implement random walk for enemies

fixes carts running too slow in chrome

examples/zig/.gitignore

@@ -1,2 +1,2 @@
-/zig-cache/
+zig-cache/
-/zig-out/
+zig-out/

examples/zig/game/build.zig

@@ -5,11 +5,7 @@ pub fn build(b: *std.build.Builder) void {
 
     const lib = b.addSharedLibrary("cart", "main.zig", .unversioned);
     lib.setBuildMode(mode);
-    lib.setTarget(.{
+    lib.setTarget(.{ .cpu_arch = .wasm32, .os_tag = .freestanding, .cpu_features_add = std.Target.wasm.featureSet(&.{.nontrapping_fptoint}) });
-        .cpu_arch = .wasm32,
-        .os_tag = .freestanding,
-        .cpu_features_add = std.Target.wasm.featureSet(&.{ .nontrapping_fptoint })
-    });
     lib.import_memory = true;
     lib.initial_memory = 262144;
     lib.max_memory = 262144;
@@ -18,19 +14,13 @@ pub fn build(b: *std.build.Builder) void {
     lib.install();
 
     if (lib.install_step) |install_step| {
-        const run_filter_exports = b.addSystemCommand(&[_][]const u8{
+        const run_filter_exports = b.addSystemCommand(&[_][]const u8{ "uw8", "filter-exports", "zig-out/lib/cart.wasm", "zig-out/lib/cart-filtered.wasm" });
-            "uw8", "filter-exports", "zig-out/lib/cart.wasm", "zig-out/lib/cart-filtered.wasm"
-        });
         run_filter_exports.step.dependOn(&install_step.step);
 
-        const run_wasm_opt = b.addSystemCommand(&[_][]const u8{
+        const run_wasm_opt = b.addSystemCommand(&[_][]const u8{ "wasm-opt", "--enable-nontrapping-float-to-int", "-Oz", "-o", "zig-out/cart.wasm", "zig-out/lib/cart-filtered.wasm" });
-            "wasm-opt", "-Oz", "-o", "zig-out/cart.wasm", "zig-out/lib/cart-filtered.wasm"
-        });
         run_wasm_opt.step.dependOn(&run_filter_exports.step);
 
-        const run_uw8_pack = b.addSystemCommand(&[_][]const u8{
+        const run_uw8_pack = b.addSystemCommand(&[_][]const u8{ "uw8", "pack", "-l", "5", "zig-out/cart.wasm", "zig-out/cart.uw8" });
-            "uw8", "pack", "-l", "9", "zig-out/cart.wasm", "zig-out/cart.uw8"
-        });
         run_uw8_pack.step.dependOn(&run_wasm_opt.step);
 
         const make_opt = b.step("make_opt", "make size optimized cart");

