From 175851eef7a3af3e29f5ff9fda9a8caf7d435304 Mon Sep 17 00:00:00 2001 From: Georges Basile Stavracas Neto Date: Fri, 9 Oct 2020 15:54:18 -0300 Subject: [PATCH] clutter/stage: Simplify view setup ClutterStage defines the 8 vertices of a frustum: 4 ----------------------------- 5 | \ / | | \ / | | 0 --------------------- 1 | | | | | | | | | | 3 --------------------- 2 | | / \ | | / \ | 7 ----------------------------- 6 Then, it uses triplets of vertices to create each clipping plane. It only sets up 4 planes (it doesn't clip based on depth), defined by the following vertices: * 0 - 4 - 5 * 1 - 5 - 6 * 2 - 6 - 7 * 0 - 7 - 4 The first 3 triplets are selected using the for-loop. However, the last triplet is different, and is done out of the loop. It could have been made simpler by using the "3 - 7 - 4" triplet. Simplify the current code by using the suggested triplet, calculated inside the for-loop. https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1489 --- clutter/clutter/clutter-stage.c | 22 ++-------------------- 1 file changed, 2 insertions(+), 20 deletions(-) diff --git a/clutter/clutter/clutter-stage.c b/clutter/clutter/clutter-stage.c index 00335f07e..184bbee07 100644 --- a/clutter/clutter/clutter-stage.c +++ b/clutter/clutter/clutter-stage.c @@ -674,7 +674,6 @@ _cogl_util_get_eye_planes_for_screen_poly (float *polygon, graphene_vec3_t b; graphene_vec3_t c; float zw, ww; - int count; tmp_poly = g_alloca (sizeof (Vector4) * n_vertices * 2); @@ -738,8 +737,7 @@ _cogl_util_get_eye_planes_for_screen_poly (float *polygon, * cogl_vector APIs just took pointers to floats. */ - count = n_vertices - 1; - for (i = 0; i < count; i++) + for (i = 0; i < n_vertices; i++) { plane = &planes[i]; @@ -749,7 +747,7 @@ _cogl_util_get_eye_planes_for_screen_poly (float *polygon, poly = &tmp_poly[n_vertices + i]; graphene_vec3_init (&b, poly->x, poly->y, poly->z); - poly = &tmp_poly[n_vertices + i + 1]; + poly = &tmp_poly[n_vertices + ((i + 1) % n_vertices)]; graphene_vec3_init (&c, poly->x, poly->y, poly->z); graphene_vec3_subtract (&b, &plane->v0, &b); @@ -757,22 +755,6 @@ _cogl_util_get_eye_planes_for_screen_poly (float *polygon, graphene_vec3_cross (&b, &c, &plane->n); graphene_vec3_normalize (&plane->n, &plane->n); } - - plane = &planes[n_vertices - 1]; - - poly = &tmp_poly[0]; - graphene_vec3_init (&plane->v0, poly->x, poly->y, poly->z); - - poly = &tmp_poly[2 * n_vertices - 1]; - graphene_vec3_init (&b, poly->x, poly->y, poly->z); - - poly = &tmp_poly[n_vertices]; - graphene_vec3_init (&c, poly->x, poly->y, poly->z); - - graphene_vec3_subtract (&b, &plane->v0, &b); - graphene_vec3_subtract (&c, &plane->v0, &c); - graphene_vec3_cross (&b, &c, &plane->n); - graphene_vec3_normalize (&plane->n, &plane->n); } /* XXX: Instead of having a toplevel 2D clip region, it might be