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/* $Id: s_blend.c,v 1.1 2003-02-28 11:49:41 pj Exp $ */
/*
* Mesa 3-D graphics library
* Version: 4.1
*
* Copyright (C) 1999-2002 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.
*/
#include "glheader.h"
#include "context.h"
#include "colormac.h"
#include "macros.h"
#include "s_alphabuf.h"
#include "s_blend.h"
#include "s_context.h"
#include "s_span.h"
#if defined(USE_MMX_ASM)
#include "X86/mmx.h"
#include "X86/common_x86_asm.h"
#define _BLENDAPI _ASMAPI
#else
#define _BLENDAPI
#endif
/*
* Special case for glBlendFunc(GL_ZERO, GL_ONE)
*/
static void _BLENDAPI
blend_noop( GLcontext *ctx, GLuint n, const GLubyte mask[],
GLchan rgba[][4], CONST GLchan dest[][4] )
{
GLuint i;
ASSERT(ctx->Color.BlendEquation==GL_FUNC_ADD_EXT);
ASSERT(ctx->Color.BlendSrcRGB==GL_ZERO);
ASSERT(ctx->Color.BlendDstRGB==GL_ONE);
(void) ctx;
for (i = 0; i < n; i++) {
if (mask[i]) {
COPY_CHAN4( rgba[i], dest[i] );
}
}
}
/*
* Special case for glBlendFunc(GL_ONE, GL_ZERO)
*/
static void _BLENDAPI
blend_replace( GLcontext *ctx, GLuint n, const GLubyte mask[],
GLchan rgba[][4], CONST GLchan dest[][4] )
{
ASSERT(ctx->Color.BlendEquation==GL_FUNC_ADD_EXT);
ASSERT(ctx->Color.BlendSrcRGB==GL_ONE);
ASSERT(ctx->Color.BlendDstRGB==GL_ZERO);
(void) ctx;
(void) n;
(void) mask;
(void) rgba;
(void) dest;
}
/*
* Common transparency blending mode.
*/
static void _BLENDAPI
blend_transparency( GLcontext *ctx, GLuint n, const GLubyte mask[],
GLchan rgba[][4], CONST GLchan dest[][4] )
{
GLuint i;
ASSERT(ctx->Color.BlendEquation==GL_FUNC_ADD_EXT);
ASSERT(ctx->Color.BlendSrcRGB==GL_SRC_ALPHA);
ASSERT(ctx->Color.BlendDstRGB==GL_ONE_MINUS_SRC_ALPHA);
(void) ctx;
for (i=0;i<n;i++) {
if (mask[i]) {
const GLchan t = rgba[i][ACOMP]; /* t in [0, CHAN_MAX] */
if (t == 0) {
/* 0% alpha */
rgba[i][RCOMP] = dest[i][RCOMP];
rgba[i][GCOMP] = dest[i][GCOMP];
rgba[i][BCOMP] = dest[i][BCOMP];
rgba[i][ACOMP] = dest[i][ACOMP];
}
else if (t == CHAN_MAX) {
/* 100% alpha, no-op */
}
else {
#if 0
/* This is pretty close, but Glean complains */
const GLint s = CHAN_MAX - t;
const GLint r = (rgba[i][RCOMP] * t + dest[i][RCOMP] * s + 1) >> 8;
const GLint g = (rgba[i][GCOMP] * t + dest[i][GCOMP] * s + 1) >> 8;
const GLint b = (rgba[i][BCOMP] * t + dest[i][BCOMP] * s + 1) >> 8;
const GLint a = (rgba[i][ACOMP] * t + dest[i][ACOMP] * s + 1) >> 8;
#elif 0
/* This is slower but satisfies Glean */
const GLint s = CHAN_MAX - t;
const GLint r = (rgba[i][RCOMP] * t + dest[i][RCOMP] * s) / 255;