examples/zig/game/main.zig

@@ -0,0 +1,142 @@
+const uw8 = @import("uw8.zig");
+
+var redBallSprite: [16 * 16]u8 = undefined;
+var greenBallSprite: [16 * 16]u8 = undefined;
+var blueBallSprite: [16 * 16]u8 = undefined;
+var wallSprite: [24 * 24]u8 = undefined;
+
+const SphereConfigStep = struct { size: u8, color: u8 };
+// zig fmt: off
+const redSphereConfig: [4]SphereConfigStep = .{
+    .{ .size = 0, .color = 0x3d },
+    .{ .size = 2, .color = 0x48 },
+    .{ .size = 6, .color = 0x65 },
+    .{ .size = 9, .color = 0x55 }
+};
+const greenSphereConfig: [4]SphereConfigStep = .{
+    .{ .size = 0, .color = 0x7d },
+    .{ .size = 2, .color = 0x88 },
+    .{ .size = 6, .color = 0x96 },
+    .{ .size = 9, .color = 0xa3 }
+};
+const blueSphereConfig: [4]SphereConfigStep = .{
+    .{ .size = 0, .color = 0x2e },
+    .{ .size = 2, .color = 0x19 },
+    .{ .size = 6, .color = 0x17 },
+    .{ .size = 9, .color = 0x24 }
+};
+
+const levelData: [14] *const [19]u8 = .{
+  "xxxxxxxxxxxxxxxxxxx",
+  "x      x   x      x",
+  "x x xx   x   xx x x",
+  "x x  xxx x xxx  x x",
+  "x xx x       x xx x",
+  "x xx   xxxxx   xx x",
+  "x    x       x    x",
+  "x xx xx xxx xx xx x",
+  "x  x xx     xx x  x",
+  "xx x    x x    x xx",
+  "x  xx xxx xxx xx  x",
+  "x xx   x   x   xx x",
+  "x    x   x   x    x",
+  "xxxxxxxxxxxxxxxxxxx",
+};
+// zig fmt: on
+
+export fn start() void {
+    blitSphere(&redBallSprite, &redSphereConfig);
+    blitSphere(&greenBallSprite, &greenSphereConfig);
+    blitSphere(&blueBallSprite, &blueSphereConfig);
+
+    createWallSprite();
+}
+
+fn blitSphere(sprite: [*]u8, config: []const SphereConfigStep) void {
+    for (config) |circle| {
+        uw8.circle(8, 8, 8, circle.color);
+        uw8.circle(5, 6, @intToFloat(f32, circle.size), 0);
+        uw8.grabSprite(sprite, 16, 0, 0, 0x100);
+    }
+}
+
+fn createWallSprite() void {
+    uw8.cls(0xe4);
+    var i: i32 = 0;
+    while (i < 50) : (i += 1) {
+        const x = uw8.randomf() * 16;
+        const y = uw8.randomf() * 16;
+        const radius = uw8.randomf() * 2 + 1;
+        const c = @intCast(u8, (uw8.random() & 3)) + 0x95;
+        var j: i32 = 0;
+        while (j < 9) : (j += 1) {
+            uw8.circle(x + @intToFloat(f32, @rem(j, 3) * 16), y + @intToFloat(f32, @divFloor(j, 3) * 16), radius, c);
+        }
+    }
+    uw8.grabSprite(&wallSprite, 16, 16, 16, 0);
+}
+
+export fn upd() void {
+    uw8.cls(0);
+
+    var y: usize = 0;
+    while (y < levelData.len) : (y += 1) {
+        var x: usize = 0;
+        while (x < levelData[y].len) : (x += 1) {
+            if (levelData[y][x] == 'x') {
+                uw8.blitSprite(&wallSprite, 16, 8 + @intCast(i32, x) * 16, @intCast(i32, y) * 16, 0);
+            }
+        }
+    }
+
+    updateEnemy(&enemies[0], &redBallSprite);
+    updateEnemy(&enemies[1], &greenBallSprite);
+    updateEnemy(&enemies[2], &blueBallSprite);
+}
+
+const EntityState = struct { x: i32, y: i32, dir: u2 };
+var enemies: [3]EntityState = .{
+    .{ .x = 16, .y = 16, .dir = 1 },
+    .{ .x = 16 * 18, .y = 16, .dir = 3 },
+    .{ .x = 16, .y = 16 * 12, .dir = 1 },
+};
+
+fn updateEnemy(enemy: *EntityState, sprite: [*]u8) void {
+    switch (enemy.dir) {
+        0 => enemy.y -= 1,
+        1 => enemy.x += 1,
+        2 => enemy.y += 1,
+        3 => enemy.x -= 1,
+    }
+    if (((enemy.x | enemy.y) & 15) == 0) {
+        const tx = @intCast(usize, enemy.x) / 16;
+        const ty = @intCast(usize, enemy.y) / 16;
+        var dir = enemy.dir;
+        var count: u32 = 0;
+        if (enemy.dir != 2 and levelData[ty - 1][tx] == ' ') {
+            dir = 0;
+            count += 1;
+        }
+        if (enemy.dir != 3 and levelData[ty][tx + 1] == ' ') {
+            count += 1;
+            if (uw8.random() % count == 0) {
+                dir = 1;
+            }
+        }
+        if (enemy.dir != 0 and levelData[ty + 1][tx] == ' ') {
+            count += 1;
+            if (uw8.random() % count == 0) {
+                dir = 2;
+            }
+        }
+        if (enemy.dir != 1 and levelData[ty][tx - 1] == ' ') {
+            count += 1;
+            if (uw8.random() % count == 0) {
+                dir = 3;
+            }
+        }
+        enemy.dir = dir;
+    }
+
+    uw8.blitSprite(sprite, 16, 8 + enemy.x, enemy.y, 0x100);
+}

examples/zig/game/uw8.zig

@@ -0,0 +1,10 @@
+pub extern fn random() u32;
+pub extern fn randomf() f32;
+pub extern fn time() f32;
+pub extern fn cls(color: u8) void;
+pub extern fn circle(x: f32, y: f32, radiu: f32, color: u8) void;
+pub extern fn blitSprite(spriteData: [*]u8, size: u32, x: i32, y: i32, ctrl: u32) void;
+pub extern fn grabSprite(spriteData: [*]u8, size: u32, x: i32, y: i32, ctrl: u32) void;
+pub extern fn printString(str: [*:0]u8) void;
+pub extern fn printInt(value: i32) void;
+pub extern fn printChar(char: u32) void;

