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examples: custom-renderer working
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Signed-off-by: Stephen Gutekanst <stephen@hexops.com>
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@emidoots
emidoots committed Dec 25, 2024
1 parent eae5aa4 commit df3091b
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Showing 3 changed files with 127 additions and 152 deletions.
2 changes: 1 addition & 1 deletion build.zig
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Original file line number Diff line number Diff line change
Expand Up @@ -74,7 +74,7 @@ pub fn build(b: *std.Build) !void {
.{ .name = "core-custom-entrypoint", .deps = &.{} },
.{ .name = "core-triangle", .deps = &.{} },
.{ .name = "core-transparent-window", .deps = &.{} },
// .{ .name = "custom-renderer", .deps = &.{} },
.{ .name = "custom-renderer", .deps = &.{} },
// .{ .name = "glyphs", .deps = &.{ .assets, .freetype } },
// .{ .name = "hardware-check", .deps = &.{ .assets, .zigimg } },
.{ .name = "piano", .deps = &.{} },
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182 changes: 78 additions & 104 deletions examples/custom-renderer/App.zig
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Original file line number Diff line number Diff line change
Expand Up @@ -11,76 +11,56 @@ const App = @This();

pub const mach_module = .app;

pub const mach_systems = .{ .start, .init, .deinit, .tick };
pub const mach_systems = .{ .main, .init, .deinit, .tick };

// Global state for our game module.
// Global state for our app module.
timer: mach.time.Timer,
player: mach.EntityID,
player: mach.ObjectID,
direction: Vec2 = vec2(0, 0),
spawning: bool = false,
spawn_timer: mach.time.Timer,

// TODO(object)
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 },
};
pub const main = mach.schedule(.{
.{ mach.Core, .init },
.{ App, .init },
.{ mach.Core, .main },
});

pub fn deinit(renderer: *Renderer) void {
renderer.schedule(.deinit);
}

fn start(
core: *mach.Core,
renderer: *Renderer,
app: *App,
) !void {
core.schedule(.init);
renderer.schedule(.init);
app.schedule(.init);
}
pub const deinit = mach.schedule(.{
.{ Renderer, .deinit },
});

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:
entities: *mach.Entities.Mod,
pub fn init(
core: *mach.Core,
renderer: *Renderer,
app: *App,
app_mod: mach.Mod(App),
renderer: *Renderer,
) !void {
core.on_tick = app_mod.id.tick;
core.on_exit = app_mod.id.deinit;

const window = try core.windows.new(.{
.title = "custom renderer",
});
renderer.window = window;

// Create our player entity.
const player = try entities.new();
const player = try renderer.objects.new(.{
.position = vec3(0, 0, 0),
.scale = 1.0,
});

// 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` 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 app. will panic indicating the state was never
// initialized.
app.init(.{
app.* = .{
.timer = try mach.time.Timer.start(),
.spawn_timer = try mach.time.Timer.start(),
.player = player,
});
};
}

fn tick(
entities: *mach.Entities.Mod,
pub fn tick(
core: *mach.Core,
renderer: *Renderer,
renderer_mod: mach.Mod(Renderer),
app: *App,
) !void {
var direction = app.direction;
Expand All @@ -107,6 +87,9 @@ fn tick(
else => {},
}
},
.window_open => |_| {
renderer_mod.call(.init);
},
.close => core.exit(),
else => {},
}
Expand All @@ -121,20 +104,22 @@ fn tick(
app.spawning = spawning;

// Get the current player position
var player_pos = renderer.get(app.player, .position).?;
var player = renderer.objects.getValue(app.player);
defer renderer.objects.setValue(app.player, player);

// If we want to spawn new entities, then spawn them now. The timer just makes spawning rate
// independent of frame rate.
if (spawning and app.spawn_timer.read() > 1.0 / 60.0) {
_ = app.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 entities.new();
try renderer.set(new_entity, .position, player_pos);
try renderer.set(new_entity, .scale, 1.0 / 6.0);
// Spawn a new object at the same position as the player, but smaller in scale.
const new_obj = try renderer.objects.new(.{
.position = player.position,
.scale = 1.0 / 6.0,
});

// Tag the entity as one that follows the player
try app.set(new_entity, .follower, {});
// Parent the object to the player, we'll make children 'follow' the parent below.
try renderer.objects.addChild(app.player, new_obj);
}
}

Expand All @@ -144,62 +129,51 @@ fn tick(
// 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(app.player, .position, player_pos);

// Query all the entities that have the .follower tag indicating they should follow the player.
// TODO(important): better querying API

// Iterate the ID and position of each follower entity
var q = try entities.query(.{
.ids = mach.Entities.Mod.read(.id),
.followers = Mod.read(.follower),
.positions = Renderer.write(.position),
});
while (q.next()) |v| {
for (v.ids, v.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;

var q2 = try entities.query(.{
.ids = mach.Entities.Mod.read(.id),
.followers = Mod.read(.follower),
.positions = Renderer.read(.position),
});
while (q2.next()) |v2| {
for (v2.ids, v2.positions) |other_id, other_position| {
if (id == other_id) continue;
if (position.dist(&other_position) < close_dist) {
avoidance = avoidance.sub(&position.dir(&other_position, 0.0000001));
avoidance_div += 1.0;
}
}
}

// Avoid the player if we're too close to it
var avoid_player_multiplier: f32 = 1.0;
if (position.dist(&player_pos) < close_dist * 6.0) {
avoidance = avoidance.sub(&position.dir(&player_pos, 0.0000001));
player.position.v[0] += direction.x() * speed * delta_time;
player.position.v[1] += direction.y() * speed * delta_time;

// Find the children of the player and make them 'follow' the player position.
var children = try renderer.objects.getChildren(app.player);
defer children.deinit();
for (children.items) |child_id| {
if (!renderer.objects.is(child_id)) continue;
var child = renderer.objects.getValue(child_id);
defer renderer.objects.setValue(child_id, child);

// 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;

var children2 = try renderer.objects.getChildren(app.player);
defer children2.deinit();
for (children2.items) |child2_id| {
if (!renderer.objects.is(child2_id)) continue;
if (child_id == child2_id) continue;
const child2 = renderer.objects.getValue(child2_id);
if (child.position.dist(&child2.position) < close_dist) {
avoidance = avoidance.sub(&child.position.dir(&child2.position, 0.0000001));
avoidance_div += 1.0;
avoid_player_multiplier = 4.0;
}
}

// Determine our new position, taking into account things we want to avoid
const move_speed = 1.0 * delta_time;
var new_position = position.add(&avoidance.divScalar(avoidance_div).mulScalar(move_speed * avoid_player_multiplier));
// Avoid the player if we're too close to it
var avoid_player_multiplier: f32 = 1.0;
if (child.position.dist(&player.position) < close_dist * 6.0) {
avoidance = avoidance.sub(&child.position.dir(&player.position, 0.0000001));
avoidance_div += 1.0;
avoid_player_multiplier = 4.0;
}

// 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);
// Determine our new position, taking into account things we want to avoid
const move_speed = 1.0 * delta_time;
var new_position = child.position.add(&avoidance.divScalar(avoidance_div).mulScalar(move_speed * avoid_player_multiplier));

// Finally, update our entity position.
position.* = new_position;
}
// Try to move towards the center of the world if we don't need to avoid something else
child.position = new_position.lerp(&vec3(0, 0, 0), move_speed / avoidance_div);
}

renderer.schedule(.render_frame);
renderer_mod.call(.renderFrame);
}
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