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examples/custom-renderer: cleanup docs

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Signed-off-by: Stephen Gutekanst <stephen@hexops.com>
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Stephen Gutekanst 2024-04-06 12:09:29 -07:00 • committed by Stephen Gutekanst
parent af3c1e9155
commit 5659dd6266
4 changed files with 91 additions and 58 deletions
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133
examples/custom-renderer/Game.zig
View file

@ -10,51 +10,65 @@ const vec2 = math.vec2;
const Vec2 = math.Vec2;
const Vec3 = math.Vec3;
// Global state for our game module.
timer: mach.Timer,
player: ecs.EntityID,
direction: Vec2 = vec2(0, 0),
spawning: bool = false,
spawn_timer: mach.Timer,
// Components our game module defines.
pub const components = .{
// Whether an entity is a "follower" of our player entity or not. The type is void because we
// don't need any information, this is just a tag we assign to an entity with no data.
.follower = .{ .type = void },
};
// Global events that we will listen for.
pub const global_events = .{
.init = .{ .handler = init },
.tick = .{ .handler = tick },
.init = .{ .handler = init }, // Event sent on app startup
.tick = .{ .handler = tick }, // Event sent on each frame
};
// Each module must have a globally unique name declared, it is impossible to use two modules with
// the same name in a program. To avoid name conflicts, we follow naming conventions:
//
// 1. `.mach` and the `.mach_foobar` namespace is reserved for Mach itself and the modules it
// provides.
// 2. Single-word names like `.renderer`, `.game`, etc. are reserved for the application itself.
// 3. Libraries which provide modules MUST be prefixed with an "owner" name, e.g. `.ziglibs_imgui`
// instead of `.imgui`. We encourage using e.g. your GitHub name, as these must be globally
// unique.
//
// Define the globally unique name of our module. You can use any name here, but keep in mind no
// two modules in the program can have the same name.
pub const name = .game;
// The mach.Mod type corresponding to our module struct (this file.) This provides methods for
// working with this module (e.g. sending events, working with its components, etc.)
//
// Note that Mod.state() returns an instance of our module struct.
pub const Mod = mach.Mod(@This());
// TODO(engine): remove need for returning an error here
// TODO(important): remove need for returning an error here
fn init(
// These are injected dependencies - as long as these modules were registered in the top-level
// of the program we can have these types injected here, letting us work with other modules in
// our program seamlessly and with a type-safe API:
engine: *mach.Engine.Mod,
renderer: *Renderer.Mod,
game: *Mod,
) !void {
// The Mach .core is where we set window options, etc.
// TODO(important): replace this API with something better
core.setTitle("Hello, ECS!");
// We can create entities, and set components on them. Note that components live in a module
// namespace, e.g. the `.renderer` module could have a 3D `.location` component with a different
// type than the `.physics2d` module's `.location` component if you desire.
// Create our player entity.
const player = try engine.newEntity();
try renderer.set(player, .location, vec3(0, 0, 0));
// Give our player entity a .renderer.position and .renderer.scale component. Note that these
// are defined by the Renderer module, so we use `renderer: *Renderer.Mod` to interact with
// them.
//
// Components live in a module's namespace, so e.g. a physics2d module and renderer3d module could
// both define a .position component with a different data type, and both could be added to the
// same entity.
try renderer.set(player, .position, vec3(0, 0, 0));
try renderer.set(player, .scale, 1.0);
// Initialize our game module's state - these are the struct fields defined at the top of this
// file. If this is not done, then game.state() will panic indicating the state was never
// initialized.
game.init(.{
.timer = try mach.Timer.start(),
.spawn_timer = try mach.Timer.start(),
@ -62,13 +76,13 @@ fn init(
});
}
// TODO(engine): remove need for returning an error here
// TODO(important): remove need for returning an error here
fn tick(
engine: *mach.Engine.Mod,
renderer: *Renderer.Mod,
game: *Mod,
) !void {
// TODO(engine): event polling should occur in mach.Engine module and get fired as ECS events.
// TODO(important): event polling should occur in mach.Engine module and get fired as ECS event.
var iter = core.pollEvents();
var direction = game.state().direction;
var spawning = game.state().spawning;
@ -98,33 +112,56 @@ fn tick(
else => {},
}
}
// Keep track of which direction we want the player to move based on input, and whether we want
// to be spawning entities.
//
// Note that game.state() simply returns a pointer to a global singleton of the struct defined
// by this file, so we can access fields defined at the top of this file.
game.state().direction = direction;
game.state().spawning = spawning;
var player_pos = renderer.get(game.state().player, .location).?;
// Get the current player position
var player_pos = renderer.get(game.state().player, .position).?;
// If we want to spawn new entities, then spawn them now. The timer just makes spawning rate
// independent of frame rate.
if (spawning and game.state().spawn_timer.read() > 1.0 / 60.0) {
for (0..10) |_| {
// Spawn a new follower entity
_ = game.state().spawn_timer.lap();
_ = game.state().spawn_timer.lap(); // Reset the timer
for (0..5) |_| {
// Spawn a new entity at the same position as the player, but smaller in scale.
const new_entity = try engine.newEntity();
try game.set(new_entity, .follower, {});
try renderer.set(new_entity, .location, player_pos);
try renderer.set(new_entity, .position, player_pos);
try renderer.set(new_entity, .scale, 1.0 / 6.0);
// Tag the entity as one that follows the player
try game.set(new_entity, .follower, {});
}
}
// Multiply by delta_time to ensure that movement is the same speed regardless of the frame rate.
const delta_time = game.state().timer.lap();
// Move following entities closer to us.
// Calculate the player position, by moving in the direction the player wants to go
// by the speed amount.
const speed = 1.0;
player_pos.v[0] += direction.x() * speed * delta_time;
player_pos.v[1] += direction.y() * speed * delta_time;
try renderer.set(game.state().player, .position, player_pos);
// Query all the entities that have the .follower tag indicating they should follow the player.
// TODO(important): better querying API
var archetypes_iter = engine.entities.query(.{ .all = &.{
.{ .game = &.{.follower} },
} });
while (archetypes_iter.next()) |archetype| {
// Iterate the ID and position of each entity
const ids = archetype.slice(.entity, .id);
const locations = archetype.slice(.renderer, .location);
for (ids, locations) |id, location| {
// Avoid other follower entities by moving away from them if they are close to us.
const positions = archetype.slice(.renderer, .position);
for (ids, positions) |id, position| {
// Nested query to find all the other follower entities that we should move away from.
// We will avoid all other follower entities if we're too close to them.
// This is not very efficient, but it works!
const close_dist = 1.0 / 15.0;
var avoidance = Vec3.splat(0);
var avoidance_div: f32 = 1.0;
@ -133,37 +170,33 @@ fn tick(
} });
while (archetypes_iter_2.next()) |archetype_2| {
const other_ids = archetype_2.slice(.entity, .id);
const other_locations = archetype_2.slice(.renderer, .location);
for (other_ids, other_locations) |other_id, other_location| {
const other_positions = archetype_2.slice(.renderer, .position);
for (other_ids, other_positions) |other_id, other_position| {
if (id == other_id) continue;
if (location.dist(&other_location) < close_dist) {
avoidance = avoidance.sub(&location.dir(&other_location, 0.0000001));
if (position.dist(&other_position) < close_dist) {
avoidance = avoidance.sub(&position.dir(&other_position, 0.0000001));
avoidance_div += 1.0;
}
}
}
// Avoid the player
// Avoid the player if we're too close to it
var avoid_player_multiplier: f32 = 1.0;
if (location.dist(&player_pos) < close_dist * 6.0) {
avoidance = avoidance.sub(&location.dir(&player_pos, 0.0000001));
if (position.dist(&player_pos) < close_dist * 6.0) {
avoidance = avoidance.sub(&position.dir(&player_pos, 0.0000001));
avoidance_div += 1.0;
avoid_player_multiplier = 4.0;
}
// Move away from things we want to avoid
// Determine our new position, taking into account things we want to avoid
const move_speed = 1.0 * delta_time;
var new_location = location.add(&avoidance.divScalar(avoidance_div).mulScalar(move_speed * avoid_player_multiplier));
var new_position = position.add(&avoidance.divScalar(avoidance_div).mulScalar(move_speed * avoid_player_multiplier));
// Move towards the center
new_location = new_location.lerp(&vec3(0, 0, 0), move_speed / avoidance_div);
try renderer.set(id, .location, new_location);
}
}
// Try to move towards the center of the world if we don't need to avoid something else
new_position = new_position.lerp(&vec3(0, 0, 0), move_speed / avoidance_div);
// Calculate the player position, by moving in the direction the player wants to go
// by the speed amount.
const speed = 1.0;
player_pos.v[0] += direction.x() * speed * delta_time;
player_pos.v[1] += direction.y() * speed * delta_time;
try renderer.set(game.state().player, .location, player_pos);
// Finally, update our entity position.
try renderer.set(id, .position, new_position);
}
}
}

