WebSVN - shark - Blame - Rev 57 - /shark/trunk/ports/mesa/src/swrast/s

Rev	Author	Line No.	Line
57	pj	1	/* $Id: s_alpha.c,v 1.1 2003-02-28 11:49:40 pj Exp $ */
		2
		3	/*
		4	* Mesa 3-D graphics library
		5	* Version: 4.1
		6	*
		7	* Copyright (C) 1999-2002 Brian Paul All Rights Reserved.
		8	*
		9	* Permission is hereby granted, free of charge, to any person obtaining a
		10	* copy of this software and associated documentation files (the "Software"),
		11	* to deal in the Software without restriction, including without limitation
		12	* the rights to use, copy, modify, merge, publish, distribute, sublicense,
		13	* and/or sell copies of the Software, and to permit persons to whom the
		14	* Software is furnished to do so, subject to the following conditions:
		15	*
		16	* The above copyright notice and this permission notice shall be included
		17	* in all copies or substantial portions of the Software.
		18	*
		19	* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
		20	* OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
		21	* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
		22	* BRIAN PAUL BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
		23	* AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
		24	* CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
		25	*/
		26
		27	/**
		28	* \file swrast/s_alpha.c
		29	* \brief Functions to apply alpha test.
		30	*/
		31
		32	#include "glheader.h"
		33	#include "context.h"
		34	#include "colormac.h"
		35	#include "macros.h"
		36	#include "mmath.h"
		37
		38	#include "s_alpha.h"
		39	#include "s_context.h"
		40
		41
		42	/**
		43	* \fn GLint _mesa_alpha_test( const GLcontext ctx, struct sw_span span )
		44	* \brief Apply the alpha test to a span of pixels.
		45	* \return
		46	* - "0" = all pixels in the span failed the alpha test.
		47	* - "1" = one or more pixels passed the alpha test.
		48	*/
		49	GLint
		50	_mesa_alpha_test( const GLcontext ctx, struct sw_span span )
		51	{
		52	const GLchan (rgba)[4] = (const GLchan ()[4]) span->array->rgba;
		53	GLchan ref;
		54	const GLuint n = span->end;
		55	GLubyte *mask = span->array->mask;
		56	GLuint i;
		57
		58	CLAMPED_FLOAT_TO_CHAN(ref, ctx->Color.AlphaRef);
		59
		60	if (span->arrayMask & SPAN_RGBA) {
		61	/* Use the array values */
		62	switch (ctx->Color.AlphaFunc) {
		63	case GL_LESS:
		64	for (i = 0; i < n; i++)
		65	mask[i] &= (rgba[i][ACOMP] < ref);
		66	break;
		67	case GL_LEQUAL:
		68	for (i = 0; i < n; i++)
		69	mask[i] &= (rgba[i][ACOMP] <= ref);
		70	break;
		71	case GL_GEQUAL:
		72	for (i = 0; i < n; i++)
		73	mask[i] &= (rgba[i][ACOMP] >= ref);
		74	break;
		75	case GL_GREATER:
		76	for (i = 0; i < n; i++)
		77	mask[i] &= (rgba[i][ACOMP] > ref);
		78	break;
		79	case GL_NOTEQUAL:
		80	for (i = 0; i < n; i++)
		81	mask[i] &= (rgba[i][ACOMP] != ref);
		82	break;
		83	case GL_EQUAL:
		84	for (i = 0; i < n; i++)
		85	mask[i] &= (rgba[i][ACOMP] == ref);
		86	break;
		87	case GL_ALWAYS:
		88	/* do nothing */
		89	return 1;
		90	case GL_NEVER:
		91	/* caller should check for zero! */
		92	span->writeAll = GL_FALSE;
		93	return 0;
		94	default:
		95	_mesa_problem( ctx, "Invalid alpha test in _mesa_alpha_test" );
		96	return 0;
		97	}
		98	}
		99	else {
