added Steven Baker's GPU physics code (work in progress)

Extras/GPUphysics/fboSupport.h

@@ -0,0 +1,84 @@
+
+GLuint makeTextureTarget ( GLuint textureHandle ) ;
+void renderTo2DTexture ( GLuint fboHandle ) ;
+void renderToFrameBuffer () ;
+
+enum fboDataType
+{
+#ifndef GL_BYTE
+ FBO_BYTE           = 0x1400,
+ FBO_UNSIGNED_BYTE  = 0x1401,
+ FBO_SHORT          = 0x1402,
+ FBO_UNSIGNED_SHORT = 0x1403,
+ FBO_INT            = 0x1404,
+ FBO_UNSIGNED_INT   = 0x1405,
+ FBO_FLOAT          = 0x1406,
+ FBO_DOUBLE         = 0x140A,
+#else
+ FBO_BYTE           = GL_BYTE,
+ FBO_UNSIGNED_BYTE  = GL_UNSIGNED_BYTE,
+ FBO_SHORT          = GL_SHORT,
+ FBO_UNSIGNED_SHORT = GL_UNSIGNED_SHORT,
+ FBO_INT            = GL_INT,
+ FBO_UNSIGNED_INT   = GL_UNSIGNED_INT,
+ FBO_FLOAT          = GL_FLOAT,
+ FBO_DOUBLE         = GL_DOUBLE,
+#endif
+#ifndef GL_HALF_FLOAT_NV
+ FBO_HALF            = 0x140B
+#else
+ FBO_HALF            = GL_HALF_FLOAT_NV
+#endif
+} ;
+
+class FrameBufferObject
+{
+  int width  ;
+  int height ;
+  int ncomps ;
+  fboDataType type ;
+  GLenum  format ;
+  GLenum iformat ;
+
+  GLuint textureHandle ;
+  GLuint fboHandle ;
+  GLuint depth_rb ;
+
+#ifdef NEED_STENCIL
+  GLuint stencil_rb ;
+#endif
+
+  void fillTexture ( void *data ) ;
+
+public:
+  FrameBufferObject ( int _width,          /* Must be a power of two! */
+                      int _height,         /* Must be a power of two! */
+                      int _numComponents,  /* 1, 2, 3 or 4 only! */
+                      fboDataType _type ) ;
+
+  void makeDestination ()
+  {
+    glBindFramebufferEXT ( GL_FRAMEBUFFER_EXT, fboHandle ) ;
+  }
+
+  void use ( int texture_unit )
+  {
+    glActiveTexture ( GL_TEXTURE0 + texture_unit ) ;
+    glBindTexture ( GL_TEXTURE_2D, textureHandle ) ;
+  }
+
+  void paint () ;
+
+  void fillTexture ( float         *data ) ;
+  void fillTexture ( unsigned char *data ) ;
+
+  void fetchTexture ( float         *data ) ;
+  void fetchTexture ( unsigned char *data ) ;
+} ;
+
+
+inline void restoreFrameBuffer ()
+{
+  glBindFramebufferEXT ( GL_FRAMEBUFFER_EXT, 0 ) ;
+}
+