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/* $Id: s_alphabuf.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.
*/
/*
* Software alpha planes. Many frame buffers don't have alpha bits so
* we simulate them in software.
*/
#include "glheader.h"
#include "context.h"
#include "imports.h"
#include "s_context.h"
#include "s_alphabuf.h"
/*
* Allocate a new front and back alpha buffer.
*/
void
_mesa_alloc_alpha_buffers( GLframebuffer *buffer )
{
const GLint bytes = buffer->Width * buffer->Height * sizeof(GLchan);
ASSERT(buffer->UseSoftwareAlphaBuffers);
if (buffer->FrontLeftAlpha) {
MESA_PBUFFER_FREE( buffer->FrontLeftAlpha );
}
buffer->FrontLeftAlpha = MESA_PBUFFER_ALLOC( bytes );
if (!buffer->FrontLeftAlpha) {
/* out of memory */
_mesa_error( NULL, GL_OUT_OF_MEMORY,
"Couldn't allocate front-left alpha buffer" );
}
if (buffer->Visual.doubleBufferMode) {
if (buffer->BackLeftAlpha) {
MESA_PBUFFER_FREE( buffer->BackLeftAlpha );
}
buffer->BackLeftAlpha = MESA_PBUFFER_ALLOC( bytes );
if (!buffer->BackLeftAlpha) {
/* out of memory */
_mesa_error( NULL, GL_OUT_OF_MEMORY,
"Couldn't allocate back-left alpha buffer" );
}
}
if (buffer->Visual.stereoMode) {
if (buffer->FrontRightAlpha) {
MESA_PBUFFER_FREE( buffer->FrontRightAlpha );
}
buffer->FrontRightAlpha = MESA_PBUFFER_ALLOC( bytes );
if (!buffer->FrontRightAlpha) {
/* out of memory */
_mesa_error( NULL, GL_OUT_OF_MEMORY,
"Couldn't allocate front-right alpha buffer" );
}
if (buffer->Visual.doubleBufferMode) {
if (buffer->BackRightAlpha) {
MESA_PBUFFER_FREE( buffer->BackRightAlpha );
}
buffer->BackRightAlpha = MESA_PBUFFER_ALLOC( bytes );
if (!buffer->BackRightAlpha) {
/* out of memory */
_mesa_error( NULL, GL_OUT_OF_MEMORY,
"Couldn't allocate back-right alpha buffer" );
}
}
}
}
/*
* Clear all the alpha buffers
*/
void
_mesa_clear_alpha_buffers( GLcontext *ctx )
{
const GLchan aclear = (GLchan) ctx->Color.ClearColor[3];
GLuint bufferBit;
ASSERT(ctx->DrawBuffer->UseSoftwareAlphaBuffers);
ASSERT(ctx->Color.ColorMask[ACOMP]);
/* loop over four possible alpha buffers */
for (bufferBit = 1; bufferBit <= 8; bufferBit = bufferBit << 1) {
if (bufferBit & ctx->Color._DrawDestMask) {
GLchan *buffer;
if (bufferBit == FRONT_LEFT_BIT) {
buffer = (GLchan *) ctx->DrawBuffer->FrontLeftAlpha;
}
else if (bufferBit == FRONT_RIGHT_BIT) {
buffer = (GLchan *) ctx->DrawBuffer->FrontRightAlpha;
}
else if (bufferBit == BACK_LEFT_BIT) {
buffer = (GLchan *) ctx->DrawBuffer->BackLeftAlpha;
}
else {
buffer = (GLchan *) ctx->DrawBuffer->BackRightAlpha;
}
if (ctx->Scissor.Enabled) {
/* clear scissor region */
GLint j;
GLint rowLen = ctx->DrawBuffer->_Xmax - ctx->DrawBuffer->_Xmin;
GLint rows = ctx->DrawBuffer->_Ymax - ctx->DrawBuffer->_Ymin;
GLint width = ctx->DrawBuffer->Width;
GLchan *aptr = buffer
+ ctx->DrawBuffer->_Ymin * ctx->DrawBuffer->Width
+ ctx->DrawBuffer->_Xmin;
for (j = 0; j < rows; j++) {
#if CHAN_BITS == 8
MEMSET( aptr, aclear, rowLen );
#elif CHAN_BITS == 16
MEMSET16( aptr, aclear, rowLen );
#else
GLint i;
for (i = 0; i < rowLen; i++) {
aptr[i] = aclear;
}
#endif
aptr += width;
}
}
else {
