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zig-bloxel-game
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Move primitive generation to separate file

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main
copygirl 9 months ago
parent f735d49fc2
commit 3761035aea
2 changed files with 125 additions and 91 deletions
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  1. 114
      src/main.zig
  2. 102
      src/primitives.zig

114
src/main.zig
Unescape View File

@ -8,6 +8,10 @@ const zm = @import("zmath");
const vec = zm.f32x4;
const Mat = zm.Mat;
const primitives = @import("./primitives.zig");
const VertexData = primitives.VertexData;
const PrimitiveData = primitives.PrimitiveData;
/// Holds information about how a perticular scene should be rendered.
const SceneUniformBuffer = struct {
view_proj_matrix: zm.Mat,
@ -25,30 +29,8 @@ const ObjectData = struct {
uniform_buffer: *gpu.Buffer,
/// Bind group used to associate the buffer to the `object` shader parameter.
uniform_bind_group: *gpu.BindGroup,
/// Index into `primitives` to specify which primitive to render.
primitive_index: usize,
};
/// Describes the layout of each vertex that a primitive is made of.
const VertexData = struct {
position: [3]f32,
};
/// Contains the data to render a primitive (3D shape or model).
const PrimitiveData = struct {
/// Vertices describe the "points" that a primitive is made out of.
/// This buffer is of type `[]VertexData`.
vertex_buffer: *gpu.Buffer,
vertex_count: u32,
/// Indices describe what vertices make up the triangles in a primitive.
/// This buffer is of type `[]u32`.
index_buffer: *gpu.Buffer,
index_count: u32,
// For example, `vertex_buffer` may have 4 points defining a square, but
// since it needs to be rendered using 2 triangles, `index_buffer` will
// contain 6 entries, `0, 1, 2` and `3, 2, 1` making up one triangle each.
/// Reference to the primitive (shape or model) to render for this object.
primitive: *PrimitiveData,
};
pub const App = @This();
@ -65,7 +47,7 @@ depth_texture_view: *gpu.TextureView,
pipeline: *gpu.RenderPipeline,
scene_uniform_buffer: *gpu.Buffer,
scene_uniform_bind_group: *gpu.BindGroup,
primitives: []PrimitiveData,
primitive_data: [2]PrimitiveData,
object_data: []ObjectData,
pub fn init(app: *App) !void {
@ -146,48 +128,10 @@ pub fn init(app: *App) !void {
}
// Set up the primitives we want to render.
app.primitives = try app.allocator.alloc(PrimitiveData, 2);
// Triangle
app.primitives[0] = createPrimitive(
&.{
// zig fmt: off
.{ .position = .{ 0.0, 0.5, 0.0 } },
.{ .position = .{ 0.5, -0.5, 0.0 } },
.{ .position = .{ -0.5, -0.5, 0.0 } },
// zig fmt: on
},
// Note that the back faces of triangles are "culled", and thus not visible.
// We need to take care to specify the vertices in counter-clock orientation.
&.{
0, 1, 2,
},
);
// Square
app.primitives[1] = createPrimitive(
// A square is made up of 4 vertices.
// 0--2
// | |
// | |
// 1--3
&.{
// zig fmt: off
.{ .position = .{ -0.5, -0.5, 0.0 } },
.{ .position = .{ -0.5, 0.5, 0.0 } },
.{ .position = .{ 0.5, -0.5, 0.0 } },
.{ .position = .{ 0.5, 0.5, 0.0 } },
// zig fmt: on
},
// But it has to be split up into 2 triangles,
// specified in a counter-clockwise orientation.
// 0--2 4
// | / /|
// |/ / |
// 1 5--3
&.{
0, 1, 2,
3, 2, 1,
},
);
app.primitive_data = .{
primitives.createTrianglePrimitive(1.0),
primitives.createSquarePrimitive(1.0),
};
// Set up object related uniform buffers and bind groups.
// This uploads data to the GPU about all the object we
@ -230,12 +174,16 @@ pub fn init(app: *App) !void {
},
);
// Pick a "random" primitive to use for this object.
const primitive_index = app.random.int(usize) % app.primitive_data.len;
const primitive = &app.primitive_data[primitive_index];
// 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,
.primitive = primitive,
};
}
}
@ -244,7 +192,7 @@ pub fn init(app: *App) !void {
/// Creates a buffer on the GPU to store uniform parameter information as
/// well as a bind group with the specified layout pointing to that buffer.
/// Additionally, immediately fills the buffer with the provided data.
fn createAndWriteUniformBuffer(
pub fn createAndWriteUniformBuffer(
layout: *gpu.BindGroupLayout,
data: anytype,
) struct {
@ -267,7 +215,7 @@ fn createAndWriteUniformBuffer(
/// Creates a buffer on the GPU with the specified usage
/// flags and immediately fills it with the provided data.
fn createAndWriteBuffer(
pub fn createAndWriteBuffer(
comptime T: type,
data: []const T,
usage: gpu.Buffer.UsageFlags,
@ -281,20 +229,6 @@ fn createAndWriteBuffer(
return buffer;
}
/// Creates a primitive from the provided vertices and indices,
/// and uploads the buffers necessary to render it to the GPU.
fn createPrimitive(
vertices: []const VertexData,
indices: []const u32,
) PrimitiveData {
return .{
.vertex_buffer = createAndWriteBuffer(VertexData, vertices, .{ .vertex = true, .copy_dst = true }),
.vertex_count = @intCast(vertices.len),
.index_buffer = createAndWriteBuffer(u32, indices, .{ .index = true, .copy_dst = true }),
.index_count = @intCast(indices.len),
};
}
pub fn deinit(app: *App) void {
// Using `defer` here, so we can specify them
// in the order they were created in `init`.
@ -305,8 +239,7 @@ 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.primitives);
defer for (app.primitives) |p| {
defer for (app.primitive_data) |p| {
p.vertex_buffer.release();
p.index_buffer.release();
};
@ -389,16 +322,15 @@ pub fn update(app: *App) !bool {
for (app.object_data) |object| {
// Set the vertex and index buffer used to render this object
// to the primitive it wants to use (either triangle or square).
const primitive_index = object.primitive_index;
const primitive = app.primitives[primitive_index];
pass.setVertexBuffer(0, primitive.vertex_buffer, 0, primitive.vertex_count * @sizeOf(VertexData));
pass.setIndexBuffer(primitive.index_buffer, .uint32, 0, primitive.index_count * @sizeOf(u32));
const prim = object.primitive;
pass.setVertexBuffer(0, prim.vertex_buffer, 0, prim.vertex_count * @sizeOf(VertexData));
pass.setIndexBuffer(prim.index_buffer, .uint32, 0, prim.index_count * @sizeOf(u32));
// Set the bind group for an object we want to render.
pass.setBindGroup(1, object.uniform_bind_group, &.{});
// Draw a number of triangles as specified in the index buffer.
pass.drawIndexed(primitive.index_count, 1, 0, 0, 0);
pass.drawIndexed(prim.index_count, 1, 0, 0, 0);
}
}

