From e3a051e0538a605551f4d58294c94f5eb00ed07f Mon Sep 17 00:00:00 2001
From: Keith Whitwell <keith@tungstengraphics.com>
Date: Tue, 31 Oct 2000 18:00:04 +0000
Subject: Moved software rasterizer functionality to new directory.

---
 src/mesa/swrast/s_alpha.c | 99 +++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 99 insertions(+)
 create mode 100644 src/mesa/swrast/s_alpha.c

(limited to 'src/mesa/swrast/s_alpha.c')

diff --git a/src/mesa/swrast/s_alpha.c b/src/mesa/swrast/s_alpha.c
new file mode 100644
index 0000000000..07e8dacd4a
--- /dev/null
+++ b/src/mesa/swrast/s_alpha.c
@@ -0,0 +1,99 @@
+/* $Id: s_alpha.c,v 1.1 2000/10/31 18:00:04 keithw Exp $ */
+
+/*
+ * Mesa 3-D graphics library
+ * Version:  3.3
+ * 
+ * Copyright (C) 1999-2000  Brian Paul   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, sublicense,
+ * 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 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 NONINFRINGEMENT.  IN NO EVENT SHALL
+ * BRIAN PAUL 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.
+ */
+
+
+#include "glheader.h"
+#include "context.h"
+#include "colormac.h"
+#include "macros.h"
+#include "mmath.h"
+
+#include "s_alpha.h"
+
+
+
+
+
+/*
+ * Apply the alpha test to a span of pixels.
+ * In:  rgba - array of pixels
+ * In/Out:  mask - current pixel mask.  Pixels which fail the alpha test
+ *                 will set the corresponding mask flag to 0.
+ * Return:  0 = all pixels in the span failed the alpha test.
+ *          1 = one or more pixels passed the alpha test.
+ */
+GLint
+_mesa_alpha_test( const GLcontext *ctx,
+                  GLuint n, CONST GLchan rgba[][4], GLubyte mask[] )
+{
+   GLuint i;
+   GLchan ref = ctx->Color.AlphaRef;
+
+   /* switch cases ordered from most frequent to less frequent */
+   switch (ctx->Color.AlphaFunc) {
+      case GL_LESS:
+         for (i=0;i<n;i++) {
+	    mask[i] &= (rgba[i][ACOMP] < ref);
+	 }
+	 return 1;
+      case GL_LEQUAL:
+         for (i=0;i<n;i++) {
+	    mask[i] &= (rgba[i][ACOMP] <= ref);
+	 }
+	 return 1;
+      case GL_GEQUAL:
+         for (i=0;i<n;i++) {
+	    mask[i] &= (rgba[i][ACOMP] >= ref);
+	 }
+	 return 1;
+      case GL_GREATER:
+         for (i=0;i<n;i++) {
+	    mask[i] &= (rgba[i][ACOMP] > ref);
+	 }
+	 return 1;
+      case GL_NOTEQUAL:
+         for (i=0;i<n;i++) {
+	    mask[i] &= (rgba[i][ACOMP] != ref);
+	 }
+	 return 1;
+      case GL_EQUAL:
+         for (i=0;i<n;i++) {
+	    mask[i] &= (rgba[i][ACOMP] == ref);
+	 }
+	 return 1;
+      case GL_ALWAYS:
+	 /* do nothing */
+	 return 1;
+      case GL_NEVER:
+         /* caller should check for zero! */
+	 return 0;
+      default:
+	 gl_problem( ctx, "Invalid alpha test in gl_alpha_test" );
+         return 0;
+   }
+   /* Never get here */
+   /*return 1;*/
+}
-- 
cgit v1.2.3