From 8c2f6c5059a60d845716277973c826f4069926e6 Mon Sep 17 00:00:00 2001
From: Brian Paul <brian.paul@tungstengraphics.com>
Date: Tue, 26 Jun 2001 01:32:48 +0000
Subject: added GL_IBM_rasterpos_clip extension

---
 src/mesa/main/rastpos.c | 24 ++++++++++++++++++++++--
 1 file changed, 22 insertions(+), 2 deletions(-)

(limited to 'src/mesa/main/rastpos.c')

diff --git a/src/mesa/main/rastpos.c b/src/mesa/main/rastpos.c
index adc81ed478..c4f87c2ba4 100644
--- a/src/mesa/main/rastpos.c
+++ b/src/mesa/main/rastpos.c
@@ -1,4 +1,4 @@
-/* $Id: rastpos.c,v 1.26 2001/06/18 17:26:08 brianp Exp $ */
+/* $Id: rastpos.c,v 1.27 2001/06/26 01:32:48 brianp Exp $ */
 
 /*
  * Mesa 3-D graphics library
@@ -66,6 +66,20 @@ viewclip_point( const GLfloat v[] )
 }
 
 
+/* As above, but only clip test against far/near Z planes */
+static GLuint
+viewclip_point_z( const GLfloat v[] )
+{
+   if (v[2] > v[3] || v[2] < -v[3] ) {
+      return 0;
+   }
+   else {
+      return 1;
+   }
+}
+
+
+
 /*
  * Clip a point against the user clipping planes.
  * Input:  v - vertex-vector describing the point to clip.
@@ -292,7 +306,13 @@ raster_pos4f(GLcontext *ctx, GLfloat x, GLfloat y, GLfloat z, GLfloat w)
    TRANSFORM_POINT( clip, ctx->ProjectionMatrix.m, eye );
 
    /* clip to view volume */
-   if (viewclip_point( clip )==0) {
+   if (ctx->Transform.RasterPositionUnclipped) {
+      /* GL_IBM_rasterpos_clip: only clip against Z */
+      if (viewclip_point_z(clip) == 0)
+         ctx->Current.RasterPosValid = GL_FALSE;
+   }
+   else if (viewclip_point(clip) == 0) {
+      /* Normal OpenGL behaviour */
       ctx->Current.RasterPosValid = GL_FALSE;
       return;
    }
-- 
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