Avoid re-rendering stencil clip for every draw with reducable clip stack
Fixes the cases where clip stack reduction would cause clip to be
re-rendered to stencil for each draw call. This causes unneeded
slowdown.
Stencil cache would not be used because the clip stack generation id communicated
by the clip stack element list would be invalid. This happended due to
a) clip stack reduction creating new elements in the element list.
b) purging logic removing the generation id, but reduction logic
selecting already purged element, and thus the generation id, as
the representative state of the clip.
Cases of a) where reduction would flatten the stack to a single new
element were fixed by assigning the generation id of the top-most
element of the clip stack as the generation id of the new
element. This is not strictly minimal, but enables more caching than
using invalid id.
Cases of a) where reduction would substitute a stack element with a
new element the generation id of the substituted element is used.
The b) part was fixed by removing the purging logic. It was not
exactly correct, as the previously purged states were actually
used. The purging was not used for anything.
Changes SkClipStack API to highlight that invalid generation id is
never returned by SkClipStack. Empty stacks are wide open. Changes the
clients to reflect this.
Fixes a crash when not passing anti-alias out parameter to
GrReducedClip::ReduceClipStack. The crash is not exercised in the
current code.
Committed: http://code.google.com/p/skia/source/detail?r=12084
R=bsalomon@google.com, robertphillips@google.com
Author: kkinnunen@nvidia.com
Review URL: https://codereview.chromium.org/48593003
git-svn-id: http://skia.googlecode.com/svn/trunk@12127 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/src/gpu/GrClipMaskManager.cpp b/src/gpu/GrClipMaskManager.cpp
index 0f91566..3aef3de 100644
--- a/src/gpu/GrClipMaskManager.cpp
+++ b/src/gpu/GrClipMaskManager.cpp
@@ -113,6 +113,7 @@
fCurrClipMaskType = kNone_ClipMaskType;
ElementList elements(16);
+ int32_t genID;
InitialState initialState;
SkIRect clipSpaceIBounds;
bool requiresAA;
@@ -132,6 +133,7 @@
ReduceClipStack(*clipDataIn->fClipStack,
clipSpaceRTIBounds,
&elements,
+ &genID,
&initialState,
&clipSpaceIBounds,
&requiresAA);
@@ -156,7 +158,6 @@
// If MSAA is enabled we can do everything in the stencil buffer.
if (0 == rt->numSamples() && requiresAA) {
- int32_t genID = clipDataIn->fClipStack->getTopmostGenID();
GrTexture* result = NULL;
if (this->useSWOnlyPath(elements)) {
@@ -207,7 +208,8 @@
// use the stencil clip if we can't represent the clip as a rectangle.
SkIPoint clipSpaceToStencilSpaceOffset = -clipDataIn->fOrigin;
- this->createStencilClipMask(initialState,
+ this->createStencilClipMask(genID,
+ initialState,
elements,
clipSpaceIBounds,
clipSpaceToStencilSpaceOffset);
@@ -390,11 +392,11 @@
// Handles caching & allocation (if needed) of a clip alpha-mask texture for both the sw-upload
// or gpu-rendered cases. Returns true if there is no more work to be done (i.e., we got a cache
// hit)
-bool GrClipMaskManager::getMaskTexture(int32_t clipStackGenID,
+bool GrClipMaskManager::getMaskTexture(int32_t elementsGenID,
const SkIRect& clipSpaceIBounds,
GrTexture** result,
bool willUpload) {
- bool cached = fAACache.canReuse(clipStackGenID, clipSpaceIBounds);
+ bool cached = fAACache.canReuse(elementsGenID, clipSpaceIBounds);
if (!cached) {
// There isn't a suitable entry in the cache so we create a new texture to store the mask.
@@ -412,7 +414,7 @@
desc.fConfig = kAlpha_8_GrPixelConfig;
}
- fAACache.acquireMask(clipStackGenID, desc, clipSpaceIBounds);
+ fAACache.acquireMask(elementsGenID, desc, clipSpaceIBounds);
}
*result = fAACache.getLastMask();
@@ -421,14 +423,14 @@
////////////////////////////////////////////////////////////////////////////////
// Create a 8-bit clip mask in alpha
-GrTexture* GrClipMaskManager::createAlphaClipMask(int32_t clipStackGenID,
+GrTexture* GrClipMaskManager::createAlphaClipMask(int32_t elementsGenID,
InitialState initialState,
const ElementList& elements,
const SkIRect& clipSpaceIBounds) {
SkASSERT(kNone_ClipMaskType == fCurrClipMaskType);
GrTexture* result;
- if (this->getMaskTexture(clipStackGenID, clipSpaceIBounds, &result, false)) {
+ if (this->getMaskTexture(elementsGenID, clipSpaceIBounds, &result, false)) {
fCurrClipMaskType = kAlpha_ClipMaskType;
return result;
}
@@ -569,7 +571,8 @@
////////////////////////////////////////////////////////////////////////////////
// Create a 1-bit clip mask in the stencil buffer. 'devClipBounds' are in device
// (as opposed to canvas) coordinates
-bool GrClipMaskManager::createStencilClipMask(InitialState initialState,
+bool GrClipMaskManager::createStencilClipMask(int32_t elementsGenID,
+ InitialState initialState,
const ElementList& elements,
const SkIRect& clipSpaceIBounds,
const SkIPoint& clipSpaceToStencilOffset) {
@@ -587,11 +590,10 @@
if (NULL == stencilBuffer) {
return false;
}
- int32_t genID = elements.tail()->getGenID();
- if (stencilBuffer->mustRenderClip(genID, clipSpaceIBounds, clipSpaceToStencilOffset)) {
+ if (stencilBuffer->mustRenderClip(elementsGenID, clipSpaceIBounds, clipSpaceToStencilOffset)) {
- stencilBuffer->setLastClip(genID, clipSpaceIBounds, clipSpaceToStencilOffset);
+ stencilBuffer->setLastClip(elementsGenID, clipSpaceIBounds, clipSpaceToStencilOffset);
// Set the matrix so that rendered clip elements are transformed from clip to stencil space.
SkVector translate = {
@@ -921,14 +923,14 @@
}
////////////////////////////////////////////////////////////////////////////////
-GrTexture* GrClipMaskManager::createSoftwareClipMask(int32_t clipStackGenID,
+GrTexture* GrClipMaskManager::createSoftwareClipMask(int32_t elementsGenID,
GrReducedClip::InitialState initialState,
const GrReducedClip::ElementList& elements,
const SkIRect& clipSpaceIBounds) {
SkASSERT(kNone_ClipMaskType == fCurrClipMaskType);
GrTexture* result;
- if (this->getMaskTexture(clipStackGenID, clipSpaceIBounds, &result, true)) {
+ if (this->getMaskTexture(elementsGenID, clipSpaceIBounds, &result, true)) {
return result;
}