From 5f118170abe44af5383e897b207e85a5870a22c4 Mon Sep 17 00:00:00 2001
From: gewlitys <gewlitys@8092fc87-c524-0410-9efc-e669fe64eaf9>
Date: Tue, 3 Dec 2002 20:59:35 +0000
Subject: [PATCH] Slayne's pixel-perfect collision detection patch

git-svn-id: svn://svn.code.sf.net/p/sc2/code/trunk@304 8092fc87-c524-0410-9efc-e669fe64eaf9
---
 sc2/ChangeLog                                 |  1 +
 sc2/TODO                                      |  8 ----
 sc2/src/sc2code/libs/graphics/sdl/3do_funcs.c | 41 +++++++++++++++++--
 3 files changed, 38 insertions(+), 12 deletions(-)

diff --git a/sc2/ChangeLog b/sc2/ChangeLog
index 7cb5ebb67..c4180d093 100644
--- a/sc2/ChangeLog
+++ b/sc2/ChangeLog
@@ -1,4 +1,5 @@
 0.2:
+- Collision detection is now pixel-perfect (fixes Sa-Matra, BUTT missile, etc)
 - Fixed lander position sign bug which was introduced by previous fixes
 - Initial display of planet surface on landing is at correct position
 - Planet scan is now properly erased when cancelling/landing
diff --git a/sc2/TODO b/sc2/TODO
index b678ae366..b17bda9d3 100644
--- a/sc2/TODO
+++ b/sc2/TODO
@@ -157,13 +157,6 @@ Stuff still to do (large):
 Stuff still to do (medium size):
 - oscilloscope
 - loading teams in melee
-- pixel-perfect collision checks
-  Currently bounding boxes are used for checks, causing (among others)
-  Spathi and Mycon to frequently hit themselves, and making the Sa-Matra
-  indestructable.
-- remove libtool dependancy
-  This will probably mean the empty dummy.c files can be removed too.
-  (note that src/sc2code/dummy.c DOES contain data)
 - lines and colouring of planet surface display when scanning.
   Its speed isn't correct either.
 - get all code to compile without warnings, when the most strict
@@ -192,7 +185,6 @@ Stuff still to do (small):
 - add some icon in the cvs tree
 
 Questions:
-- remove src/sc2code/test.c?
 - Is there some way to automatically do CRLF translations on commits,
   with the -t and -f options in cvswrapper disabled by sourceforge?
 - What is the displist stuff for? Is it needed at all?
diff --git a/sc2/src/sc2code/libs/graphics/sdl/3do_funcs.c b/sc2/src/sc2code/libs/graphics/sdl/3do_funcs.c
index 2c3c9562f..3557e6f6b 100644
--- a/sc2/src/sc2code/libs/graphics/sdl/3do_funcs.c
+++ b/sc2/src/sc2code/libs/graphics/sdl/3do_funcs.c
@@ -21,6 +21,7 @@
 #include "sdl_common.h"
 #include "pure.h"
 #include "opengl.h"
+#include "primitives.h"
 
 int batch_depth = 0;
 static const BOOLEAN pausing_transition = TRUE; // change to FALSE for non-pausing version
@@ -297,15 +298,47 @@ _init_video_file(PVOID pStr)
 	return (ret);
 }
 
-// Status: Unimplemented
+// Status: Implemented
 BOOLEAN
 _image_intersect (PIMAGE_BOX box1, PIMAGE_BOX box2, PRECT rect)
-		// This is a biggie.
 {
 	BOOLEAN ret;
+	SDL_Surface *img1, *img2;
+	int img1w, img1xpos, img1ypos, img2w, img2xpos, img2ypos;
+	int x,y;
+	Uint32 img1colourkey, img2colourkey;
+	GetPixelFn getpixel1, getpixel2;
+
+	/* Image is (TFB_IMAGE*)(box1->FramePtr + box1->FramePtr->DataOffs) */
+	img1 = ((TFB_Image*)((BYTE*)(box1->FramePtr) + box1->FramePtr->DataOffs))->NormalImg;
+	img2 = ((TFB_Image*)((BYTE*)(box2->FramePtr) + box2->FramePtr->DataOffs))->NormalImg;
+	
+	getpixel1 = getpixel_for(img1);
+	getpixel2 = getpixel_for(img2);
+
+	img1w = img1->w;
+	img1xpos = box1->Box.corner.x;
+	img1ypos = box1->Box.corner.y;
+	img1colourkey = img1->format->colorkey;
+
+	img2w = img2->w;
+	img2xpos = box2->Box.corner.x;
+	img2ypos = box2->Box.corner.y;
+	img2colourkey = img2->format->colorkey;
+
+	for (y = rect->corner.y; y < rect->corner.y + rect->extent.height; ++y)
+	{
+		for (x = rect->corner.x; x < rect->corner.x + rect->extent.width; ++x)
+		{
+			if ((getpixel1(img1, x - img1xpos, y - img1ypos) != img1colourkey) &&
+					(getpixel2(img2, x - img2xpos, y - img2ypos) != img2colourkey))
+			{
+				return TRUE;
+			}
+		}
+	}
+	ret = FALSE;
 
-// fprintf (stderr, "Unimplemented function activated: _image_intersect()\n");
-	ret = TRUE;
 	return (ret);
 }