diff --git a/src/compositor.c b/src/compositor.c
index ba201afe..ab4c9706 100644
--- a/src/compositor.c
+++ b/src/compositor.c
@@ -225,9 +225,9 @@ weston_surface_create(struct weston_compositor *compositor)
 
 	surface->compositor = compositor;
 	surface->image = EGL_NO_IMAGE_KHR;
-	surface->alpha = 255;
-	surface->brightness = 255;
-	surface->saturation = 255;
+	surface->alpha = 1.0;
+	surface->brightness = 1.0;
+	surface->saturation = 1.0;
 	surface->blend = 1;
 	surface->opaque_rect[0] = 0.0;
 	surface->opaque_rect[1] = 0.0;
@@ -359,7 +359,7 @@ weston_surface_update_transform_disable(struct weston_surface *surface)
 				  surface->geometry.width,
 				  surface->geometry.height);
 
-	if (surface->alpha == 255) {
+	if (surface->alpha == 1.0) {
 		pixman_region32_copy(&surface->transform.opaque,
 				     &surface->opaque);
 		pixman_region32_translate(&surface->transform.opaque,
@@ -868,9 +868,9 @@ weston_surface_draw(struct weston_surface *es, struct weston_output *output,
 			   1, GL_FALSE, output->matrix.d);
 	glUniform1i(es->shader->tex_uniform, 0);
 	glUniform4fv(es->shader->color_uniform, 1, es->color);
-	glUniform1f(es->shader->alpha_uniform, es->alpha / 255.0);
-	glUniform1f(es->shader->brightness_uniform, es->brightness / 255.0);
-	glUniform1f(es->shader->saturation_uniform, es->saturation / 255.0);
+	glUniform1f(es->shader->alpha_uniform, es->alpha);
+	glUniform1f(es->shader->brightness_uniform, es->brightness);
+	glUniform1f(es->shader->saturation_uniform, es->saturation);
 	glUniform1f(es->shader->texwidth_uniform,
 		    (GLfloat)es->geometry.width / es->pitch);
 	glUniform4fv(es->shader->opaque_uniform, 1, es->opaque_rect);
diff --git a/src/compositor.h b/src/compositor.h
index 0ba51d78..32bccd25 100644
--- a/src/compositor.h
+++ b/src/compositor.h
@@ -333,9 +333,9 @@ struct weston_surface {
 	struct weston_shader *shader;
 	GLfloat color[4];
 	GLfloat opaque_rect[4];
-	uint32_t alpha;
-	uint32_t brightness;
-	uint32_t saturation;
+	GLfloat alpha;
+	GLfloat brightness;
+	GLfloat saturation;
 	int blend;
 
 	/* Surface geometry state, mutable.
diff --git a/src/shell.c b/src/shell.c
index 60f8643d..e23600d6 100644
--- a/src/shell.c
+++ b/src/shell.c
@@ -2398,11 +2398,11 @@ switcher_next(struct switcher *switcher)
 		      &switcher->listener);
 
 	switcher->current = next;
-	next->alpha = 255;
+	next->alpha = 1.0;
 
 	shsurf = get_shell_surface(switcher->current);
 	if (shsurf && shsurf->type ==SHELL_SURFACE_FULLSCREEN)
-		shsurf->fullscreen.black_surface->alpha = 255;
+		shsurf->fullscreen.black_surface->alpha = 1.0;
 }
 
 static void
@@ -2422,7 +2422,7 @@ switcher_destroy(struct switcher *switcher, uint32_t time)
 	struct wl_keyboard *keyboard = switcher->grab.keyboard;
 
 	wl_list_for_each(surface, &compositor->surface_list, link) {
-		surface->alpha = 255;
+		surface->alpha = 1.0;
 		weston_surface_damage(surface);
 	}
 
diff --git a/src/util.c b/src/util.c
index b06efd08..33dd7dbe 100644
--- a/src/util.c
+++ b/src/util.c
@@ -153,9 +153,9 @@ weston_zoom_frame(struct weston_animation *animation,
 				0.5f * es->geometry.width,
 				0.5f * es->geometry.height, 0);
 
-	es->alpha = zoom->spring.current * 255;
-	if (es->alpha > 255)
-		es->alpha = 255;
+	es->alpha = zoom->spring.current;
+	if (es->alpha > 1.0)
+		es->alpha = 1.0;
 
 	zoom->surface->geometry.dirty = 1;
 	weston_compositor_schedule_repaint(es->compositor);
@@ -375,7 +375,7 @@ weston_fade_frame(struct weston_animation *animation,
 		fade_factor = 0;
 	else
 		fade_factor = fade->spring.current;
-	es->alpha = fade_factor * 255;
+	es->alpha = fade_factor;
 
 	fade->surface->geometry.dirty = 1;
 	weston_compositor_schedule_repaint(es->compositor);