--- /dev/null
+/* $Id: accum.c,v 1.5 1997/07/24 01:24:28 brianp Exp $ */
+
+/*
+ * Mesa 3-D graphics library
+ * Version: 2.4
+ * Copyright (C) 1995-1997 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 1.5 1997/07/24 01:24:28 brianp
+ * changed precompiled header symbol from PCH to PC_HEADER
+ *
+ * Revision 1.4 1997/05/28 03:23:09 brianp
+ * added precompiled header (PCH) support
+ *
+ * Revision 1.3 1997/04/30 01:54:48 brianp
+ * call gl_warning() if calling gl_Accum w/out accum buffer
+ *
+ * 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
+ *
+ */
+
+
+#ifdef PC_HEADER
+#include "all.h"
+#else
+#include <limits.h>
+#include <stdlib.h>
+#include <string.h>
+#include "accum.h"
+#include "context.h"
+#include "dlist.h"
+#include "macros.h"
+#include "types.h"
+#endif
+
+
+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 (INSIDE_BEGIN_END(ctx)) {
+ gl_error( ctx, GL_INVALID_OPERATION, "glAccum" );
+ return;
+ }
+
+ if (ctx->Visual->AccumBits==0 || !ctx->Buffer->Accum) {
+ /* No accumulation buffer! */
+ gl_warning(ctx, "Calling glAccum() without an 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;
+ }
+
+ /* 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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