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-rw-r--r--src/mesa/swrast/s_stencil.c1325
1 files changed, 1325 insertions, 0 deletions
diff --git a/src/mesa/swrast/s_stencil.c b/src/mesa/swrast/s_stencil.c
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+++ b/src/mesa/swrast/s_stencil.c
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+/*
+ * Mesa 3-D graphics library
+ * Version: 6.1
+ *
+ * Copyright (C) 1999-2004 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.
+ */
+
+
+#include "glheader.h"
+#include "context.h"
+#include "macros.h"
+#include "imports.h"
+
+#include "s_context.h"
+#include "s_depth.h"
+#include "s_stencil.h"
+
+
+
+/* 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
+ * face - 0 or 1 for front or back face operation
+ * 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 face,
+ GLuint n, GLstencil stencil[], const GLubyte mask[] )
+{
+ const GLstencil ref = ctx->Stencil.Ref[face];
+ const GLstencil wrtmask = ctx->Stencil.WriteMask[face];
+ const GLstencil invmask = (GLstencil) (~wrtmask);
+ 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:
+ _mesa_problem(ctx, "Bad stencil op in apply_stencil_op");
+ }
+}
+
+
+
+
+/**
+ * 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( GLcontext *ctx, GLuint face, GLuint n, GLstencil stencil[],
+ GLubyte mask[] )
+{
+ GLubyte fail[MAX_WIDTH];
+ GLboolean allfail = GL_FALSE;
+ GLuint i;
+ GLstencil r, s;
+ const GLuint valueMask = ctx->Stencil.ValueMask[face];
+
+ 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:
+ r = (GLstencil) (ctx->Stencil.Ref[face] & valueMask);
+ for (i=0;i<n;i++) {
+ if (mask[i]) {
+ s = (GLstencil) (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:
+ r = (GLstencil) (ctx->Stencil.Ref[face] & valueMask);
+ for (i=0;i<n;i++) {
+ if (mask[i]) {
+ s = (GLstencil) (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:
+ r = (GLstencil) (ctx->Stencil.Ref[face] & valueMask);
+ for (i=0;i<n;i++) {
+ if (mask[i]) {
+ s = (GLstencil) (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:
+ r = (GLstencil) (ctx->Stencil.Ref[face] & valueMask);
+ for (i=0;i<n;i++) {
+ if (mask[i]) {
+ s = (GLstencil) (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:
+ r = (GLstencil) (ctx->Stencil.Ref[face] & valueMask);
+ for (i=0;i<n;i++) {
+ if (mask[i]) {
+ s = (GLstencil) (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:
+ r = (GLstencil) (ctx->Stencil.Ref[face] & valueMask);
+ for (i=0;i<n;i++) {
+ if (mask[i]) {
+ s = (GLstencil) (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;
+}
+
+
+
+/**
+ * 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 */
+}
+
+
+
+
+/**
+ * Apply the given stencil operator for each pixel in the array whose
+ * mask flag is set.
+ * \note 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, GLuint face, const GLubyte mask[] )
+{
+ const GLstencil ref = ctx->Stencil.Ref[face];
+ const GLstencil wrtmask = ctx->Stencil.WriteMask[face];
+ const GLstencil invmask = (GLstencil) (~wrtmask);
+ GLuint i;
+
+ ASSERT(!SWRAST_CONTEXT(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:
+ _mesa_problem(ctx, "Bad stencilop in apply_stencil_op_to_pixels");
+ }
+}
+
+
+
+/**
+ * Apply stencil test to an array of pixels before depth buffering.
+ *
+ * \note 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 GL_FALSE = all pixels failed, GL_TRUE = zero or more pixels passed.
