/**
* 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( struct gl_context *ctx, SWspan *span, GLuint face )
{
GLubyte passMask[MAX_WIDTH], failMask[MAX_WIDTH], origMask[MAX_WIDTH];
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 */
GLubyte stencil[MAX_WIDTH];
ASSERT(rb->DataType == GL_UNSIGNED_BYTE);
_swrast_get_values(ctx, rb, n, x, y, stencil, sizeof(GLubyte));
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 {
GLubyte tmpMask[MAX_WIDTH];
memcpy(tmpMask, mask, n * sizeof(GLubyte));
_swrast_depth_test_span(ctx, span);
compute_pass_fail_masks(n, tmpMask, mask, passMask, failMask);
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 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 {
memcpy(origMask, mask, n * sizeof(GLubyte));
_swrast_depth_test_span(ctx, span);
compute_pass_fail_masks(n, origMask, mask, passMask, failMask);
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(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 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 */
}
