rootston: Add alpha channel to views

include/rootston/view.h

@@ -83,6 +83,7 @@ struct roots_view {
 	double x, y;
 	uint32_t width, height;
 	float rotation;
+	float alpha;
 
 	bool decorated;
 	int border_width;
@@ -94,6 +95,7 @@ struct roots_view {
 		double x, y;
 		uint32_t width, height;
 		float rotation;
+		float alpha;
 	} saved;
 
 	struct {
@@ -191,6 +193,7 @@ void view_maximize(struct roots_view *view, bool maximized);
 void view_set_fullscreen(struct roots_view *view, bool fullscreen,
 	struct wlr_output *output);
 void view_rotate(struct roots_view *view, float rotation);
+void view_cycle_alpha(struct roots_view *view);
 void view_close(struct roots_view *view);
 bool view_center(struct roots_view *view);
 void view_setup(struct roots_view *view);

rootston/desktop.c

@@ -25,6 +25,10 @@
 
 struct roots_view *view_create() {
 	struct roots_view *view = calloc(1, sizeof(struct roots_view));
+	if (!view) {
+		return NULL;
+	}
+	view->alpha = 1.0f;
 	return view;
 }
 

rootston/output.c

@@ -202,6 +202,7 @@ struct render_data {
 	struct roots_output *output;
 	struct timespec *when;
 	pixman_region32_t *damage;
+	float alpha;
 };
 
 /**
@@ -296,7 +297,7 @@ static void render_surface(struct wlr_surface *surface, double lx, double ly,
 	pixman_box32_t *rects = pixman_region32_rectangles(&damage, &nrects);
 	for (int i = 0; i < nrects; ++i) {
 		scissor_output(output, &rects[i]);
-		wlr_render_with_matrix(renderer, surface->texture, &matrix, 1.0f);
+		wlr_render_with_matrix(renderer, surface->texture, &matrix, data->alpha);
 	}
 
 damage_finish:
@@ -376,6 +377,7 @@ static void render_view(struct roots_view *view, struct render_data *data) {
 		return;
 	}
 
+	data->alpha = view->alpha;
 	render_decorations(view, data);
 	view_for_each_surface(view, render_surface, data);
 }