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zig-bloxel-game
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Consolidate object rendering information

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main
copygirl 9 months ago
parent 0776a95a1a
commit e595f9a9b2
1 changed files with 110 additions and 80 deletions
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  1. 162
      src/main.zig

162
src/main.zig
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@ -17,6 +17,16 @@ const ObjectUniformBuffer = struct {
color: [3]f32,
};
/// Holds data on what is needed to render an object in a rendering pass.
const ObjectData = struct {
/// Reference to data stored on the GPU of type `ObjectUniformBuffer`.
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,
@ -45,14 +55,9 @@ app_timer: core.Timer,
title_timer: core.Timer,
pipeline: *gpu.RenderPipeline,
scene_uniform_buffer: *gpu.Buffer,
scene_bind_group: *gpu.BindGroup,
object_uniform_buffers: [3]*gpu.Buffer,
object_bind_groups: [3]*gpu.BindGroup,
object_primitive_indices: [3]usize,
scene_uniform_bind_group: *gpu.BindGroup,
object_data: [3]ObjectData,
primitives: [2]PrimitiveData,
pub fn init(app: *App) !void {
@ -91,69 +96,63 @@ pub fn init(app: *App) !void {
},
});
// Set up uniform buffers and bind groups.
// The "scene" uniform contains information for each rendered scene.
app.scene_uniform_buffer = core.device.createBuffer(&.{
.usage = .{ .copy_dst = true, .uniform = true },
.size = @sizeOf(SceneUniformBuffer),
.mapped_at_creation = .false,
});
// "Bind groups" are used to associate data from buffers with shader parameters.
// So for example the `scene_bind_group` is accessible via `scene` in our shader.
// Essentially, buffer = data, and bind group = binding parameter to that data.
app.scene_bind_group = core.device.createBindGroup(
&gpu.BindGroup.Descriptor.init(.{
.layout = app.pipeline.getBindGroupLayout(0),
.entries = &.{
gpu.BindGroup.Entry.buffer(0, app.scene_uniform_buffer, 0, @sizeOf(SceneUniformBuffer)),
},
}),
// Set up scene related uniform buffers and bind groups.
{
const result = createAndWriteUniformBuffer(
app.pipeline.getBindGroupLayout(0),
SceneUniformBuffer{ .view_proj_matrix = zm.identity() },
);
// The "object" uniforms contain information about how to render each object in a scene.
for (0..3) |i| {
app.object_uniform_buffers[i] = core.device.createBuffer(&.{
.usage = .{ .copy_dst = true, .uniform = true },
.size = @sizeOf(ObjectUniformBuffer),
.mapped_at_creation = .false,
});
app.object_bind_groups[i] = core.device.createBindGroup(
&gpu.BindGroup.Descriptor.init(.{
.layout = app.pipeline.getBindGroupLayout(1),
.entries = &.{
gpu.BindGroup.Entry.buffer(0, app.object_uniform_buffers[i], 0, @sizeOf(ObjectUniformBuffer)),
},
}),
);
app.scene_uniform_buffer = result.buffer;
app.scene_uniform_bind_group = result.bind_group;
}
// Upload object information (model matrix + color) to the GPU.
const rotation = zm.rotationY(std.math.tau / 2.0);
// 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.
core.queue.writeBuffer(app.object_uniform_buffers[0], 0, &[_]ObjectUniformBuffer{.{
.model_matrix = zm.transpose(zm.mul(rotation, zm.translation(-1.0, 0.25, 0.0))),
.color = .{ 1.0, 0.0, 0.0 },
}});
app.object_primitive_indices[0] = 0;
core.queue.writeBuffer(app.object_uniform_buffers[1], 0, &[_]ObjectUniformBuffer{.{
.model_matrix = zm.transpose(zm.mul(rotation, zm.translation(0.0, -0.25, 0.0))),
.color = .{ 0.0, 1.0, 0.0 },
}});
app.object_primitive_indices[1] = 1;
core.queue.writeBuffer(app.object_uniform_buffers[2], 0, &[_]ObjectUniformBuffer{.{
.model_matrix = zm.transpose(zm.mul(rotation, zm.translation(1.0, 0.0, 0.0))),
.color = .{ 0.0, 0.0, 1.0 },
}});
app.object_primitive_indices[2] = 0;
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.
// 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.
@ -163,16 +162,21 @@ pub fn init(app: *App) !void {
);
// 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
// | / /|
// |/ / |
@ -184,6 +188,30 @@ 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(
layout: *gpu.BindGroupLayout,
data: anytype,
) struct {
buffer: *gpu.Buffer,
bind_group: *gpu.BindGroup,
} {
const T = @TypeOf(data);
const usage = gpu.Buffer.UsageFlags{ .copy_dst = true, .uniform = true };
const buffer = createAndWriteBuffer(T, &.{data}, usage);
// "Bind groups" are used to associate data from buffers with shader parameters.
// So for example the `scene_uniform_bind_group` is accessible via `scene` in our shader.
// Essentially, buffer = data, and bind group = binding parameter to that data.
const bind_group_entry = gpu.BindGroup.Entry.buffer(0, buffer, 0, @sizeOf(T));
const bind_group_desc = gpu.BindGroup.Descriptor.init(.{ .layout = layout, .entries = &.{bind_group_entry} });
const bind_group = core.device.createBindGroup(&bind_group_desc);
return .{ .buffer = buffer, .bind_group = bind_group };
}
/// Creates a buffer on the GPU with the specified usage
/// flags and immediately fills it with the provided data.
fn createAndWriteBuffer(
@ -200,8 +228,8 @@ fn createAndWriteBuffer(
return buffer;
}
// Creates a primitive from the provided vertices and indices,
// and uploads the buffers necessary to render it to the GPU.
/// 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,
@ -220,9 +248,11 @@ pub fn deinit(app: *App) void {
defer core.deinit();
defer app.pipeline.release();
defer app.scene_uniform_buffer.release();
defer app.scene_bind_group.release();
defer for (app.object_uniform_buffers) |b| b.release();
defer for (app.object_bind_groups) |g| g.release();
defer app.scene_uniform_bind_group.release();
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();
@ -288,18 +318,18 @@ pub fn update(app: *App) !bool {
defer pass.end();
pass.setPipeline(app.pipeline);
pass.setBindGroup(0, app.scene_bind_group, &.{});
pass.setBindGroup(0, app.scene_uniform_bind_group, &.{});
for (app.object_bind_groups, 0..) |object_bind_group, i| {
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 = app.object_primitive_indices[i];
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));
// Set the bind group for an object we want to render.
pass.setBindGroup(1, object_bind_group, &.{});
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);

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