const GLint g = (rgba[i][GCOMP] * t + dest[i][GCOMP] * s) / 255;
const GLint b = (rgba[i][BCOMP] * t + dest[i][BCOMP] * s) / 255;
const GLint a = (rgba[i][ACOMP] * t + dest[i][ACOMP] * s) / 255;
#else
#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
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];
#undef DIV255
#elif CHAN_BITS == 16
const GLfloat tt = (GLfloat) t / CHAN_MAXF;
const GLint r = (GLint) ((rgba[i][RCOMP] - dest[i][RCOMP]) * tt + dest[i][RCOMP]);
const GLint g = (GLint) ((rgba[i][GCOMP] - dest[i][GCOMP]) * tt + dest[i][GCOMP]);
const GLint b = (GLint) ((rgba[i][BCOMP] - dest[i][BCOMP]) * tt + dest[i][BCOMP]);
const GLint a = (GLint) ((rgba[i][ACOMP] - dest[i][ACOMP]) * tt + dest[i][ACOMP]);
#else /* CHAN_BITS == 32 */
const GLfloat tt = (GLfloat) t / CHAN_MAXF;
const GLfloat r = (rgba[i][RCOMP] - dest[i][RCOMP]) * tt + dest[i][RCOMP];
const GLfloat g = (rgba[i][GCOMP] - dest[i][GCOMP]) * tt + dest[i][GCOMP];
const GLfloat b = (rgba[i][BCOMP] - dest[i][BCOMP]) * tt + dest[i][BCOMP];
const GLfloat a = CLAMP( rgba[i][ACOMP], 0.0F, CHAN_MAXF ) * t +
CLAMP( dest[i][ACOMP], 0.0F, CHAN_MAXF ) * (1.0F - t);
#endif
#endif
ASSERT(r <= CHAN_MAX);
ASSERT(g <= CHAN_MAX);
ASSERT(b <= CHAN_MAX);
ASSERT(a <= CHAN_MAX);
rgba[i][RCOMP] = (GLchan) r;
rgba[i][GCOMP] = (GLchan) g;
rgba[i][BCOMP] = (GLchan) b;
rgba[i][ACOMP] = (GLchan) a;
}
}
}
}
/*
* Add src and dest.
*/
static void _BLENDAPI
blend_add( GLcontext *ctx, GLuint n, const GLubyte mask[],
GLchan rgba[][4], CONST GLchan dest[][4] )
{
GLuint i;
ASSERT(ctx->Color.BlendEquation==GL_FUNC_ADD_EXT);
ASSERT(ctx->Color.BlendSrcRGB==GL_ONE);
ASSERT(ctx->Color.BlendDstRGB==GL_ONE);
(void) ctx;
for (i=0;i<n;i++) {
if (mask[i]) {
#if CHAN_TYPE == GL_FLOAT
/* don't RGB clamp to max */
GLfloat a = CLAMP(rgba[i][ACOMP], 0.0F, CHAN_MAXF) + dest[i][ACOMP];
rgba[i][RCOMP] += dest[i][RCOMP];
rgba[i][GCOMP] += dest[i][GCOMP];
rgba[i][BCOMP] += dest[i][BCOMP];
rgba[i][ACOMP] = (GLchan) MIN2( a, CHAN_MAXF );
#else
GLint r = rgba[i][RCOMP] + dest[i][RCOMP];
GLint g = rgba[i][GCOMP] + dest[i][GCOMP];
GLint b = rgba[i][BCOMP] + dest[i][BCOMP];
GLint a = rgba[i][ACOMP] + dest[i][ACOMP];
rgba[i][RCOMP] = (GLchan) MIN2( r, CHAN_MAX );
rgba[i][GCOMP] = (GLchan) MIN2( g, CHAN_MAX );
rgba[i][BCOMP] = (GLchan) MIN2( b, CHAN_MAX );
rgba[i][ACOMP] = (GLchan) MIN2( a, CHAN_MAX );
#endif
}
}
}
/*
* Blend min function (for GL_EXT_blend_minmax)
*/
static void _BLENDAPI
