/**
* Apply stencil test to an array of stencil values (before depth buffering).
* For the values that fail, we'll apply the GL_STENCIL_FAIL operator to
* the stencil values.
*
* @param face 0 or 1 for front or back-face polygons
* @param n number of pixels in the array
* @param stencil array of [n] stencil values (in/out)
* @param mask array [n] of flag: 0=skip the pixel, 1=stencil the pixel,
* values are set to zero where the stencil test fails.
* @param stride stride between stencil values
* @return GL_FALSE = all pixels failed, GL_TRUE = zero or more pixels passed.
*/
static GLboolean
do_stencil_test(struct gl_context *ctx, GLuint face, GLuint n,
GLubyte stencil[], GLubyte mask[], GLint stride)
{
SWcontext *swrast = SWRAST_CONTEXT(ctx);
GLubyte *fail = swrast->stencil_temp.buf2;
GLboolean allfail = GL_FALSE;
GLuint i, j;
const GLuint valueMask = ctx->Stencil.ValueMask[face];
const GLubyte ref = (GLubyte) (_mesa_get_stencil_ref(ctx, face) & valueMask);
GLubyte s;
/*
* 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[face]) {
case GL_NEVER:
STENCIL_TEST(0);
allfail = GL_TRUE;
break;
case GL_LESS:
STENCIL_TEST(ref < s);
break;
case GL_LEQUAL:
STENCIL_TEST(ref <= s);
break;
case GL_GREATER:
STENCIL_TEST(ref > s);
break;
case GL_GEQUAL:
STENCIL_TEST(ref >= s);
break;
case GL_EQUAL:
STENCIL_TEST(ref == s);
break;
case GL_NOTEQUAL:
STENCIL_TEST(ref != s);
break;
case GL_ALWAYS:
STENCIL_TEST(1);
break;
default:
_mesa_problem(ctx, "Bad stencil func in gl_stencil_span");
return 0;
}
if (ctx->Stencil.FailFunc[face] != GL_KEEP) {
apply_stencil_op(ctx, ctx->Stencil.FailFunc[face], face, n, stencil,
fail, stride);
}
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_ztest_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 */
_mesa_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 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.
* 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_ztest_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
_mesa_stencil_and_ztest_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 origMask[PB_SIZE];
ASSERT(ctx->Driver.ReadStencilPixels);
(*ctx->Driver.ReadStencilPixels)(ctx, n, x, y, stencil);
MEMCPY(origMask, mask, n * sizeof(GLubyte));
(void) do_stencil_test( ctx, n, stencil, mask );
if (ctx->Depth.Test == GL_FALSE) {
apply_stencil_op( ctx, ctx->Stencil.ZPassFunc, n, stencil, mask );
}
else {
_mesa_depth_test_pixels(ctx, n, x, y, z, mask);
if (ctx->Stencil.ZFailFunc != GL_KEEP) {
GLubyte failmask[PB_SIZE];
GLuint i;
for (i = 0; i < n; i++) {
ASSERT(mask[i] == 0 || mask[i] == 1);
failmask[i] = origMask[i] & (mask[i] ^ 1);
}
apply_stencil_op(ctx, ctx->Stencil.ZFailFunc, n, stencil, failmask);
}
if (ctx->Stencil.ZPassFunc != GL_KEEP) {
GLubyte passmask[PB_SIZE];
GLuint i;
for (i = 0; i < n; i++) {
ASSERT(mask[i] == 0 || mask[i] == 1);
passmask[i] = origMask[i] & mask[i];
}
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, origMask );
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));
_mesa_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 */
}
}
/**
* 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_ztest_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_FALSE - all fragments failed the testing
* GL_TRUE - one or more fragments passed the testing
*/
