From e6ca78b0e4b81e02958628c4b3b4db911b51714b Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Guido=20G=C3=BCnther?= <agx@sigxcpu.org>
Date: Fri, 23 Feb 2018 11:50:09 +0100
Subject: [PATCH 1/5] rootston: add view_create

so we can do basic view setup. Will be used to initialize alpha.
---
 include/rootston/view.h | 1 +
 rootston/desktop.c      | 6 ++++++
 rootston/wl_shell.c     | 2 +-
 rootston/xdg_shell.c    | 2 +-
 rootston/xdg_shell_v6.c | 2 +-
 rootston/xwayland.c     | 2 +-
 6 files changed, 11 insertions(+), 4 deletions(-)

diff --git a/include/rootston/view.h b/include/rootston/view.h
index 198086c1..c92cbcb1 100644
--- a/include/rootston/view.h
+++ b/include/rootston/view.h
@@ -180,6 +180,7 @@ struct roots_xdg_popup {
 	struct wl_listener new_popup;
 };
 
+struct roots_view *view_create();
 void view_get_box(const struct roots_view *view, struct wlr_box *box);
 void view_activate(struct roots_view *view, bool active);
 void view_move(struct roots_view *view, double x, double y);
diff --git a/rootston/desktop.c b/rootston/desktop.c
index 6b28a41c..57e2d54b 100644
--- a/rootston/desktop.c
+++ b/rootston/desktop.c
@@ -22,6 +22,12 @@
 #include "rootston/view.h"
 #include "rootston/xcursor.h"
 
+
+struct roots_view *view_create() {
+	struct roots_view *view = calloc(1, sizeof(struct roots_view));
+	return view;
+}
+
 void view_get_box(const struct roots_view *view, struct wlr_box *box) {
 	box->x = view->x;
 	box->y = view->y;
diff --git a/rootston/wl_shell.c b/rootston/wl_shell.c
index 44a65cf5..899df1c6 100644
--- a/rootston/wl_shell.c
+++ b/rootston/wl_shell.c
@@ -227,7 +227,7 @@ void handle_wl_shell_surface(struct wl_listener *listener, void *data) {
 	roots_surface->surface_commit.notify = handle_surface_commit;
 	wl_signal_add(&surface->surface->events.commit, &roots_surface->surface_commit);
 
-	struct roots_view *view = calloc(1, sizeof(struct roots_view));
+	struct roots_view *view = view_create();
 	if (!view) {
 		free(roots_surface);
 		return;
diff --git a/rootston/xdg_shell.c b/rootston/xdg_shell.c
index 8340de46..9368ce0b 100644
--- a/rootston/xdg_shell.c
+++ b/rootston/xdg_shell.c
@@ -333,7 +333,7 @@ void handle_xdg_shell_surface(struct wl_listener *listener, void *data) {
 	roots_surface->new_popup.notify = handle_new_popup;
 	wl_signal_add(&surface->events.new_popup, &roots_surface->new_popup);
 
-	struct roots_view *view = calloc(1, sizeof(struct roots_view));
+	struct roots_view *view = view_create();
 	if (!view) {
 		free(roots_surface);
 		return;
diff --git a/rootston/xdg_shell_v6.c b/rootston/xdg_shell_v6.c
index 8e6674ab..eda349cb 100644
--- a/rootston/xdg_shell_v6.c
+++ b/rootston/xdg_shell_v6.c
@@ -333,7 +333,7 @@ void handle_xdg_shell_v6_surface(struct wl_listener *listener, void *data) {
 	roots_surface->new_popup.notify = handle_new_popup;
 	wl_signal_add(&surface->events.new_popup, &roots_surface->new_popup);
 
-	struct roots_view *view = calloc(1, sizeof(struct roots_view));
+	struct roots_view *view = view_create();
 	if (!view) {
 		free(roots_surface);
 		return;
diff --git a/rootston/xwayland.c b/rootston/xwayland.c
index e9e0d5e0..f917fe5d 100644
--- a/rootston/xwayland.c
+++ b/rootston/xwayland.c
@@ -317,7 +317,7 @@ void handle_xwayland_surface(struct wl_listener *listener, void *data) {
 	wl_signal_add(&surface->surface->events.commit,
 		&roots_surface->surface_commit);
 
-	struct roots_view *view = calloc(1, sizeof(struct roots_view));
+	struct roots_view *view = view_create();
 	if (view == NULL) {
 		free(roots_surface);
 		return;