blend_min( GLcontext *ctx, GLuint n, const GLubyte mask[],
GLchan rgba[][4], CONST GLchan dest[][4] )
{
GLuint i;
ASSERT(ctx->Color.BlendEquation==GL_MIN_EXT);
(void) ctx;
for (i=0;i<n;i++) {
if (mask[i]) {
rgba[i][RCOMP] = (GLchan) MIN2( rgba[i][RCOMP], dest[i][RCOMP] );
rgba[i][GCOMP] = (GLchan) MIN2( rgba[i][GCOMP], dest[i][GCOMP] );
rgba[i][BCOMP] = (GLchan) MIN2( rgba[i][BCOMP], dest[i][BCOMP] );
#if CHAN_TYPE == GL_FLOAT
rgba[i][ACOMP] = (GLchan) MIN2(CLAMP(rgba[i][ACOMP], 0.0F, CHAN_MAXF),
dest[i][ACOMP]);
#else
rgba[i][ACOMP] = (GLchan) MIN2( rgba[i][ACOMP], dest[i][ACOMP] );
#endif
}
}
}
/*
* Blend max function (for GL_EXT_blend_minmax)
*/
static void _BLENDAPI
blend_max( GLcontext *ctx, GLuint n, const GLubyte mask[],
GLchan rgba[][4], CONST GLchan dest[][4] )
{
GLuint i;
ASSERT(ctx->Color.BlendEquation==GL_MAX_EXT);
(void) ctx;
for (i=0;i<n;i++) {
if (mask[i]) {
rgba[i][RCOMP] = (GLchan) MAX2( rgba[i][RCOMP], dest[i][RCOMP] );
rgba[i][GCOMP] = (GLchan) MAX2( rgba[i][GCOMP], dest[i][GCOMP] );
rgba[i][BCOMP] = (GLchan) MAX2( rgba[i][BCOMP], dest[i][BCOMP] );
#if CHAN_TYPE == GL_FLOAT
rgba[i][ACOMP] = (GLchan) MAX2(CLAMP(rgba[i][ACOMP], 0.0F, CHAN_MAXF),
dest[i][ACOMP]);
#else
rgba[i][ACOMP] = (GLchan) MAX2( rgba[i][ACOMP], dest[i][ACOMP] );
#endif
}
}
}
/*
* Modulate: result = src * dest
*/
static void _BLENDAPI
blend_modulate( GLcontext *ctx, GLuint n, const GLubyte mask[],
GLchan rgba[][4], CONST GLchan dest[][4] )
{
GLuint i;
(void) ctx;
for (i=0;i<n;i++) {
if (mask[i]) {
#if CHAN_TYPE == GL_FLOAT
rgba[i][RCOMP] = rgba[i][RCOMP] * dest[i][RCOMP];
rgba[i][GCOMP] = rgba[i][GCOMP] * dest[i][GCOMP];
rgba[i][BCOMP] = rgba[i][BCOMP] * dest[i][BCOMP];
rgba[i][ACOMP] = rgba[i][ACOMP] * dest[i][ACOMP];
#elif CHAN_TYPE == GL_UNSIGNED_SHORT
GLint r = (rgba[i][RCOMP] * dest[i][RCOMP] + 65535) >> 16;
GLint g = (rgba[i][GCOMP] * dest[i][GCOMP] + 65535) >> 16;
GLint b = (rgba[i][BCOMP] * dest[i][BCOMP] + 65535) >> 16;
GLint a = (rgba[i][ACOMP] * dest[i][ACOMP] + 65535) >> 16;
rgba[i][RCOMP] = (GLchan) r;
rgba[i][GCOMP] = (GLchan) g;
rgba[i][BCOMP] = (GLchan) b;
rgba[i][ACOMP] = (GLchan) a;
#else
GLint r = (rgba[i][RCOMP] * dest[i][RCOMP] + 255) >> 8;
GLint g = (rgba[i][GCOMP] * dest[i][GCOMP] + 255) >> 8;
GLint b = (rgba[i][BCOMP] * dest[i][BCOMP] + 255) >> 8;
GLint a = (rgba[i][ACOMP] * dest[i][ACOMP] + 255) >> 8;
rgba[i][RCOMP] = (GLchan) r;
rgba[i][GCOMP] = (GLchan) g;
rgba[i][BCOMP] = (GLchan) b;
rgba[i][ACOMP] = (GLchan) a;
#endif
}
}
}
/*
* General case blend pixels.