static GLboolean
stencil_and_ztest_pixels( GLcontext *ctx, struct sw_span *span, GLuint face )
{
const GLuint n = span->end;
const GLint *x = span->array->x;
const GLint *y = span->array->y;
GLubyte *mask = span->array->mask;
SWcontext *swrast = SWRAST_CONTEXT(ctx);
ASSERT(span->arrayMask & SPAN_XY);
ASSERT(ctx->Stencil.Enabled);
ASSERT(n <= MAX_WIDTH);
if (swrast->Driver.WriteStencilPixels) {
/*** Hardware stencil buffer ***/
GLstencil stencil[MAX_WIDTH];
GLubyte origMask[MAX_WIDTH];
ASSERT(!ctx->DrawBuffer->UseSoftwareStencilBuffer);
ASSERT(swrast->Driver.ReadStencilPixels);
(*swrast->Driver.ReadStencilPixels)(ctx, n, x, y, stencil);
MEMCPY(origMask, mask, n * sizeof(GLubyte));
(void) do_stencil_test(ctx, face, n, stencil, mask);
if (ctx->Depth.Test == GL_FALSE) {
apply_stencil_op(ctx, ctx->Stencil.ZPassFunc[face], face,
n, stencil, mask);
}
else {
_swrast_depth_test_span(ctx, span);
if (ctx->Stencil.ZFailFunc[face] != GL_KEEP) {
GLubyte failmask[MAX_WIDTH];
GLuint i;
for (i = 0; i < n; i++) {
ASSERT(mask[i] == 0 || mask[i] == 1);
failmask[i] = origMask[i] & (mask[i] ^ 1);
}
apply_stencil_op(ctx, ctx->Stencil.ZFailFunc[face], face,
n, stencil, failmask);
}
if (ctx->Stencil.ZPassFunc[face] != GL_KEEP) {
GLubyte passmask[MAX_WIDTH];
GLuint i;
for (i = 0; i < n; i++) {
ASSERT(mask[i] == 0 || mask[i] == 1);
passmask[i] = origMask[i] & mask[i];
}
apply_stencil_op(ctx, ctx->Stencil.ZPassFunc[face], face,
n, stencil, passmask);
}
}
/* Write updated stencil values into hardware stencil buffer */
(swrast->Driver.WriteStencilPixels)(ctx, n, x, y, stencil, origMask);
return GL_TRUE;
}
else {
/*** Software stencil buffer ***/
ASSERT(ctx->DrawBuffer->UseSoftwareStencilBuffer);
if (stencil_test_pixels(ctx, face, 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[face], face, mask);
}
else {
GLubyte passmask[MAX_WIDTH], failmask[MAX_WIDTH], oldmask[MAX_WIDTH];
GLuint i;
MEMCPY(oldmask, mask, n * sizeof(GLubyte));
_swrast_depth_test_span(ctx, span);
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[face] != GL_KEEP) {
apply_stencil_op_to_pixels(ctx, n, x, y,
ctx->Stencil.ZFailFunc[face],
face, failmask);
}
if (ctx->Stencil.ZPassFunc[face] != GL_KEEP) {
apply_stencil_op_to_pixels(ctx, n, x, y,
ctx->Stencil.ZPassFunc[face],
face, 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_FALSE - all fragments failed the testing
* GL_TRUE - one or more fragments passed the testing
*
*/
static GLboolean
stencil_and_ztest_span(GLcontext *ctx, struct sw_span *span, GLuint face)
{
SWcontext *swrast = SWRAST_CONTEXT(ctx);
GLstencil stencilRow[MAX_WIDTH];
GLstencil *stencil;
const GLuint n = span->end;
const GLint x = span->x;
const GLint y = span->y;
GLubyte *mask = span->array->mask;
ASSERT((span->arrayMask & SPAN_XY) == 0);
ASSERT(ctx->Stencil.Enabled);
ASSERT(n <= MAX_WIDTH);
#ifdef DEBUG
if (ctx->Depth.Test) {
ASSERT(span->arrayMask & SPAN_Z);
}
#endif
/* Get initial stencil values */
if (swrast->Driver.WriteStencilSpan) {
/* Get stencil values from the hardware stencil buffer */
ASSERT(swrast->Driver.ReadStencilSpan);
(*swrast->Driver.ReadStencilSpan)(ctx, n, x, y, stencilRow);
stencil = stencilRow;
}
else {
/* Get pointer into software stencil buffer */
stencil = STENCIL_ADDRESS(x, y);
}
/*
* Apply the stencil test to the fragments.
