Development checkin

4 files changed, 130 insertions, 19 deletions

diff --git a/BUILD b/BUILD
index d5a19b5..eb26ee9 100644
--- a/BUILD
+++ b/BUILD
@@ -7,7 +7,7 @@ grav has the following dependencies:
 To build grav:
 
 $ cd grav
-$ make depend
+$ ./configure
 $ make
 
 This will generate the executable, grav.  See INSTRUCTIONS for instructions on
@@ -23,5 +23,3 @@ directory.
     * SDL 1.2
     * SDL Image
     * OpenGL
-
-
diff --git a/config/config b/config/config
index 08a7a4a..288fdb8 100644
--- a/config/config
+++ b/config/config
@@ -10,23 +10,43 @@
 #
 
 
-# This defines any textures to load, and the names applied to them.  Any image
-# format supported by SDL Image should be loadable.
+# This defines the GFX driver.  If left undefined then the data generated is
+# simply dumped to stdout.
 #
-[textures]
-example1 = files/file.png
-example2 = files/file.png
+# Drivers can have their own personal configuration section elsewhere.
+#
+[gfx]
+driver		= drivers/sdl-gl.so
 
 
-# This enables or disables various graphical effects.  The defaults for the
-# effects are given here.
+# Example driver configuration.
 #
-[gfx]
-trails = yes
+[sdl-gl]
+width		= 800
+height		= 600
+fullscreen	= yes
 
 
-# This defines the bodies that will be placed in the simulation.
+# This defines any textures to load, and the names applied to them.  Supported
+# image formats will depend on the loaded GFX driver.
+#
+[textures]
+example1	= files/file.png
+example2	= files/file.png
+
+
+# This defines the bodies that will be placed in the simulation and the
+# constants for this universe.
+#
+# For this simulation the force acting on mass m1 from mass m2 is calculated
+# as: 
+#
+#	F = G x (m2 / r^2)
+#
+# This force is a vector, which normalised is the equivalent of one of the
+# co-ordinate axes discrete values in a single step of the simulation.
 #
 [universe]
-body = sun
-body = planet
+G		= 1
+body		= sun
+body		= planet
diff --git a/driver/BUILD b/driver/BUILD
index ae16a7a..84b11e6 100644
--- a/driver/BUILD
+++ b/driver/BUILD
@@ -1,7 +1,9 @@
 
-The following display drivers are available:
+Following are the build instructions for each individual driver.
 
-SDL-GL	[NOT YET AVAILABLE]
+============================================================================
+
+SDL-GL	[NOT YET COMPLETE]
 
     Displays using OpenGL and SDL.  Require the following:
 
@@ -12,7 +14,7 @@ SDL-GL	[NOT YET AVAILABLE]
     To make:
 
     	$ cd sdl-gl
-	$ make depend
+	$ ./configure
 	$ make
 
-    This generates sdl-gl.so
+    This generates a sharable object for sdl-gl.
diff --git a/include/graviface.h b/include/graviface.h
new file mode 100644
index 0000000..9e422fa
--- /dev/null
+++ b/include/graviface.h
@@ -0,0 +1,91 @@
+/*
+   grav - N-body gravity simulation
+
+   Copyright (C) 2011  Ian Cowburn <ianc@noddybox.co.uk>
+   
+   This program is free software: you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation, either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.
+  
+   $Id$
+
+   This file provides a common interface shared between the core grav
+   program and the GFX drivers.
+*/
+
+#ifndef GRAV_GRAVIFACE_H
+#define GRAV_GRAVIFACE_H "$Id$"
+
+#include <mp.h>
+
+
+/* ---------------------------------------------------------------------------
+   This determinate the version of the interface, so both sides can
+   check they were built with the same interface.
+*/
+#define GRAV_INTERFACE_VERSION	1
+
+
+/* ---------------------------------------------------------------------------
+   This type defines an instance of any data that the driver needs to maintain.
+   As the drivers are sharable objects, it is recommended that this points to
+   dynamic memory.
+*/
+typedef void	*grav_interface_t;
+
+
+/* ---------------------------------------------------------------------------
+   This structure is passed to the driver on initialisation so it can check
+   compataility.  The first field is guaranteed to be an int 
+   holding GRAV_INTERFACE_VERSION.
+*/
+typedef struct
+{
+    /* Interface version info.
+    */
+    int		grav_interface_version;
+
+    /* The version of the GNU MP library the core is compiled against.
+    */
+    int		grav_mp_version_major;
+    int		grav_mp_version_minor;
+
+    /* An interface the driver can use to query the loaded config.  If the
+       variable is undefined NULL is returned, else its value.
+    */
+    const char	(*grav_config_func)(const char *p_section,
+				    const char *p_variable);
+
+    /* An interface the driver can use to request termination.  p_reason can
+       be NULL.
+    */
+    void	(*grav_exit_func)(const char *p_reason);,
+
+} grav_icb_t;
+
+
+/* ---------------------------------------------------------------------------
+   Drawing commands?  -- Pass structs with masses, or discrete drawing funcs?
+*/
+
+
+/* ---------------------------------------------------------------------------
+   This function must be exported by the driver, and is used to initialise the
+   driver.  If the driver disagrees with the version then false should be
+   returned, otherwise true.
+
+   The passed pointer is a pointer to a grav_icb_t.
+*/
+typedef int	(*grav_interface_init_func)(const void *p);
+
+
+#endif	/* GRAV_GRAVIFACE_H */