* Input: n - number of pixels
* mask - the usual write mask
* In/Out: rgba - the incoming and modified pixels
* Input: dest - the pixels from the dest color buffer
*/
static void _BLENDAPI
blend_general( GLcontext *ctx, GLuint n, const GLubyte mask[],
GLchan rgba[][4], CONST GLchan dest[][4] )
{
const GLfloat rscale = 1.0F / CHAN_MAXF;
const GLfloat gscale = 1.0F / CHAN_MAXF;
const GLfloat bscale = 1.0F / CHAN_MAXF;
const GLfloat ascale = 1.0F / CHAN_MAXF;
GLuint i;
for (i=0;i<n;i++) {
if (mask[i]) {
#if CHAN_TYPE == GL_FLOAT
GLfloat Rs, Gs, Bs, As; /* Source colors */
GLfloat Rd, Gd, Bd, Ad; /* Dest colors */
#else
GLint Rs, Gs, Bs, As; /* Source colors */
GLint Rd, Gd, Bd, Ad; /* Dest colors */
#endif
GLfloat sR, sG, sB, sA; /* Source scaling */
GLfloat dR, dG, dB, dA; /* Dest scaling */
GLfloat r, g, b, a; /* result color */
/* Incoming/source Color */
Rs = rgba[i][RCOMP];
Gs = rgba[i][GCOMP];
Bs = rgba[i][BCOMP];
As = rgba[i][ACOMP];
#if CHAN_TYPE == GL_FLOAT
/* clamp */
Rs = MIN2(Rs, CHAN_MAXF);
Gs = MIN2(Gs, CHAN_MAXF);
Bs = MIN2(Bs, CHAN_MAXF);
As = MIN2(As, CHAN_MAXF);
#endif
/* Frame buffer/dest color */
Rd = dest[i][RCOMP];
Gd = dest[i][GCOMP];
Bd = dest[i][BCOMP];
Ad = dest[i][ACOMP];
#if CHAN_TYPE == GL_FLOAT
/* clamp */
Rd = MIN2(Rd, CHAN_MAXF);
Gd = MIN2(Gd, CHAN_MAXF);
Bd = MIN2(Bd, CHAN_MAXF);
Ad = MIN2(Ad, CHAN_MAXF);
#endif
/* Source RGB factor */
switch (ctx->Color.BlendSrcRGB) {
case GL_ZERO:
sR = sG = sB = 0.0F;
break;
case GL_ONE:
sR = sG = sB = 1.0F;
break;
case GL_DST_COLOR:
sR = (GLfloat) Rd * rscale;
sG = (GLfloat) Gd * gscale;
sB = (GLfloat) Bd * bscale;
break;
case GL_ONE_MINUS_DST_COLOR:
sR = 1.0F - (GLfloat) Rd * rscale;
sG = 1.0F - (GLfloat) Gd * gscale;
sB = 1.0F - (GLfloat) Bd * bscale;
break;
case GL_SRC_ALPHA:
sR = sG = sB = (GLfloat) As * ascale;
break;
case GL_ONE_MINUS_SRC_ALPHA:
sR = sG = sB = 1.0F - (GLfloat) As * ascale;
break;
case GL_DST_ALPHA:
sR = sG = sB = (GLfloat) Ad * ascale;
break;
case GL_ONE_MINUS_DST_ALPHA:
sR = sG = sB = 1.0F - (GLfloat) Ad * ascale;
break;
case GL_SRC_ALPHA_SATURATE:
if (As < CHAN_MAX - Ad) {
sR = sG = sB = (GLfloat) As * ascale;
}
else {
sR = sG = sB = 1.0F - (GLfloat) Ad * ascale;
}
break;
case GL_CONSTANT_COLOR:
sR = ctx->Color.BlendColor[0];
sG = ctx->Color.BlendColor[1];
sB = ctx->Color.BlendColor[2];
