clear stencil buffer using special purpose FBO
Review URL: https://codereview.chromium.org/941383003
diff --git a/src/gpu/GrGpu.cpp b/src/gpu/GrGpu.cpp
index efe1a61..df8de57 100644
--- a/src/gpu/GrGpu.cpp
+++ b/src/gpu/GrGpu.cpp
@@ -97,15 +97,6 @@
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;
diff --git a/src/gpu/gl/GrGLGpu.cpp b/src/gpu/gl/GrGLGpu.cpp
index 8710931..9c0f772 100644
--- a/src/gpu/gl/GrGLGpu.cpp
+++ b/src/gpu/gl/GrGLGpu.cpp
@@ -153,6 +153,7 @@
fHWProgramID = 0;
fTempSrcFBOID = 0;
fTempDstFBOID = 0;
+ fStencilClearFBOID = 0;
if (this->glCaps().pathRenderingSupport()) {
fPathRendering.reset(new GrGLPathRendering(this));
@@ -173,6 +174,9 @@
if (0 != fTempDstFBOID) {
GL_CALL(DeleteFramebuffers(1, &fTempDstFBOID));
}
+ if (0 != fStencilClearFBOID) {
+ GL_CALL(DeleteFramebuffers(1, &fStencilClearFBOID));
+ }
delete fProgramCache;
}
@@ -183,6 +187,7 @@
fHWProgramID = 0;
fTempSrcFBOID = 0;
fTempDstFBOID = 0;
+ fStencilClearFBOID = 0;
if (this->glCaps().pathRenderingSupport()) {
this->glPathRendering()->abandonGpuResources();
}
@@ -1172,11 +1177,44 @@
// whatever sizes GL gives us. In that case we query for the size.
GrGLStencilBuffer::Format format = sFmt;
get_stencil_rb_sizes(this->glInterface(), &format);
- SkAutoTUnref<GrStencilBuffer> sb(SkNEW_ARGS(GrGLStencilBuffer,
+ SkAutoTUnref<GrGLStencilBuffer> sb(SkNEW_ARGS(GrGLStencilBuffer,
(this, sbDesc, width, height, samples, format)));
if (this->attachStencilBufferToRenderTarget(sb, rt)) {
fLastSuccessfulStencilFmtIdx = sIdx;
rt->renderTargetPriv().didAttachStencilBuffer(sb);
+
+ // Clear the stencil buffer. We use a special purpose FBO for this so that the
+ // entire stencil buffer is cleared, even if it is attached to an FBO with a
+ // smaller color target.
+ if (0 == fStencilClearFBOID) {
+ GL_CALL(GenFramebuffers(1, &fStencilClearFBOID));
+ }
+
+ GL_CALL(BindFramebuffer(GR_GL_FRAMEBUFFER, fStencilClearFBOID));
+ fHWBoundRenderTargetUniqueID = SK_InvalidUniqueID;
+ fStats.incRenderTargetBinds();
+ GL_CALL(FramebufferRenderbuffer(GR_GL_FRAMEBUFFER,
+ GR_GL_STENCIL_ATTACHMENT,
+ GR_GL_RENDERBUFFER, sbDesc.fRenderbufferID));
+ if (sFmt.fPacked) {
+ GL_CALL(FramebufferRenderbuffer(GR_GL_FRAMEBUFFER,
+ GR_GL_DEPTH_ATTACHMENT,
+ GR_GL_RENDERBUFFER, sbDesc.fRenderbufferID));
+ }
+
+ GL_CALL(ClearStencil(0));
+ GL_CALL(Clear(GR_GL_STENCIL_BUFFER_BIT));
+
+ // Unbind the SB from the FBO so that we don't keep it alive.
+ GL_CALL(FramebufferRenderbuffer(GR_GL_FRAMEBUFFER,
+ GR_GL_STENCIL_ATTACHMENT,
+ GR_GL_RENDERBUFFER, 0));
+ if (sFmt.fPacked) {
+ GL_CALL(FramebufferRenderbuffer(GR_GL_FRAMEBUFFER,
+ GR_GL_DEPTH_ATTACHMENT,
+ GR_GL_RENDERBUFFER, 0));
+ }
+
return true;
}
// Remove the scratch key from this resource so we don't grab it from the cache ever
diff --git a/src/gpu/gl/GrGLGpu.h b/src/gpu/gl/GrGLGpu.h
index 7cbca01..b93080b 100644
--- a/src/gpu/gl/GrGLGpu.h
+++ b/src/gpu/gl/GrGLGpu.h
@@ -312,6 +312,8 @@
GrGLuint fTempSrcFBOID;
GrGLuint fTempDstFBOID;
+ GrGLuint fStencilClearFBOID;
+
// last scissor / viewport scissor state seen by the GL.
struct {
TriState fEnabled;