1 files changed, 92 insertions, 0 deletions
diff --git a/src/mesa/state_tracker/st_atom_scissor.c b/src/mesa/state_tracker/st_atom_scissor.c
new file mode 100644
index 0000000000..3fd59e1945
--- /dev/null
+++ b/src/mesa/state_tracker/st_atom_scissor.c
@@ -0,0 +1,92 @@
+/**************************************************************************
+ * 
+ * Copyright 2007 Tungsten Graphics, Inc., Cedar Park, Texas.
+ * All Rights Reserved.
+ * 
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the
+ * "Software"), to deal in the Software without restriction, including
+ * without limitation the rights to use, copy, modify, merge, publish,
+ * distribute, sub license, and/or sell copies of the Software, and to
+ * permit persons to whom the Software is furnished to do so, subject to
+ * the following conditions:
+ * 
+ * The above copyright notice and this permission notice (including the
+ * next paragraph) shall be included in all copies or substantial portions
+ * of the Software.
+ * 
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
+ * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT.
+ * IN NO EVENT SHALL TUNGSTEN GRAPHICS AND/OR ITS SUPPLIERS BE LIABLE FOR
+ * ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
+ * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
+ * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ * 
+ **************************************************************************/
+
+ /*
+  * Authors:
+  *   Keith Whitwell <keith@tungstengraphics.com>
+  */
+ 
+
+#include "st_context.h"
+#include "pipe/p_context.h"
+#include "st_atom.h"
+
+
+/**
+ * Scissor depends on the scissor box, and the framebuffer dimensions.
+ */
+static void
+update_scissor( struct st_context *st )
+{
+   struct pipe_scissor_state scissor;
+   const struct gl_framebuffer *fb = st->ctx->DrawBuffer;
+   GLint miny, maxy;
+
+   scissor.minx = 0;
+   scissor.miny = 0;
+   scissor.maxx = fb->Width;
+   scissor.maxy = fb->Height;
+
+   if (st->ctx->Scissor.Enabled) {
+      if ((GLuint)st->ctx->Scissor.X > scissor.minx)
+         scissor.minx = st->ctx->Scissor.X;
+      if ((GLuint)st->ctx->Scissor.Y > scissor.miny)
+         scissor.miny = st->ctx->Scissor.Y;
+
+      if ((GLuint)st->ctx->Scissor.X + st->ctx->Scissor.Width < scissor.maxx)
+         scissor.maxx = st->ctx->Scissor.X + st->ctx->Scissor.Width;
+      if ((GLuint)st->ctx->Scissor.Y + st->ctx->Scissor.Height < scissor.maxy)
+         scissor.maxy = st->ctx->Scissor.Y + st->ctx->Scissor.Height;
+
+      /* check for null space */
+      if (scissor.minx >= scissor.maxx || scissor.miny >= scissor.maxy)
+         scissor.minx = scissor.miny = scissor.maxx = scissor.maxy = 0;
+   }
+
+   /* Now invert Y.  Pipe drivers use the convention Y=0=top for surfaces
+    */
+   miny = fb->Height - scissor.maxy;
+   maxy = fb->Height - scissor.miny;
+   scissor.miny = miny;
+   scissor.maxy = maxy;
+
+   if (memcmp(&scissor, &st->state.scissor, sizeof(scissor)) != 0) {
+      /* state has changed */
+      st->state.scissor = scissor;  /* struct copy */
+      st->pipe->set_scissor_state(st->pipe, &scissor); /* activate */
+   }
+}
+
+
+const struct st_tracked_state st_update_scissor = {
+   "st_update_scissor",					/* name */
+   {							/* dirty */
+      (_NEW_SCISSOR | _NEW_BUFFERS),			/* mesa */
+      0,						/* st */
+   },
+   update_scissor					/* update */
+};