Metal: Clear depth pbuffers to 1 for robust init

Robust resource initialization would init depth pbuffers as 0.0
instead of 1.0. This would differ from the FBO initialization, where
the uninitialized depth buffers would be initialized to 1.0.

Bug: angleproject:348199042
Change-Id: I0f251e85d6e08ce992fe323b257a0906d237f5b1
Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/5642763
Reviewed-by: Geoff Lang <[email protected]>
Commit-Queue: Kimmo Kinnunen <[email protected]>
Auto-Submit: Kimmo Kinnunen <[email protected]>
Reviewed-by: Quyen Le <[email protected]>

Author: kkinnunen-apple

extensions/EGL_ANGLE_robust_resource_initialization.txt

@@ -78,11 +78,11 @@ Additions to the EGL 1.5 Specification
     Add a new paragrah to section 3.5.1 "Creating On-Screen Rendering
     Surfaces" and section 3.5.2 "Creating Off-Screen Rendering Surfaces":
 
-    "EGL_ROBUST_RESOURCE_INITIALIZATION_ANGLE specifies if the pixel
-    values of the surface are initialized.  If its value is EGL_TRUE then all
-    pixel values in the surface are initialized to zero, otherwise the contents
-    are undefined. The default value of
-    EGL_ROBUST_RESOURCE_INITIALIZATION_ANGLE is EGL_FALSE."
+    "EGL_ROBUST_RESOURCE_INITIALIZATION_ANGLE specifies if the pixel values of
+    the surface are initialized.  If its value is EGL_TRUE then all pixel and
+    stencil values in the surface are initialized to zero, depth values are
+    initialized to 1.0. Otherwise the contents are undefined. The default value
+    of EGL_ROBUST_RESOURCE_INITIALIZATION_ANGLE is EGL_FALSE."
 
     Add a new paragrah to section 3.5.6 "Surface Attributes" under
     eglQuerySurface:
@@ -92,10 +92,15 @@ Additions to the EGL 1.5 Specification
 
     Modify the 2nd paragraph of section 3.10.1 "Posting to a Window":
 
-    "... The contents of the color buffer are undefined if the value of the
-    EGL_SWAP_BEHAVIOR attribute of surface is not EGL_BUFFER_PRESERVED and
-    the value of the EGL_ROBUST_RESOURCE_INITIALIZATION_ANGLE is
-    EGL_FALSE. ..."
+    "... If EGL_ROBUST_RESOURCE_INITIALIZATION_ANGLE is EGL_TRUE, following
+    conditions apply. If EGL_SWAP_BEHAVIOR attribute is not
+    EGL_BUFFER_PRESERVED, color and stencil buffer values are set to zero, depth
+    buffer values are set to 1.0. Otherwise, color and ancillary buffer values
+    preserved.
+
+    If EGL_ROBUST_RESOURCE_INITIALIZATION_ANGLE is EGL_FALSE, the contents of
+    ancillary buffers are always undefined after calling eglSwapBuffers. ...
+    "
 
 Issues
 
@@ -118,4 +123,6 @@ Revision History
     Version 2, 2017/03/01 - renamed extension and enum.
     Version 3, 2017/05/31 - renamed extension and made into display extension.
     Version 4, 2017/09/19 - renamed extension and changed into a
-                            context/surface creation attribute.
+                            context/surface creation attribute.
+    Version 5, 2024/09/21 - specified that depth values are initialized to 1.0
+                            specified that stencil values are initialized to 0.0

src/libANGLE/renderer/metal/IOSurfaceSurfaceMtl.mm

@@ -199,6 +199,8 @@ int FindIOSurfaceFormatIndex(GLenum internalFormat, GLenum type)
         // Disable subsequent rendering to alpha channel.
         mColorTexture->setColorWritableMask(MTLColorWriteMaskAll & (~MTLColorWriteMaskAlpha));
     }
+    // Robust resource init: currently we do not allow passing contents with IOSurfaces.
+    mColorTextureInitialized = false;
 
     return angle::Result::Continue;
 }

src/libANGLE/renderer/metal/SurfaceMtl.h

@@ -111,7 +111,8 @@ class SurfaceMtl : public SurfaceImpl
     bool mAutoResolveMSColorTexture = false;
 
     bool mRobustResourceInit = false;
-    bool mContentInitialized = false;
+    bool mColorTextureInitialized         = true;
+    bool mDepthStencilTexturesInitialized = true;
 
     mtl::Format mColorFormat;
     mtl::Format mDepthFormat;

src/libANGLE/renderer/metal/SurfaceMtl.mm

@@ -254,11 +254,6 @@
 {
     ASSERT(mColorTexture);
 