13
examples/custom-renderer/Renderer.zig
View file

@ -1,3 +1,4 @@
// TODO(important): docs
const std = @import("std");
const mach = @import("mach");
@ -21,7 +22,7 @@ pub const name = .renderer;
pub const Mod = mach.Mod(@This());
pub const components = .{
.location = .{ .type = Vec3 },
.position = .{ .type = Vec3 },
.rotation = .{ .type = Vec3 },
.scale = .{ .type = f32 },
};
@ -32,7 +33,7 @@ pub const global_events = .{
.tick = .{ .handler = tick },
};
// TODO: this shouldn't be a packed struct, it should be extern.
// TODO(important): this shouldn't be a packed struct, it should be extern.
const UniformBufferObject = packed struct {
offset: Vec3.Vector,
scale: f32,
@ -134,18 +135,18 @@ fn tick(
// Update uniform buffer
var archetypes_iter = engine.entities.query(.{ .all = &.{
.{ .renderer = &.{ .location, .scale } },
.{ .renderer = &.{ .position, .scale } },
} });
var num_entities: usize = 0;
while (archetypes_iter.next()) |archetype| {
const ids = archetype.slice(.entity, .id);
const locations = archetype.slice(.renderer, .location);
const positions = archetype.slice(.renderer, .position);
const scales = archetype.slice(.renderer, .scale);
for (ids, locations, scales) |id, location, scale| {
for (ids, positions, scales) |id, position, scale| {
_ = id;
const ubo = UniformBufferObject{
.offset = location.v,
.offset = position.v,
.scale = scale,
};
encoder.writeBuffer(renderer.state().uniform_buffer, uniform_offset * num_entities, &[_]UniformBufferObject{ubo});

4
examples/custom-renderer/main.zig
View file

@ -1,11 +1,9 @@
// Experimental ECS app example. Not yet ready for actual use.
const mach = @import("mach");
const Renderer = @import("Renderer.zig");
const Game = @import("Game.zig");
// The list of modules to be used in our application. Our game itself is implemented in our own
// module called Game.
// The global list of Mach modules registered for use in our application.
pub const modules = .{
mach.Engine,
Renderer,

1
examples/custom-renderer/shader.wgsl
View file

@ -1,3 +1,4 @@
// TODO(important): docs
struct Uniform {
pos: vec3<f32>,
scale: f32,