102
src/primitives.zig
Unescape View File

@ -0,0 +1,102 @@
const std = @import("std");
const core = @import("mach-core");
const gpu = core.gpu;
const main = @import("./main.zig");
const createAndWriteBuffer = main.createAndWriteBuffer;
/// Describes the layout of each vertex that a primitive is made of.
pub const VertexData = struct {
position: [3]f32,
};
/// Contains the data to render a primitive (3D shape or model).
pub const PrimitiveData = struct {
/// Vertices describe the "points" that a primitive is made out of.
/// This buffer is of type `[]VertexData`.
vertex_buffer: *gpu.Buffer,
vertex_count: u32,
/// Indices describe what vertices make up the triangles in a primitive.
/// This buffer is of type `[]u32`.
index_buffer: *gpu.Buffer,
index_count: u32,
// For example, `vertex_buffer` may have 4 points defining a square, but
// since it needs to be rendered using 2 triangles, `index_buffer` will
// contain 6 entries, `0, 1, 2` and `3, 2, 1` making up one triangle each.
};
/// Creates a primitive from the provided vertices and indices,
/// and uploads the buffers necessary to render it to the GPU.
pub fn createPrimitive(
vertices: []const VertexData,
indices: []const u32,
) PrimitiveData {
return .{
.vertex_buffer = createAndWriteBuffer(VertexData, vertices, .{ .vertex = true, .copy_dst = true }),
.vertex_count = @intCast(vertices.len),
.index_buffer = createAndWriteBuffer(u32, indices, .{ .index = true, .copy_dst = true }),
.index_count = @intCast(indices.len),
};
}
fn vert(x: f32, y: f32, z: f32) VertexData {
return .{ .position = .{ x, y, z } };
}
pub fn createTrianglePrimitive(length: f32) PrimitiveData {
const radius = length / @sqrt(3.0);
const a0 = 0.0;
const a1 = std.math.tau / 3.0;
const a2 = std.math.tau / 3.0 * 2.0;
return createPrimitive(
// A triangle is made up of 3 vertices.
//
// 0
// / \
// / \
// 1-----2
&.{
vert(@sin(a0) * radius, @cos(a0) * radius, 0.0),
vert(@sin(a1) * radius, @cos(a1) * radius, 0.0),
vert(@sin(a2) * radius, @cos(a2) * radius, 0.0),
},
// Vertices have to be specified in counter-clockwise,
// so the "front" of the triangle is facing the right way.
&.{
0, 1, 2,
},
);
}
pub fn createSquarePrimitive(width: f32) PrimitiveData {
const half_width = width / 2.0;
return createPrimitive(
// A square is made up of 4 vertices, ...
//
// 0---2
// | |
// | |
// 1---3
&.{
// zig fmt: off
vert(-half_width, -half_width, 0.0),
vert(-half_width, half_width, 0.0),
vert( half_width, -half_width, 0.0),
vert( half_width, half_width, 0.0),
// zig fmt: on
},
// ... but it has to be split up into 2 triangles.
//
// 0--2 4
// | / /|
// |/ / |
// 1 5--3
&.{
0, 1, 2,
3, 2, 1,
},
);
}
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