From 5577363aaff0d84f26526528b5b106b29e384d2f Mon Sep 17 00:00:00 2001
From: Bernd Busse <bernd@busse-net.de>
Date: Mon, 12 Oct 2020 18:34:51 +0200
Subject: [PATCH] win: keep track of window specific shader in `managed_win`

---
 src/win.c | 37 +++++++++++++++++++++++++++++++++++++
 src/win.h |  6 +++++-
 2 files changed, 42 insertions(+), 1 deletion(-)

diff --git a/src/win.c b/src/win.c
index 7bdb05f..58f71a9 100644
--- a/src/win.c
+++ b/src/win.c
@@ -1052,6 +1052,19 @@ win_set_blur_background(session_t *ps, struct managed_win *w, bool blur_backgrou
 	add_damage_from_win(ps, w);
 }
 
+static void
+win_set_fg_shader(session_t *ps, struct managed_win *w, struct shader_info *shader_new) {
+	if (w->fg_shader == shader_new) {
+		return;
+	}
+
+	w->fg_shader = shader_new;
+
+	// A different shader might change how the window is drawn, these changes should
+	// be rare however, so this should be fine.
+	add_damage_from_win(ps, w);
+}
+
 /**
  * Determine if a window should have background blurred.
  */
@@ -1098,6 +1111,28 @@ static void win_determine_rounded_corners(session_t *ps, struct managed_win *w)
 	}
 }
 
+/**
+ * Determine custom window shader to use for a window.
+ */
+static void win_determine_fg_shader(session_t *ps, struct managed_win *w) {
+	if (w->a.map_state != XCB_MAP_STATE_VIEWABLE) {
+		return;
+	}
+
+	auto shader_new = ps->o.window_shader_fg;
+	void *val = NULL;
+	if (c2_match(ps, w, ps->o.window_shader_fg_rules, &val)) {
+		shader_new = val;
+	}
+
+	struct shader_info *shader = NULL;
+	if (shader_new) {
+		HASH_FIND_STR(ps->shaders, shader_new, shader);
+	}
+
+	win_set_fg_shader(ps, w, shader);
+}
+
 /**
  * Update window opacity according to opacity rules.
  */
@@ -1134,6 +1169,7 @@ void win_on_factor_change(session_t *ps, struct managed_win *w) {
 	win_determine_invert_color(ps, w);
 	win_determine_blur_background(ps, w);
 	win_determine_rounded_corners(ps, w);
+	win_determine_fg_shader(ps, w);
 	w->mode = win_calc_mode(w);
 	log_debug("Window mode changed to %d", w->mode);
 	win_update_opacity_rule(ps, w);
@@ -1463,6 +1499,7 @@ struct win *fill_win(session_t *ps, struct win *w) {
 	    .prev_trans = NULL,
 	    .shadow = false,
 	    .clip_shadow_above = false,
+	    .fg_shader = NULL,
 	    .xinerama_scr = -1,
 	    .mode = WMODE_TRANS,
 	    .ever_damaged = false,
diff --git a/src/win.h b/src/win.h
index 6c6ae32..1039f52 100644
--- a/src/win.h
+++ b/src/win.h
@@ -209,7 +209,8 @@ struct managed_win {
 	/// Previous window opacity.
 	double opacity_target_old;
 	/// true if window (or client window, for broken window managers
-	/// not transferring client window's _NET_WM_WINDOW_OPACITY value) has opacity prop
+	/// not transferring client window's _NET_WM_WINDOW_OPACITY value) has opacity
+	/// prop
 	bool has_opacity_prop;
 	/// Cached value of opacity window attribute.
 	opacity_t opacity_prop;
@@ -270,6 +271,9 @@ struct managed_win {
 	/// Whether to blur window background.
 	bool blur_background;
 
+	/// The custom window shader to use when rendering.
+	struct shader_info *fg_shader;
+
 #ifdef CONFIG_OPENGL
 	/// Textures and FBO background blur use.
 	glx_blur_cache_t glx_blur_cache;