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/* $Id: accum.c,v 1.2 1996/09/15 14:19:44 brianp Exp $ */
/*
* Mesa 3-D graphics library
* Version: 2.0
* Copyright (C) 1995-1996 Brian Paul
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Library General Public
* License as published by the Free Software Foundation; either
* version 2 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Library General Public License for more details.
*
* You should have received a copy of the GNU Library General Public
* License along with this library; if not, write to the Free
* Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
/*
* $Log: accum.c,v $
* Revision 1.2 1996/09/15 14:19:44 brianp
* now use GLframebuffer and GLvisual
* added gl_alloc_accum_buffer()
*
* Revision 1.1 1996/09/13 01:38:16 brianp
* Initial revision
*
*/
#include <limits.h>
#include <stdlib.h>
#include <string.h>
#include "accum.h"
#include "context.h"
#include "dlist.h"
#include "macros.h"
#include "types.h"
void gl_alloc_accum_buffer( GLcontext *ctx )
{
GLint n;
if (ctx->Buffer->Accum) {
free( ctx->Buffer->Accum );
ctx->Buffer->Accum = NULL;
}
/* allocate accumulation buffer if not already present */
n = ctx->Buffer->Width * ctx->Buffer->Height * 4 * sizeof(GLaccum);
ctx->Buffer->Accum = (GLaccum *) malloc( n );
if (!ctx->Buffer->Accum) {
/* unable to setup accumulation buffer */
gl_error( ctx, GL_OUT_OF_MEMORY, "glAccum" );
}
}
void gl_ClearAccum( GLcontext *ctx,
GLfloat red, GLfloat green, GLfloat blue, GLfloat alpha )
{
if (INSIDE_BEGIN_END(ctx)) {
gl_error( ctx, GL_INVALID_OPERATION, "glAccum" );
return;
}
ctx->Accum.ClearColor[0] = CLAMP( red, -1.0, 1.0 );
ctx->Accum.ClearColor[1] = CLAMP( green, -1.0, 1.0 );
ctx->Accum.ClearColor[2] = CLAMP( blue, -1.0, 1.0 );
ctx->Accum.ClearColor[3] = CLAMP( alpha, -1.0, 1.0 );
}
void gl_Accum( GLcontext *ctx, GLenum op, GLfloat value )
{
GLuint xpos, ypos, width, height;
GLfloat acc_scale;
if (ctx->Visual->AccumBits==0 || !ctx->Buffer->Accum) {
/* No accumulation buffer! */
return;
}
if (sizeof(GLaccum)==1) {
acc_scale = 127.0;
}
else if (sizeof(GLaccum)==2) {
acc_scale = 32767.0;
}
else {
/* sizeof(GLaccum) > 2 (Cray) */
acc_scale = (float) SHRT_MAX;
}
if (INSIDE_BEGIN_END(ctx)) {
gl_error( ctx, GL_INVALID_OPERATION, "glAccum" );
return;
}
/* Determine region to operate upon. */
if (ctx->Scissor.Enabled) {
xpos = ctx->Scissor.X;
ypos = ctx->Scissor.Y;
width = ctx->Scissor.Width;
height = ctx->Scissor.Height;
}
else {
/* whole window */
xpos = 0;
ypos = 0;
width = ctx->Buffer->Width;
height = ctx->Buffer->Height;
}
switch (op) {
case GL_ADD:
{
GLaccum ival, *acc;
GLuint i, j;
ival = (GLaccum) (value * acc_scale);
for (j=0;j<height;j++) {
acc = ctx->Buffer->Accum
+ (ypos * ctx->Buffer->Width + xpos) * 4;
for (i=0;i<width;i++) {
*acc += ival; acc++; /* red */
*acc += ival; acc++; /* green */