		100	/* Use the interpolation values */
		101	#if CHAN_TYPE == GL_FLOAT
		102	const GLfloat alphaStep = span->alphaStep;
		103	GLfloat alpha = span->alpha;
		104	ASSERT(span->interpMask & SPAN_RGBA);
		105	switch (ctx->Color.AlphaFunc) {
		106	case GL_LESS:
		107	for (i = 0; i < n; i++) {
		108	mask[i] &= (alpha < ref);
		109	alpha += alphaStep;
		110	}
		111	break;
		112	case GL_LEQUAL:
		113	for (i = 0; i < n; i++) {
		114	mask[i] &= (alpha <= ref);
		115	alpha += alphaStep;
		116	}
		117	break;
		118	case GL_GEQUAL:
		119	for (i = 0; i < n; i++) {
		120	mask[i] &= (alpha >= ref);
		121	alpha += alphaStep;
		122	}
		123	break;
		124	case GL_GREATER:
		125	for (i = 0; i < n; i++) {
		126	mask[i] &= (alpha > ref);
		127	alpha += alphaStep;
		128	}
		129	break;
		130	case GL_NOTEQUAL:
		131	for (i = 0; i < n; i++) {
		132	mask[i] &= (alpha != ref);
		133	alpha += alphaStep;
		134	}
		135	break;
		136	case GL_EQUAL:
		137	for (i = 0; i < n; i++) {
		138	mask[i] &= (alpha == ref);
		139	alpha += alphaStep;
		140	}
		141	break;
		142	case GL_ALWAYS:
		143	/* do nothing */
		144	return 1;
		145	case GL_NEVER:
		146	/* caller should check for zero! */
		147	span->writeAll = GL_FALSE;
		148	return 0;
		149	default:
		150	_mesa_problem( ctx, "Invalid alpha test in gl_alpha_test" );
		151	return 0;
		152	}
		153	#else
		154	/* 8 or 16-bit channel interpolation */
		155	const GLfixed alphaStep = span->alphaStep;
		156	GLfixed alpha = span->alpha;
		157	ASSERT(span->interpMask & SPAN_RGBA);
		158	switch (ctx->Color.AlphaFunc) {
		159	case GL_LESS:
		160	for (i = 0; i < n; i++) {
		161	mask[i] &= (FixedToChan(alpha) < ref);
		162	alpha += alphaStep;
		163	}
		164	break;
		165	case GL_LEQUAL:
		166	for (i = 0; i < n; i++) {
		167	mask[i] &= (FixedToChan(alpha) <= ref);
		168	alpha += alphaStep;
		169	}
		170	break;
		171	case GL_GEQUAL:
		172	for (i = 0; i < n; i++) {
		173	mask[i] &= (FixedToChan(alpha) >= ref);
		174	alpha += alphaStep;
		175	}
		176	break;
		177	case GL_GREATER:
		178	for (i = 0; i < n; i++) {
		179	mask[i] &= (FixedToChan(alpha) > ref);
		180	alpha += alphaStep;
		181	}
		182	break;
		183	case GL_NOTEQUAL:
		184	for (i = 0; i < n; i++) {
		185	mask[i] &= (FixedToChan(alpha) != ref);
		186	alpha += alphaStep;
		187	}
		188	break;
		189	case GL_EQUAL:
		190	for (i = 0; i < n; i++) {
		191	mask[i] &= (FixedToChan(alpha) == ref);
		192	alpha += alphaStep;
		193	}
		194	break;
		195	case GL_ALWAYS:
		196	/* do nothing */
		197	return 1;
		198	case GL_NEVER:
		199	/* caller should check for zero! */
		200	span->writeAll = GL_FALSE;
		201	return 0;
		202	default:
		203	_mesa_problem( ctx, "Invalid alpha test in gl_alpha_test" );
		204	return 0;
		205	}
		206	#endif /* CHAN_TYPE */
		207	}
		208
		209	#if 0
		210	/* XXXX This causes conformance failures!!!! */
		211	while ((span->start <= span->end) &&
		212	(mask[span->start] == 0))
		213	span->start ++;
		214
		215	while ((span->end >= span->start) &&
		216	(mask[span->end] == 0))
		217	span->end --;
		218	#endif
		219
		220	span->writeAll = GL_FALSE;
		221
		222	if (span->start >= span->end)
		223	return 0;
		224	else
		225	return 1;
		226	}

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(root)/shark/trunk/ports/mesa/src/swrast/s_alpha.c - Rev 57