bool GrGpu::attachStencilBufferToRenderTarget(GrRenderTarget* rt) {
GrAssert(NULL == rt->getStencilBuffer());
GrStencilBuffer* sb =
this->getContext()->findStencilBuffer(rt->width(),
rt->height(),
rt->numSamples());
if (NULL != sb) {
rt->setStencilBuffer(sb);
bool attached = this->attachStencilBufferToRenderTarget(sb, rt);
if (!attached) {
rt->setStencilBuffer(NULL);
}
return attached;
}
if (this->createStencilBufferForRenderTarget(rt,
rt->width(), rt->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.
GrDrawState::AutoRenderTargetRestore artr(this->drawState(), rt);
this->clearStencil();
return true;
} else {
return false;
}
}
/**
* Move the result of the software mask generation back to the gpu
*/
void GrSWMaskHelper::toTexture(GrTexture *texture, uint8_t alpha) {
SkAutoLockPixels alp(fBM);
// The destination texture is almost always larger than "fBM". Clear
// it appropriately so we don't get mask artifacts outside of the path's
// bounding box
// "texture" needs to be installed as the render target for the clear
// and the texture upload but cannot remain the render target upon
// return. Callers typically use it as a texture and it would then
// be both source and dest.
GrDrawState::AutoRenderTargetRestore artr(fContext->getGpu()->drawState(),
texture->asRenderTarget());
fContext->getGpu()->clear(NULL, GrColorPackRGBA(alpha, alpha, alpha, alpha));
texture->writePixels(0, 0, fBM.width(), fBM.height(),
kAlpha_8_GrPixelConfig,
fBM.getPixels(), fBM.rowBytes());
}
