-/* $Id: stencil.c,v 1.10 1999/11/24 18:48:31 brianp Exp $ */
+/* $Id: stencil.c,v 1.11 1999/12/04 21:23:55 brianp Exp $ */
/*
* Mesa 3-D graphics library
#endif
-#if STENCIL_BITS==8
-# define STENCIL_MAX 0xff
-#elif STENCIL_BITS==16
-# define STENCIL_MAX 0xffff
-#else
- illegal number of stencil bits
-#endif
-
void
/* Stencil Logic:
IF stencil test fails THEN
+ Apply fail-op to stencil value
Don't write the pixel (RGBA,Z)
- Execute FailOp
-ELSE
- Write the pixel
-ENDIF
-
-Perform Depth Test
-
-IF depth test passes OR no depth buffer THEN
- Execute ZPass
- Write the pixel
ELSE
- Execute ZFail
+ 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:
*/
/*
- * Apply the given stencil operator for each pixel in the span whose
- * mask flag is set.
+ * Apply the given stencil operator to the array of stencil values.
+ * Don't touch stencil[i] if mask[i] is zero.
* Input: n - number of pixels in the span
- * x, y - location of leftmost pixel in the span
* oper - the stencil buffer operator
+ * stencil - array of stencil values
* mask - array [n] of flag: 1=apply operator, 0=don't apply operator
*/
-static void apply_stencil_op_to_span( GLcontext *ctx,
- GLuint n, GLint x, GLint y,
- GLenum oper, GLubyte mask[] )
+static void apply_stencil_op( GLcontext *ctx, GLenum oper,
+ GLuint n, GLstencil stencil[], GLubyte mask[] )
{
const GLstencil ref = ctx->Stencil.Ref;
const GLstencil wrtmask = ctx->Stencil.WriteMask;
const GLstencil invmask = (GLstencil) (~ctx->Stencil.WriteMask);
- GLstencil *stencil = STENCIL_ADDRESS( x, y );
GLuint i;
switch (oper) {
}
break;
default:
- gl_problem(ctx, "Bad stencilop in apply_stencil_op_to_span");
+ gl_problem(ctx, "Bad stencil op in apply_stencil_op");
}
}
return 0;
}
- apply_stencil_op_to_span( ctx, n, x, y, ctx->Stencil.FailFunc, fail );
+ if (ctx->Stencil.FailFunc != GL_KEEP) {
+ apply_stencil_op( ctx, ctx->Stencil.FailFunc, n, stencil, fail );
+ }
return (allfail) ? 0 : 1;
}
GLuint n, GLint x, GLint y, const GLdepth z[],
GLubyte mask[] )
{
+ GLstencil *stencil = STENCIL_ADDRESS(x, y);
+
if (ctx->Depth.Test==GL_FALSE) {
/*
* No depth buffer, just apply zpass stencil function to active pixels.
*/
- apply_stencil_op_to_span( ctx, n, x, y, ctx->Stencil.ZPassFunc, mask );
+ apply_stencil_op( ctx, ctx->Stencil.ZPassFunc, n, stencil, mask );
}
else {
/*
GLubyte passmask[MAX_WIDTH], failmask[MAX_WIDTH], oldmask[MAX_WIDTH];
GLuint i;
- /* init pass and fail masks to zero, copy mask[] to oldmask[] */
- for (i=0;i<n;i++) {
- passmask[i] = failmask[i] = 0;
- oldmask[i] = mask[i];
- }
+ /* save the current mask bits */
+ MEMCPY(oldmask, mask, n * sizeof(GLubyte));
/* apply the depth test */
if (ctx->Driver.DepthTestSpan)
(*ctx->Driver.DepthTestSpan)( ctx, n, x, y, z, mask );
- /* set the stencil pass/fail flags according to result of depth test */
+ /* 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++) {
- if (oldmask[i]) {
- if (mask[i]) {
- passmask[i] = 1;
- }
- else {
- failmask[i] = 1;
- }
- }
+ 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 */
- apply_stencil_op_to_span( ctx, n, x, y, ctx->Stencil.ZFailFunc, failmask );
- apply_stencil_op_to_span( ctx, n, x, y, ctx->Stencil.ZPassFunc, passmask );
+ 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 );
+ }
}
}
GLubyte passmask[PB_SIZE], failmask[PB_SIZE], oldmask[PB_SIZE];
GLuint i;
- /* init pass and fail masks to zero */
- for (i=0;i<n;i++) {
- passmask[i] = failmask[i] = 0;
- oldmask[i] = mask[i];
- }
+ /* save the current mask bits */
+ MEMCPY(oldmask, mask, n * sizeof(GLubyte));
/* apply the depth test */
if (ctx->Driver.DepthTestPixels)
(*ctx->Driver.DepthTestPixels)( ctx, n, x, y, z, mask );
- /* set the stencil pass/fail flags according to result of depth test */
+ /* 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++) {
- if (oldmask[i]) {
- if (mask[i]) {
- passmask[i] = 1;
- }
- else {
- failmask[i] = 1;
- }
- }
+ 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 */
-/*
- * Clear the stencil buffer. If the stencil buffer doesn't exist yet we'll
- * allocate it now.
