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-rw-r--r--src/mesa/swrast/s_blend.c14
1 files changed, 13 insertions, 1 deletions
diff --git a/src/mesa/swrast/s_blend.c b/src/mesa/swrast/s_blend.c
index 05b38fd580..f37a44015f 100644
--- a/src/mesa/swrast/s_blend.c
+++ b/src/mesa/swrast/s_blend.c
@@ -1,4 +1,4 @@
-/* $Id: s_blend.c,v 1.14 2002/03/27 15:49:27 brianp Exp $ */
+/* $Id: s_blend.c,v 1.15 2002/04/02 16:16:45 brianp Exp $ */
/*
* Mesa 3-D graphics library
@@ -132,12 +132,24 @@ blend_transparency( GLcontext *ctx, GLuint n, const GLubyte mask[],
#if CHAN_BITS == 8
/* This satisfies Glean and should be reasonably fast */
/* Contributed by Nathan Hand */
+#if 0
#define DIV255(X) (((X) << 8) + (X) + 256) >> 16
+#else
+ GLint temp;
+#define DIV255(X) (temp = (X), ((temp << 8) + temp + 256) >> 16)
+#endif
+#if 0
const GLint s = CHAN_MAX - t;
const GLint r = DIV255(rgba[i][RCOMP] * t + dest[i][RCOMP] * s);
const GLint g = DIV255(rgba[i][GCOMP] * t + dest[i][GCOMP] * s);
const GLint b = DIV255(rgba[i][BCOMP] * t + dest[i][BCOMP] * s);
const GLint a = DIV255(rgba[i][ACOMP] * t + dest[i][ACOMP] * s);
+#else
+ const GLint r = DIV255((rgba[i][RCOMP] - dest[i][RCOMP]) * t) + dest[i][RCOMP];
+ const GLint g = DIV255((rgba[i][GCOMP] - dest[i][GCOMP]) * t) + dest[i][GCOMP];
+ const GLint b = DIV255((rgba[i][BCOMP] - dest[i][BCOMP]) * t) + dest[i][BCOMP];
+ const GLint a = DIV255((rgba[i][ACOMP] - dest[i][ACOMP]) * t) + dest[i][ACOMP];
+#endif
#undef DIV255
#elif CHAN_BITS == 16
const GLfloat tt = (GLfloat) t / CHAN_MAXF;