* failMask[i] is 1 if the stencil test failed.
*/
if (do_stencil_test( ctx, face, n, stencil, mask ) == GL_FALSE) {
/* all fragments failed the stencil test, we're done. */
span->writeAll = GL_FALSE;
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[face], face, 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 */
_swrast_depth_test_span(ctx, span);
/* 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[face] != GL_KEEP) {
apply_stencil_op( ctx, ctx->Stencil.ZFailFunc[face], face,
n, stencil, failmask );
}
if (ctx->Stencil.ZPassFunc[face] != GL_KEEP) {
apply_stencil_op( ctx, ctx->Stencil.ZPassFunc[face], face,
n, stencil, passmask );
}
}
/*
* Write updated stencil values back into hardware stencil buffer.
*/
if (swrast->Driver.WriteStencilSpan) {
ASSERT(stencil == stencilRow);
(swrast->Driver.WriteStencilSpan)(ctx, n, x, y, stencil, mask );
}
span->writeAll = GL_FALSE;
return GL_TRUE; /* one or more fragments passed both tests */
}
/**
* /return GL_TRUE = one or more fragments passed,
* GL_FALSE = all fragments failed.
*/
GLboolean
_swrast_stencil_and_ztest_span(struct gl_context *ctx, SWspan *span)
{
struct gl_framebuffer *fb = ctx->DrawBuffer;
struct gl_renderbuffer *rb = fb->Attachment[BUFFER_STENCIL].Renderbuffer;
const GLint stencilOffset = get_stencil_offset(rb->Format);
const GLint stencilStride = _mesa_get_format_bytes(rb->Format);
const GLuint face = (span->facing == 0) ? 0 : ctx->Stencil._BackFace;
const GLuint count = span->end;
GLubyte *mask = span->array->mask;
GLubyte stencilTemp[MAX_WIDTH];
GLubyte *stencilBuf;
if (span->arrayMask & SPAN_XY) {
/* read stencil values from random locations */
get_s8_values(ctx, rb, count, span->array->x, span->array->y,
stencilTemp);
stencilBuf = stencilTemp;
}
else {
/* Processing a horizontal run of pixels. Since stencil is always
* 8 bits for all MESA_FORMATs, we just need to use the right offset
* and stride to access them.
*/
stencilBuf = _swrast_pixel_address(rb, span->x, span->y) + stencilOffset;
}
/*
* Apply the stencil test to the fragments.
* failMask[i] is 1 if the stencil test failed.
*/
if (!do_stencil_test(ctx, face, count, stencilBuf, mask, stencilStride)) {
/* all fragments failed the stencil test, we're done. */
span->writeAll = GL_FALSE;
if (span->arrayMask & SPAN_XY) {
/* need to write the updated stencil values back to the buffer */
put_s8_values(ctx, rb, count, span->array->x, span->array->y,
stencilTemp);
}
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 ||
ctx->DrawBuffer->Attachment[BUFFER_DEPTH].Renderbuffer == NULL) {
/*
* No depth buffer, just apply zpass stencil function to active pixels.
*/
apply_stencil_op(ctx, ctx->Stencil.ZPassFunc[face], face, count,
stencilBuf, mask, stencilStride);
}
else {
/*
* Perform depth buffering, then apply zpass or zfail stencil function.
