From ef5e3186c624ba89dfadfedd09672482bd901f22 Mon Sep 17 00:00:00 2001
From: malc <moosotc@gmail.com>
Date: Sun, 20 Dec 2015 19:57:03 +0300
Subject: [PATCH] Manual buffer clears

On this hardware/software combination glClear is evidently rather
power taxing. The effect is not noticeable when measuring system load
in the usual way but RAPL readings (and/or external wattmeter) tell
different story - glClear is not free. More investigation is required
though, for now just clear parts of the buffer manually, and only in
single column mode, hopefully "not this" systems wouldn't suffer.
---
 main.ml | 35 +++++++++++++++++++++++++++++++----
 1 file changed, 31 insertions(+), 4 deletions(-)

diff --git a/main.ml b/main.ml
index a49c675..1a5103f 100644
--- a/main.ml
+++ b/main.ml
@@ -627,11 +627,15 @@ let puttileopaque l col row gen colorspace angle opaque size elapsed =
   Hashtbl.add state.tilemap key (opaque, size, elapsed)
 ;;
 
-let filledrect x0 y0 x1 y1 =
-  GlArray.disable `texture_coord;
+let filledrect1 x0 y0 x1 y1 =
   Raw.sets_float state.vraw ~pos:0 [| x0; y0; x0; y1; x1; y0; x1; y1 |];
   GlArray.vertex `two state.vraw;
   GlArray.draw_arrays `triangle_strip ~first:0 ~count:4;
+;;
+
+let filledrect x0 y0 x1 y1 =
+  GlArray.disable `texture_coord;
+  filledrect1 x0 y0 x1 y1;
   GlArray.enable `texture_coord;
 ;;
 
@@ -5544,8 +5548,31 @@ let showrects = function [] -> () | rects ->
 ;;
 
 let display () =
-  GlClear.color (scalecolor2 conf.bgcolor);
-  GlClear.clear [`color];
+  begin match conf.columns, state.layout with
+  | Csingle _, _ :: _ ->
+     GlDraw.color (scalecolor2 conf.bgcolor);
+     List.fold_left (fun y l ->
+         let x0 = 0 in
+         let y0 = y in
+         let x1 = l.pagedispx + xadjsb () in
+         let y1 = (l.pagedispy + l.pagevh) in
+         filledrect (float x0) (float y0) (float x1) (float y1);
+         let x0 = x1 + l.pagevw in
+         let x1 = state.winw in
+         filledrect1 (float x0) (float y0) (float x1) (float y1);
+         if y != l.pagedispy
+         then (
+           let x0 = 0
+           and x1 = state.winw in
+           let y0 = y
+           and y1 = l.pagedispy in
+           filledrect1 (float x0) (float y0) (float x1) (float y1);
+         );
+         l.pagedispy + l.pagevh) 0 state.layout |> ignore
+  | (Cmulti _ | Csplit _), _ | Csingle _, [] ->
+     GlClear.color (scalecolor2 conf.bgcolor);
+     GlClear.clear [`color];
+  end;
   List.iter drawpage state.layout;
   let rects =
     match state.mode with
-- 
2.11.4.GIT