From 82d2cc7c234393beaea5d3cf30957e0dd4594b05 Mon Sep 17 00:00:00 2001
From: Simon Ser <contact@emersion.fr>
Date: Fri, 29 May 2026 16:55:37 +0200
Subject: [PATCH] output: add brightness state

---
 include/wlr/types/wlr_output.h |  8 ++++++++
 types/output/output.c          | 16 ++++++++++++++++
 types/output/state.c           |  5 +++++
 3 files changed, 29 insertions(+)

diff --git a/include/wlr/types/wlr_output.h b/include/wlr/types/wlr_output.h
index c8e44b0e6..ca3ed90e3 100644
--- a/include/wlr/types/wlr_output.h
+++ b/include/wlr/types/wlr_output.h
@@ -78,6 +78,7 @@ enum wlr_output_state_field {
 	WLR_OUTPUT_STATE_COLOR_TRANSFORM = 1 << 12,
 	WLR_OUTPUT_STATE_IMAGE_DESCRIPTION = 1 << 13,
 	WLR_OUTPUT_STATE_COLOR_REPRESENTATION = 1 << 14,
+	WLR_OUTPUT_STATE_BRIGHTNESS = 1 << 15,
 };
 
 enum wlr_output_state_mode_type {
@@ -165,6 +166,8 @@ struct wlr_output_state {
 	struct wlr_color_transform *color_transform;
 
 	struct wlr_output_image_description *image_description;
+
+	float brightness;
 };
 
 struct wlr_output_impl;
@@ -213,11 +216,14 @@ struct wlr_output {
 	enum wlr_color_encoding color_encoding;
 	enum wlr_color_range color_range;
 	const struct wlr_output_image_description *image_description;
+	float brightness;
 
 	// Indicates whether making changes to adaptive sync status is supported.
 	// If false, changes to adaptive sync status is guaranteed to fail. If
 	// true, changes may either succeed or fail.
 	bool adaptive_sync_supported;
+	// Indicates whether brightness changes are supported.
+	bool brightness_supported;
 
 	bool needs_frame;
 	// damage for cursors and fullscreen surface, in output-local coordinates
@@ -632,6 +638,8 @@ void wlr_output_state_set_color_transform(struct wlr_output_state *state,
 bool wlr_output_state_set_image_description(struct wlr_output_state *state,
 	const struct wlr_output_image_description *image_desc);
 
+void wlr_output_state_set_brightness(struct wlr_output_state *state, float value);
+
 /**
  * Set the color encoding and range of the primary scanout buffer.
  *
diff --git a/types/output/output.c b/types/output/output.c
index 46da1f425..273cbfed3 100644
--- a/types/output/output.c
+++ b/types/output/output.c
@@ -261,6 +261,10 @@ static void output_apply_state(struct wlr_output *output,
 		}
 	}
 
+	if (state->committed & WLR_OUTPUT_STATE_BRIGHTNESS) {
+		output->brightness = state->brightness;
+	}
+
 	bool geometry_updated = state->committed &
 		(WLR_OUTPUT_STATE_MODE | WLR_OUTPUT_STATE_TRANSFORM |
 		WLR_OUTPUT_STATE_SUBPIXEL);
@@ -359,6 +363,7 @@ void wlr_output_init(struct wlr_output *output, struct wlr_backend *backend,
 		.render_format = DRM_FORMAT_XRGB8888,
 		.transform = WL_OUTPUT_TRANSFORM_NORMAL,
 		.scale = 1,
+		.brightness = 1,
 		.commit_seq = 0,
 	};
 
@@ -590,6 +595,10 @@ static uint32_t output_compare_state(struct wlr_output *output,
 			output->color_range == state->color_range) {
 		fields |= WLR_OUTPUT_STATE_COLOR_REPRESENTATION;
 	}
+	if ((state->committed & WLR_OUTPUT_STATE_BRIGHTNESS) &&
+			output->brightness == state->brightness) {
+		fields |= WLR_OUTPUT_STATE_BRIGHTNESS;
+	}
 	return fields;
 }
 
@@ -687,6 +696,7 @@ static bool output_basic_test(struct wlr_output *output,
 		{ WLR_OUTPUT_STATE_SUBPIXEL, "subpixel" },
 		{ WLR_OUTPUT_STATE_COLOR_TRANSFORM, "color transform" },
 		{ WLR_OUTPUT_STATE_IMAGE_DESCRIPTION, "image description" },
+		{ WLR_OUTPUT_STATE_BRIGHTNESS, "brightness" },
 	};
 	if (!enabled) {
 		for (size_t i = 0; i < sizeof(needs_enabled) / sizeof(needs_enabled[0]); i++) {
@@ -726,6 +736,12 @@ static bool output_basic_test(struct wlr_output *output,
 		}
 	}
 
+	if ((state->committed & WLR_OUTPUT_STATE_BRIGHTNESS) &&
+			!output->brightness_supported) {
+		wlr_log(WLR_DEBUG, "Brightness is not supported for this output");
+		return false;
+	}
+
 	return true;
 }
 
diff --git a/types/output/state.c b/types/output/state.c
index 5f44c18e8..f62f3ab87 100644
--- a/types/output/state.c
+++ b/types/output/state.c
@@ -149,6 +149,11 @@ void wlr_output_state_set_color_encoding_and_range(
 	state->color_range = range;
 }
 
+void wlr_output_state_set_brightness(struct wlr_output_state *state, float value) {
+	state->committed |= WLR_OUTPUT_STATE_BRIGHTNESS;
+	state->brightness = value;
+}
+
 bool wlr_output_state_copy(struct wlr_output_state *dst,
 		const struct wlr_output_state *src) {
 	struct wlr_output_state copy = *src;