/* $Id: stencil.c,v 1.13 1999/12/10 19:09:22 brianp Exp $ */
/*
* Mesa 3-D graphics library
* Version: 3.3
*
* Copyright (C) 1999 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.
*/
#ifdef PC_HEADER
#include "all.h"
#else
#include "glheader.h"
#include "context.h"
#include "depth.h"
#include "mem.h"
#include "pb.h"
#include "stencil.h"
#include "types.h"
#include "enable.h"
#endif
void
_mesa_ClearStencil( GLint s )
{
GET_CURRENT_CONTEXT(ctx);
ASSERT_OUTSIDE_BEGIN_END_AND_FLUSH(ctx, "glClearStencil");
ctx->Stencil.Clear = (GLstencil) s;
if (ctx->Driver.ClearStencil) {
(*ctx->Driver.ClearStencil)( ctx, s );
}
}
void
_mesa_StencilFunc( GLenum func, GLint ref, GLuint mask )
{
GET_CURRENT_CONTEXT(ctx);
GLint maxref;
ASSERT_OUTSIDE_BEGIN_END_AND_FLUSH(ctx, "glStencilFunc");
switch (func) {
case GL_NEVER:
case GL_LESS:
case GL_LEQUAL:
case GL_GREATER:
case GL_GEQUAL:
case GL_EQUAL:
case GL_NOTEQUAL:
case GL_ALWAYS:
ctx->Stencil.Function = func;
break;
default:
gl_error( ctx, GL_INVALID_ENUM, "glStencilFunc" );
return;
}
maxref = (1 << STENCIL_BITS) - 1;
ctx->Stencil.Ref = (GLstencil) CLAMP( ref, 0, maxref );
ctx->Stencil.ValueMask = (GLstencil) mask;
if (ctx->Driver.StencilFunc) {
(*ctx->Driver.StencilFunc)( ctx, func, ctx->Stencil.Ref, mask );
}
}
void
_mesa_StencilMask( GLuint mask )
{
GET_CURRENT_CONTEXT(ctx);
ASSERT_OUTSIDE_BEGIN_END_AND_FLUSH(ctx, "glStencilMask");
ctx->Stencil.WriteMask = (GLstencil) mask;
if (ctx->Driver.StencilMask) {
(*ctx->Driver.StencilMask)( ctx, mask );
}
}
void
_mesa_StencilOp( GLenum fail, GLenum zfail, GLenum zpass )
{
GET_CURRENT_CONTEXT(ctx);
ASSERT_OUTSIDE_BEGIN_END_AND_FLUSH(ctx, "glStencilOp");
switch (fail) {
case GL_KEEP:
case GL_ZERO:
case GL_REPLACE:
case GL_INCR:
case GL_DECR:
case GL_INVERT:
case GL_INCR_WRAP_EXT:
case GL_DECR_WRAP_EXT:
ctx->Stencil.FailFunc = fail;
break;
default:
gl_error( ctx, GL_INVALID_ENUM, "glStencilOp" );
return;
}
switch (zfail) {
case GL_KEEP:
case GL_ZERO:
case GL_REPLACE:
case GL_INCR:
case GL_DECR:
case GL_INVERT:
case GL_INCR_WRAP_EXT:
case GL_DECR_WRAP_EXT:
ctx->Stencil.ZFailFunc = zfail;
break;
default:
gl_error( ctx, GL_INVALID_ENUM, "glStencilOp" );
return;
}
switch (zpass) {
case GL_KEEP:
case GL_ZERO:
case GL_REPLACE:
case GL_INCR:
case GL_DECR:
case GL_INVERT:
case GL_INCR_WRAP_EXT:
case GL_DECR_WRAP_EXT:
ctx->Stencil.ZPassFunc = zpass;
break;
default:
gl_error( ctx, GL_INVALID_ENUM, "glStencilOp" );
return;
}
if (ctx->Driver.StencilOp) {
(*ctx->Driver.StencilOp)( ctx, fail, zfail, zpass );
}
}
/* Stencil Logic:
IF stencil test fails THEN
Apply fail-op to stencil value
Don't write the pixel (RGBA,Z)
ELSE
IF doing depth test && depth test fails THEN
Apply zfail-op to stencil value
Write RGBA and Z to appropriate buffers
ELSE
Apply zpass-op to stencil value
ENDIF
*/
/*
* Return the address of a stencil buffer value given the window coords:
*/
#define STENCIL_ADDRESS(X,Y) \
(ctx->DrawBuffer->Stencil + ctx->DrawBuffer->Width * (Y) + (X))
/*
* Apply the given stencil operator to the array of stencil values.
* Don't touch stencil[i] if mask[i] is zero.