examples/zig/tunnel/build.zig

@@ -0,0 +1,31 @@
+const std = @import("std");
+
+pub fn build(b: *std.build.Builder) void {
+    const mode = std.builtin.Mode.ReleaseSmall;
+
+    const lib = b.addSharedLibrary("cart", "main.zig", .unversioned);
+    lib.setBuildMode(mode);
+    lib.setTarget(.{ .cpu_arch = .wasm32, .os_tag = .freestanding, .cpu_features_add = std.Target.wasm.featureSet(&.{.nontrapping_fptoint}) });
+    lib.import_memory = true;
+    lib.initial_memory = 262144;
+    lib.max_memory = 262144;
+    lib.global_base = 81920;
+    lib.stack_size = 8192;
+    lib.install();
+
+    if (lib.install_step) |install_step| {
+        const run_filter_exports = b.addSystemCommand(&[_][]const u8{ "uw8", "filter-exports", "zig-out/lib/cart.wasm", "zig-out/lib/cart-filtered.wasm" });
+        run_filter_exports.step.dependOn(&install_step.step);
+
+        const run_wasm_opt = b.addSystemCommand(&[_][]const u8{ "wasm-opt", "--enable-nontrapping-float-to-int", "-Oz", "-o", "zig-out/cart.wasm", "zig-out/lib/cart-filtered.wasm" });
+        run_wasm_opt.step.dependOn(&run_filter_exports.step);
+
+        const run_uw8_pack = b.addSystemCommand(&[_][]const u8{ "uw8", "pack", "-l", "9", "zig-out/cart.wasm", "zig-out/cart.uw8" });
+        run_uw8_pack.step.dependOn(&run_wasm_opt.step);
+
+        const make_opt = b.step("make_opt", "make size optimized cart");
+        make_opt.dependOn(&run_uw8_pack.step);
+
+        b.default_step = make_opt;
+    }
+}

examples/zig/tunnel/main.zig

@@ -1,11 +1,11 @@
 extern fn atan2(x: f32, y: f32) f32;
 extern fn time() f32;
 
-pub const FRAMEBUFFER: *[320*240]u8 = @intToPtr(*[320*240]u8, 120);
+pub const FRAMEBUFFER: *[320 * 240]u8 = @intToPtr(*[320 * 240]u8, 120);
 
 export fn upd() void {
     var i: u32 = 0;
-    while(true) {
+    while (true) {
         var t = time() * 63.0;
         var x = @intToFloat(f32, (@intCast(i32, i % 320) - 160));
         var y = @intToFloat(f32, (@intCast(i32, i / 320) - 120));
@@ -13,8 +13,10 @@ export fn upd() void {
         var u = atan2(x, y) * 512.0 / 3.141;
         var c = @intCast(u8, (@floatToInt(i32, d + t * 2.0) ^ @floatToInt(i32, u + t)) & 255) >> 4;
 
-        FRAMEBUFFER[@as(usize, i)] = c;
+        FRAMEBUFFER[i] = c;
         i += 1;
-        if(i >= 320*240) { break; }
+        if (i >= 320 * 240) {
+            break;
+        }
     }
 }

src/run_native.rs

@@ -181,10 +181,12 @@ impl super::Runtime for MicroW8 {
         if let Some(mut instance) = self.instance.take() {
             let time = (now - instance.start_time).as_millis() as i32;
             let next_frame = {
-                let offset = ((time as u32 as i64 * 6) % 100 - 50) / 6;
+                let frame = (time as u32 as u64 * 6 / 100) as u32;
-                let max = now + Duration::from_millis(17);
+                let cur_offset = (time as u32).wrapping_sub((frame as u64 * 100 / 6) as u32);
-                let next_center = now + Duration::from_millis((16 - offset) as u64);
+                let next_time =
-                next_center.min(max)
+                    ((frame as u64 + 1) * 100 / 6 + cur_offset.max(1).min(4) as u64) as u32;
+                let offset = next_time.wrapping_sub(time as u32);
+                now + Duration::from_millis(offset as u64)
             };
 
             {

uw8-tool/src/filter_exports.rs

@@ -1,13 +1,17 @@
-use std::path::Path;
 use anyhow::Result;
+use std::path::Path;
 
 pub fn filter_exports(in_path: &Path, out_path: &Path) -> Result<()> {
     let mut module = walrus::Module::from_file(in_path)?;
 
-    let exports_to_delete: Vec<_> = module.exports.iter().filter_map(|export| match export.name.as_str() {
+    let exports_to_delete: Vec<_> = module
-        "upd" => None,
+        .exports
-        _ => Some(export.id())
+        .iter()
-    }).collect();
+        .filter_map(|export| match export.name.as_str() {
+            "upd" | "snd" | "start" => None,
+            _ => Some(export.id()),
+        })
+        .collect();
 
     for id in exports_to_delete {
         module.exports.delete(id);

web/src/microw8.js

@@ -274,7 +274,7 @@ export default function MicroW8(screen, config = {}) {
     
                 try {
                     let restart = false;
-                    let thisFrame;
+                    let nextFrame = 0;
                     if (!isPaused) {
                         let gamepads = navigator.getGamepads();
                         let gamepad = 0;
@@ -321,13 +321,12 @@ export default function MicroW8(screen, config = {}) {
                         }
                         canvasCtx.putImageData(imageData, 0, 0);
 
-                        let timeOffset = ((time * 6) % 100 - 50) / 6;
+                        let thisFrame = Math.floor(time * 6 / 100);
-                        thisFrame = startTime + time - timeOffset / 8;
+                        let timeOffset = time - thisFrame * 100 / 6;
-                    } else {
+                        nextFrame = Math.ceil(startTime + (thisFrame + 1) * 100 / 6 + Math.min(4, timeOffset));
-                        thisFrame = Date.now();
                     }
                     let now = Date.now();
-                    let nextFrame = Math.max(thisFrame + timePerFrame, now);
+                    nextFrame = Math.max(nextFrame, now);
     
                     if (restart) {
                         runModule(currentData);