*/
GLubyte passMask[MAX_WIDTH], failMask[MAX_WIDTH], origMask[MAX_WIDTH];
/* save the current mask bits */
memcpy(origMask, mask, count * sizeof(GLubyte));
/* apply the depth test */
_swrast_depth_test_span(ctx, span);
compute_pass_fail_masks(count, origMask, mask, passMask, failMask);
/* apply the pass and fail operations */
if (ctx->Stencil.ZFailFunc[face] != GL_KEEP) {
apply_stencil_op(ctx, ctx->Stencil.ZFailFunc[face], face,
count, stencilBuf, failMask, stencilStride);
}
if (ctx->Stencil.ZPassFunc[face] != GL_KEEP) {
apply_stencil_op(ctx, ctx->Stencil.ZPassFunc[face], face,
count, stencilBuf, passMask, stencilStride);
}
}
/* Write updated stencil values back into hardware stencil buffer */
if (span->arrayMask & SPAN_XY) {
put_s8_values(ctx, rb, count, span->array->x, span->array->y,
stencilBuf);
}
span->writeAll = GL_FALSE;
return GL_TRUE; /* one or more fragments passed both tests */
}
/**
* 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_ztest_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_FALSE - all fragments failed the testing
* GL_TRUE - one or more fragments passed the testing
*/
static GLboolean
stencil_and_ztest_pixels( GLcontext *ctx, SWspan *span, GLuint face )
{
struct gl_framebuffer *fb = ctx->DrawBuffer;
struct gl_renderbuffer *rb = fb->_StencilBuffer;
const GLuint n = span->end;
const GLint *x = span->array->x;
const GLint *y = span->array->y;
GLubyte *mask = span->array->mask;
ASSERT(span->arrayMask & SPAN_XY);
ASSERT(ctx->Stencil.Enabled);
ASSERT(n <= MAX_WIDTH);
if (!rb->GetPointer(ctx, rb, 0, 0)) {
/* No direct access */
GLstencil stencil[MAX_WIDTH];
GLubyte origMask[MAX_WIDTH];
ASSERT(rb->DataType == GL_UNSIGNED_BYTE);
_swrast_get_values(ctx, rb, n, x, y, stencil, sizeof(GLubyte));
_mesa_memcpy(origMask, mask, n * sizeof(GLubyte));
(void) do_stencil_test(ctx, face, n, stencil, mask);
if (ctx->Depth.Test == GL_FALSE) {
apply_stencil_op(ctx, ctx->Stencil.ZPassFunc[face], face,
n, stencil, mask);
}
else {
_swrast_depth_test_span(ctx, span);
if (ctx->Stencil.ZFailFunc[face] != GL_KEEP) {
GLubyte failmask[MAX_WIDTH];
GLuint i;
for (i = 0; i < n; i++) {
ASSERT(mask[i] == 0 || mask[i] == 1);
failmask[i] = origMask[i] & (mask[i] ^ 1);
}
apply_stencil_op(ctx, ctx->Stencil.ZFailFunc[face], face,
n, stencil, failmask);
}
if (ctx->Stencil.ZPassFunc[face] != GL_KEEP) {
GLubyte passmask[MAX_WIDTH];
GLuint i;
for (i = 0; i < n; i++) {
ASSERT(mask[i] == 0 || mask[i] == 1);
passmask[i] = origMask[i] & mask[i];
}
apply_stencil_op(ctx, ctx->Stencil.ZPassFunc[face], face,
n, stencil, passmask);
}
}
/* Write updated stencil values into hardware stencil buffer */
rb->PutValues(ctx, rb, n, x, y, stencil, origMask);
return GL_TRUE;
}
else {
/* Direct access to stencil buffer */
if (stencil_test_pixels(ctx, face, 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[face], face, mask);
}
else {
GLubyte passmask[MAX_WIDTH], failmask[MAX_WIDTH], oldmask[MAX_WIDTH];
GLuint i;
_mesa_memcpy(oldmask, mask, n * sizeof(GLubyte));
_swrast_depth_test_span(ctx, span);
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[face] != GL_KEEP) {
apply_stencil_op_to_pixels(ctx, n, x, y,
ctx->Stencil.ZFailFunc[face],
face, failmask);
}
if (ctx->Stencil.ZPassFunc[face] != GL_KEEP) {
apply_stencil_op_to_pixels(ctx, n, x, y,
ctx->Stencil.ZPassFunc[face],
face, 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_FALSE - all fragments failed the testing
* GL_TRUE - one or more fragments passed the testing
*
*/
static GLboolean
stencil_and_ztest_span(GLcontext *ctx, SWspan *span, GLuint face)
{
struct gl_framebuffer *fb = ctx->DrawBuffer;
struct gl_renderbuffer *rb = fb->_StencilBuffer;
GLstencil stencilRow[MAX_WIDTH];
GLstencil *stencil;
const GLuint n = span->end;
const GLint x = span->x;
const GLint y = span->y;
GLubyte *mask = span->array->mask;
ASSERT((span->arrayMask & SPAN_XY) == 0);
ASSERT(ctx->Stencil.Enabled);
ASSERT(n <= MAX_WIDTH);
#ifdef DEBUG
if (ctx->Depth.Test) {
ASSERT(span->arrayMask & SPAN_Z);
}
#endif
stencil = (GLstencil *) rb->GetPointer(ctx, rb, x, y);
if (!stencil) {
rb->GetRow(ctx, rb, n, x, y, stencilRow);
stencil = stencilRow;
}
/*
* Apply the stencil test to the fragments.