* Input: n - size of stencil array
* oper - the stencil buffer operator
* stencil - array of stencil values
* mask - array [n] of flag: 1=apply operator, 0=don't apply operator
* Output: stencil - modified values
*/
static void apply_stencil_op( const GLcontext *ctx, GLenum oper,
GLuint n, GLstencil stencil[],
const GLubyte mask[] )
{
const GLstencil ref = ctx->Stencil.Ref;
const GLstencil wrtmask = ctx->Stencil.WriteMask;
const GLstencil invmask = (GLstencil) (~ctx->Stencil.WriteMask);
GLuint i;
switch (oper) {
case GL_KEEP:
/* do nothing */
break;
case GL_ZERO:
if (invmask==0) {
for (i=0;i<n;i++) {
if (mask[i]) {
stencil[i] = 0;
}
}
}
else {
for (i=0;i<n;i++) {
if (mask[i]) {
stencil[i] = (GLstencil) (stencil[i] & invmask);
}
}
}
break;
case GL_REPLACE:
if (invmask==0) {
for (i=0;i<n;i++) {
if (mask[i]) {
stencil[i] = ref;
}
}
}
else {
for (i=0;i<n;i++) {
if (mask[i]) {
GLstencil s = stencil[i];
stencil[i] = (GLstencil) ((invmask & s ) | (wrtmask & ref));
}
}
}
break;
case GL_INCR:
if (invmask==0) {
for (i=0;i<n;i++) {
if (mask[i]) {
GLstencil s = stencil[i];
if (s < STENCIL_MAX) {
stencil[i] = (GLstencil) (s+1);
}
}
}
}
else {
for (i=0;i<n;i++) {
if (mask[i]) {
/* VERIFY logic of adding 1 to a write-masked value */
GLstencil s = stencil[i];
if (s < STENCIL_MAX) {
stencil[i] = (GLstencil) ((invmask & s) | (wrtmask & (s+1)));
}
}
}
}
break;
case GL_DECR:
if (invmask==0) {
for (i=0;i<n;i++) {
if (mask[i]) {
GLstencil s = stencil[i];
if (s>0) {
stencil[i] = (GLstencil) (s-1);
}
}
}
}
else {
for (i=0;i<n;i++) {
if (mask[i]) {
/* VERIFY logic of subtracting 1 to a write-masked value */
GLstencil s = stencil[i];
if (s>0) {
stencil[i] = (GLstencil) ((invmask & s) | (wrtmask & (s-1)));
}
}
}
}
break;
case GL_INCR_WRAP_EXT:
if (invmask==0) {
for (i=0;i<n;i++) {
if (mask[i]) {
stencil[i]++;
}
}
}
else {
for (i=0;i<n;i++) {
if (mask[i]) {
GLstencil s = stencil[i];
stencil[i] = (GLstencil) ((invmask & s) | (wrtmask & (s+1)));
}
}
}
break;
case GL_DECR_WRAP_EXT:
if (invmask==0) {
for (i=0;i<n;i++) {
if (mask[i]) {
stencil[i]--;
}
}
}
else {
for (i=0;i<n;i++) {
if (mask[i]) {
GLstencil s = stencil[i];
stencil[i] = (GLstencil) ((invmask & s) | (wrtmask & (s-1)));
}
}
}
break;
case GL_INVERT:
if (invmask==0) {
for (i=0;i<n;i++) {
if (mask[i]) {
GLstencil s = stencil[i];
stencil[i] = (GLstencil) ~s;
}
}
}
else {
for (i=0;i<n;i++) {
if (mask[i]) {
GLstencil s = stencil[i];
stencil[i] = (GLstencil) ((invmask & s) | (wrtmask & ~s));
}
}
}
break;
default:
gl_problem(ctx, "Bad stencil op in apply_stencil_op");
}
}
/*
* Apply stencil test to an array of stencil values (before depth buffering).
* Input: n - number of pixels in the array
* stencil - array of [n] stencil values
* mask - array [n] of flag: 0=skip the pixel, 1=stencil the pixel
* Output: mask - pixels which fail the stencil test will have their
* mask flag set to 0.
* stencil - updated stencil values (where the test passed)
* Return: GL_FALSE = all pixels failed, GL_TRUE = zero or more pixels passed.
