From eeb861df0b1843ffd765b969ed80394f663a7dc9 Mon Sep 17 00:00:00 2001
From: Brian Paul <brian.paul@tungstengraphics.com>
Date: Tue, 30 Jan 2001 18:08:51 +0000
Subject: make gluPerspective() call glMultMatrix() instead of glFrustum() to
 get correct error semantics

---
 src/glu/mesa/glu.c | 36 +++++++++++++++++++++++++++++++-----
 1 file changed, 31 insertions(+), 5 deletions(-)

(limited to 'src/glu/mesa/glu.c')

diff --git a/src/glu/mesa/glu.c b/src/glu/mesa/glu.c
index c3772e786c..d7d8b93bdb 100644
--- a/src/glu/mesa/glu.c
+++ b/src/glu/mesa/glu.c
@@ -1,9 +1,9 @@
-/* $Id: glu.c,v 1.22 2000/11/13 15:33:17 brianp Exp $ */
+/* $Id: glu.c,v 1.23 2001/01/30 18:08:51 brianp Exp $ */
 
 /*
  * Mesa 3-D graphics library
- * Version:  3.3
- * Copyright (C) 1995-2000  Brian Paul
+ * Version:  3.5
+ * Copyright (C) 1995-2001  Brian Paul
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
@@ -137,6 +137,32 @@ gluOrtho2D(GLdouble left, GLdouble right, GLdouble bottom, GLdouble top)
 
 
 
+static void
+frustum(GLdouble left, GLdouble right,
+        GLdouble bottom, GLdouble top, 
+        GLdouble nearval, GLdouble farval)
+{
+   GLdouble x, y, a, b, c, d;
+   GLdouble m[16];
+
+   x = (2.0 * nearval) / (right - left);
+   y = (2.0 * nearval) / (top - bottom);
+   a = (right + left) / (right - left);
+   b = (top + bottom) / (top - bottom);
+   c = -(farval + nearval) / ( farval - nearval);
+   d = -(2.0 * farval * nearval) / (farval - nearval);
+
+#define M(row,col)  m[col*4+row]
+   M(0,0) = x;     M(0,1) = 0.0F;  M(0,2) = a;      M(0,3) = 0.0F;
+   M(1,0) = 0.0F;  M(1,1) = y;     M(1,2) = b;      M(1,3) = 0.0F;
+   M(2,0) = 0.0F;  M(2,1) = 0.0F;  M(2,2) = c;      M(2,3) = d;
+   M(3,0) = 0.0F;  M(3,1) = 0.0F;  M(3,2) = -1.0F;  M(3,3) = 0.0F;
+#undef M
+
+   glMultMatrixd(m);
+}
+
+
 void GLAPIENTRY
 gluPerspective(GLdouble fovy, GLdouble aspect, GLdouble zNear, GLdouble zFar)
 {
@@ -144,11 +170,11 @@ gluPerspective(GLdouble fovy, GLdouble aspect, GLdouble zNear, GLdouble zFar)
 
    ymax = zNear * tan(fovy * M_PI / 360.0);
    ymin = -ymax;
-
    xmin = ymin * aspect;
    xmax = ymax * aspect;
 
-   glFrustum(xmin, xmax, ymin, ymax, zNear, zFar);
+   /* don't call glFrustum() because of error semantics (covglu) */
+   frustum(xmin, xmax, ymin, ymax, zNear, zFar);
 }
 
 
-- 
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