* failMask[i] is 1 if the stencil test failed.
*/
if (do_stencil_test( ctx, face, n, stencil, mask ) == GL_FALSE) {
/* all fragments failed the stencil test, we're done. */
span->writeAll = GL_FALSE;
if (!rb->GetPointer(ctx, rb, 0, 0)) {
/* put updated stencil values into buffer */
rb->PutRow(ctx, rb, n, x, y, stencil, NULL);
}
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[face], face, 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 */
_mesa_memcpy(oldmask, mask, n * sizeof(GLubyte));
/* apply the depth test */
_swrast_depth_test_span(ctx, span);
/* 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[face] != GL_KEEP) {
apply_stencil_op( ctx, ctx->Stencil.ZFailFunc[face], face,
n, stencil, failmask );
}
if (ctx->Stencil.ZPassFunc[face] != GL_KEEP) {
apply_stencil_op( ctx, ctx->Stencil.ZPassFunc[face], face,
n, stencil, passmask );
}
}
/*
* Write updated stencil values back into hardware stencil buffer.
*/
if (!rb->GetPointer(ctx, rb, 0, 0)) {
rb->PutRow(ctx, rb, n, x, y, stencil, NULL);
}
span->writeAll = GL_FALSE;
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_FALSE - all fragments failed the testing
* GL_TRUE - one or more fragments passed the testing
*
*/
static GLboolean
stencil_and_ztest_span(struct gl_context *ctx, SWspan *span, GLuint face)
{
struct gl_framebuffer *fb = ctx->DrawBuffer;
struct gl_renderbuffer *rb = fb->_StencilBuffer;
GLubyte stencilRow[MAX_WIDTH];
GLubyte *stencil;
const GLuint n = span->end;
const GLint x = span->x;
const GLint y = span->y;
GLubyte *mask = span->array->mask;
ASSERT((span->arrayMask & SPAN_XY) == 0);
ASSERT(ctx->Stencil.Enabled);
ASSERT(n <= MAX_WIDTH);
#ifdef DEBUG
if (ctx->Depth.Test) {
ASSERT(span->arrayMask & SPAN_Z);
}
#endif
stencil = (GLubyte *) rb->GetPointer(ctx, rb, x, y);
if (!stencil) {
rb->GetRow(ctx, rb, n, x, y, stencilRow);
stencil = stencilRow;
}
/*
* Apply the stencil test to the fragments.
* failMask[i] is 1 if the stencil test failed.
*/
if (do_stencil_test( ctx, face, n, stencil, mask ) == GL_FALSE) {
/* all fragments failed the stencil test, we're done. */
span->writeAll = GL_FALSE;
if (!rb->GetPointer(ctx, rb, 0, 0)) {
/* put updated stencil values into buffer */
rb->PutRow(ctx, rb, n, x, y, stencil, NULL);
}
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 ||
ctx->DrawBuffer->_DepthBuffer == NULL) {
/*
* No depth buffer, just apply zpass stencil function to active pixels.