break;
case GL_ONE_MINUS_CONSTANT_COLOR:
sR = 1.0F - ctx->Color.BlendColor[0];
sG = 1.0F - ctx->Color.BlendColor[1];
sB = 1.0F - ctx->Color.BlendColor[2];
break;
case GL_CONSTANT_ALPHA:
sR = sG = sB = ctx->Color.BlendColor[3];
break;
case GL_ONE_MINUS_CONSTANT_ALPHA:
sR = sG = sB = 1.0F - ctx->Color.BlendColor[3];
break;
case GL_SRC_COLOR: /* GL_NV_blend_square */
sR = (GLfloat) Rs * rscale;
sG = (GLfloat) Gs * gscale;
sB = (GLfloat) Bs * bscale;
break;
case GL_ONE_MINUS_SRC_COLOR: /* GL_NV_blend_square */
sR = 1.0F - (GLfloat) Rs * rscale;
sG = 1.0F - (GLfloat) Gs * gscale;
sB = 1.0F - (GLfloat) Bs * bscale;
break;
default:
/* this should never happen */
_mesa_problem(ctx, "Bad blend source RGB factor in do_blend");
return;
}
/* Source Alpha factor */
switch (ctx->Color.BlendSrcA) {
case GL_ZERO:
sA = 0.0F;
break;
case GL_ONE:
sA = 1.0F;
break;
case GL_DST_COLOR:
sA = (GLfloat) Ad * ascale;
break;
case GL_ONE_MINUS_DST_COLOR:
sA = 1.0F - (GLfloat) Ad * ascale;
break;
case GL_SRC_ALPHA:
sA = (GLfloat) As * ascale;
break;
case GL_ONE_MINUS_SRC_ALPHA:
sA = 1.0F - (GLfloat) As * ascale;
break;
case GL_DST_ALPHA:
sA =(GLfloat) Ad * ascale;
break;
case GL_ONE_MINUS_DST_ALPHA:
sA = 1.0F - (GLfloat) Ad * ascale;
break;
case GL_SRC_ALPHA_SATURATE:
sA = 1.0;
break;
case GL_CONSTANT_COLOR:
sA = ctx->Color.BlendColor[3];
break;
case GL_ONE_MINUS_CONSTANT_COLOR:
sA = 1.0F - ctx->Color.BlendColor[3];
break;
case GL_CONSTANT_ALPHA:
sA = ctx->Color.BlendColor[3];
break;
case GL_ONE_MINUS_CONSTANT_ALPHA:
sA = 1.0F - ctx->Color.BlendColor[3];
break;
case GL_SRC_COLOR: /* GL_NV_blend_square */
sA = (GLfloat) As * ascale;
break;
case GL_ONE_MINUS_SRC_COLOR: /* GL_NV_blend_square */
sA = 1.0F - (GLfloat) As * ascale;
break;
default:
/* this should never happen */
sA = 0.0F;
_mesa_problem(ctx, "Bad blend source A factor in do_blend");
}
/* Dest RGB factor */
switch (ctx->Color.BlendDstRGB) {
case GL_ZERO:
dR = dG = dB = 0.0F;
break;
case GL_ONE:
dR = dG = dB = 1.0F;
break;
case GL_SRC_COLOR:
dR = (GLfloat) Rs * rscale;
dG = (GLfloat) Gs * gscale;
dB = (GLfloat) Bs * bscale;
break;
case GL_ONE_MINUS_SRC_COLOR:
dR = 1.0F - (GLfloat) Rs * rscale;
dG = 1.0F - (GLfloat) Gs * gscale;
dB = 1.0F - (GLfloat) Bs * bscale;
break;
case GL_SRC_ALPHA:
dR = dG = dB = (GLfloat) As * ascale;
break;
