moved rendering to a system.

To ensure that the rendering system is being run in the main thread, I
added the concept of "Sync systems", so that when a system group is
created it's possible to specify whether it's possible to run it on a
separate thread or not.

assets/shaders/shader.vert

@@ -2,12 +2,10 @@
 
 layout(location = 0) in vec3 vertPos;
 
-layout(binding = 0) uniform UniformObject {
+layout (binding = 0) uniform Uniform {
     mat4 proj;
-    mat4 view;
-    mat4 model;
 } ubo;
 
 void main() {
-    gl_Position = ubo.view * ubo.proj * vec4(vertPos, 1.0);
+    gl_Position = ubo.proj * vec4(vertPos, 1.0);
 }

build.zig

@@ -118,6 +118,7 @@ pub fn build(b: *std.Build) void {
         .root_module = mods,
         .name = "mods",
     });
+
     const mods_docs = b.addInstallDirectory(.{
         .source_dir = mods_lib.getEmittedDocs(),
         .install_dir = .prefix,

src/ecs/ecs.zig

@@ -1,7 +1,12 @@
 pub const components = @import("components.zig");
 pub const entities = @import("entities.zig");
 
+pub const SystemError = error{
+    fail,
+    die,
+};
+
 pub const Pool = entities.Pool;
 pub const Resources = entities.Resources;
-pub const System = *const fn (*Pool) void;
+pub const System = *const fn (*Pool) anyerror!void;
 pub const SystemGroup = []const System;

src/ecs/entities.zig

@@ -4,14 +4,17 @@ const components = @import("components.zig");
 const sparse = @import("sparse.zig");
 const Renderer = @import("renderer");
 const Input = @import("sideros").Input;
+const ecs = @import("ecs.zig");
 
-pub const System = *const fn (*Pool) void;
+pub const System = ecs.System;
 pub const SystemGroup = []const System;
+pub const SyncGroup = []const System;
 
 pub const Resources = struct {
     window: Renderer.Window,
     renderer: Renderer,
     input: Input,
+    delta_time: f64 = 0.0,
 };
 
 pub const Human = struct {
@@ -24,6 +27,7 @@ pub const Pool = struct {
     resources: Resources,
     allocator: Allocator,
     system_groups: std.ArrayList(SystemGroup),
+    sync_groups: std.ArrayList(SyncGroup),
     thread_pool: *std.Thread.Pool,
     wait_group: std.Thread.WaitGroup,
     mutex: std.Thread.Mutex,
@@ -33,6 +37,7 @@ pub const Pool = struct {
             .humans = .{},
             .resources = resources,
             .system_groups = std.ArrayList(SystemGroup).init(allocator),
+            .sync_groups = std.ArrayList(SystemGroup).init(allocator),
             .thread_pool = try allocator.create(std.Thread.Pool),
             .wait_group = .{},
             .mutex = .{},
@@ -47,8 +52,12 @@ pub const Pool = struct {
         return pool;
     }
 
-    pub fn addSystemGroup(self: *@This(), group: SystemGroup) !void {
+    pub fn addSystemGroup(self: *@This(), group: SystemGroup, sync: bool) !void {
-        try self.system_groups.append(group);
+        if (sync) {
+            try self.sync_groups.append(group);
+        } else {
+            try self.system_groups.append(group);
+        }
     }
 
     pub fn deinit(self: *@This()) void {
@@ -65,11 +74,18 @@ pub const Pool = struct {
                 fn run(pool: *Pool, index: usize) void {
                     const group = pool.system_groups.items[index];
                     for (group) |system| {
-                        system(pool);
+                        // TODO: system errors should be correctly handled
+                        system(pool) catch unreachable;
                     }
                 }
             }.run, .{ self, i });
         }
+        for (0..self.sync_groups.items.len) |i| {
+            const group = self.sync_groups.items[i];
+            for (group) |system| {
+                system(self) catch unreachable;
+            }
+        }
     }
 