*/
static GLboolean
do_stencil_test( GLcontext *ctx, GLuint n, GLstencil stencil[],
GLubyte mask[] )
{
GLubyte fail[PB_SIZE];
GLboolean allfail = GL_FALSE;
GLuint i;
GLstencil r, s;
ASSERT(n <= PB_SIZE);
/*
* Perform stencil test. The results of this operation are stored
* in the fail[] array:
* IF fail[i] is non-zero THEN
* the stencil fail operator is to be applied
* ELSE
* the stencil fail operator is not to be applied
* ENDIF
*/
switch (ctx->Stencil.Function) {
case GL_NEVER:
/* always fail */
for (i=0;i<n;i++) {
if (mask[i]) {
mask[i] = 0;
fail[i] = 1;
}
else {
fail[i] = 0;
}
}
allfail = GL_TRUE;
break;
case GL_LESS:
r = (GLstencil) (ctx->Stencil.Ref & ctx->Stencil.ValueMask);
for (i=0;i<n;i++) {
if (mask[i]) {
s = (GLstencil) (stencil[i] & ctx->Stencil.ValueMask);
if (r < s) {
/* passed */
fail[i] = 0;
}
else {
fail[i] = 1;
mask[i] = 0;
}
}
else {
fail[i] = 0;
}
}
break;
case GL_LEQUAL:
r = (GLstencil) (ctx->Stencil.Ref & ctx->Stencil.ValueMask);
for (i=0;i<n;i++) {
if (mask[i]) {
s = (GLstencil) (stencil[i] & ctx->Stencil.ValueMask);
if (r <= s) {
/* pass */
fail[i] = 0;
}
else {
fail[i] = 1;
mask[i] = 0;
}
}
else {
fail[i] = 0;
}
}
break;
case GL_GREATER:
r = (GLstencil) (ctx->Stencil.Ref & ctx->Stencil.ValueMask);
for (i=0;i<n;i++) {
if (mask[i]) {
s = (GLstencil) (stencil[i] & ctx->Stencil.ValueMask);
if (r > s) {
/* passed */
fail[i] = 0;
}
else {
fail[i] = 1;
mask[i] = 0;
}
}
else {
fail[i] = 0;
}
}
break;
case GL_GEQUAL:
r = (GLstencil) (ctx->Stencil.Ref & ctx->Stencil.ValueMask);
for (i=0;i<n;i++) {
if (mask[i]) {
s = (GLstencil) (stencil[i] & ctx->Stencil.ValueMask);
if (r >= s) {
/* passed */
fail[i] = 0;
}
else {
fail[i] = 1;
mask[i] = 0;
}
}
else {
fail[i] = 0;
}
}
break;
case GL_EQUAL:
r = (GLstencil) (ctx->Stencil.Ref & ctx->Stencil.ValueMask);
for (i=0;i<n;i++) {
if (mask[i]) {
s = (GLstencil) (stencil[i] & ctx->Stencil.ValueMask);
if (r == s) {
/* passed */
fail[i] = 0;
}
else {
fail[i] = 1;
mask[i] = 0;
}
}
else {
fail[i] = 0;
}
}
break;
case GL_NOTEQUAL:
r = (GLstencil) (ctx->Stencil.Ref & ctx->Stencil.ValueMask);
for (i=0;i<n;i++) {
if (mask[i]) {
s = (GLstencil) (stencil[i] & ctx->Stencil.ValueMask);
if (r != s) {
/* passed */
fail[i] = 0;
}
else {
fail[i] = 1;
mask[i] = 0;
}
}
else {
fail[i] = 0;
}
}
break;
case GL_ALWAYS:
/* always pass */
for (i=0;i<n;i++) {
fail[i] = 0;
}
break;
default:
gl_problem(ctx, "Bad stencil func in gl_stencil_span");
return 0;
}
if (ctx->Stencil.FailFunc != GL_KEEP) {
apply_stencil_op( ctx, ctx->Stencil.FailFunc, n, stencil, fail );
}
return !allfail;
}
/*
* Apply stencil and depth testing to an array of pixels.
* Hardware or software stencil buffer acceptable.
* Input: n - number of pixels in the span
* z - array [n] of z values
* stencil - array [n] of stencil values
* mask - array [n] of flags (1=test this pixel, 0=skip the pixel)
* Output: stencil - modified stencil values
* mask - array [n] of flags (1=stencil and depth test passed)
* Return: GL_TRUE - all fragments failed the testing
* GL_FALSE - one or more fragments passed the testing
*
*/
static GLboolean
stencil_and_depth_test_span( GLcontext *ctx, GLuint n, GLint x, GLint y,
const GLdepth z[], GLstencil stencil[],
GLubyte mask[] )
{
ASSERT(ctx->Stencil.Enabled);
ASSERT(n <= PB_SIZE);
/*
* Apply the stencil test to the fragments.
* failMask[i] is 1 if the stencil test failed.
*/
if (do_stencil_test( ctx, n, stencil, mask ) == GL_FALSE) {
/* all fragments failed the stencil test, we're done. */
return GL_FALSE;
}
/*
* Some fragments passed the stencil test, apply depth test to them
* and apply Zpass and Zfail stencil ops.
*/
if (ctx->Depth.Test==GL_FALSE) {
/*
* No depth buffer, just apply zpass stencil function to active pixels.
*/
apply_stencil_op( ctx, ctx->Stencil.ZPassFunc, n, stencil, mask );
}
else {
/*
* Perform depth buffering, then apply zpass or zfail stencil function.
*/
GLubyte passmask[MAX_WIDTH], failmask[MAX_WIDTH], oldmask[MAX_WIDTH];
GLuint i;
/* save the current mask bits */
MEMCPY(oldmask, mask, n * sizeof(GLubyte));
/* apply the depth test */
gl_depth_test_span(ctx, n, x, y, z, mask);
/* Set the stencil pass/fail flags according to result of depth testing.
* if oldmask[i] == 0 then
* Don't touch the stencil value
* else if oldmask[i] and newmask[i] then
* Depth test passed
* else
* assert(oldmask[i] && !newmask[i])
* Depth test failed
* endif
*/
for (i=0;i<n;i++) {
ASSERT(mask[i] == 0 || mask[i] == 1);
passmask[i] = oldmask[i] & mask[i];
failmask[i] = oldmask[i] & (mask[i] ^ 1);
}
/* apply the pass and fail operations */
if (ctx->Stencil.ZFailFunc != GL_KEEP) {
apply_stencil_op( ctx, ctx->Stencil.ZFailFunc, n, stencil, failmask );
}
if (ctx->Stencil.ZPassFunc != GL_KEEP) {
apply_stencil_op( ctx, ctx->Stencil.ZPassFunc, n, stencil, passmask );
}
}
return GL_TRUE; /* one or more fragments passed both tests */
}
/*
* Apply stencil and depth testing to the span of pixels.