+ */
+static GLboolean
+stencil_test_pixels( GLcontext *ctx, GLuint face, GLuint n,
+ const GLint x[], const GLint y[], GLubyte mask[] )
+{
+ GLubyte fail[MAX_WIDTH];
+ GLstencil r, s;
+ GLuint i;
+ GLboolean allfail = GL_FALSE;
+ const GLuint valueMask = ctx->Stencil.ValueMask[face];
+
+ /* software stencil buffer only! */
+ ASSERT(ctx->DrawBuffer->UseSoftwareStencilBuffer);
+ ASSERT(!SWRAST_CONTEXT(ctx)->Driver.ReadStencilSpan);
+ ASSERT(!SWRAST_CONTEXT(ctx)->Driver.WriteStencilSpan);
+
+ /*
+ * 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:
+ /* 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[face] & valueMask);
+ for (i=0;i<n;i++) {
+ if (mask[i]) {
+ GLstencil *sptr = STENCIL_ADDRESS(x[i],y[i]);
+ s = (GLstencil) (*sptr & 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[face] & valueMask);
+ for (i=0;i<n;i++) {
+ if (mask[i]) {
+ GLstencil *sptr = STENCIL_ADDRESS(x[i],y[i]);
+ s = (GLstencil) (*sptr & 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[face] & valueMask);
+ for (i=0;i<n;i++) {
+ if (mask[i]) {
+ GLstencil *sptr = STENCIL_ADDRESS(x[i],y[i]);
+ s = (GLstencil) (*sptr & 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[face] & valueMask);
+ for (i=0;i<n;i++) {
+ if (mask[i]) {
+ GLstencil *sptr = STENCIL_ADDRESS(x[i],y[i]);
+ s = (GLstencil) (*sptr & 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[face] & valueMask);
+ for (i=0;i<n;i++) {
+ if (mask[i]) {
+ GLstencil *sptr = STENCIL_ADDRESS(x[i],y[i]);
+ s = (GLstencil) (*sptr & 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[face] & valueMask);
+ for (i=0;i<n;i++) {
+ if (mask[i]) {
+ GLstencil *sptr = STENCIL_ADDRESS(x[i],y[i]);
+ s = (GLstencil) (*sptr & 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_pixels");
+ return 0;
+ }
+
+ if (ctx->Stencil.FailFunc[face] != GL_KEEP) {
+ apply_stencil_op_to_pixels( ctx, n, x, y, ctx->Stencil.FailFunc[face],
+ face, 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_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 */
+ }
+}
+
+
+/**
+ * /return GL_TRUE = one or more fragments passed,
+ * GL_FALSE = all fragments failed.
+ */
+GLboolean
+_swrast_stencil_and_ztest_span(GLcontext *ctx, struct sw_span *span)
+{
+ /* span->facing can only be non-zero if using two-sided stencil */
+ ASSERT(ctx->Stencil.TestTwoSide || span->facing == 0);
+ if (span->arrayMask & SPAN_XY)
+ return stencil_and_ztest_pixels(ctx, span, span->facing);
+ else
+ return stencil_and_ztest_span(ctx, span, span->facing);
+}
+
+
+/**
+ * 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
+_swrast_read_stencil_span( GLcontext *ctx,
+ GLint n, GLint x, GLint y, GLstencil stencil[] )
+{
+ SWcontext *swrast = SWRAST_CONTEXT(ctx);
+ const GLint bufWidth = (GLint) ctx->DrawBuffer->Width;
+ const GLint bufHeight = (GLint) ctx->DrawBuffer->Height;
+
+ if (y < 0 || y >= bufHeight || x + n <= 0 || x >= bufWidth) {
+ /* span is completely outside framebuffer */
+ return; /* undefined values OK */
+ }
+
+ if (x < 0) {
+ GLint dx = -x;
+ x = 0;
+ n -= dx;
+ stencil += dx;
+ }
+ if (x + n > bufWidth) {
+ GLint dx = x + n - bufWidth;
+ n -= dx;
+ }
+ if (n <= 0) {
+ return;
+ }
+
+
+ ASSERT(n >= 0);
+ if (swrast->Driver.ReadStencilSpan) {
+ (*swrast->Driver.ReadStencilSpan)( ctx, (GLuint) n, x, y, stencil );
+ }
+ else if (ctx->DrawBuffer->Stencil) {
+ 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
+_swrast_write_stencil_span( GLcontext *ctx, GLint n, GLint x, GLint y,
+ const GLstencil stencil[] )
+{
+ SWcontext *swrast = SWRAST_CONTEXT(ctx);
+ const GLstencil *ssrc = stencil;