-    if (mContentInitialized)
-    {
-        return angle::Result::Continue;
-    }
-
     ContextMtl *contextMtl = mtl::GetImpl(context);
 
     // Use loadAction=clear
@@ -269,17 +264,26 @@
     {
         case GL_BACK:
         {
+            if (mColorTextureInitialized)
+            {
+                return angle::Result::Continue;
+            }
             rpDesc.numColorAttachments = 1;
             mColorRenderTarget.toRenderPassAttachmentDesc(&rpDesc.colorAttachments[0]);
             rpDesc.colorAttachments[0].loadAction = MTLLoadActionClear;
             MTLClearColor black                   = {};
             rpDesc.colorAttachments[0].clearColor =
                 mtl::EmulatedAlphaClearColor(black, mColorTexture->getColorWritableMask());
+            mColorTextureInitialized = true;
             break;
         }
         case GL_DEPTH:
         case GL_STENCIL:
         {
+            if (mDepthStencilTexturesInitialized)
+            {
+                return angle::Result::Continue;
+            }
             if (mDepthTexture)
             {
                 mDepthRenderTarget.toRenderPassAttachmentDesc(&rpDesc.depthAttachment);
@@ -290,6 +294,7 @@
                 mStencilRenderTarget.toRenderPassAttachmentDesc(&rpDesc.stencilAttachment);
                 rpDesc.stencilAttachment.loadAction = MTLLoadActionClear;
             }
+            mDepthStencilTexturesInitialized = true;
             break;
         }
         default:
@@ -298,7 +303,6 @@
     }
     mtl::RenderCommandEncoder *encoder = contextMtl->getRenderPassCommandEncoder(rpDesc);
     encoder->setStoreAction(MTLStoreActionStore);
-    mContentInitialized = true;
 
     return angle::Result::Continue;
 }
@@ -374,6 +378,8 @@
                                         /** renderTargetOnly */ false, &mDepthTexture));
 
         mDepthRenderTarget.set(mDepthTexture, mtl::kZeroNativeMipLevel, 0, mDepthFormat);
+        // Robust resource init: should initialize depth to 1.0.
+        mDepthStencilTexturesInitialized = false;
     }
 
     if (mStencilFormat.valid() && (!mStencilTexture || mStencilTexture->sizeAt0() != size))
@@ -390,6 +396,8 @@
         }
 
         mStencilRenderTarget.set(mStencilTexture, mtl::kZeroNativeMipLevel, 0, mStencilFormat);
+        // Robust resource init: should initialize stencil to zero.
+        mDepthStencilTexturesInitialized = false;
     }
 
     return angle::Result::Continue;
@@ -671,7 +679,6 @@
             mMetalLayer.get().allowsNextDrawableTimeout = NO;
             mCurrentDrawable.retainAssign([mMetalLayer nextDrawable]);
             mMetalLayer.get().allowsNextDrawableTimeout = YES;
-            mContentInitialized                         = false;
         }
 
         if (!mColorTexture)
@@ -685,6 +692,7 @@
         {
             mColorTexture->set(mCurrentDrawable.get().texture);
         }
+        mColorTextureInitialized = false;
 
         ANGLE_MTL_LOG("Current metal drawable size=%d,%d", mColorTexture->width(),
                       mColorTexture->height());
@@ -718,7 +726,11 @@
         mColorTexture->set(nil);
         mCurrentDrawable = nil;
     }
-
+    // Robust resource init: should initialize stencil zero and depth to 1.0 after swap.
+    if (mDepthTexture || mStencilTexture)
+    {
+        mDepthStencilTexturesInitialized = false;
+    }
     return angle::Result::Continue;
 }
 

src/libANGLE/renderer/metal/mtl_state_cache.h

@@ -349,7 +349,7 @@ struct RenderPassDepthAttachmentDesc : public RenderPassAttachmentDesc
         return !(*this == other);
     }
 