From d08792bfffc6b7b28f59d7ee100091805367b7fa Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Guido=20G=C3=BCnther?= <agx@sigxcpu.org>
Date: Wed, 21 Feb 2018 23:20:09 +0100
Subject: [PATCH 2/5] Add alpha to wlr_render_with_matrix

so we can use the alpha channel to e.g. blend in textures
---
 backend/drm/drm.c              | 2 +-
 backend/drm/renderer.c         | 2 +-
 examples/output-layout.c       | 2 +-
 examples/rotation.c            | 2 +-
 examples/touch.c               | 2 +-
 include/wlr/render.h           | 7 ++++---
 include/wlr/render/interface.h | 2 +-
 render/gles2/renderer.c        | 6 +++---
 render/wlr_renderer.c          | 4 ++--
 rootston/output.c              | 2 +-
 types/wlr_output.c             | 4 ++--
 11 files changed, 18 insertions(+), 17 deletions(-)

diff --git a/backend/drm/drm.c b/backend/drm/drm.c
index e60b7e1c..b2863414 100644
--- a/backend/drm/drm.c
+++ b/backend/drm/drm.c
@@ -647,7 +647,7 @@ static bool wlr_drm_connector_set_cursor(struct wlr_output *output,
 	float matrix[16];
 	wlr_texture_get_matrix(plane->wlr_tex, &matrix, &plane->matrix, 0, 0);
 	wlr_render_with_matrix(plane->surf.renderer->wlr_rend, plane->wlr_tex,
-		&matrix);
+		&matrix, 1.0f);
 
 	glFinish();
 	glPixelStorei(GL_UNPACK_ROW_LENGTH_EXT, bo_stride);
diff --git a/backend/drm/renderer.c b/backend/drm/renderer.c
index f3e570f7..7ee13843 100644
--- a/backend/drm/renderer.c
+++ b/backend/drm/renderer.c
@@ -239,7 +239,7 @@ struct gbm_bo *wlr_drm_surface_mgpu_copy(struct wlr_drm_surface *dest,
 	glViewport(0, 0, dest->width, dest->height);
 	glClearColor(0.0, 0.0, 0.0, 1.0);
 	glClear(GL_COLOR_BUFFER_BIT);
-	wlr_render_with_matrix(dest->renderer->wlr_rend, tex, &matrix);
+	wlr_render_with_matrix(dest->renderer->wlr_rend, tex, &matrix, 1.0f);
 
 	return wlr_drm_surface_swap_buffers(dest, NULL);
 }
diff --git a/examples/output-layout.c b/examples/output-layout.c
index 91ab80f4..45257be9 100644
--- a/examples/output-layout.c
+++ b/examples/output-layout.c
@@ -122,7 +122,7 @@ static void handle_output_frame(struct output_state *output,
 		wlr_texture_get_matrix(sample->cat_texture, &matrix,
 			&wlr_output->transform_matrix, local_x, local_y);
 		wlr_render_with_matrix(sample->renderer,
-			sample->cat_texture, &matrix);
+			sample->cat_texture, &matrix, 1.0f);
 	}
 
 	wlr_renderer_end(sample->renderer);
diff --git a/examples/rotation.c b/examples/rotation.c
index e390daaf..1158ccc4 100644
--- a/examples/rotation.c
+++ b/examples/rotation.c
@@ -52,7 +52,7 @@ static void handle_output_frame(struct output_state *output, struct timespec *ts
 			wlr_texture_get_matrix(sample->cat_texture, &matrix,
 				&wlr_output->transform_matrix, x, y);
 			wlr_render_with_matrix(sample->renderer,
-					sample->cat_texture, &matrix);
+					sample->cat_texture, &matrix, 1.0f);
 		}
 	}
 
diff --git a/examples/touch.c b/examples/touch.c
index 3cf00e9c..278252cc 100644
--- a/examples/touch.c
+++ b/examples/touch.c
@@ -53,7 +53,7 @@ static void handle_output_frame(struct output_state *output, struct timespec *ts
 			(int)(p->x * width) - sample->cat_texture->width / 2,
 			(int)(p->y * height) - sample->cat_texture->height / 2);
 		wlr_render_with_matrix(sample->renderer,
-			sample->cat_texture, &matrix);
+			sample->cat_texture, &matrix, 1.0f);
 	}
 