*/
apply_stencil_op( ctx, ctx->Stencil.ZPassFunc[face], face, n, stencil, mask );
}
else {
/*
* Perform depth buffering, then apply zpass or zfail stencil function.
*/
GLubyte passMask[MAX_WIDTH], failMask[MAX_WIDTH], origMask[MAX_WIDTH];
/* save the current mask bits */
memcpy(origMask, mask, n * sizeof(GLubyte));
/* apply the depth test */
_swrast_depth_test_span(ctx, span);
compute_pass_fail_masks(n, origMask, mask, passMask, failMask);
/* apply the pass and fail operations */
if (ctx->Stencil.ZFailFunc[face] != GL_KEEP) {
apply_stencil_op( ctx, ctx->Stencil.ZFailFunc[face], face,
n, stencil, failMask );
}
if (ctx->Stencil.ZPassFunc[face] != GL_KEEP) {
apply_stencil_op( ctx, ctx->Stencil.ZPassFunc[face], face,
n, stencil, passMask );
}
}
/*
* Write updated stencil values back into hardware stencil buffer.
*/
if (!rb->GetPointer(ctx, rb, 0, 0)) {
rb->PutRow(ctx, rb, n, x, y, stencil, NULL);
}
span->writeAll = GL_FALSE;
return GL_TRUE; /* one or more fragments passed both tests */
}
/**
* Apply stencil test to an array of stencil values (before depth buffering).
* Input: face - 0 or 1 for front or back-face polygons
* 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( struct gl_context *ctx, GLuint face, GLuint n, GLubyte stencil[],
GLubyte mask[] )
{
GLubyte fail[MAX_WIDTH];
GLboolean allfail = GL_FALSE;
GLuint i;
const GLuint valueMask = ctx->Stencil.ValueMask[face];
const GLubyte r = (GLubyte) (ctx->Stencil.Ref[face] & valueMask);
GLubyte s;
ASSERT(n <= MAX_WIDTH);
/*
* 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[face]) {
case GL_NEVER:
/* never pass; 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:
for (i=0;i<n;i++) {
if (mask[i]) {
s = (GLubyte) (stencil[i] & valueMask);
if (r < s) {
/* passed */
fail[i] = 0;
}
else {
fail[i] = 1;
mask[i] = 0;
}
}
else {
fail[i] = 0;
}
}
break;
case GL_LEQUAL:
for (i=0;i<n;i++) {
if (mask[i]) {
s = (GLubyte) (stencil[i] & valueMask);
if (r <= s) {
/* pass */
fail[i] = 0;
}
else {
fail[i] = 1;
mask[i] = 0;
}
}
else {
fail[i] = 0;
}
}
break;
case GL_GREATER:
for (i=0;i<n;i++) {
if (mask[i]) {
s = (GLubyte) (stencil[i] & valueMask);
if (r > s) {
/* passed */
fail[i] = 0;
}
else {
fail[i] = 1;
mask[i] = 0;
}
}
else {
fail[i] = 0;
}
}
break;
case GL_GEQUAL:
for (i=0;i<n;i++) {
if (mask[i]) {
s = (GLubyte) (stencil[i] & valueMask);
if (r >= s) {
/* passed */
fail[i] = 0;
}
else {
fail[i] = 1;
mask[i] = 0;
}
}
else {
fail[i] = 0;
}
}
break;
case GL_EQUAL:
for (i=0;i<n;i++) {
if (mask[i]) {
s = (GLubyte) (stencil[i] & valueMask);
if (r == s) {
/* passed */
fail[i] = 0;
}
else {
fail[i] = 1;
mask[i] = 0;
}
}
else {
fail[i] = 0;
}
}
break;
case GL_NOTEQUAL:
for (i=0;i<n;i++) {
if (mask[i]) {
s = (GLubyte) (stencil[i] & 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:
_mesa_problem(ctx, "Bad stencil func in gl_stencil_span");
return 0;
}
if (ctx->Stencil.FailFunc[face] != GL_KEEP) {
apply_stencil_op( ctx, ctx->Stencil.FailFunc[face], face, n, stencil, fail );
}
return !allfail;
}