     fn getEntities(self: *@This(), T: type) *std.MultiArrayList(T) {

src/main.zig

@@ -22,13 +22,13 @@ pub fn main() !void {
     const file = try std.fs.cwd().openFile("assets/core.wasm", .{});
     const all = try file.readToEndAlloc(allocator, 1_000_000); // 1 MB
     var parser = mods.Parser{
-      .bytes = all,
+        .bytes = all,
-      .byte_idx = 0,
+        .byte_idx = 0,
-      .allocator = allocator,
+        .allocator = allocator,
     };
     const module = parser.parseModule() catch |err| {
-      std.debug.print("[ERROR]: error at byte {x}(0x{x})\n", .{ parser.byte_idx, parser.bytes[parser.byte_idx] });
+        std.debug.print("[ERROR]: error at byte {x}(0x{x})\n", .{ parser.byte_idx, parser.bytes[parser.byte_idx] });
-      return err;
+        return err;
     };
     var runtime = try mods.Runtime.init(allocator, module, &global_runtime);
     defer runtime.deinit(allocator);
@@ -40,8 +40,8 @@ pub fn main() !void {
     var w = try Renderer.Window.create(800, 600, "sideros");
     defer w.destroy();
 
-    var r = try Renderer.create(allocator, w);
+    var r = try Renderer.init(allocator, w);
-    defer r.destroy();
+    defer r.deinit();
 
     const resources = ecs.Resources{
         .window = w,
@@ -52,9 +52,9 @@ pub fn main() !void {
     var pool = try ecs.Pool.init(allocator, resources);
     defer pool.deinit();
     w.setResources(&pool.resources);
-    //try pool.addSystemGroup(&[_]entities.System{
+    try pool.addSystemGroup(&[_]ecs.System{
-    //    testSystem,
+        Renderer.render,
-    //});
+    }, true);
     // try pool.addSystemGroup(&[_]ecs.System{
     // testSystem2,
     // });
@@ -64,10 +64,12 @@ pub fn main() !void {
     //     try pool.addComponent(entity, ecs.components.Position{ .x = 1.0, .y = 0.5, .z = 3.0 });
     //     try pool.addComponent(entity, ecs.components.Speed{ .speed = 5.0 });
     // }
-
+    var last_time: f64 = 0.0;
     while (!w.shouldClose()) {
+        const current_time = Renderer.Window.getTime();
+        pool.resources.delta_time = current_time - last_time;
+        last_time = current_time;
         Renderer.Window.pollEvents();
-        try r.tick();
         pool.tick();
     }
 }

src/renderer/Camera.zig

@@ -1,6 +1,8 @@
 const std = @import("std");
 const ecs = @import("ecs");
-const math = @import("../math.zig");
+const sideros = @import("sideros");
+const math = sideros.math;
+
 const Camera = @This();
 const UP = @Vector(3, f32){ 0.0, 1.0, 0.0 };
 
@@ -19,15 +21,15 @@ front: @Vector(3, f32),
 up: @Vector(3, f32),
 speed: f32 = 2.5,
 
-fn getProjection(width: usize, height: usize) math.Matrix {
+pub fn getProjection(width: usize, height: usize) math.Matrix {
     return math.Matrix.perspective(math.rad(45.0), (@as(f32, @floatFromInt(width)) / @as(f32, @floatFromInt(height))), 0.1, 10.0);
 }
 
-fn getView(self: Camera) math.Matrix {
+pub fn getView(self: Camera) math.Matrix {
     math.lookAt(self.position, self.position + self.front, self.up);
 }
 
-fn moveCamera(pool: *ecs.Pool) void {
+pub fn moveCamera(pool: *ecs.Pool) void {
     const input = pool.resources.input;
     const camera = pool.resources.camera;
     if (input.isKeyDown(.w)) {

src/renderer/Renderer.zig

@@ -1,4 +1,5 @@
 const c = @import("c.zig");
+const ecs = @import("ecs");
 const std = @import("std");
 const vk = @import("vulkan.zig");
 pub const Window = @import("Window.zig");
@@ -18,7 +19,7 @@ current_frame: u32,
 vertex_buffer: vk.Buffer,
 index_buffer: vk.Buffer,
 
