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const std = @import("std");
const c = @import("c.zig").c;
const Server = @import("server.zig").Server;
const View = @import("view.zig").View;
const RenderData = struct {
output: *c.wlr_output,
renderer: *c.wlr_renderer,
view: *View,
when: *c.struct_timespec,
};
pub const Output = struct {
const Self = @This();
server: *Server,
wlr_output: *c.wlr_output,
listen_frame: c.wl_listener,
pub fn init(self: *Self, server: *Server, wlr_output: *c.wlr_output) !void {
// Some backends don't have modes. DRM+KMS does, and we need to set a mode
// before we can use the output. The mode is a tuple of (width, height,
// refresh rate), and each monitor supports only a specific set of modes. We
// just pick the monitor's preferred mode, a more sophisticated compositor
// would let the user configure it.
// if not empty
if (c.wl_list_empty(&wlr_output.modes) == 0) {
const mode = c.wlr_output_preferred_mode(wlr_output);
c.wlr_output_set_mode(wlr_output, mode);
c.wlr_output_enable(wlr_output, true);
if (!c.wlr_output_commit(wlr_output)) {
return error.CantCommitWlrOutputMode;
}
}
self.server = server;
self.wlr_output = wlr_output;
// Sets up a listener for the frame notify event.
self.listen_frame.notify = handle_frame;
c.wl_signal_add(&wlr_output.events.frame, &self.listen_frame);
// Add the new output to the layout. The add_auto function arranges outputs
// from left-to-right in the order they appear. A more sophisticated
// compositor would let the user configure the arrangement of outputs in the
// layout.
c.wlr_output_layout_add_auto(server.wlr_output_layout, wlr_output);
// Creating the global adds a wl_output global to the display, which Wayland
// clients can see to find out information about the output (such as
// DPI, scale factor, manufacturer, etc).
c.wlr_output_create_global(wlr_output);
}
fn handle_frame(listener: ?*c.wl_listener, data: ?*c_void) callconv(.C) void {
// This function is called every time an output is ready to display a frame,
// generally at the output's refresh rate (e.g. 60Hz).
const output = @fieldParentPtr(Output, "listen_frame", listener.?);
const renderer = output.server.wlr_renderer;
var now: c.struct_timespec = undefined;
_ = c.clock_gettime(c.CLOCK_MONOTONIC, &now);
// wlr_output_attach_render makes the OpenGL context current.
if (!c.wlr_output_attach_render(output.wlr_output, null)) {
return;
}
// The "effective" resolution can change if you rotate your outputs.
var width: c_int = undefined;
var height: c_int = undefined;
c.wlr_output_effective_resolution(output.wlr_output, &width, &height);
// Begin the renderer (calls glViewport and some other GL sanity checks)
c.wlr_renderer_begin(renderer, width, height);
const color = [_]f32{ 0.3, 0.3, 0.3, 1.0 };
c.wlr_renderer_clear(renderer, &color);
// Each subsequent view is rendered on top of the last.
// The first view in the list is "on top" so iterate in reverse.
var it = output.server.views.last;
while (it) |node| : (it = node.prev) {
const view = &node.data;
if (!view.mapped) {
// An unmapped view should not be rendered.
continue;
}
var rdata = RenderData{
.output = output.wlr_output,
.view = view,
.renderer = renderer,
.when = &now,
};
// This calls our render_surface function for each surface among the
// xdg_surface's toplevel and popups.
c.wlr_xdg_surface_for_each_surface(view.wlr_xdg_surface, render_surface, &rdata);
}
// Hardware cursors are rendered by the GPU on a separate plane, and can be
// moved around without re-rendering what's beneath them - which is more
// efficient. However, not all hardware supports hardware cursors. For this
// reason, wlroots provides a software fallback, which we ask it to render
// here. wlr_cursor handles configuring hardware vs software cursors for you,
// and this function is a no-op when hardware cursors are in use.
c.wlr_output_render_software_cursors(output.wlr_output, null);
// Conclude rendering and swap the buffers, showing the final frame
// on-screen.
c.wlr_renderer_end(renderer);
// TODO: handle failure
_ = c.wlr_output_commit(output.wlr_output);
}
fn render_surface(opt_surface: ?*c.wlr_surface, sx: c_int, sy: c_int, data: ?*c_void) callconv(.C) void {
// wlroots says this will never be null
const surface = opt_surface.?;
// This function is called for every surface that needs to be rendered.
const rdata = @ptrCast(*RenderData, @alignCast(@alignOf(RenderData), data));
const view = rdata.view;
const output = rdata.output;
// We first obtain a wlr_texture, which is a GPU resource. wlroots
// automatically handles negotiating these with the client. The underlying
// resource could be an opaque handle passed from the client, or the client
// could have sent a pixel buffer which we copied to the GPU, or a few other
// means. You don't have to worry about this, wlroots takes care of it.
const texture = c.wlr_surface_get_texture(surface);
if (texture == null) {
return;
}
// The view has a position in layout coordinates. If you have two displays,
// one next to the other, both 1080p, a view on the rightmost display might
// have layout coordinates of 2000,100. We need to translate that to
// output-local coordinates, or (2000 - 1920).
var ox: f64 = 0.0;
var oy: f64 = 0.0;
c.wlr_output_layout_output_coords(view.server.wlr_output_layout, output, &ox, &oy);
ox += @intToFloat(f64, view.x + sx);
oy += @intToFloat(f64, view.y + sy);
// We also have to apply the scale factor for HiDPI outputs. This is only
// part of the puzzle, TinyWL does not fully support HiDPI.
const box = c.wlr_box{
.x = @floatToInt(c_int, ox * output.scale),
.y = @floatToInt(c_int, oy * output.scale),
.width = @floatToInt(c_int, @intToFloat(f32, surface.current.width) * output.scale),
.height = @floatToInt(c_int, @intToFloat(f32, surface.current.height) * output.scale),
};
// Those familiar with OpenGL are also familiar with the role of matricies
// in graphics programming. We need to prepare a matrix to render the view
// with. wlr_matrix_project_box is a helper which takes a box with a desired
// x, y coordinates, width and height, and an output geometry, then
// prepares an orthographic projection and multiplies the necessary
// transforms to produce a model-view-projection matrix.
//
// Naturally you can do this any way you like, for example to make a 3D
// compositor.
var matrix: [9]f32 = undefined;
const transform = c.wlr_output_transform_invert(surface.current.transform);
c.wlr_matrix_project_box(&matrix, &box, transform, 0.0, &output.transform_matrix);
// This takes our matrix, the texture, and an alpha, and performs the actual
// rendering on the GPU.
_ = c.wlr_render_texture_with_matrix(rdata.renderer, texture, &matrix, 1.0);
// This lets the client know that we've displayed that frame and it can
// prepare another one now if it likes.
c.wlr_surface_send_frame_done(surface, rdata.when);
}
};
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