screen: add vsync and double buffering

1 files changed, 23 insertions, 3 deletions

diff --git a/src/screen/drm/card.zig b/src/screen/drm/card.zig
index d66a5f1..6147cf2 100644
--- a/src/screen/drm/card.zig
+++ b/src/screen/drm/card.zig
@@ -7,7 +7,8 @@ const Resources = @import("resources.zig").Resources;
 const Connector = @import("connector/root.zig").Connector;
 const Encoder = @import("encoder/root.zig").Encoder;
 const Crtc = @import("crtc/root.zig").Crtc;
-const FrameBuffer = @import("frame-buffer/root.zig").FrameBuffer;
+const DoubleBuffer = @import("frame-buffer/root.zig").DoubleBuffer;
+const Event = @import("event.zig").Event;
 
 
 pub const Card = struct {
@@ -25,6 +26,7 @@ pub const Card = struct {
                 .mode = .read_write,
                 .lock_nonblocking = true,
             }),
+
             .allocator = allocator,
         };
     }
@@ -54,7 +56,25 @@ pub const Card = struct {
         return Crtc.init(self, id);
     }
 
-    pub fn create_frame_buffer(self: *Card, width: u32, height: u32, bpp: u32) !FrameBuffer {
-        return FrameBuffer.init(self, width, height, bpp);
+    pub fn create_double_buffer(self: *Card, width: u32, height: u32, bpp: u32) !DoubleBuffer {
+        return DoubleBuffer.init(self, width, height, bpp);
+    }
+
+    pub fn poll_event(self: *Card, timeout: i32) !?Event {
+        var pollfd = os.pollfd {
+            .fd = self.file.handle,
+            .events = os.POLL.IN,
+            .revents = 0
+        };
+
+        try cerror.from_usize(os.poll(@ptrCast(&pollfd), 1, timeout));
+
+        if ((pollfd.revents & os.POLL.IN) != 0) {
+            var event = std.mem.zeroes(Event);
+            try cerror.from_usize(os.read(self.file.handle, @ptrCast(&event), @sizeOf(Event)));
+            return event;
+        }
+
+        return null;
     }
 };