* Both software and hardware stencil buffers are acceptable.
* Input: n - number of pixels in the span
* x, y - location of leftmost pixel in span
* z - array [n] of z values
* mask - array [n] of flags (1=test this pixel, 0=skip the pixel)
* Output: mask - array [n] of flags (1=stencil and depth test passed)
* Return: GL_TRUE - all fragments failed the testing
* GL_FALSE - one or more fragments passed the testing
*
*/
GLboolean
gl_stencil_and_depth_test_span( GLcontext *ctx, GLuint n, GLint x, GLint y,
const GLdepth z[], GLubyte mask[] )
{
GLstencil stencilRow[MAX_WIDTH];
GLstencil *stencil;
GLboolean result;
ASSERT(ctx->Stencil.Enabled);
ASSERT(n <= MAX_WIDTH);
/* Get initial stencil values */
if (ctx->Driver.WriteStencilSpan) {
ASSERT(ctx->Driver.ReadStencilSpan);
/* Get stencil values from the hardware stencil buffer */
(*ctx->Driver.ReadStencilSpan)(ctx, n, x, y, stencilRow);
stencil = stencilRow;
}
else {
/* software stencil buffer */
stencil = STENCIL_ADDRESS(x, y);
}
/* do all the stencil/depth testing/updating */
result = stencil_and_depth_test_span( ctx, n, x, y, z, stencil, mask );
if (ctx->Driver.WriteStencilSpan) {
/* Write updated stencil values into hardware stencil buffer */
(ctx->Driver.WriteStencilSpan)(ctx, n, x, y, stencil, mask );
}
return result;
}
/*
* Apply the given stencil operator for each pixel in the array whose
* mask flag is set. This is for software stencil buffers only.
* Input: n - number of pixels in the span
* x, y - array of [n] pixels
* operator - the stencil buffer operator
* mask - array [n] of flag: 1=apply operator, 0=don't apply operator
*/
static void
apply_stencil_op_to_pixels( const GLcontext *ctx,
GLuint n, const GLint x[], const GLint y[],
GLenum oper, const GLubyte mask[] )
{
const GLstencil ref = ctx->Stencil.Ref;
const GLstencil wrtmask = ctx->Stencil.WriteMask;
const GLstencil invmask = (GLstencil) (~ctx->Stencil.WriteMask);
GLuint i;
ASSERT(!ctx->Driver.WriteStencilSpan); /* software stencil buffer only! */
switch (oper) {
case GL_KEEP:
/* do nothing */
break;
case GL_ZERO:
if (invmask==0) {
for (i=0;i<n;i++) {
if (mask[i]) {
GLstencil *sptr = STENCIL_ADDRESS( x[i], y[i] );
*sptr = 0;
}
}
}
else {
for (i=0;i<n;i++) {
if (mask[i]) {
GLstencil *sptr = STENCIL_ADDRESS( x[i], y[i] );
*sptr = (GLstencil) (invmask & *sptr);
}
}
}
break;
case GL_REPLACE:
if (invmask==0) {
for (i=0;i<n;i++) {
if (mask[i]) {
GLstencil *sptr = STENCIL_ADDRESS( x[i], y[i] );
*sptr = ref;
}
}
}
else {
for (i=0;i<n;i++) {
if (mask[i]) {
GLstencil *sptr = STENCIL_ADDRESS( x[i], y[i] );
*sptr = (GLstencil) ((invmask & *sptr ) | (wrtmask & ref));
}
}
}
break;
case GL_INCR:
if (invmask==0) {
for (i=0;i<n;i++) {
if (mask[i]) {
GLstencil *sptr = STENCIL_ADDRESS( x[i], y[i] );
if (*sptr < STENCIL_MAX) {
*sptr = (GLstencil) (*sptr + 1);
}
}
}
}
else {
for (i=0;i<n;i++) {
if (mask[i]) {
GLstencil *sptr = STENCIL_ADDRESS( x[i], y[i] );
if (*sptr < STENCIL_MAX) {
*sptr = (GLstencil) ((invmask & *sptr) | (wrtmask & (*sptr+1)));
}
}
}
}
break;
case GL_DECR:
if (invmask==0) {
for (i=0;i<n;i++) {
if (mask[i]) {
GLstencil *sptr = STENCIL_ADDRESS( x[i], y[i] );
if (*sptr>0) {
*sptr = (GLstencil) (*sptr - 1);
}
}
}
}
else {
for (i=0;i<n;i++) {
if (mask[i]) {
GLstencil *sptr = STENCIL_ADDRESS( x[i], y[i] );
if (*sptr>0) {
*sptr = (GLstencil) ((invmask & *sptr) | (wrtmask & (*sptr-1)));
}
}
}
}
break;
case GL_INCR_WRAP_EXT:
if (invmask==0) {
for (i=0;i<n;i++) {
if (mask[i]) {
GLstencil *sptr = STENCIL_ADDRESS( x[i], y[i] );
*sptr = (GLstencil) (*sptr + 1);
}
}
}
else {
for (i=0;i<n;i++) {
