Added MesaLib-7.6

1 files changed, 160 insertions, 0 deletions

diff --git a/mesalib/src/mesa/swrast/s_alpha.c b/mesalib/src/mesa/swrast/s_alpha.c
new file mode 100644
index 000000000..5761bb00b
--- /dev/null
+++ b/mesalib/src/mesa/swrast/s_alpha.c
@@ -0,0 +1,160 @@
+/*
+ * Mesa 3-D graphics library
+ * Version:  6.5.2
+ *
+ * Copyright (C) 1999-2006  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.
+ */
+
+/**
+ * \file swrast/s_alpha.c
+ * \brief Functions to apply alpha test.
+ */
+
+#include "main/glheader.h"
+#include "main/context.h"
+#include "main/colormac.h"
+#include "main/macros.h"
+
+#include "s_alpha.h"
+#include "s_context.h"
+
+
+#define ALPHA_TEST(ALPHA, LOOP_CODE)		\
+do {						\
+   switch (ctx->Color.AlphaFunc) {		\
+      case GL_LESS:				\
+         for (i = 0; i < n; i++) {		\
+            mask[i] &= (ALPHA < ref);		\
+            LOOP_CODE;				\
+         }					\
+         break;					\
+      case GL_LEQUAL:				\
+         for (i = 0; i < n; i++) {		\
+            mask[i] &= (ALPHA <= ref);		\
+            LOOP_CODE;				\
+         }					\
+         break;					\
+      case GL_GEQUAL:				\
+         for (i = 0; i < n; i++) {		\
+            mask[i] &= (ALPHA >= ref);		\
+            LOOP_CODE;				\
+         }					\
+         break;					\
+      case GL_GREATER:				\
+         for (i = 0; i < n; i++) {		\
+            mask[i] &= (ALPHA > ref);		\
+            LOOP_CODE;				\
+         }					\
+         break;					\
+      case GL_NOTEQUAL:				\
+         for (i = 0; i < n; i++) {		\
+            mask[i] &= (ALPHA != ref);		\
+            LOOP_CODE;				\
+         }					\
+         break;					\
+      case GL_EQUAL:				\
+         for (i = 0; i < n; i++) {		\
+            mask[i] &= (ALPHA == ref);		\
+            LOOP_CODE;				\
+         }					\
+         break;					\
+      default:					\
+         _mesa_problem(ctx, "Invalid alpha test in _swrast_alpha_test" ); \
+         return 0;				\
+   }						\
+} while (0)
+
+
+
+/**
+ * Perform the alpha test for an array of pixels.
+ * For pixels that fail the test, mask[i] will be set to 0.
+ * \return  0 if all pixels in the span failed the alpha test,
+ *          1 if one or more pixels passed the alpha test.
+ */
+GLint
+_swrast_alpha_test(const GLcontext *ctx, SWspan *span)
+{
+   const GLuint n = span->end;
+   GLubyte *mask = span->array->mask;
+   GLuint i;
+
+   if (ctx->Color.AlphaFunc == GL_ALWAYS) {
+      /* do nothing */
+      return 1;
+   }
+   else if (ctx->Color.AlphaFunc == GL_NEVER) {
+      /* All pixels failed - caller should check for this return value and
+       * act accordingly.
+       */
+      span->writeAll = GL_FALSE;
+      return 0;
+   }
+
+   if (span->arrayMask & SPAN_RGBA) {
+      /* Use array's alpha values */
+      if (span->array->ChanType == GL_UNSIGNED_BYTE) {
+         GLubyte (*rgba)[4] = span->array->rgba8;
+         GLubyte ref;
+         CLAMPED_FLOAT_TO_UBYTE(ref, ctx->Color.AlphaRef);
+         ALPHA_TEST(rgba[i][ACOMP], ;);
+      }
+      else if (span->array->ChanType == GL_UNSIGNED_SHORT) {
+         GLushort (*rgba)[4] = span->array->rgba16;
+         GLushort ref;
+         CLAMPED_FLOAT_TO_USHORT(ref, ctx->Color.AlphaRef);
+         ALPHA_TEST(rgba[i][ACOMP], ;);
+      }
+      else {
+         GLfloat (*rgba)[4] = span->array->attribs[FRAG_ATTRIB_COL0];
+         const GLfloat ref = ctx->Color.AlphaRef;
+         ALPHA_TEST(rgba[i][ACOMP], ;);
+      }
+   }
+   else {
+      /* Interpolate alpha values */
+      ASSERT(span->interpMask & SPAN_RGBA);
+      if (span->array->ChanType == GL_UNSIGNED_BYTE) {
+         const GLfixed alphaStep = span->alphaStep;
+         GLfixed alpha = span->alpha;
+         GLubyte ref;
+         CLAMPED_FLOAT_TO_UBYTE(ref, ctx->Color.AlphaRef);
+         ALPHA_TEST(FixedToInt(alpha), alpha += alphaStep);
+      }
+      else if (span->array->ChanType == GL_UNSIGNED_SHORT) {
+         const GLfixed alphaStep = span->alphaStep;
+         GLfixed alpha = span->alpha;
+         GLushort ref;
+         CLAMPED_FLOAT_TO_USHORT(ref, ctx->Color.AlphaRef);
+         ALPHA_TEST(FixedToInt(alpha), alpha += alphaStep);
+      }
+      else {
+         const GLfloat alphaStep = span->alphaStep;
+         GLfloat alpha = span->alpha;
+         const GLfloat ref = ctx->Color.AlphaRef;
+         ALPHA_TEST(alpha, alpha += alphaStep);
+      }
+   }
+
+   span->writeAll = GL_FALSE;
+
+   /* XXX examine mask[] values? */
+   return 1;
+}