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authormarha <marha@users.sourceforge.net>2009-10-08 13:15:52 +0000
committermarha <marha@users.sourceforge.net>2009-10-08 13:15:52 +0000
commita0c4815433ccd57322f4f7703ca35e9ccfa59250 (patch)
treef5213802ec12adb86ec3136001c1c29fe5343700 /mesalib/src/mesa/swrast/s_alpha.c
parentc73dc01b6de45612b24dc2dd34fba24d81ebf46c (diff)
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Added MesaLib-7.6
Diffstat (limited to 'mesalib/src/mesa/swrast/s_alpha.c')
-rw-r--r--mesalib/src/mesa/swrast/s_alpha.c160
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
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+/*
+ * 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;
+}