if (mask[i]) {
GLstencil *sptr = STENCIL_ADDRESS( x[i], y[i] );
*sptr = (GLstencil) ((invmask & *sptr) | (wrtmask & (*sptr+1)));
}
}
}
break;
case GL_DECR_WRAP_EXT:
if (invmask==0) {
for (i=0;i<n;i++) {
if (mask[i]) {
GLstencil *sptr = STENCIL_ADDRESS( x[i], y[i] );
*sptr = (GLstencil) (*sptr - 1);
}
}
}
else {
for (i=0;i<n;i++) {
if (mask[i]) {
GLstencil *sptr = STENCIL_ADDRESS( x[i], y[i] );
*sptr = (GLstencil) ((invmask & *sptr) | (wrtmask & (*sptr-1)));
}
}
}
break;
case GL_INVERT:
if (invmask==0) {
for (i=0;i<n;i++) {
if (mask[i]) {
GLstencil *sptr = STENCIL_ADDRESS( x[i], y[i] );
*sptr = (GLstencil) (~*sptr);
}
}
}
else {
for (i=0;i<n;i++) {
if (mask[i]) {
GLstencil *sptr = STENCIL_ADDRESS( x[i], y[i] );
*sptr = (GLstencil) ((invmask & *sptr) | (wrtmask & ~*sptr));
}
}
}
break;
default:
gl_problem(ctx, "Bad stencilop in apply_stencil_op_to_pixels");
}
}
/*
* Apply stencil test to an array of pixels before depth buffering.
* Used for software stencil buffer only.
* Input: n - number of pixels in the span
* x, y - array of [n] pixels to stencil
* mask - array [n] of flag: 0=skip the pixel, 1=stencil the pixel
* Output: mask - pixels which fail the stencil test will have their
* mask flag set to 0.
* Return: 0 = all pixels failed, 1 = zero or more pixels passed.
*/
static GLboolean
stencil_test_pixels( GLcontext *ctx, GLuint n,
const GLint x[], const GLint y[], GLubyte mask[] )
{
GLubyte fail[PB_SIZE];
GLstencil r, s;
GLuint i;
GLboolean allfail = GL_FALSE;
ASSERT(!ctx->Driver.WriteStencilSpan); /* software stencil buffer only! */
/*
* Perform stencil test. The results of this operation are stored
* in the fail[] array:
* IF fail[i] is non-zero THEN
* the stencil fail operator is to be applied
* ELSE
* the stencil fail operator is not to be applied
* ENDIF
*/
switch (ctx->Stencil.Function) {
case GL_NEVER:
/* always fail */
for (i=0;i<n;i++) {
if (mask[i]) {
mask[i] = 0;
fail[i] = 1;
}
else {
fail[i] = 0;
}
}
allfail = GL_TRUE;
break;
case GL_LESS:
r = (GLstencil) (ctx->Stencil.Ref & ctx->Stencil.ValueMask);
for (i=0;i<n;i++) {
if (mask[i]) {
GLstencil *sptr = STENCIL_ADDRESS(x[i],y[i]);
s = (GLstencil) (*sptr & ctx->Stencil.ValueMask);
if (r < s) {
/* passed */
fail[i] = 0;
}
else {
fail[i] = 1;
mask[i] = 0;
}
}
else {
fail[i] = 0;
}
}
break;
case GL_LEQUAL:
r = (GLstencil) (ctx->Stencil.Ref & ctx->Stencil.ValueMask);
for (i=0;i<n;i++) {
if (mask[i]) {
GLstencil *sptr = STENCIL_ADDRESS(x[i],y[i]);
s = (GLstencil) (*sptr & ctx->Stencil.ValueMask);
if (r <= s) {
/* pass */
fail[i] = 0;
}
else {
fail[i] = 1;
mask[i] = 0;
}
}
else {
fail[i] = 0;
}
}
break;
case GL_GREATER:
r = (GLstencil) (ctx->Stencil.Ref & ctx->Stencil.ValueMask);
for (i=0;i<n;i++) {
if (mask[i]) {
GLstencil *sptr = STENCIL_ADDRESS(x[i],y[i]);
s = (GLstencil) (*sptr & ctx->Stencil.ValueMask);
if (r > s) {
/* passed */
fail[i] = 0;
}
else {
fail[i] = 1;
mask[i] = 0;
}
}
else {
fail[i] = 0;
}
}
break;
case GL_GEQUAL:
r = (GLstencil) (ctx->Stencil.Ref & ctx->Stencil.ValueMask);
for (i=0;i<n;i++) {
if (mask[i]) {
GLstencil *sptr = STENCIL_ADDRESS(x[i],y[i]);
s = (GLstencil) (*sptr & ctx->Stencil.ValueMask);
if (r >= s) {
/* passed */
fail[i] = 0;
}
else {
fail[i] = 1;
mask[i] = 0;
}
}
else {
fail[i] = 0;
}
}
break;
case GL_EQUAL:
r = (GLstencil) (ctx->Stencil.Ref & ctx->Stencil.ValueMask);
for (i=0;i<n;i++) {
if (mask[i]) {
GLstencil *sptr = STENCIL_ADDRESS(x[i],y[i]);
s = (GLstencil) (*sptr & ctx->Stencil.ValueMask);
if (r == s) {
/* passed */
fail[i] = 0;
}
else {
fail[i] = 1;
mask[i] = 0;
}
}
else {
fail[i] = 0;