case GL_ONE_MINUS_SRC_ALPHA:
dR = dG = dB = 1.0F - (GLfloat) As * ascale;
break;
case GL_DST_ALPHA:
dR = dG = dB = (GLfloat) Ad * ascale;
break;
case GL_ONE_MINUS_DST_ALPHA:
dR = dG = dB = 1.0F - (GLfloat) Ad * ascale;
break;
case GL_CONSTANT_COLOR:
dR = ctx->Color.BlendColor[0];
dG = ctx->Color.BlendColor[1];
dB = ctx->Color.BlendColor[2];
break;
case GL_ONE_MINUS_CONSTANT_COLOR:
dR = 1.0F - ctx->Color.BlendColor[0];
dG = 1.0F - ctx->Color.BlendColor[1];
dB = 1.0F - ctx->Color.BlendColor[2];
break;
case GL_CONSTANT_ALPHA:
dR = dG = dB = ctx->Color.BlendColor[3];
break;
case GL_ONE_MINUS_CONSTANT_ALPHA:
dR = dG = dB = 1.0F - ctx->Color.BlendColor[3];
break;
case GL_DST_COLOR: /* GL_NV_blend_square */
dR = (GLfloat) Rd * rscale;
dG = (GLfloat) Gd * gscale;
dB = (GLfloat) Bd * bscale;
break;
case GL_ONE_MINUS_DST_COLOR: /* GL_NV_blend_square */
dR = 1.0F - (GLfloat) Rd * rscale;
dG = 1.0F - (GLfloat) Gd * gscale;
dB = 1.0F - (GLfloat) Bd * bscale;
break;
default:
/* this should never happen */
dR = dG = dB = 0.0F;
_mesa_problem(ctx, "Bad blend dest RGB factor in do_blend");
}
/* Dest Alpha factor */
switch (ctx->Color.BlendDstA) {
case GL_ZERO:
dA = 0.0F;
break;
case GL_ONE:
dA = 1.0F;
break;
case GL_SRC_COLOR:
dA = (GLfloat) As * ascale;
break;
case GL_ONE_MINUS_SRC_COLOR:
dA = 1.0F - (GLfloat) As * ascale;
break;
case GL_SRC_ALPHA:
dA = (GLfloat) As * ascale;
break;
case GL_ONE_MINUS_SRC_ALPHA:
dA = 1.0F - (GLfloat) As * ascale;
break;
case GL_DST_ALPHA:
dA = (GLfloat) Ad * ascale;
break;
case GL_ONE_MINUS_DST_ALPHA:
dA = 1.0F - (GLfloat) Ad * ascale;
break;
case GL_CONSTANT_COLOR:
dA = ctx->Color.BlendColor[3];
break;
case GL_ONE_MINUS_CONSTANT_COLOR:
dA = 1.0F - ctx->Color.BlendColor[3];
break;
case GL_CONSTANT_ALPHA:
dA = ctx->Color.BlendColor[3];
break;
case GL_ONE_MINUS_CONSTANT_ALPHA:
dA = 1.0F - ctx->Color.BlendColor[3];
break;
case GL_DST_COLOR: /* GL_NV_blend_square */
dA = (GLfloat) Ad * ascale;
break;
case GL_ONE_MINUS_DST_COLOR: /* GL_NV_blend_square */
dA = 1.0F - (GLfloat) Ad * ascale;
break;
default:
/* this should never happen */
dA = 0.0F;
_mesa_problem(ctx, "Bad blend dest A factor in do_blend");
return;
}
/* Due to round-off problems we have to clamp against zero. */
/* Optimization: we don't have to do this for all src & dst factors */
if (dA < 0.0F) dA = 0.0F;
