bool GrGpu::attachStencilBufferToRenderTarget(GrRenderTarget* rt) {
SkASSERT(NULL == rt->renderTargetPriv().getStencilBuffer());
GrUniqueKey sbKey;
int width = rt->width();
int height = rt->height();
if (this->caps()->oversizedStencilSupport()) {
width = SkNextPow2(width);
height = SkNextPow2(height);
}
GrStencilBuffer::ComputeSharedStencilBufferKey(width, height, rt->numSamples(), &sbKey);
SkAutoTUnref<GrStencilBuffer> sb(static_cast<GrStencilBuffer*>(
this->getContext()->getResourceCache()->findAndRefUniqueResource(sbKey)));
if (sb) {
if (this->attachStencilBufferToRenderTarget(sb, rt)) {
rt->renderTargetPriv().didAttachStencilBuffer(sb);
return true;
}
return false;
}
if (this->createStencilBufferForRenderTarget(rt, width, height)) {
GrStencilBuffer* sb = rt->renderTargetPriv().getStencilBuffer();
sb->resourcePriv().setUniqueKey(sbKey);
return true;
} else {
return false;
}
}
bool GrGpu::attachStencilBufferToRenderTarget(GrRenderTarget* rt) {
SkASSERT(NULL == rt->renderTargetPriv().getStencilBuffer());
GrUniqueKey sbKey;
int width = rt->width();
int height = rt->height();
if (this->caps()->oversizedStencilSupport()) {
width = SkNextPow2(width);
height = SkNextPow2(height);
}
GrStencilBuffer::ComputeSharedStencilBufferKey(width, height, rt->numSamples(), &sbKey);
SkAutoTUnref<GrStencilBuffer> sb(static_cast<GrStencilBuffer*>(
this->getContext()->getResourceCache()->findAndRefUniqueResource(sbKey)));
if (sb) {
if (this->attachStencilBufferToRenderTarget(sb, rt)) {
rt->renderTargetPriv().didAttachStencilBuffer(sb);
return true;
}
return false;
}
if (this->createStencilBufferForRenderTarget(rt, width, height)) {
// Right now we're clearing the stencil buffer here after it is
// attached to an RT for the first time. When we start matching
// stencil buffers with smaller color targets this will no longer
// be correct because it won't be guaranteed to clear the entire
// sb.
// We used to clear down in the GL subclass using a special purpose
// FBO. But iOS doesn't allow a stencil-only FBO. It reports unsupported
// FBO status.
this->clearStencil(rt);
GrStencilBuffer* sb = rt->renderTargetPriv().getStencilBuffer();
sb->resourcePriv().setUniqueKey(sbKey);
return true;
} else {
return false;
}
}