-pub fn create(allocator: Allocator, w: Window) !Renderer {
+pub fn init(allocator: Allocator, w: Window) !Renderer {
     const instance = try vk.Instance.create(allocator);
 
     const surface = try vk.Surface.create(instance, w);
@@ -61,7 +62,7 @@ pub fn create(allocator: Allocator, w: Window) !Renderer {
     };
 }
 
-pub fn destroy(self: Renderer) void {
+pub fn deinit(self: Renderer) void {
     self.device.waitIdle();
     self.index_buffer.destroy(self.device.handle);
     self.vertex_buffer.destroy(self.device.handle);
@@ -73,22 +74,24 @@ pub fn destroy(self: Renderer) void {
     self.instance.destroy();
 }
 
-// TODO: tick is maybe a bad name? something like present() or submit() is better?
+// TODO: render is maybe a bad name? something like present() or submit() is better?
-pub fn tick(self: *Renderer) !void {
+pub fn render(pool: *ecs.Pool) anyerror!void {
-    try self.device.waitFence(self.current_frame);
+    var renderer = pool.resources.renderer;
-    const image = try self.swapchain.nextImage(self.device, self.current_frame);
-    try self.device.resetCommand(self.current_frame);
-    try self.device.beginCommand(self.current_frame);
-    self.render_pass.begin(self.swapchain, self.device, image, self.current_frame);
-    self.graphics_pipeline.bind(self.device, self.current_frame);
-    self.device.bindVertexBuffer(self.vertex_buffer, self.current_frame);
-    self.device.bindIndexBuffer(self.index_buffer, self.current_frame);
-    self.device.bindDescriptorSets(self.graphics_pipeline, self.current_frame);
-    self.device.draw(@intCast(self.index_buffer.size / @sizeOf(u16)), self.current_frame);
-    self.render_pass.end(self.device, self.current_frame);
-    try self.device.endCommand(self.current_frame);
 
-    try self.device.submit(self.swapchain, image, self.current_frame);
+    try renderer.device.waitFence(renderer.current_frame);
+    const image = try renderer.swapchain.nextImage(renderer.device, renderer.current_frame);
+    try renderer.device.resetCommand(renderer.current_frame);
+    try renderer.device.beginCommand(renderer.current_frame);
+    renderer.render_pass.begin(renderer.swapchain, renderer.device, image, renderer.current_frame);
+    renderer.graphics_pipeline.bind(renderer.device, renderer.current_frame);
+    renderer.device.bindVertexBuffer(renderer.vertex_buffer, renderer.current_frame);
+    renderer.device.bindIndexBuffer(renderer.index_buffer, renderer.current_frame);
+    renderer.device.bindDescriptorSets(renderer.graphics_pipeline, renderer.current_frame);
+    renderer.device.draw(@intCast(renderer.index_buffer.size / @sizeOf(u16)), renderer.current_frame);
+    renderer.render_pass.end(renderer.device, renderer.current_frame);
+    try renderer.device.endCommand(renderer.current_frame);
 
-    self.current_frame = (self.current_frame + 1) % 2;
+    try renderer.device.submit(renderer.swapchain, image, renderer.current_frame);
+
+    renderer.current_frame = (renderer.current_frame + 1) % 2;
 }

src/renderer/Window.zig

@@ -74,7 +74,7 @@ pub fn destroy(self: Window) void {
     c.glfwTerminate();
 }
 
-pub fn getTime() f32 {
+pub fn getTime() f64 {
     return c.glfwGetTime();
 }
 

src/renderer/vulkan.zig

@@ -3,6 +3,7 @@ const c = @import("c.zig");
 const Window = @import("Window.zig");
 const Mesh = @import("Mesh.zig");
 const sideros = @import("sideros");
+const Camera = @import("Camera.zig");
 const math = sideros.math;
 const Allocator = std.mem.Allocator;
 
@@ -302,7 +303,7 @@ pub fn GraphicsPipeline(comptime n: usize) type {
         descriptor_pool: c.VkDescriptorPool,
         descriptor_set: c.VkDescriptorSet,
         descriptor_set_layout: c.VkDescriptorSetLayout,
-        uniform_buffer: Buffer,
+        projection_buffer: Buffer,
 
         const Self = @This();
 
