viewport: add a way to access front and back buffers.

3 files changed, 10 insertions, 2 deletions

diff --git a/graphics.h b/graphics.h
index f109be3..b523c2b 100644
--- a/graphics.h
+++ b/graphics.h
@@ -216,6 +216,7 @@ struct Viewport
 	void (*draw)(Viewport*, Image*);
 	void (*memdraw)(Viewport*, Memimage*);
 	Framebuf *(*getfb)(Viewport*);
+	Framebuf *(*getbb)(Viewport*);
 };
 
 struct Camera
diff --git a/render.c b/render.c
index 6be8179..bef319e 100644
--- a/render.c
+++ b/render.c
@@ -527,7 +527,7 @@ sendparams:
 			if(ent != nil && ent != &sc->ents){
 				params = emalloc(sizeof *params);
 				memset(params, 0, sizeof *params);
-				params->fb = job->v->getfb(job->v);
+				params->fb = job->v->getbb(job->v);
 				params->id = job->lastid++;
 				params->frag = rgb(DBlack);
 				params->donec = donec;
diff --git a/viewport.c b/viewport.c
index 2089d50..7f963a8 100644
--- a/viewport.c
+++ b/viewport.c
@@ -23,7 +23,13 @@ viewport_memdraw(Viewport *v, Memimage *dst)
 static Framebuf *
 viewport_getfb(Viewport *v)
 {
-	return v->fbctl->fb[v->fbctl->idx^1];	/* address the back buffer */
+	return v->fbctl->fb[v->fbctl->idx];	/* front buffer */
+}
+
+static Framebuf *
+viewport_getbb(Viewport *v)
+{
+	return v->fbctl->fb[v->fbctl->idx^1];	/* back buffer */
 }
 
 Viewport *
@@ -39,6 +45,7 @@ mkviewport(Rectangle r)
 	v->draw = viewport_draw;
 	v->memdraw = viewport_memdraw;
 	v->getfb = viewport_getfb;
+	v->getbb = viewport_getbb;
 	return v;
 }