}
}
break;
case GL_NOTEQUAL:
r = (GLstencil) (ctx->Stencil.Ref & ctx->Stencil.ValueMask);
for (i=0;i<n;i++) {
if (mask[i]) {
GLstencil *sptr = STENCIL_ADDRESS(x[i],y[i]);
s = (GLstencil) (*sptr & ctx->Stencil.ValueMask);
if (r != s) {
/* passed */
fail[i] = 0;
}
else {
fail[i] = 1;
mask[i] = 0;
}
}
else {
fail[i] = 0;
}
}
break;
case GL_ALWAYS:
/* always pass */
for (i=0;i<n;i++) {
fail[i] = 0;
}
break;
default:
gl_problem(ctx, "Bad stencil func in gl_stencil_pixels");
return 0;
}
if (ctx->Stencil.FailFunc != GL_KEEP) {
apply_stencil_op_to_pixels( ctx, n, x, y, ctx->Stencil.FailFunc, fail );
}
return !allfail;
}
/*
* Apply stencil and depth testing to an array of pixels.
* This is used both for software and hardware stencil buffers.
*
* The comments in this function are a bit sparse but the code is
* almost identical to stencil_and_depth_test_span(), which is well
* commented.
*
* Input: n - number of pixels in the array
* x, y - array of [n] pixel positions
* z - array [n] of z values
* mask - array [n] of flags (1=test this pixel, 0=skip the pixel)
* Output: mask - array [n] of flags (1=stencil and depth test passed)
* Return: GL_TRUE - all fragments failed the testing
* GL_FALSE - one or more fragments passed the testing
*/
GLboolean
gl_stencil_and_depth_test_pixels( GLcontext *ctx,
GLuint n, const GLint x[], const GLint y[],
const GLdepth z[], GLubyte mask[] )
{
ASSERT(ctx->Stencil.Enabled);
ASSERT(n <= PB_SIZE);
if (ctx->Driver.WriteStencilPixels) {
/*** Hardware stencil buffer ***/
GLstencil stencil[PB_SIZE];
GLubyte mask[PB_SIZE];
ASSERT(ctx->Driver.ReadStencilPixels);
(*ctx->Driver.ReadStencilPixels)(ctx, n, x, y, stencil);
if (do_stencil_test( ctx, n, stencil, mask ) == GL_FALSE) {
/* all fragments failed the stencil test, we're done. */
return GL_FALSE;
}
if (ctx->Depth.Test == GL_FALSE) {
apply_stencil_op( ctx, ctx->Stencil.ZPassFunc, n, stencil, mask );
}
else {
GLubyte passmask[PB_SIZE], failmask[PB_SIZE], oldmask[PB_SIZE];
GLuint i;
MEMCPY(oldmask, mask, n * sizeof(GLubyte));
gl_depth_test_pixels(ctx, n, x, y, z, mask);
for (i=0;i<n;i++) {
ASSERT(mask[i] == 0 || mask[i] == 1);
passmask[i] = oldmask[i] & mask[i];
failmask[i] = oldmask[i] & (mask[i] ^ 1);
}
if (ctx->Stencil.ZFailFunc != GL_KEEP) {
apply_stencil_op( ctx, ctx->Stencil.ZFailFunc, n, stencil, failmask );
}
if (ctx->Stencil.ZPassFunc != GL_KEEP) {
apply_stencil_op( ctx, ctx->Stencil.ZPassFunc, n, stencil, passmask );
}
}
/* Write updated stencil values into hardware stencil buffer */
(ctx->Driver.WriteStencilPixels)(ctx, n, x, y, stencil, mask );
return GL_TRUE;
}
else {
/*** Software stencil buffer ***/
if (stencil_test_pixels(ctx, n, x, y, mask) == GL_FALSE) {
/* all fragments failed the stencil test, we're done. */
return GL_FALSE;
}
if (ctx->Depth.Test==GL_FALSE) {
apply_stencil_op_to_pixels( ctx, n, x, y, ctx->Stencil.ZPassFunc, mask );
}
else {
GLubyte passmask[PB_SIZE], failmask[PB_SIZE], oldmask[PB_SIZE];
GLuint i;
MEMCPY(oldmask, mask, n * sizeof(GLubyte));
gl_depth_test_pixels(ctx, n, x, y, z, mask);
for (i=0;i<n;i++) {
ASSERT(mask[i] == 0 || mask[i] == 1);
passmask[i] = oldmask[i] & mask[i];
failmask[i] = oldmask[i] & (mask[i] ^ 1);
}
if (ctx->Stencil.ZFailFunc != GL_KEEP) {
apply_stencil_op_to_pixels( ctx, n, x, y,
ctx->Stencil.ZFailFunc, failmask );
}
if (ctx->Stencil.ZPassFunc != GL_KEEP) {
apply_stencil_op_to_pixels( ctx, n, x, y,
ctx->Stencil.ZPassFunc, passmask );
}
}
return GL_TRUE; /* one or more fragments passed both tests */
}
}
/*
* Return a span of stencil values from the stencil buffer.
