunk or the tile is exposed, create a tile surface.
if (x == 31 or chunk.getTileRawShifted(x + 1, y, z, d) == 0) positive_tile_surfaces[y][z] = tile; if (x == 31 or chunk.getTileRawShifted(x + 1, y, z, d) == 0) positive_tile_surfaces[y][z] = tile;
if (x == 0 or chunk.getTileRawShifted(x - 1, y, z, d) == 0) negative_tile_surfaces[y][z] = tile; if (x == 0 or chunk.getTileRawShifted(x - 1, y, z, d) == 0) negative_tile_surfaces[y][z] = tile;
}; };
const xf: f32 = @floatFromInt(raw_x);
inline for (.{ -1, 1 }) |sign| { inline for (.{ -1, 1 }) |sign| {
var tile_surfaces = if (sign == 1) positive_tile_surfaces else negative_tile_surfaces; var tile_surfaces = if (sign == 1) positive_tile_surfaces else negative_tile_surfaces;
for (0..32) |y| for (0..32) |z| { for (0..32) |y_start| for (0..32) |z_start| {
const surface = tile_surfaces[y][z]; const surface = tile_surfaces[y_start][z_start]; // Starting surface tile type.
if (surface == 0) continue; if (surface == 0) continue; // No surface if air.
var y2 = y + 1; tile_surfaces[y_start][z_start] = 0; // Replace this surface with air, since the corresponding quad will be created.
var z2 = z + 1; // The end coordinates of the quad. The quad is therefore covers rectangle from start coordinates (inclusive) to end coordinates (exclusive).
while (y2 <= 31 and tile_surfaces[y2][z] == surface) : (y2 += 1) { var y_end = y_start + 1;
tile_surfaces[y2][z] = 0; var z_end = z_start + 1;
// Greedy meshing: Extend the quad in the +y direction, until we hit a tile of a different type or the end of the chunk.
while (y_end <= 31 and tile_surfaces[y_end][z_start] == surface) : (y_end += 1) {
tile_surfaces[y_end][z_start] = 0;
} }
zloop: while (z2 <= 31) : (z2 += 1) { // Greedy meshing: Extend the quad in the +z direction, until the next line does not consist of tiles of correct type.
for (y..y2) |ytmp| if (tile_surfaces[ytmp][z2] != surface) break :zloop; zloop: while (z_end <= 31) : (z_end += 1) {
for (y..y2) |ytmp| tile_surfaces[ytmp][z2] = 0; for (y_start..y_end) |y| if (tile_surfaces[y][z_end] != surface) break :zloop; // Stop extending if we hit a tile of incorrect type.
for (y_start..y_end) |y| tile_surfaces[y][z_end] = 0;
} }
// todo: scan tiles around quad surface for ambient occlusion // todo: scan tiles around quad surface for ambient occlusion
y2 -= 1; const raw_quad = pack_raw_quad(@floatFromInt(raw_x), y_start, y_end, z_start, z_end, sign, d, surface);
z2 -= 1;
tile_surfaces[y][z] = 0;
const raw_quad = pack_raw_quad(y, y2, z, z2, sign, d, surface, xf);
try raw_quads.append(raw_quad); try raw_quads.append(raw_quad);
}; };
} }
@ -290,7 +295,7 @@ pub const Chunk = struct {
} }
} }
// Create mesh. // Create mesh using the buffers.
var mesh = raylib.Mesh{ var mesh = raylib.Mesh{
.triangleCount = triangle_count, .triangleCount = triangle_count,
.vertexCount = triangle_count * 3, .vertexCount = triangle_count * 3,