@@ -486,36 +487,25 @@ pub fn GraphicsPipeline(comptime n: usize) type {
 
             try mapError(c.vkAllocateDescriptorSets(device.handle, &descriptor_allocate_info, &descriptor_set));
 
-            const proj = math.Matrix.perspective(math.rad(45.0), (@as(f32, @floatFromInt(swapchain.extent.width)) / @as(f32, @floatFromInt(swapchain.extent.height))), 0.1, 10.0);
+            const projection_buffer = try device.createBuffer(BufferUsage{ .uniform_buffer = true, .transfer_dst = true }, BufferFlags{ .device_local = true }, @sizeOf(math.Matrix));
-
-            const view = math.Matrix.lookAt(@Vector(3, f32){ 0.0, 0.0, 10.0 }, @Vector(3, f32){ 0.0, 0.0, 0.0 }, @Vector(3, f32){ 0.0, 1.0, 0.0 });
-            const model = math.Matrix.identity();
-
-            const uniform = Uniform{
-                .proj = proj,
-                .view = view,
-                .model = model,
-            };
-
-            const uniform_buffer = try device.createBuffer(BufferUsage{ .uniform_buffer = true, .transfer_dst = true }, BufferFlags{ .device_local = true }, @sizeOf(Uniform));
 
             var data: [*c]u8 = undefined;
 
             try mapError(c.vkMapMemory(
                 device.handle,
-                uniform_buffer.memory,
+                projection_buffer.memory,
                 0,
-                uniform_buffer.size,
+                projection_buffer.size,
                 0,
                 @ptrCast(&data),
             ));
 
-            @memcpy(data[0..(@sizeOf(math.Matrix) * 3)], std.mem.asBytes(&uniform));
+            @memcpy(data[0..@sizeOf(math.Matrix)], std.mem.asBytes(&Camera.getProjection(swapchain.extent.width, swapchain.extent.height)));
 
             const descriptor_buffer_info = c.VkDescriptorBufferInfo{
-                .buffer = uniform_buffer.handle,
+                .buffer = projection_buffer.handle,
                 .offset = 0,
-                .range = uniform_buffer.size,
+                .range = projection_buffer.size,
             };
 
             const write_descriptor_set = c.VkWriteDescriptorSet{
@@ -536,7 +526,7 @@ pub fn GraphicsPipeline(comptime n: usize) type {
                 .descriptor_pool = descriptor_pool,
                 .descriptor_set = descriptor_set,
                 .descriptor_set_layout = descriptor_set_layout,
-                .uniform_buffer = uniform_buffer,
+                .projection_buffer = projection_buffer,
             };
         }
 
@@ -546,7 +536,7 @@ pub fn GraphicsPipeline(comptime n: usize) type {
         }
 
         pub fn destroy(self: Self, device: Device(n)) void {
-            self.uniform_buffer.destroy(device.handle);
+            self.projection_buffer.destroy(device.handle);
             c.vkDestroyDescriptorSetLayout(device.handle, self.descriptor_set_layout, null);
             c.vkDestroyDescriptorPool(device.handle, self.descriptor_pool, null);
             c.vkDestroyPipeline(device.handle, self.handle, null);
@@ -871,6 +861,10 @@ pub fn Device(comptime n: usize) type {
             c.vkCmdBindDescriptorSets(self.command_buffers[frame], c.VK_PIPELINE_BIND_POINT_GRAPHICS, pipeline.layout, 0, 1, &pipeline.descriptor_set, 0, null);
         }
 
+        pub fn updateBuffer(self: Self, comptime T: type, buffer: Buffer, data: [*]T, frame: usize) void {
+            c.vkCmdUpdateBuffer(self.command_buffers[frame], buffer.handle, 0, @sizeOf(T), @ptrCast(@alignCast(data)));
+        }
+
         pub fn pick_memory_type(self: Self, type_bits: u32, flags: u32) u32 {
             var memory_type_index: u32 = 0;
             for (0..self.memory_properties.memoryTypeCount) |index| {