From 86fe8aadfa4d4713fe1c38f49b39d66d317830ba Mon Sep 17 00:00:00 2001
From: plouj <plouj@b8c14938-b733-429d-887c-d66ed1f8cd15>
Date: Sun, 23 Dec 2007 01:00:59 +0000
Subject: [PATCH] drawing random pixels with random colour inside a program
 loop

git-svn-id: http://svn.plouj.com/repos/eraytracer@2 b8c14938-b733-429d-887c-d66ed1f8cd15
---
 raytracer.erl | 30 ++++++++++++++++++++++++++----
 1 file changed, 26 insertions(+), 4 deletions(-)

diff --git a/raytracer.erl b/raytracer.erl
index e986003..f890f56 100644
--- a/raytracer.erl
+++ b/raytracer.erl
@@ -2,6 +2,7 @@
 -include_lib("esdl/include/sdl.hrl").
 -include_lib("esdl/include/sdl_video.hrl").
 -include_lib("esdl/include/sdl_events.hrl").
+%-include_lib("/home/plouj/programming/sdl_util.hrl").
 -export([go/0]).
 
 go() ->
@@ -17,22 +18,43 @@ go(Config) ->
 		    ?SDL_ANYFORMAT bor ?SDL_RESIZABLE
 	    end,
     ScreenRef = sdl_video:setVideoMode(640, 480, 32, Flags),
+    sdl_video:wm_setCaption(["Erlang SDL"], []),
     %io:format("Video Driver Name: ~s~n", [sdl_video:videoDriverName()]),
     Screen=sdl_video:getSurface(ScreenRef),
     {R1, R2, R3} = erlang:now(),
     random:seed(R1, R2, R3),
-    main_loop(),
+%    sdl_video:fillRect(Screen, null, sdl_video:mapRGB(Screen, 0, 128, 255)),
+%    io:format("pixels: ~p~n", [sdl_video:getPixels(Screen,
+%						  #sdl_rect{x = 0, y = 0,
+%							   w = Screen#sdl_surface.w,
+%							   h = Screen#sdl_surface.h})]),
+    main_loop(Screen),
     timer:sleep(1000),
     sdl:quit().
 
-main_loop() ->
+main_loop(Screen) ->
     Event = sdl_events:pollEvent(),
 
     case Event of
 	{quit} ->
 	    done;
 	_Else ->
-	    timer:sleep(100),
-	    main_loop()
+	    putRandomPixel(Screen),
+	    sdl_video:flip(Screen),
+	    %timer:sleep(1),
+	    main_loop(Screen)
     end.
 
+putPixel(Surface, X, Y, {Red, Green, Blue}) ->
+    io:format("putting pixel ~w at ~w,~w~n",[{Red, Green, Blue}, X, Y]), 
+    %PixelFormat = sdl_video:getPixelFormat(Surface),
+    %OriginalPixels = sdl_video:getPixels(Surface),
+    sdl_video:fillRect(Surface,
+		       #sdl_rect{x = X, y = Y, w = 1, h = 1},
+		       sdl_video:mapRGB(Surface, Red, Green, Blue)).
+
+putRandomPixel(Surface) ->
+    putPixel(Surface,
+	     random:uniform(Surface#sdl_surface.w)-1,
+	     random:uniform(Surface#sdl_surface.h)-1,
+	     {random:uniform(256)-1, random:uniform(256)-1, random:uniform(256)-1}).
-- 
2.11.4.GIT