if (dR < 0.0F) dR = 0.0F;
if (dG < 0.0F) dG = 0.0F;
if (dB < 0.0F) dB = 0.0F;
if (sA < 0.0F) sA = 0.0F;
if (sR < 0.0F) sR = 0.0F;
if (sG < 0.0F) sG = 0.0F;
if (sB < 0.0F) sB = 0.0F;
ASSERT( sR <= 1.0 );
ASSERT( sG <= 1.0 );
ASSERT( sB <= 1.0 );
ASSERT( sA <= 1.0 );
ASSERT( dR <= 1.0 );
ASSERT( dG <= 1.0 );
ASSERT( dB <= 1.0 );
ASSERT( dA <= 1.0 );
/* compute blended color */
#if CHAN_TYPE == GL_FLOAT
if (ctx->Color.BlendEquation==GL_FUNC_ADD_EXT) {
r = Rs * sR + Rd * dR;
g = Gs * sG + Gd * dG;
b = Bs * sB + Bd * dB;
a = As * sA + Ad * dA;
}
else if (ctx->Color.BlendEquation==GL_FUNC_SUBTRACT_EXT) {
r = Rs * sR - Rd * dR;
g = Gs * sG - Gd * dG;
b = Bs * sB - Bd * dB;
a = As * sA - Ad * dA;
}
else if (ctx->Color.BlendEquation==GL_FUNC_REVERSE_SUBTRACT_EXT) {
r = Rd * dR - Rs * sR;
g = Gd * dG - Gs * sG;
b = Bd * dB - Bs * sB;
a = Ad * dA - As * sA;
}
else {
/* should never get here */
r = g = b = a = 0.0F; /* silence uninitialized var warning */
_mesa_problem(ctx, "unexpected BlendEquation in blend_general()");
}
/* final clamping */
rgba[i][RCOMP] = MAX2( r, 0.0F );
rgba[i][GCOMP] = MAX2( g, 0.0F );
rgba[i][BCOMP] = MAX2( b, 0.0F );
rgba[i][ACOMP] = CLAMP( a, 0.0F, CHAN_MAXF );
#else
if (ctx->Color.BlendEquation==GL_FUNC_ADD_EXT) {
r = Rs * sR + Rd * dR + 0.5F;
g = Gs * sG + Gd * dG + 0.5F;
b = Bs * sB + Bd * dB + 0.5F;
a = As * sA + Ad * dA + 0.5F;
}
else if (ctx->Color.BlendEquation==GL_FUNC_SUBTRACT_EXT) {
r = Rs * sR - Rd * dR + 0.5F;
g = Gs * sG - Gd * dG + 0.5F;
b = Bs * sB - Bd * dB + 0.5F;
a = As * sA - Ad * dA + 0.5F;
}
else if (ctx->Color.BlendEquation==GL_FUNC_REVERSE_SUBTRACT_EXT) {
r = Rd * dR - Rs * sR + 0.5F;
g = Gd * dG - Gs * sG + 0.5F;
b = Bd * dB - Bs * sB + 0.5F;
a = Ad * dA - As * sA + 0.5F;
}
else {
/* should never get here */
r = g = b = a = 0.0F; /* silence uninitialized var warning */
_mesa_problem(ctx, "unexpected BlendEquation in blend_general()");
}
/* final clamping */
rgba[i][RCOMP] = (GLchan) (GLint) CLAMP( r, 0.0F, CHAN_MAXF );
rgba[i][GCOMP] = (GLchan) (GLint) CLAMP( g, 0.0F, CHAN_MAXF );
rgba[i][BCOMP] = (GLchan) (GLint) CLAMP( b, 0.0F, CHAN_MAXF );
rgba[i][ACOMP] = (GLchan) (GLint) CLAMP( a, 0.0F, CHAN_MAXF );
#endif
}
}
}
/*
* Analyze current blending parameters to pick fastest blending function.
* Result: the ctx->Color.BlendFunc pointer is updated.