/* clear whole buffer */
GLuint pixels = ctx->DrawBuffer->Width * ctx->DrawBuffer->Height;
#if CHAN_BITS == 8
MEMSET(buffer, aclear, pixels);
#elif CHAN_BITS == 16
MEMSET16(buffer, aclear, pixels);
#else
GLuint i;
for (i = 0; i < pixels; i++) {
buffer[i] = aclear;
}
#endif
}
}
}
}
static INLINE
GLchan *get_alpha_buffer( GLcontext *ctx )
{
SWcontext *swrast = SWRAST_CONTEXT(ctx);
switch (swrast->CurrentBuffer) {
case FRONT_LEFT_BIT:
return (GLchan *) ctx->DrawBuffer->FrontLeftAlpha;
break;
case BACK_LEFT_BIT:
return (GLchan *) ctx->DrawBuffer->BackLeftAlpha;
break;
case FRONT_RIGHT_BIT:
return (GLchan *) ctx->DrawBuffer->FrontRightAlpha;
break;
case BACK_RIGHT_BIT:
return (GLchan *) ctx->DrawBuffer->BackRightAlpha;
break;
default:
_mesa_problem(ctx, "Bad CurrentBuffer in get_alpha_buffer()");
return (GLchan *) ctx->DrawBuffer->FrontLeftAlpha;
}
}
void
_mesa_write_alpha_span( GLcontext *ctx, GLuint n, GLint x, GLint y,
CONST GLchan rgba[][4], const GLubyte mask[] )
{
GLchan *buffer, *aptr;
GLuint i;
buffer = get_alpha_buffer(ctx);
aptr = buffer + y * ctx->DrawBuffer->Width + x;
if (mask) {
for (i=0;i<n;i++) {
if (mask[i]) {
*aptr = rgba[i][ACOMP];
}
aptr++;
}
}
else {
for (i=0;i<n;i++) {
*aptr++ = rgba[i][ACOMP];
}
}
}
void
_mesa_write_mono_alpha_span( GLcontext *ctx, GLuint n, GLint x, GLint y,
GLchan alpha, const GLubyte mask[] )
{
GLchan *buffer, *aptr;
GLuint i;
buffer = get_alpha_buffer(ctx);
aptr = buffer + y * ctx->DrawBuffer->Width + x;
if (mask) {
for (i=0;i<n;i++) {
if (mask[i]) {
*aptr = alpha;
}
aptr++;
}
}
else {
for (i=0;i<n;i++) {
*aptr++ = alpha;
}
}
}
void
_mesa_write_alpha_pixels( GLcontext *ctx,
GLuint n, const GLint x[], const GLint y[],
CONST GLchan rgba[][4], const GLubyte mask[] )
{
GLchan *buffer;
GLuint i;
buffer = get_alpha_buffer(ctx);
if (mask) {
for (i=0;i<n;i++) {
if (mask[i]) {
GLchan *aptr = buffer + y[i] * ctx->DrawBuffer->Width + x[i];
*aptr = rgba[i][ACOMP];
}
}
}
else {
for (i=0;i<n;i++) {
GLchan *aptr = buffer + y[i] * ctx->DrawBuffer->Width + x[i];
*aptr = rgba[i][ACOMP];
}
}
}
void
_mesa_write_mono_alpha_pixels( GLcontext *ctx,
GLuint n, const GLint x[], const GLint y[],
GLchan alpha, const GLubyte mask[] )
{
GLchan *buffer;
GLuint i;
buffer = get_alpha_buffer(ctx);
if (mask) {
for (i=0;i<n;i++) {
if (mask[i]) {
GLchan *aptr = buffer + y[i] * ctx->DrawBuffer->Width + x[i];
*aptr = alpha;
}
}
}
else {
for (i=0;i<n;i++) {
GLchan *aptr = buffer + y[i] * ctx->DrawBuffer->Width + x[i];
*aptr = alpha;
}
}
}
void
_mesa_read_alpha_span( GLcontext *ctx,
GLuint n, GLint x, GLint y, GLchan rgba[][4] )
{
const GLchan *buffer, *aptr;
GLuint i;
buffer = get_alpha_buffer(ctx);
aptr = buffer + y * ctx->DrawBuffer->Width + x;
for (i = 0; i < n; i++)
rgba[i][ACOMP] = *aptr++;
}
void
_mesa_read_alpha_pixels( GLcontext *ctx,
GLuint n, const GLint x[], const GLint y[],
GLchan rgba[][4], const GLubyte mask[] )
{
const GLchan *buffer;
GLuint i;
buffer = get_alpha_buffer(ctx);
for (i = 0; i < n; i++) {
if (mask[i]) {
const GLchan *aptr = buffer + y[i] * ctx->DrawBuffer->Width + x[i];
rgba[i][ACOMP] = *aptr;
}
}
}