Bug 1128001 - Workaround ANGLE DEPTH16 being DEPTH24_STENCIL8. - r=kamidphish

dom/canvas/WebGLContext.cpp

@@ -205,6 +205,7 @@ WebGLContext::WebGLContext()
     , mBypassShaderValidation(false)
     , mGLMaxSamples(1)
     , mNeedsFakeNoAlpha(false)
+    , mNeedsFakeNoStencil(false)
 {
     mGeneration = 0;
     mInvalidated = false;
@@ -236,9 +237,10 @@ WebGLContext::WebGLContext()
     mViewportWidth = 0;
     mViewportHeight = 0;
 
-    mScissorTestEnabled = 0;
     mDitherEnabled = 1;
     mRasterizerDiscardEnabled = 0; // OpenGL ES 3.0 spec p244
+    mScissorTestEnabled = 0;
+    mStencilTestEnabled = 0;
 
     // initialize some GL values: we're going to get them from the GL and use them as the sizes of arrays,
     // so in case glGetIntegerv leaves them uninitialized because of a GL bug, we would have very weird crashes.
@@ -899,9 +901,13 @@ WebGLContext::SetDimensions(int32_t signedWidth, int32_t signedHeight)
     ++mGeneration;
 
     // Update our internal stuff:
-    if (gl->WorkAroundDriverBugs()) {
+    if (gl->WorkAroundDriverBugs() && gl->IsANGLE()) {
         if (!mOptions.alpha && gl->Caps().alpha)
             mNeedsFakeNoAlpha = true;
+
+        // ANGLE doesn't quite handle this properly.
+        if (gl->Caps().depth && !gl->Caps().stencil)
+            mNeedsFakeNoStencil = true;
     }
 
     // Update mOptions.
@@ -1862,24 +1868,31 @@ size_t mozilla::RoundUpToMultipleOf(size_t value, size_t multiple)
 
 WebGLContext::ScopedMaskWorkaround::ScopedMaskWorkaround(WebGLContext& webgl)
     : mWebGL(webgl)
-    , mNeedsChange(NeedsChange(webgl))
+    , mFakeNoAlpha(ShouldFakeNoAlpha(webgl))
+    , mFakeNoStencil(ShouldFakeNoStencil(webgl))
 {
-    if (mNeedsChange) {
+    if (mFakeNoAlpha) {
         mWebGL.gl->fColorMask(mWebGL.mColorWriteMask[0],
                               mWebGL.mColorWriteMask[1],
                               mWebGL.mColorWriteMask[2],
                               false);
     }
+    if (mFakeNoStencil) {
+        mWebGL.gl->fDisable(LOCAL_GL_STENCIL_TEST);
+    }
 }
 
 WebGLContext::ScopedMaskWorkaround::~ScopedMaskWorkaround()
 {
-    if (mNeedsChange) {
+    if (mFakeNoAlpha) {
         mWebGL.gl->fColorMask(mWebGL.mColorWriteMask[0],
                               mWebGL.mColorWriteMask[1],
                               mWebGL.mColorWriteMask[2],
                               mWebGL.mColorWriteMask[3]);
     }
+    if (mFakeNoStencil) {
+        mWebGL.gl->fEnable(LOCAL_GL_STENCIL_TEST);
+    }
 }
 
 ////////////////////////////////////////////////////////////////////////////////

dom/canvas/WebGLContext.h

@@ -965,6 +965,7 @@ private:
     realGLboolean mDitherEnabled;
     realGLboolean mRasterizerDiscardEnabled;
     realGLboolean mScissorTestEnabled;
+    realGLboolean mStencilTestEnabled;
 
     bool ValidateCapabilityEnum(GLenum cap, const char* info);
     realGLboolean* GetStateTrackingSlot(GLenum cap);
@@ -1529,12 +1530,14 @@ protected:
     uint64_t mLastUseIndex;
 
     bool mNeedsFakeNoAlpha;
+    bool mNeedsFakeNoStencil;
 
     struct ScopedMaskWorkaround {
         WebGLContext& mWebGL;
-        const bool mNeedsChange;
+        const bool mFakeNoAlpha;
+        const bool mFakeNoStencil;
 
-        static bool NeedsChange(WebGLContext& webgl) {
+        static bool ShouldFakeNoAlpha(WebGLContext& webgl) {
             // We should only be doing this if we're about to draw to the backbuffer, but
             // the backbuffer needs to have this fake-no-alpha workaround.
             return !webgl.mBoundDrawFramebuffer &&
@@ -1542,6 +1545,13 @@ protected:
                    webgl.mColorWriteMask[3] != false;
         }
 
+        static bool ShouldFakeNoStencil(WebGLContext& webgl) {
+            // We should only be doing this if we're about to draw to the backbuffer.
+            return !webgl.mBoundDrawFramebuffer &&
+                   webgl.mNeedsFakeNoStencil &&
+                   webgl.mStencilTestEnabled;
+        }
+
         explicit ScopedMaskWorkaround(WebGLContext& webgl);
 
         ~ScopedMaskWorkaround();

dom/canvas/WebGLContextState.cpp

@@ -628,12 +628,14 @@ realGLboolean*
 WebGLContext::GetStateTrackingSlot(GLenum cap)
 {
     switch (cap) {
-        case LOCAL_GL_SCISSOR_TEST:
-            return &mScissorTestEnabled;
         case LOCAL_GL_DITHER:
             return &mDitherEnabled;
         case LOCAL_GL_RASTERIZER_DISCARD:
             return &mRasterizerDiscardEnabled;
+        case LOCAL_GL_SCISSOR_TEST:
+            return &mScissorTestEnabled;
+        case LOCAL_GL_STENCIL_TEST:
+            return &mStencilTestEnabled;
     }
 
     return nullptr;

dom/canvas/WebGLContextUtils.cpp

@@ -1097,11 +1097,11 @@ WebGLContext::AssertCachedState()
     }
 
     // Draw state
-    MOZ_ASSERT(gl->fIsEnabled(LOCAL_GL_SCISSOR_TEST) == mScissorTestEnabled);
     MOZ_ASSERT(gl->fIsEnabled(LOCAL_GL_DITHER) == mDitherEnabled);
     MOZ_ASSERT_IF(IsWebGL2(),
                   gl->fIsEnabled(LOCAL_GL_RASTERIZER_DISCARD) == mRasterizerDiscardEnabled);
-
+    MOZ_ASSERT(gl->fIsEnabled(LOCAL_GL_SCISSOR_TEST) == mScissorTestEnabled);
+    MOZ_ASSERT(gl->fIsEnabled(LOCAL_GL_STENCIL_TEST) == mStencilTestEnabled);
 
     realGLboolean colorWriteMask[4] = {0, 0, 0, 0};
     gl->fGetBooleanv(LOCAL_GL_COLOR_WRITEMASK, colorWriteMask);