1 changed files with 52 additions and 118 deletions
--- a/src/main.zig
+++ b/src/main.zig
@ -1,6 +1,4 @@
 const std = @import("std");
 const GeneralPurposeAllocator = std.heap.GeneralPurposeAllocator(.{});
 const core = @import("mach-core");
 const gpu = core.gpu;
@ -53,52 +51,21 @@ const PrimitiveData = struct {
 pub const App = @This();
 gpa: GeneralPurposeAllocator,
 allocator: std.mem.Allocator,
 random: std.rand.Random,
 app_timer: core.Timer,
 title_timer: core.Timer,
 depth_texture: *gpu.Texture,
 depth_texture_view: *gpu.TextureView,
 pipeline: *gpu.RenderPipeline,
 scene_uniform_buffer: *gpu.Buffer,
 scene_uniform_bind_group: *gpu.BindGroup,
-primitives: []PrimitiveData,
+object_data: [3]ObjectData,
-object_data: []ObjectData,
+primitives: [2]PrimitiveData,
 pub fn init(app: *App) !void {
    try core.init(.{});
    // Set up a "general purpose allocator" that will handle allocations for
    // the lifetime of the application, for which a more specific allocation
    // strategy is not necessary.
    //
    // Here, `gpa` is an instance of this allocator, which handles the
    // allocation logic, while `allocator` is the interface through which
    // functions such as `alloc` and `free` are called.
    app.gpa = GeneralPurposeAllocator{};
    app.allocator = app.gpa.allocator();
    // Create a pseudo-random number generator, but initialize it with
    // a constant seed so we always get the same result when launching.
    var prng = std.rand.DefaultPrng.init(0);
    app.random = prng.random();
    app.app_timer = try core.Timer.start();
    app.title_timer = try core.Timer.start();
    // Create a depth texture. This is used to ensure that when things are
    // rendered, an object behind another won't draw over one in front, simply
    // because it was rendered at a later point in time.
    app.depth_texture = core.device.createTexture(&.{
        .usage = .{ .render_attachment = true },
        .size = .{ .width = core.descriptor.width, .height = core.descriptor.height },
        .format = .depth24_plus,
    });
    app.depth_texture_view = app.depth_texture.createView(null);
    const shader_module = core.device.createShaderModuleWGSL("shader.wgsl", @embedFile("shader.wgsl"));
    defer shader_module.release();
@ -117,21 +84,16 @@ pub fn init(app: *App) !void {
                }),
            },
        }),
        .primitive = .{
            .topology = .triangle_list,
            .front_face = .ccw,
            .cull_mode = .back,
        },
        .depth_stencil = &.{
            .format = .depth24_plus,
            .depth_write_enabled = .true,
            .depth_compare = .less,
        },
        .fragment = &gpu.FragmentState.init(.{
            .module = shader_module,
            .entry_point = "frag_main",
            .targets = &.{.{ .format = core.descriptor.format }},
        }),
        .primitive = .{
            .topology = .triangle_list,
            .front_face = .ccw,
            .cull_mode = .back,
        },
    });
    // Set up scene related uniform buffers and bind groups.
@ -145,8 +107,44 @@ pub fn init(app: *App) !void {
        app.scene_uniform_bind_group = result.bind_group;
    }
    // Set up object related uniform buffers and bind groups.
    // This uploads data to the GPU about all the object we
    // want to render, such as their location and color.
    {
        const ObjectDescription = struct { pos: [3]f32, color: [3]f32, prim: usize };
        const object_desc = [_]ObjectDescription{
            // zig fmt: off
            .{ .pos = .{ -1.25,  0.25, 0.0 }, .color = .{ 1.0, 0.0, 0.0 }, .prim = 0 },
            .{ .pos = .{  0.0 , -0.25, 0.0 }, .color = .{ 0.0, 1.0, 0.0 }, .prim = 1 },
            .{ .pos = .{  1.25,  0.0 , 0.0 }, .color = .{ 0.0, 0.0, 1.0 }, .prim = 0 },
            // zig fmt: on
        };
        // The objects are rotated 180° to face the camera, or else we
        // would see the back side of the triangles, which are culled.
        const rotation = zm.rotationY(std.math.tau / 2.0);
        for (object_desc, &app.object_data) |desc, *object| {
            const translation = zm.translation(desc.pos[0], desc.pos[1], desc.pos[2]);
            const model_matrix = zm.mul(rotation, translation);
            const result = createAndWriteUniformBuffer(
                app.pipeline.getBindGroupLayout(1),
                ObjectUniformBuffer{
                    .model_matrix = zm.transpose(model_matrix),
                    .color = desc.color,
                },
            );
            object.* = .{
                .uniform_buffer = result.buffer,
                .uniform_bind_group = result.bind_group,
                .primitive_index = desc.prim,
            };
        }
    }
    // Set up the primitives we want to render.
    app.primitives = try app.allocator.alloc(PrimitiveData, 2);
    // Triangle
    app.primitives[0] = createPrimitive(
        &.{
@ -188,57 +186,6 @@ pub fn init(app: *App) !void {
            3, 2, 1,
        },
    );
    // Set up object related uniform buffers and bind groups.