* Used for glRead/CopyPixels
* Input: n - how many pixels
* x,y - location of first pixel
* Output: stencil - the array of stencil values
*/
void gl_read_stencil_span( GLcontext *ctx,
GLint n, GLint x, GLint y, GLstencil stencil[] )
{
ASSERT(n >= 0);
if (ctx->DrawBuffer->Stencil) {
if (ctx->Driver.ReadStencilSpan) {
(*ctx->Driver.ReadStencilSpan)( ctx, (GLuint) n, x, y, stencil );
}
else {
const GLstencil *s = STENCIL_ADDRESS( x, y );
#if STENCIL_BITS == 8
MEMCPY( stencil, s, n * sizeof(GLstencil) );
#else
GLuint i;
for (i=0;i<n;i++)
stencil[i] = s[i];
#endif
}
}
}
/*
* Write a span of stencil values to the stencil buffer.
* Used for glDraw/CopyPixels
* Input: n - how many pixels
* x, y - location of first pixel
* stencil - the array of stencil values
*/
void gl_write_stencil_span( GLcontext *ctx,
GLint n, GLint x, GLint y,
const GLstencil stencil[] )
{
ASSERT(n >= 0);
if (ctx->DrawBuffer->Stencil) {
/* do clipping */
if (y < ctx->DrawBuffer->Ymin || y > ctx->DrawBuffer->Ymax)
return;
if (x < ctx->DrawBuffer->Xmin) {
GLint diff = ctx->DrawBuffer->Xmin - x;
n -= diff;
stencil += diff;
x = ctx->DrawBuffer->Xmin;
}
if (x + n > ctx->DrawBuffer->Xmax) {
GLint diff = x + n - ctx->DrawBuffer->Xmax;
n -= diff;
}
ASSERT( n >= 0);
if (ctx->Driver.WriteStencilSpan) {
(*ctx->Driver.WriteStencilSpan)( ctx, n, x, y, stencil, NULL );
}
else {
GLstencil *s = STENCIL_ADDRESS( x, y );
#if STENCIL_BITS == 8
MEMCPY( s, stencil, n * sizeof(GLstencil) );
#else
GLuint i;
for (i=0;i<n;i++)
s[i] = stencil[i];
#endif
}
}
}
/*
* Allocate a new stencil buffer. If there's an old one it will be
* deallocated first. The new stencil buffer will be uninitialized.
*/
void gl_alloc_stencil_buffer( GLcontext *ctx )
{
GLuint buffersize = ctx->DrawBuffer->Width * ctx->DrawBuffer->Height;
/* deallocate current stencil buffer if present */
if (ctx->DrawBuffer->Stencil) {
FREE(ctx->DrawBuffer->Stencil);
ctx->DrawBuffer->Stencil = NULL;
}
/* allocate new stencil buffer */
ctx->DrawBuffer->Stencil = (GLstencil *) MALLOC(buffersize * sizeof(GLstencil));
if (!ctx->DrawBuffer->Stencil) {
/* out of memory */
_mesa_set_enable( ctx, GL_STENCIL_TEST, GL_FALSE );
gl_error( ctx, GL_OUT_OF_MEMORY, "gl_alloc_stencil_buffer" );
}
}
/*
* Clear the software (malloc'd) stencil buffer.
*/
static void
clear_software_stencil_buffer( GLcontext *ctx )
{
if (ctx->Visual->StencilBits==0 || !ctx->DrawBuffer->Stencil) {
/* no stencil buffer */
return;
}
if (ctx->Scissor.Enabled) {
/* clear scissor region only */
const GLint width = ctx->DrawBuffer->Xmax - ctx->DrawBuffer->Xmin + 1;
if (ctx->Stencil.WriteMask != STENCIL_MAX) {
/* must apply mask to the clear */
GLint y;
for (y = ctx->DrawBuffer->Ymin; y <= ctx->DrawBuffer->Ymax; y++) {
const GLstencil mask = ctx->Stencil.WriteMask;
const GLstencil invMask = ~mask;
const GLstencil clearVal = (ctx->Stencil.Clear & mask);
GLstencil *stencil = STENCIL_ADDRESS( ctx->DrawBuffer->Xmin, y );
GLint i;
for (i = 0; i < width; i++) {
stencil[i] = (stencil[i] & invMask) | clearVal;
}
}
}
else {
/* no masking */
GLint y;
for (y = ctx->DrawBuffer->Ymin; y <= ctx->DrawBuffer->Ymax; y++) {
GLstencil *stencil = STENCIL_ADDRESS( ctx->DrawBuffer->Xmin, y );
#if STENCIL_BITS==8
MEMSET( stencil, ctx->Stencil.Clear, width * sizeof(GLstencil) );
#else
GLint i;
for (i = 0; i < width; i++)
stencil[x] = ctx->Stencil.Clear;
#endif
}
}
}
else {
/* clear whole stencil buffer */
if (ctx->Stencil.WriteMask != STENCIL_MAX) {
/* must apply mask to the clear */
const GLuint n = ctx->DrawBuffer->Width * ctx->DrawBuffer->Height;
GLstencil *stencil = ctx->DrawBuffer->Stencil;
const GLstencil mask = ctx->Stencil.WriteMask;
const GLstencil invMask = ~mask;
const GLstencil clearVal = (ctx->Stencil.Clear & mask);
GLuint i;
for (i = 0; i < n; i++) {
stencil[i] = (stencil[i] & invMask) | clearVal;
}
}
else {
/* clear whole buffer without masking */
const GLuint n = ctx->DrawBuffer->Width * ctx->DrawBuffer->Height;
GLstencil *stencil = ctx->DrawBuffer->Stencil;
#if STENCIL_BITS==8
MEMSET(stencil, ctx->Stencil.Clear, n * sizeof(GLstencil) );
#else
GLuint i;
for (i = 0; i < n; i++) {
stencil[i] = ctx->Stencil.Clear;
}
#endif
}
}
}
/*
* Clear the hardware (in graphics card) stencil buffer.
