-/* $Id: s_alpha.c,v 1.2 2000/11/13 20:02:57 keithw Exp $ */
-
/*
* Mesa 3-D graphics library
- * Version: 3.3
- *
- * Copyright (C) 1999-2000 Brian Paul All Rights Reserved.
- *
+ * 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
* 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 "glheader.h"
-#include "context.h"
-#include "colormac.h"
-#include "macros.h"
-#include "mmath.h"
+#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)
-/*
- * 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.
+/**
+ * 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
-_mesa_alpha_test( const GLcontext *ctx,
- GLuint n, CONST GLchan rgba[][4], GLubyte mask[] )
+_swrast_alpha_test(const GLcontext *ctx, SWspan *span)
{
+ const GLuint n = span->end;
+ GLubyte *mask = span->array->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;
+ if (ctx->Color.AlphaFunc == GL_ALWAYS) {
+ /* do nothing */
+ return 1;
}
- /* Never get here */
- /*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 = FixedToFloat(span->alphaStep);
+ GLfloat alpha = FixedToFloat(span->alpha);
+ const GLfloat ref = ctx->Color.AlphaRef;
+ ALPHA_TEST(alpha, alpha += alphaStep);
+ }
+ }
+
+ span->writeAll = GL_FALSE;
+
+ /* XXX examine mask[] values? */
+ return 1;
}
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