 	wlr_renderer_end(sample->renderer);
diff --git a/include/wlr/render.h b/include/wlr/render.h
index 3743482b..747603da 100644
--- a/include/wlr/render.h
+++ b/include/wlr/render.h
@@ -33,12 +33,13 @@ struct wlr_texture *wlr_render_texture_create(struct wlr_renderer *r);
  * 	float projection[16];
  * 	float matrix[16];
  * 	wlr_texture_get_matrix(texture, &matrix, &projection, 123, 321);
- * 	wlr_render_with_matrix(renderer, texture, &matrix);
+ * 	wlr_render_with_matrix(renderer, texture, &matrix, 0.5f);
  *
- * This will render the texture at <123, 321>.
+ * This will render the texture at <123, 321> with an alpha channel of 0.5.
  */
 bool wlr_render_with_matrix(struct wlr_renderer *r,
-	struct wlr_texture *texture, const float (*matrix)[16]);
+	struct wlr_texture *texture, const float (*matrix)[16], float alpha);
+
 /**
  * Renders a solid quad in the specified color.
  */
diff --git a/include/wlr/render/interface.h b/include/wlr/render/interface.h
index b989e399..eda5af1c 100644
--- a/include/wlr/render/interface.h
+++ b/include/wlr/render/interface.h
@@ -22,7 +22,7 @@ struct wlr_renderer_impl {
 	void (*scissor)(struct wlr_renderer *renderer, struct wlr_box *box);
 	struct wlr_texture *(*texture_create)(struct wlr_renderer *renderer);
 	bool (*render_with_matrix)(struct wlr_renderer *renderer,
-		struct wlr_texture *texture, const float (*matrix)[16]);
+		struct wlr_texture *texture, const float (*matrix)[16], float alpha);
 	void (*render_quad)(struct wlr_renderer *renderer,
 		const float (*color)[4], const float (*matrix)[16]);
 	void (*render_ellipse)(struct wlr_renderer *renderer,
diff --git a/render/gles2/renderer.c b/render/gles2/renderer.c
index 81a932e6..ad739cf8 100644
--- a/render/gles2/renderer.c
+++ b/render/gles2/renderer.c
@@ -171,7 +171,7 @@ static void draw_quad() {
 }
 
 static bool wlr_gles2_render_texture(struct wlr_renderer *wlr_renderer,
-		struct wlr_texture *texture, const float (*matrix)[16]) {
+		struct wlr_texture *texture, const float (*matrix)[16], float alpha) {
 	if (!texture || !texture->valid) {
 		wlr_log(L_ERROR, "attempt to render invalid texture");
 		return false;
@@ -179,12 +179,12 @@ static bool wlr_gles2_render_texture(struct wlr_renderer *wlr_renderer,
 
 	wlr_texture_bind(texture);
 	GL_CALL(glUniformMatrix4fv(0, 1, GL_FALSE, *matrix));
-	// TODO: source alpha from somewhere else I guess
-	GL_CALL(glUniform1f(2, 1.0f));
+	GL_CALL(glUniform1f(2, alpha));
 	draw_quad();
 	return true;
 }
 
+
 static void wlr_gles2_render_quad(struct wlr_renderer *wlr_renderer,
 		const float (*color)[4], const float (*matrix)[16]) {
 	GL_CALL(glUseProgram(shaders.quad));
diff --git a/render/wlr_renderer.c b/render/wlr_renderer.c
index fa6c6fc3..ce8fbe36 100644
--- a/render/wlr_renderer.c
+++ b/render/wlr_renderer.c
@@ -36,8 +36,8 @@ struct wlr_texture *wlr_render_texture_create(struct wlr_renderer *r) {
 }
 
 bool wlr_render_with_matrix(struct wlr_renderer *r,
-		struct wlr_texture *texture, const float (*matrix)[16]) {
-	return r->impl->render_with_matrix(r, texture, matrix);
+		struct wlr_texture *texture, const float (*matrix)[16], float alpha) {
+	return r->impl->render_with_matrix(r, texture, matrix, alpha);
 }
 
 void wlr_render_colored_quad(struct wlr_renderer *r,
diff --git a/rootston/output.c b/rootston/output.c
index a354ebf8..3fc8ea84 100644
--- a/rootston/output.c
+++ b/rootston/output.c
@@ -296,7 +296,7 @@ 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);
+		wlr_render_with_matrix(renderer, surface->texture, &matrix, 1.0f);
 	}
 
 damage_finish:
diff --git a/types/wlr_output.c b/types/wlr_output.c
index 809b1959..5a2886c7 100644
--- a/types/wlr_output.c
+++ b/types/wlr_output.c
@@ -391,7 +391,7 @@ static void output_fullscreen_surface_render(struct wlr_output *output,
 	for (int i = 0; i < nrects; ++i) {
 		output_scissor(output, &rects[i]);
 		wlr_renderer_clear(renderer, &(float[]){0, 0, 0, 0});
-		wlr_render_with_matrix(surface->renderer, surface->texture, &matrix);
+		wlr_render_with_matrix(surface->renderer, surface->texture, &matrix, 1.0f);
 	}
 	wlr_renderer_scissor(renderer, NULL);
 
@@ -448,7 +448,7 @@ static void output_cursor_render(struct wlr_output_cursor *cursor,
 	pixman_box32_t *rects = pixman_region32_rectangles(&surface_damage, &nrects);
 	for (int i = 0; i < nrects; ++i) {
 		output_scissor(cursor->output, &rects[i]);
-		wlr_render_with_matrix(renderer, texture, &matrix);
+		wlr_render_with_matrix(renderer, texture, &matrix, 1.0f);
 	}
 	wlr_renderer_scissor(renderer, NULL);
 