* This is done with the Driver.WriteStencilSpan() and Driver.ReadStencilSpan()
* functions.
* Actually, if there is a hardware stencil buffer it really should have
* been cleared in Driver.Clear()! However, if the hardware does not
* support scissored clears or masked clears (i.e. glStencilMask) then
* we have to use the span-based functions.
*/
static void
clear_hardware_stencil_buffer( GLcontext *ctx )
{
ASSERT(ctx->Driver.WriteStencilSpan);
ASSERT(ctx->Driver.ReadStencilSpan);
if (ctx->Scissor.Enabled) {
/* clear scissor region only */
const GLint x = ctx->DrawBuffer->Xmin;
const GLint width = ctx->DrawBuffer->Xmax - ctx->DrawBuffer->Xmin + 1;
if (ctx->Stencil.WriteMask != STENCIL_MAX) {
/* must apply mask to the clear */
GLint y;
for (y = ctx->DrawBuffer->Ymin; y <= ctx->DrawBuffer->Ymax; y++) {
const GLstencil mask = ctx->Stencil.WriteMask;
const GLstencil invMask = ~mask;
const GLstencil clearVal = (ctx->Stencil.Clear & mask);
GLstencil stencil[MAX_WIDTH];
GLint i;
(*ctx->Driver.ReadStencilSpan)(ctx, x, y, width, stencil);
for (i = 0; i < width; i++) {
stencil[i] = (stencil[i] & invMask) | clearVal;
}
(*ctx->Driver.WriteStencilSpan)(ctx, x, y, width, stencil, NULL);
}
}
else {
/* no masking */
GLstencil stencil[MAX_WIDTH];
GLint y, i;
for (i = 0; i < width; i++) {
stencil[i] = ctx->Stencil.Clear;
}
for (y = ctx->DrawBuffer->Ymin; y <= ctx->DrawBuffer->Ymax; y++) {
(*ctx->Driver.WriteStencilSpan)(ctx, x, y, width, stencil, NULL);
}
}
}
else {
/* clear whole stencil buffer */
if (ctx->Stencil.WriteMask != STENCIL_MAX) {
/* must apply mask to the clear */
const GLstencil mask = ctx->Stencil.WriteMask;
const GLstencil invMask = ~mask;
const GLstencil clearVal = (ctx->Stencil.Clear & mask);
const GLint width = ctx->DrawBuffer->Width;
const GLint height = ctx->DrawBuffer->Height;
const GLint x = ctx->DrawBuffer->Xmin;
GLint y;
for (y = 0; y < height; y++) {
GLstencil stencil[MAX_WIDTH];
GLuint i;
(*ctx->Driver.ReadStencilSpan)(ctx, x, y, width, stencil);
for (i = 0; i < width; i++) {
stencil[i] = (stencil[i] & invMask) | clearVal;
}
(*ctx->Driver.WriteStencilSpan)(ctx, x, y, width, stencil, NULL);
}
}
else {
/* clear whole buffer without masking */
const GLint width = ctx->DrawBuffer->Width;
const GLint height = ctx->DrawBuffer->Width;
const GLint x = ctx->DrawBuffer->Xmin;
GLstencil stencil[MAX_WIDTH];
GLint y, i;
for (i = 0; i < width; i++) {
stencil[i] = ctx->Stencil.Clear;
}
for (y = 0; y < height; y++) {
(*ctx->Driver.WriteStencilSpan)(ctx, x, y, width, stencil, NULL);
}
}
}
}
/*
* Clear the stencil buffer.
*/
void gl_clear_stencil_buffer( GLcontext *ctx )
{
if (ctx->Driver.WriteStencilSpan) {
ASSERT(ctx->Driver.ReadStencilSpan);
clear_hardware_stencil_buffer(ctx);
}
else {
clear_software_stencil_buffer(ctx);
}
}