    // This uploads data to the GPU about all the object we
    // want to render, such as their location and color.
    {
        const grid_size = 8;
        // Allocate a slice to store as many ObjectData as we want to create.
        //
        // Using a slice instead of an array means that we could change how
        // many object we want to render at compile time, however it requires
        // allocating, and later freeing, memory to store the slice.
        app.object_data = try app.allocator.alloc(ObjectData, grid_size * grid_size);
        // Note that for loops in Zig are a little different than you might
        // know from other languages. They only look over arrays, slices,
        // tuples and ranges, potentially multiple at once.
        for (app.object_data, 0..) |*object, i| {
            const grid_max: f32 = @floatFromInt(grid_size - 1);
            const x = @as(f32, @floatFromInt(i % grid_size)) / grid_max;
            const z = @as(f32, @floatFromInt(i / grid_size)) / grid_max;
            const rotation = zm.rotationY(std.math.tau * (x + z) / 2.0);
            const translation = zm.translation((x - 0.5) * grid_size, 0, (z - 0.5) * grid_size);
            const model_matrix = zm.mul(rotation, translation);
            // Make the object have a color depending on its location in the grid.
            // These values are layed out so each corner is red, green, blue and black.
            const color = .{
                std.math.clamp(1.0 - x - z, 0.0, 1.0),
                std.math.clamp(x - z, 0.0, 1.0),
                std.math.clamp(z - x, 0.0, 1.0),
            };
            const result = createAndWriteUniformBuffer(
                app.pipeline.getBindGroupLayout(1),
                ObjectUniformBuffer{
                    .model_matrix = zm.transpose(model_matrix),
                    .color = color,
                },
            );
            // The `*object` syntax gets us a pointer to each element in the
            // `object_data` slice, allowing us to override it within the loop.
            object.* = .{
                .uniform_buffer = result.buffer,
                .uniform_bind_group = result.bind_group,
                .primitive_index = app.random.int(usize) % app.primitives.len,
            };
        }
    }
 }
 /// Creates a buffer on the GPU to store uniform parameter information as
@ -299,22 +246,17 @@ pub fn deinit(app: *App) void {
    // Using `defer` here, so we can specify them
    // in the order they were created in `init`.
    defer core.deinit();
    defer _ = app.gpa.deinit(); // TODO: Check for memory leaks?
    defer app.depth_texture.release();
    defer app.depth_texture_view.release();
    defer app.pipeline.release();
    defer app.scene_uniform_buffer.release();
    defer app.scene_uniform_bind_group.release();
    defer app.allocator.free(app.primitives);
    defer for (app.primitives) |p| {
        p.vertex_buffer.release();
        p.index_buffer.release();
    };
    defer app.allocator.free(app.object_data);
    defer for (app.object_data) |o| {
        o.uniform_buffer.release();
        o.uniform_bind_group.release();
    };
    defer for (app.primitives) |p| {
        p.vertex_buffer.release();
        p.index_buffer.release();
    };
 }
 pub fn update(app: *App) !bool {
@ -331,18 +273,16 @@ pub fn update(app: *App) !bool {
    // TODO: Actually implement camera transform instead of hardcoding a look-at matrix.
    // const view_matrix = zm.inverse(app.camera_transform);
    const time = app.app_timer.read();
-    const camera_distance = 8.0;
+    const x = @cos(time * std.math.tau / 10);
-    const x = @cos(time * std.math.tau / 20) * camera_distance;
+    const y = @sin(time * std.math.tau / 10);
-    const z = @sin(time * std.math.tau / 20) * camera_distance;
+    const view_matrix = zm.lookAtLh(vec(x, y, -2, 1), vec(0, 0, 0, 1), vec(0, 1, 0, 1));
    const camera_pos = vec(x, 2.0, z, 1.0);
    const view_matrix = zm.lookAtLh(camera_pos, vec(0, 0, 0, 1), vec(0, 1, 0, 1));
    // Set up a projection matrix using the size of the window.
    // The perspective projection will make things further away appear smaller.
    const width: f32 = @floatFromInt(core.descriptor.width);
    const height: f32 = @floatFromInt(core.descriptor.height);
    const field_of_view = std.math.degreesToRadians(f32, 45.0);
-    const proj_matrix = zm.perspectiveFovLh(field_of_view, width / height, 0.05, 80.0);
+    const proj_matrix = zm.perspectiveFovLh(field_of_view, width / height, 0.1, 10);
    const view_proj_matrix = zm.mul(view_matrix, proj_matrix);
@ -359,12 +299,6 @@ pub fn update(app: *App) !bool {
            .load_op = .clear,
            .store_op = .store,
        }},
        .depth_stencil_attachment = &.{
            .view = app.depth_texture_view,
            .depth_load_op = .clear,
            .depth_store_op = .store,
            .depth_clear_value = 1.0,
        },
    });
    // Create a `WGPUCommandEncoder` which provides an interface for recording GPU commands.