From e2ea1ebe48db25f7372bbab21bc66cde5934895b Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Guido=20G=C3=BCnther?= <agx@sigxcpu.org>
Date: Fri, 23 Feb 2018 11:30:55 +0100
Subject: [PATCH 3/5] rootston: Add alpha channel to views

---
 include/rootston/view.h | 3 +++
 rootston/desktop.c      | 4 ++++
 rootston/output.c       | 4 +++-
 3 files changed, 10 insertions(+), 1 deletion(-)

diff --git a/include/rootston/view.h b/include/rootston/view.h
index c92cbcb1..7464edc5 100644
--- a/include/rootston/view.h
+++ b/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);
diff --git a/rootston/desktop.c b/rootston/desktop.c
index 57e2d54b..9d5cd2fa 100644
--- a/rootston/desktop.c
+++ b/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;
 }
 
diff --git a/rootston/output.c b/rootston/output.c
index 3fc8ea84..8d968a98 100644
--- a/rootston/output.c
+++ b/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);
 }

From 9864f1c1361c196b33f524d917d7b5e5e10b0959 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Guido=20G=C3=BCnther?= <agx@sigxcpu.org>
Date: Fri, 23 Feb 2018 11:51:30 +0100
Subject: [PATCH 4/5] rootston: wire up window alpha keybinding

---
 rootston/desktop.c            | 9 +++++++++
 rootston/keyboard.c           | 5 +++++
 rootston/rootston.ini.example | 2 ++
 3 files changed, 16 insertions(+)

diff --git a/rootston/desktop.c b/rootston/desktop.c
index 9d5cd2fa..ee0172e4 100644
--- a/rootston/desktop.c
+++ b/rootston/desktop.c
@@ -278,6 +278,15 @@ void view_rotate(struct roots_view *view, float rotation) {
 	view_damage_whole(view);
 }
 
+void view_cycle_alpha(struct roots_view *view) {
+	view->alpha -= 0.05;
+	/* Don't go completely transparent */
+	if (view->alpha < 0.1) {
+		view->alpha = 1.0;
+	}
+	view_damage_whole(view);
+}
+
 void view_close(struct roots_view *view) {
 	if (view->close) {
 		view->close(view);
diff --git a/rootston/keyboard.c b/rootston/keyboard.c
index 6ec90c31..b5dac51c 100644
--- a/rootston/keyboard.c
+++ b/rootston/keyboard.c
@@ -106,6 +106,11 @@ static void keyboard_binding_execute(struct roots_keyboard *keyboard,
 		}
 	} else if (strcmp(command, "next_window") == 0) {
 		roots_seat_cycle_focus(seat);
+	} else if (strcmp(command, "alpha") == 0) {
+		struct roots_view *focus = roots_seat_get_focus(seat);
+		if (focus != NULL) {
+			view_cycle_alpha(focus);
+		}
 	} else if (strncmp(exec_prefix, command, strlen(exec_prefix)) == 0) {
 		const char *shell_cmd = command + strlen(exec_prefix);
 		pid_t pid = fork();
diff --git a/rootston/rootston.ini.example b/rootston/rootston.ini.example
index a6619767..6f29a35d 100644
--- a/rootston/rootston.ini.example
+++ b/rootston/rootston.ini.example
@@ -42,8 +42,10 @@ meta-key = Logo
 # - "exec" to execute a shell command
 # - "close" to close the current view
 # - "next_window" to cycle through windows
+# - "alpha" to cycle a window's alpha channel
 [bindings]
 Logo+Shift+e = exit
 Logo+q = close
 Logo+m = maximize
 Alt+Tab = next_window
+Ctrl+Shift+a = alpha

From 202a728ee9a0e7dbfbcc7e51e060a2a9a5f09847 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Guido=20G=C3=BCnther?= <agx@sigxcpu.org>
Date: Sun, 25 Feb 2018 14:58:30 +0100
Subject: [PATCH 5/5] rootstion: handle alpha in server side decorations

---
 rootston/output.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/rootston/output.c b/rootston/output.c
index 8d968a98..3e954989 100644
--- a/rootston/output.c
+++ b/rootston/output.c
@@ -356,7 +356,7 @@ static void render_decorations(struct roots_view *view,
 	float matrix[16];
 	wlr_matrix_project_box(&matrix, &box, WL_OUTPUT_TRANSFORM_NORMAL,
 		view->rotation, &output->wlr_output->transform_matrix);
-	float color[] = { 0.2, 0.2, 0.2, 1 };
+	float color[] = { 0.2, 0.2, 0.2, view->alpha };
 
 	int nrects;
 	pixman_box32_t *rects =