From 703ffbff927a864c18776a1a9412896bd3994ee2 Mon Sep 17 00:00:00 2001
From: Ricardo Cruz <rick2@aeiou.pt>
Date: Sat, 1 May 2004 10:59:52 +0000
Subject: [PATCH] First atempt to add a fade in/out function. Though, it
 doesn't work, dunno why in the Open GL mode. The SDL frontend doesn't seem to
 support alpha blittling whatsoever.

SVN-Revision: 883
---
 src/intro.cpp  |  3 +++
 src/screen.cpp | 41 +++++++++++++++++++++++++++++++++++++++++
 src/screen.h   |  2 ++
 3 files changed, 46 insertions(+)

diff --git a/src/intro.cpp b/src/intro.cpp
index b8a6c4f4d..708770b29 100644
--- a/src/intro.cpp
+++ b/src/intro.cpp
@@ -31,8 +31,11 @@
 #include "intro.h"
 #include "text.h"
 
+#include "screen.h"
+
 void draw_intro()
 {
+fade("/images/background/arctis2.jpg", 30, false);
 display_text_file("intro.txt", "/images/background/arctis2.jpg", SCROLL_SPEED_MESSAGE);
 }
 
diff --git a/src/screen.cpp b/src/screen.cpp
index d323c3f1c..bf9eb895b 100644
--- a/src/screen.cpp
+++ b/src/screen.cpp
@@ -95,6 +95,47 @@ void drawgradient(Color top_clr, Color bot_clr)
 #endif
 }
 
+/* --- FADE IN --- */
+
+/** Fades the given surface into a black one. If fade_out is true, it will fade out, else
+it will fade in */
+
+void fade(Surface *surface, int seconds, bool fade_out);
+
+void fade(const std::string& surface, int seconds, bool fade_out)
+{
+Surface* sur = new Surface(datadir + surface, IGNORE_ALPHA);
+black_fade(sur, seconds, fade_out);
+delete sur;
+}
+
+void fade(Surface *surface, int seconds, bool fade_out)
+{
+float alpha;
+if (fade_out)
+  alpha = 0;
+else
+  alpha = 255;
+
+  int cur_time, old_time;
+  cur_time = SDL_GetTicks();
+
+  while(alpha >= 0 && alpha < 256)
+    {
+    old_time = cur_time;
+    cur_time = SDL_GetTicks();
+
+    surface->draw(0,0,(int)alpha, true);
+
+    /* Calculate the next alpha value */
+    float calc = (float) ((cur_time - old_time) / seconds);
+    if(fade_out)
+      alpha += 255 * calc;
+    else
+      alpha -= 255 * calc;
+    }
+}
+
 /* 'Stolen' from the SDL documentation.
  * Set the pixel at (x, y) to the given value
  * NOTE: The surface must be locked before calling this!
diff --git a/src/screen.h b/src/screen.h
index 0b4496ed1..1193cb0d4 100644
--- a/src/screen.h
+++ b/src/screen.h
@@ -48,6 +48,8 @@ void drawline(int x1, int y1, int x2, int y2, int r, int g, int b, int a);
 void clearscreen(int r, int g, int b);
 void drawgradient(Color top_clr, Color bot_clr);
 void fillrect(float x, float y, float w, float h, int r, int g, int b, int a);
+//void black_fade(Surface* surface, int seconds, bool fade_out);
+void fade(const std::string& surface, int seconds, bool fade_out);
 void updatescreen(void);
 void flipscreen(void);
 void update_rect(SDL_Surface *scr, Sint32 x, Sint32 y, Sint32 w, Sint32 h);
-- 
2.11.0