*acc += ival; acc++; /* blue */
*acc += ival; acc++; /* alpha */
}
ypos++;
}
}
break;
case GL_MULT:
{
GLaccum *acc;
GLuint i, j;
for (j=0;j<height;j++) {
acc = ctx->Buffer->Accum
+ (ypos * ctx->Buffer->Width + xpos) * 4;
for (i=0;i<width;i++) {
*acc = (GLaccum) ( (GLfloat) *acc * value ); acc++; /*r*/
*acc = (GLaccum) ( (GLfloat) *acc * value ); acc++; /*g*/
*acc = (GLaccum) ( (GLfloat) *acc * value ); acc++; /*g*/
*acc = (GLaccum) ( (GLfloat) *acc * value ); acc++; /*a*/
}
ypos++;
}
}
break;
case GL_ACCUM:
{
GLaccum *acc;
GLubyte red[MAX_WIDTH], green[MAX_WIDTH];
GLubyte blue[MAX_WIDTH], alpha[MAX_WIDTH];
GLfloat rscale, gscale, bscale, ascale;
GLuint i, j;
(void) (*ctx->Driver.SetBuffer)( ctx, ctx->Pixel.ReadBuffer );
/* Accumulate */
rscale = value * acc_scale * ctx->Visual->InvRedScale;
gscale = value * acc_scale * ctx->Visual->InvGreenScale;
bscale = value * acc_scale * ctx->Visual->InvBlueScale;
ascale = value * acc_scale * ctx->Visual->InvAlphaScale;
for (j=0;j<height;j++) {
(*ctx->Driver.ReadColorSpan)( ctx, width, xpos, ypos,
red, green, blue, alpha);
acc = ctx->Buffer->Accum
+ (ypos * ctx->Buffer->Width + xpos) * 4;
for (i=0;i<width;i++) {
*acc += (GLaccum) ( (GLfloat) red[i] * rscale ); acc++;
*acc += (GLaccum) ( (GLfloat) green[i] * gscale ); acc++;
*acc += (GLaccum) ( (GLfloat) blue[i] * bscale ); acc++;
*acc += (GLaccum) ( (GLfloat) alpha[i] * ascale ); acc++;
}
ypos++;
}
(void) (*ctx->Driver.SetBuffer)( ctx, ctx->Color.DrawBuffer );
}
break;
case GL_LOAD:
{
GLaccum *acc;
GLubyte red[MAX_WIDTH], green[MAX_WIDTH];
GLubyte blue[MAX_WIDTH], alpha[MAX_WIDTH];
GLfloat rscale, gscale, bscale, ascale;
GLuint i, j;
(void) (*ctx->Driver.SetBuffer)( ctx, ctx->Pixel.ReadBuffer );
/* Load accumulation buffer */
rscale = value * acc_scale * ctx->Visual->InvRedScale;
gscale = value * acc_scale * ctx->Visual->InvGreenScale;
bscale = value * acc_scale * ctx->Visual->InvBlueScale;
ascale = value * acc_scale * ctx->Visual->InvAlphaScale;
for (j=0;j<height;j++) {
(*ctx->Driver.ReadColorSpan)( ctx, width, xpos, ypos,
red, green, blue, alpha);
acc = ctx->Buffer->Accum
+ (ypos * ctx->Buffer->Width + xpos) * 4;
for (i=0;i<width;i++) {
*acc++ = (GLaccum) ( (GLfloat) red[i] * rscale );
*acc++ = (GLaccum) ( (GLfloat) green[i] * gscale );
*acc++ = (GLaccum) ( (GLfloat) blue[i] * bscale );
*acc++ = (GLaccum) ( (GLfloat) alpha[i] * ascale );
}
ypos++;
}
(void) (*ctx->Driver.SetBuffer)( ctx, ctx->Color.DrawBuffer );
}
break;
case GL_RETURN:
{
GLubyte red[MAX_WIDTH], green[MAX_WIDTH];
GLubyte blue[MAX_WIDTH], alpha[MAX_WIDTH];
GLaccum *acc;
GLfloat rscale, gscale, bscale, ascale;
GLint rmax, gmax, bmax, amax;
GLuint i, j;
rscale = value / acc_scale * ctx->Visual->RedScale;
gscale = value / acc_scale * ctx->Visual->GreenScale;
bscale = value / acc_scale * ctx->Visual->BlueScale;
ascale = value / acc_scale * ctx->Visual->AlphaScale;
