diff options
| author | Peter Clifton <pcjc2@cam.ac.uk> | 2010-11-24 15:24:31 +0000 |
|---|---|---|
| committer | Brian Paul <brianp@vmware.com> | 2010-11-24 12:14:54 -0700 |
| commit | ee88727df8b133e99608e5d30cbd50fb6e11628a (patch) | |
| tree | 8a05d306a234af18bb9cf0894185b29107f3e25d /src/mesa/drivers/common | |
| parent | 03a4f97a68dc0bf7008efcfdb61fd7033357d1ab (diff) | |
meta: Mask Stencil.Clear against stencilMax in _mesa_meta_Clear
This fixes incorrect behaviour when the stencil clear value exceeds
the size of the stencil buffer, for example, when set with:
glClearStencil (~1); /* Set a bit pattern of 111...11111110 */
glClear (GL_STENCIL_BUFFER_BIT);
The clear value needs to be masked by the value 2^m - 1, where m is the
number of bits in the stencil buffer. Previously, we passed the value
masked with 0x7fffffff to _mesa_StencilFuncSeparate which then clamps,
NOT masks the value to the range 0 to 2^m - 1.
The result would be clearing the stencil buffer to 0xff, rather than 0xfe.
Signed-off-by: Peter Clifton <pcjc2@cam.ac.uk>
Signed-off-by: Brian Paul <brianp@vmware.com>
Diffstat (limited to 'src/mesa/drivers/common')
| -rw-r--r-- | src/mesa/drivers/common/meta.c | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/src/mesa/drivers/common/meta.c b/src/mesa/drivers/common/meta.c index ba8be12571..95accc1813 100644 --- a/src/mesa/drivers/common/meta.c +++ b/src/mesa/drivers/common/meta.c @@ -1398,6 +1398,7 @@ _mesa_meta_Clear(struct gl_context *ctx, GLbitfield buffers) struct vertex verts[4]; /* save all state but scissor, pixel pack/unpack */ GLbitfield metaSave = META_ALL - META_SCISSOR - META_PIXEL_STORE; + const GLuint stencilMax = (1 << ctx->DrawBuffer->Visual.stencilBits) - 1; if (buffers & BUFFER_BITS_COLOR) { /* if clearing color buffers, don't save/restore colormask */ @@ -1453,7 +1454,7 @@ _mesa_meta_Clear(struct gl_context *ctx, GLbitfield buffers) _mesa_StencilOpSeparate(GL_FRONT_AND_BACK, GL_REPLACE, GL_REPLACE, GL_REPLACE); _mesa_StencilFuncSeparate(GL_FRONT_AND_BACK, GL_ALWAYS, - ctx->Stencil.Clear & 0x7fffffff, + ctx->Stencil.Clear & stencilMax, ctx->Stencil.WriteMask[0]); } else { |