*/
void _swrast_choose_blend_func( GLcontext *ctx )
{
const GLenum eq = ctx->Color.BlendEquation;
const GLenum srcRGB = ctx->Color.BlendSrcRGB;
const GLenum dstRGB = ctx->Color.BlendDstRGB;
const GLenum srcA = ctx->Color.BlendSrcA;
const GLenum dstA = ctx->Color.BlendDstA;
if (srcRGB != srcA || dstRGB != dstA) {
SWRAST_CONTEXT(ctx)->BlendFunc = blend_general;
}
else if (eq==GL_FUNC_ADD_EXT && srcRGB==GL_SRC_ALPHA
&& dstRGB==GL_ONE_MINUS_SRC_ALPHA) {
#if defined(USE_MMX_ASM)
if ( cpu_has_mmx ) {
SWRAST_CONTEXT(ctx)->BlendFunc = _mesa_mmx_blend_transparency;
}
else
#endif
SWRAST_CONTEXT(ctx)->BlendFunc = blend_transparency;
}
else if (eq==GL_FUNC_ADD_EXT && srcRGB==GL_ONE && dstRGB==GL_ONE) {
#if defined(USE_MMX_ASM)
if ( cpu_has_mmx ) {
SWRAST_CONTEXT(ctx)->BlendFunc = _mesa_mmx_blend_add;
}
else
#endif
SWRAST_CONTEXT(ctx)->BlendFunc = blend_add;
}
else if (((eq==GL_FUNC_ADD_EXT || eq==GL_FUNC_REVERSE_SUBTRACT_EXT)
&& (srcRGB==GL_ZERO && dstRGB==GL_SRC_COLOR))
||
((eq==GL_FUNC_ADD_EXT || eq==GL_FUNC_SUBTRACT_EXT)
&& (srcRGB==GL_DST_COLOR && dstRGB==GL_ZERO))) {
#if defined(USE_MMX_ASM)
if ( cpu_has_mmx ) {
SWRAST_CONTEXT(ctx)->BlendFunc = _mesa_mmx_blend_modulate;
}
else
#endif
SWRAST_CONTEXT(ctx)->BlendFunc = blend_modulate;
}
else if (eq==GL_MIN_EXT) {
#if defined(USE_MMX_ASM)
if ( cpu_has_mmx ) {
SWRAST_CONTEXT(ctx)->BlendFunc = _mesa_mmx_blend_min;
}
else
#endif
SWRAST_CONTEXT(ctx)->BlendFunc = blend_min;
}
else if (eq==GL_MAX_EXT) {
#if defined(USE_MMX_ASM)
if ( cpu_has_mmx ) {
SWRAST_CONTEXT(ctx)->BlendFunc = _mesa_mmx_blend_max;
}
else
#endif
SWRAST_CONTEXT(ctx)->BlendFunc = blend_max;
}
else if (eq==GL_FUNC_ADD_EXT && srcRGB == GL_ZERO && dstRGB == GL_ONE) {
SWRAST_CONTEXT(ctx)->BlendFunc = blend_noop;
}
else if (eq==GL_FUNC_ADD_EXT && srcRGB == GL_ONE && dstRGB == GL_ZERO) {
SWRAST_CONTEXT(ctx)->BlendFunc = blend_replace;
}
else {
SWRAST_CONTEXT(ctx)->BlendFunc = blend_general;
}
}
/*
* Apply the blending operator to a span of pixels.
* We can handle horizontal runs of pixels (spans) or arrays of x/y
* pixel coordinates.
*/
void
_mesa_blend_span( GLcontext *ctx, const struct sw_span *span,
GLchan rgba[][4] )
{
SWcontext *swrast = SWRAST_CONTEXT(ctx);
GLchan framebuffer[MAX_WIDTH][4];
ASSERT(span->end <= MAX_WIDTH);
ASSERT(span->arrayMask & SPAN_RGBA);
ASSERT(!ctx->Color.ColorLogicOpEnabled);
/* Read span of current frame buffer pixels */
if (span->arrayMask & SPAN_XY) {
/* array of x/y pixel coords */
(*swrast->Driver.ReadRGBAPixels)( ctx, span->end,
span->array->x, span->array->y,
framebuffer, span->array->mask );
if (swrast->_RasterMask & ALPHABUF_BIT) {
_mesa_read_alpha_pixels( ctx, span->end,
span->array->x, span->array->y,
framebuffer, span->array->mask );
}
}
else {
/* horizontal run of pixels */
_mesa_read_rgba_span( ctx, ctx->DrawBuffer, span->end,
span->x, span->y, framebuffer );
}
SWRAST_CONTEXT(ctx)->BlendFunc( ctx, span->end, span->array->mask, rgba,
(const GLchan (*)[4]) framebuffer );
}