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zig-bloxel-game
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Draw a colored & rotated grid of primitives

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copygirl 3 months ago
parent 302b9e7d4c
commit d2761382ec
1 changed files with 69 additions and 59 deletions
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  1. 128
      src/main.zig

128
src/main.zig
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@ -55,6 +55,7 @@ pub const App = @This();
gpa: GeneralPurposeAllocator,
allocator: std.mem.Allocator,
random: std.rand.Random,
app_timer: core.Timer,
title_timer: core.Timer,
@ -62,8 +63,8 @@ title_timer: core.Timer,
pipeline: *gpu.RenderPipeline,
scene_uniform_buffer: *gpu.Buffer,
scene_uniform_bind_group: *gpu.BindGroup,
object_data: []ObjectData,
primitives: []PrimitiveData,
object_data: []ObjectData,
pub fn init(app: *App) !void {
try core.init(.{});
@ -78,6 +79,11 @@ pub fn init(app: *App) !void {
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();
@ -122,55 +128,6 @@ 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);
// 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, object_desc.len);
// 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 (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,
},
);
// 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 = desc.prim,
};
}
}
// Set up the primitives we want to render.
app.primitives = try app.allocator.alloc(PrimitiveData, 2);
// Triangle
@ -214,6 +171,57 @@ 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
@ -278,16 +286,16 @@ pub fn deinit(app: *App) void {
defer app.pipeline.release();
defer app.scene_uniform_buffer.release();
defer app.scene_uniform_bind_group.release();
defer app.allocator.free(app.object_data);
defer for (app.object_data) |o| {
o.uniform_buffer.release();
o.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();
};
}
pub fn update(app: *App) !bool {
@ -304,16 +312,18 @@ 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 x = @cos(time * std.math.tau / 10);
const y = @sin(time * std.math.tau / 10);
const view_matrix = zm.lookAtLh(vec(x, y, -2, 1), vec(0, 0, 0, 1), vec(0, 1, 0, 1));
const camera_distance = 8.0;
const x = @cos(time * std.math.tau / 20) * camera_distance;
const z = @sin(time * std.math.tau / 20) * camera_distance;
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, 0.1, 10);
const proj_matrix = zm.perspectiveFovLh(field_of_view, width / height, 0.05, 80.0);
const view_proj_matrix = zm.mul(view_matrix, proj_matrix);

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