-    double clearDepth = 0;
+    double clearDepth = 1.0;
 };
 
 struct RenderPassStencilAttachmentDesc : public RenderPassAttachmentDesc

src/libANGLE/renderer/metal/mtl_utils.mm

@@ -659,7 +659,6 @@ bool PreferStagedTextureUploads(const gl::Context *context,
     {
         rtMTL.toRenderPassAttachmentDesc(&rpDesc.depthAttachment);
         rpDesc.depthAttachment.loadAction = MTLLoadActionClear;
-        rpDesc.depthAttachment.clearDepth = 1.0;
     }
     if (angleFormat.stencilBits)
     {

src/tests/angle_end2end_tests_expectations.txt

@@ -378,8 +378,6 @@ b/273271471 WIN INTEL VULKAN : ShaderAlgorithmTest.rgb_to_hsl_vertex_shader/* =
 40644761 MAC METAL NVIDIA : OcclusionQueriesTest.CopyNotCounted/* = SKIP
 40644783 MAC METAL NVIDIA : OcclusionQueriesTestES3.BlitNotCounted/* = SKIP
 
-40644831 MAC METAL AMD : RobustResourceInitTest.SurfaceInitializedAfterSwap/* = SKIP
-
 40644762 MAC METAL AMD : SRGBTextureTestES3.GenerateMipmaps/* = SKIP
 
 40644833 MAC METAL NVIDIA : Texture2DBaseMaxTestES3.Fuzz545ImmutableTexRenderFeedback/* = SKIP
@@ -501,6 +499,7 @@ b/273271471 WIN INTEL VULKAN : ShaderAlgorithmTest.rgb_to_hsl_vertex_shader/* =
 42264513 PIXEL4ORXL GLES : MipmapTest.TextureCubeRenderToLevelZero/* = SKIP
 42264513 PIXEL4ORXL GLES : PbufferTest.ClearAndBindTexImageSrgb/* = SKIP
 42264513 PIXEL4ORXL GLES : ReadPixelsPBOTest.ExistingDataPreserved/* = SKIP
+42264981 PIXEL4ORXL GLES : RobustResourceInitTestES3.CheckDefaultDepthStencilRenderbufferIsCleared/* = SKIP
 42264981 PIXEL4ORXL GLES : RobustResourceInitTestES3.CheckDepthStencilRenderbufferIsCleared/* = SKIP
 42264981 PIXEL4ORXL GLES : RobustResourceInitTestES3.CheckMultisampleDepthStencilRenderbufferIsCleared/* = SKIP
 42264513 PIXEL4ORXL GLES : SimpleStateChangeTestES31.ClearThenSampleWithCompute/* = SKIP

src/tests/gl_tests/RobustResourceInitTest.cpp

@@ -2400,6 +2400,35 @@ TEST_P(RobustResourceInitTestES3, CheckDepthStencilRenderbufferIsCleared)
     ASSERT_GL_NO_ERROR();
 }
 
+// Test that default framebuffer depth and stencil are cleared to values that
+// are consistent with non-default framebuffer clear values. Depth 1.0, stencil 0.0.
+TEST_P(RobustResourceInitTestES3, CheckDefaultDepthStencilRenderbufferIsCleared)
+{
+    ANGLE_SKIP_TEST_IF(!hasRobustSurfaceInit());
+
+    // Render a quad at Z = 1.0 with depth test on and depth function set to GL_EQUAL.
+    // If the depth buffer is not cleared to 1.0 this will fail
+    glEnable(GL_DEPTH_TEST);
+    glDepthFunc(GL_EQUAL);
+
+    ANGLE_GL_PROGRAM(drawGreen, essl1_shaders::vs::Simple(), essl1_shaders::fs::Green());
+    drawQuad(drawGreen, essl1_shaders::PositionAttrib(), 1.0f, 1.0f, true);
+    EXPECT_PIXEL_RECT_EQ(0, 0, kWidth, kHeight, GLColor::green);
+
+    // Render with stencil test on and stencil function set to GL_EQUAL
+    // If the stencil is not zero this will fail.
+    glDisable(GL_DEPTH_TEST);
+    glEnable(GL_STENCIL_TEST);
+    glStencilOp(GL_KEEP, GL_KEEP, GL_KEEP);
+    glStencilFunc(GL_EQUAL, 0, 0xFF);
+
+    ANGLE_GL_PROGRAM(drawRed, essl1_shaders::vs::Simple(), essl1_shaders::fs::Red());
+    drawQuad(drawRed, essl1_shaders::PositionAttrib(), 1.0f, 1.0f, true);
+    EXPECT_PIXEL_RECT_EQ(0, 0, kWidth, kHeight, GLColor::red);
+
+    ASSERT_GL_NO_ERROR();
+}
+
 TEST_P(RobustResourceInitTestES3, CheckMultisampleDepthStencilRenderbufferIsCleared)
 {
     ANGLE_SKIP_TEST_IF(!hasRobustSurfaceInit());