- */
void gl_clear_stencil_buffer( GLcontext *ctx )
{
if (ctx->Visual->StencilBits==0 || !ctx->DrawBuffer->Stencil) {
if (ctx->Scissor.Enabled) {
/* clear scissor region only */
- GLint y;
- GLint width = ctx->DrawBuffer->Xmax - ctx->DrawBuffer->Xmin + 1;
- for (y=ctx->DrawBuffer->Ymin; y<=ctx->DrawBuffer->Ymax; y++) {
- GLstencil *ptr = STENCIL_ADDRESS( ctx->DrawBuffer->Xmin, y );
+ 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++) {
+ GLstencil *ptr = STENCIL_ADDRESS( ctx->DrawBuffer->Xmin, y );
+ GLint x;
+ const GLstencil mask = ctx->Stencil.WriteMask;
+ const GLstencil invMask = ~mask;
+ const GLstencil clearVal = (ctx->Stencil.Clear & mask);
+ for (x = 0; x < width; x++) {
+ ptr[x] = (ptr[x] & invMask) | clearVal;
+ }
+ }
+ }
+ else {
+ /* no masking */
+ GLint y;
+ for (y=ctx->DrawBuffer->Ymin; y<=ctx->DrawBuffer->Ymax; y++) {
+ GLstencil *ptr = STENCIL_ADDRESS( ctx->DrawBuffer->Xmin, y );
#if STENCIL_BITS==8
- MEMSET( ptr, ctx->Stencil.Clear, width * sizeof(GLstencil) );
+ MEMSET( ptr, ctx->Stencil.Clear, width * sizeof(GLstencil) );
#else
- GLint x;
- for (x = 0; x < width; x++)
- ptr[x] = ctx->Stencil.Clear;
+ GLint x;
+ for (x = 0; x < width; x++)
+ ptr[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 *buffer = 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++) {
+ buffer[i] = (buffer[i] & invMask) | clearVal;
+ }
+ }
+ else {
+ /* clear whole buffer without masking */
+ const GLuint n = ctx->DrawBuffer->Width * ctx->DrawBuffer->Height;
+ GLstencil *buffer = ctx->DrawBuffer->Stencil;
+
#if STENCIL_BITS==8
- MEMSET( ctx->DrawBuffer->Stencil, ctx->Stencil.Clear,
- ctx->DrawBuffer->Width * ctx->DrawBuffer->Height * sizeof(GLstencil) );
+ MEMSET(buffer, ctx->Stencil.Clear, n * sizeof(GLstencil) );
#else
- GLuint i;
- GLuint pixels = ctx->DrawBuffer->Width * ctx->DrawBuffer->Height;
- GLstencil *buffer = ctx->DrawBuffer->Stencil;
- for (i = 0; i < pixels; i++)
- ptr[i] = ctx->Stencil.Clear;
+ GLuint i;
+ for (i = 0; i < n; i++) {
+ buffer[i] = ctx->Stencil.Clear;
+ }
#endif
+ }
}
}
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