rmax = (GLint) ctx->Visual->RedScale;
gmax = (GLint) ctx->Visual->GreenScale;
bmax = (GLint) ctx->Visual->BlueScale;
amax = (GLint) ctx->Visual->AlphaScale;
for (j=0;j<height;j++) {
acc = ctx->Buffer->Accum
+ (ypos * ctx->Buffer->Width + xpos) * 4;
for (i=0;i<width;i++) {
GLint r, g, b, a;
r = (GLint) ( (GLfloat) (*acc++) * rscale + 0.5F );
g = (GLint) ( (GLfloat) (*acc++) * gscale + 0.5F );
b = (GLint) ( (GLfloat) (*acc++) * bscale + 0.5F );
a = (GLint) ( (GLfloat) (*acc++) * ascale + 0.5F );
red[i] = CLAMP( r, 0, rmax );
green[i] = CLAMP( g, 0, gmax );
blue[i] = CLAMP( b, 0, bmax );
alpha[i] = CLAMP( a, 0, amax );
}
(*ctx->Driver.WriteColorSpan)( ctx, width, xpos, ypos,
red, green, blue, alpha, NULL );
ypos++;
}
}
break;
default:
gl_error( ctx, GL_INVALID_ENUM, "glAccum" );
}
}
/*
* Clear the accumulation Buffer->
*/
void gl_clear_accum_buffer( GLcontext *ctx )
{
GLuint buffersize;
GLfloat acc_scale;
if (ctx->Visual->AccumBits==0) {
/* No accumulation buffer! */
return;
}
if (sizeof(GLaccum)==1) {
acc_scale = 127.0;
}
else if (sizeof(GLaccum)==2) {
acc_scale = 32767.0;
}
else {
/* sizeof(GLaccum) > 2 (Cray) */
acc_scale = (float) SHRT_MAX;
}
/* number of pixels */
buffersize = ctx->Buffer->Width * ctx->Buffer->Height;
if (!ctx->Buffer->Accum) {
/* try to alloc accumulation buffer */
ctx->Buffer->Accum = (GLaccum *)
malloc( buffersize * 4 * sizeof(GLaccum) );
}
if (ctx->Buffer->Accum) {
if (ctx->Scissor.Enabled) {
/* Limit clear to scissor box */
GLaccum r, g, b, a;
GLint i, j;
GLint width, height;
GLaccum *row;
r = (GLaccum) (ctx->Accum.ClearColor[0] * acc_scale);
g = (GLaccum) (ctx->Accum.ClearColor[1] * acc_scale);
b = (GLaccum) (ctx->Accum.ClearColor[2] * acc_scale);
a = (GLaccum) (ctx->Accum.ClearColor[3] * acc_scale);
/* size of region to clear */
width = 4 * (ctx->Buffer->Xmax - ctx->Buffer->Xmin + 1);
height = ctx->Buffer->Ymax - ctx->Buffer->Ymin + 1;
/* ptr to first element to clear */
row = ctx->Buffer->Accum
+ 4 * (ctx->Buffer->Ymin * ctx->Buffer->Width
+ ctx->Buffer->Xmin);
for (j=0;j<height;j++) {
for (i=0;i<width;i+=4) {
row[i+0] = r;
row[i+1] = g;
row[i+2] = b;
row[i+3] = a;
}
row += 4 * ctx->Buffer->Width;
}
}
else {
/* clear whole buffer */
if (ctx->Accum.ClearColor[0]==0.0 &&
ctx->Accum.ClearColor[1]==0.0 &&
ctx->Accum.ClearColor[2]==0.0 &&
ctx->Accum.ClearColor[3]==0.0) {
/* Black */
MEMSET( ctx->Buffer->Accum, 0, buffersize * 4 * sizeof(GLaccum) );
}
else {
/* Not black */
GLaccum *acc, r, g, b, a;
GLuint i;
acc = ctx->Buffer->Accum;
r = (GLaccum) (ctx->Accum.ClearColor[0] * acc_scale);
g = (GLaccum) (ctx->Accum.ClearColor[1] * acc_scale);
b = (GLaccum) (ctx->Accum.ClearColor[2] * acc_scale);
a = (GLaccum) (ctx->Accum.ClearColor[3] * acc_scale);
for (i=0;i<buffersize;i++) {
*acc++ = r;
*acc++ = g;
*acc++ = b;
*acc++ = a;
}
}
}
}
}
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