[OPENGL32][MESA] Downgrade Mesa library to version 2.6

[reactos.git] / dll / opengl / mesa / alpha.c

diff --git a/dll/opengl/mesa/alpha.c b/dll/opengl/mesa/alpha.c
new file mode 100644 (file)
index 0000000..c99a6d4
--- /dev/null
+++ b/dll/opengl/mesa/alpha.c
@@ -0,0 +1,142 @@
+/* $Id: alpha.c,v 1.5 1997/07/24 01:24:28 brianp Exp $ */
+
+/*
+ * Mesa 3-D graphics library
+ * Version:  2.4
+ * Copyright (C) 1995-1997  Brian Paul
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Library General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Library General Public License for more details.
+ *
+ * You should have received a copy of the GNU Library General Public
+ * License along with this library; if not, write to the Free
+ * Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+
+
+/*
+ * $Log: alpha.c,v $
+ * Revision 1.5  1997/07/24 01:24:28  brianp
+ * changed precompiled header symbol from PCH to PC_HEADER
+ *
+ * Revision 1.4  1997/05/28 03:23:09  brianp
+ * added precompiled header (PCH) support
+ *
+ * Revision 1.3  1997/03/13 03:07:53  brianp
+ * optimized gl_alpha_test() by removing conditional from inside loops
+ *
+ * Revision 1.2  1996/09/15 14:15:54  brianp
+ * now use GLframebuffer and GLvisual
+ *
+ * Revision 1.1  1996/09/13 01:38:16  brianp
+ * Initial revision
+ *
+ */
+
+
+#ifdef PC_HEADER
+#include "all.h"
+#else
+#include "alpha.h"
+#include "context.h"
+#include "types.h"
+#include "dlist.h"
+#include "macros.h"
+#endif
+
+
+
+void gl_AlphaFunc( GLcontext* ctx, GLenum func, GLclampf ref )
+{
+   if (INSIDE_BEGIN_END(ctx)) {
+      gl_error( ctx, GL_INVALID_OPERATION, "glAlphaFunc" );
+      return;
+   }
+   switch (func) {
+      case GL_NEVER:
+      case GL_LESS:
+      case GL_EQUAL:
+      case GL_LEQUAL:
+      case GL_GREATER:
+      case GL_NOTEQUAL:
+      case GL_GEQUAL:
+      case GL_ALWAYS:
+         ctx->Color.AlphaFunc = func;
+         ctx->Color.AlphaRef = CLAMP( ref, 0.0F, 1.0F );
+         ctx->Color.AlphaRefUbyte = (GLubyte) (ctx->Color.AlphaRef
+                                              * ctx->Visual->AlphaScale);
+         break;
+      default:
+         gl_error( ctx, GL_INVALID_ENUM, "glAlphaFunc(func)" );
+         break;
+   }
+}
+
+
+
+
+/*
+ * Apply the alpha test to a span 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 gl_alpha_test( GLcontext* ctx,
+                     GLuint n, const GLubyte alpha[], GLubyte mask[] )
+{
+   GLuint i;
+   GLubyte ref = ctx->Color.AlphaRefUbyte;
+
+   /* switch cases ordered from most frequent to less frequent */
+   switch (ctx->Color.AlphaFunc) {
+      case GL_LESS:
+         for (i=0;i<n;i++) {
+           mask[i] &= (alpha[i] < ref);
+        }
+        return 1;
+      case GL_LEQUAL:
+         for (i=0;i<n;i++) {
+           mask[i] &= (alpha[i] <= ref);
+        }
+        return 1;
+      case GL_GEQUAL:
+         for (i=0;i<n;i++) {
+           mask[i] &= (alpha[i] >= ref);
+        }
+        return 1;
+      case GL_GREATER:
+         for (i=0;i<n;i++) {
+           mask[i] &= (alpha[i] > ref);
+        }
+        return 1;
+      case GL_NOTEQUAL:
+         for (i=0;i<n;i++) {
+           mask[i] &= (alpha[i] != ref);
+        }
+        return 1;
+      case GL_EQUAL:
+         for (i=0;i<n;i++) {
+           mask[i] &= (alpha[i] == 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;
+}