+ const GLint bufWidth = (GLint) ctx->DrawBuffer->Width;
+ const GLint bufHeight = (GLint) ctx->DrawBuffer->Height;
+
+ if (y < 0 || y >= bufHeight || x + n <= 0 || x >= bufWidth) {
+ /* span is completely outside framebuffer */
+ return; /* undefined values OK */
+ }
+
+ if (x < 0) {
+ GLint dx = -x;
+ x = 0;
+ n -= dx;
+ ssrc += dx;
+ }
+ if (x + n > bufWidth) {
+ GLint dx = x + n - bufWidth;
+ n -= dx;
+ }
+ if (n <= 0) {
+ return;
+ }
+
+ if (swrast->Driver.WriteStencilSpan) {
+ (*swrast->Driver.WriteStencilSpan)( ctx, n, x, y, ssrc, NULL );
+ }
+ else if (ctx->DrawBuffer->Stencil) {
+ GLstencil *s = STENCIL_ADDRESS( x, y );
+#if STENCIL_BITS == 8
+ MEMCPY( s, ssrc, n * sizeof(GLstencil) );
+#else
+ GLuint i;
+ for (i=0;i<n;i++)
+ s[i] = ssrc[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
+_swrast_alloc_stencil_buffer( GLframebuffer *buffer )
+{
+ /* deallocate current stencil buffer if present */
+ if (buffer->Stencil) {
+ MESA_PBUFFER_FREE(buffer->Stencil);
+ buffer->Stencil = NULL;
+ }
+
+ /* allocate new stencil buffer */
+ buffer->Stencil = (GLstencil *)
+ MESA_PBUFFER_ALLOC(buffer->Width * buffer->Height * sizeof(GLstencil));
+ if (!buffer->Stencil) {
+ /* out of memory */
+ _mesa_error( NULL, GL_OUT_OF_MEMORY, "_swrast_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;
+ if (ctx->Stencil.WriteMask[0] != 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[0];
+ 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[i] = ctx->Stencil.Clear;
+#endif
+ }
+ }
+ }
+ else {
+ /* clear whole stencil buffer */
+ if (ctx->Stencil.WriteMask[0] != 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[0];
+ 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 )
+{
+ SWcontext *swrast = SWRAST_CONTEXT(ctx);
+ ASSERT(swrast->Driver.WriteStencilSpan);
+ ASSERT(swrast->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;
+ if (ctx->Stencil.WriteMask[0] != 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[0];
+ const GLstencil invMask = ~mask;
+ const GLstencil clearVal = (ctx->Stencil.Clear & mask);
+ GLstencil stencil[MAX_WIDTH];
+ GLint i;
+ (*swrast->Driver.ReadStencilSpan)(ctx, width, x, y, stencil);
+ for (i = 0; i < width; i++) {
+ stencil[i] = (stencil[i] & invMask) | clearVal;
+ }
+ (*swrast->Driver.WriteStencilSpan)(ctx, width, x, y, 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++) {
+ (*swrast->Driver.WriteStencilSpan)(ctx, width, x, y, stencil, NULL);
+ }
+ }
+ }
+ else {
+ /* clear whole stencil buffer */
+ if (ctx->Stencil.WriteMask[0] != STENCIL_MAX) {
+ /* must apply mask to the clear */
+ const GLstencil mask = ctx->Stencil.WriteMask[0];
+ 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];
+ GLint i;
+ (*swrast->Driver.ReadStencilSpan)(ctx, width, x, y, stencil);
+ for (i = 0; i < width; i++) {
+ stencil[i] = (stencil[i] & invMask) | clearVal;
+ }
+ (*swrast->Driver.WriteStencilSpan)(ctx, width, x, y, stencil, NULL);
+ }
+ }
+ else {
+ /* clear whole buffer without masking */
+ const GLint width = ctx->DrawBuffer->Width;
+ const GLint height = ctx->DrawBuffer->Height;
+ 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++) {
+ (*swrast->Driver.WriteStencilSpan)(ctx, width, x, y, stencil, NULL);
+ }
+ }
+ }
+}
+
+
+
+/**
+ * Clear the stencil buffer (hardware or software).
+ */
+void
+_swrast_clear_stencil_buffer( GLcontext *ctx )
+{
+ SWcontext *swrast = SWRAST_CONTEXT(ctx);
+ if (swrast->Driver.WriteStencilSpan) {
+ ASSERT(swrast->Driver.ReadStencilSpan);
+ clear_hardware_stencil_buffer(ctx);
+ }
+ else {
+ clear_software_stencil_buffer(ctx);
+ }
+}
generated by cgit (git 2.34.1) at 2026-08-02 06:23:42 +0000