Bug 1258036 - Separate global state checks from fb-specific checks. - r=jrmuizel

dom/canvas/WebGLContext.cpp

@@ -984,6 +984,9 @@ WebGLContext::SetDimensions(int32_t signedWidth, int32_t signedHeight)
 
     mOptions.antialias = gl->Caps().antialias;
 
+    //////
+    // Initial setup.
+
     MakeContextCurrent();
 
     gl->fViewport(0, 0, mWidth, mHeight);
@@ -991,20 +994,13 @@ WebGLContext::SetDimensions(int32_t signedWidth, int32_t signedHeight)
     mViewportHeight = mHeight;
 
     gl->fScissor(0, 0, mWidth, mHeight);
-
-    // Make sure that we clear this out, otherwise
-    // we'll end up displaying random memory
     gl->fBindFramebuffer(LOCAL_GL_FRAMEBUFFER, 0);
 
+    //////
+    // Check everything
+
     AssertCachedBindings();
-    AssertCachedState();
-
-    // Clear immediately, because we need to present the cleared initial
-    // buffer.
-    mBackbufferNeedsClear = true;
-    ClearBackbufferIfNeeded();
-
-    mShouldPresent = true;
+    AssertCachedGlobalState();
 
     MOZ_ASSERT(gl->Caps().color);
 
@@ -1020,8 +1016,14 @@ WebGLContext::SetDimensions(int32_t signedWidth, int32_t signedHeight)
     MOZ_ASSERT(gl->Caps().antialias == mOptions.antialias);
     MOZ_ASSERT(gl->Caps().preserve == mOptions.preserveDrawingBuffer);
 
-    AssertCachedBindings();
-    AssertCachedState();
+    //////
+    // Clear immediately, because we need to present the cleared initial buffer
+    mBackbufferNeedsClear = true;
+    ClearBackbufferIfNeeded();
+
+    mShouldPresent = true;
+
+    //////
 
     reporter.SetSuccessful();
 
@@ -1416,8 +1418,7 @@ WebGLContext::ForceClearFramebufferWithDefaultValues(GLbitfield clearBits,
 
     // Fun GL fact: No need to worry about the viewport here, glViewport is just
     // setting up a coordinates transformation, it doesn't affect glClear at all.
-    AssertCachedState(); // Can't check cached bindings, as we could
-                         // have a different FB bound temporarily.
+    AssertCachedGlobalState();
 
     // Prepare GL state for clearing.
     gl->fDisable(LOCAL_GL_SCISSOR_TEST);

dom/canvas/WebGLContext.h

@@ -376,7 +376,7 @@ public:
     bool TryToRestoreContext();
 
     void AssertCachedBindings();
-    void AssertCachedState();
+    void AssertCachedGlobalState();
 
     dom::HTMLCanvasElement* GetCanvas() const { return mCanvasElement; }
 

dom/canvas/WebGLContextUtils.cpp

@@ -684,7 +684,7 @@ WebGLContext::AssertCachedBindings()
         AssertUintParamCorrect(gl, LOCAL_GL_VERTEX_ARRAY_BINDING, bound);
     }
 
-    // Bound object state
+    // Framebuffers
     if (IsWebGL2()) {
         GLuint bound = mBoundDrawFramebuffer ? mBoundDrawFramebuffer->mGLName
                                              : 0;
@@ -699,6 +699,15 @@ WebGLContext::AssertCachedBindings()
         AssertUintParamCorrect(gl, LOCAL_GL_FRAMEBUFFER_BINDING, bound);
     }
 
+    GLint stencilBits = 0;
+    if (GetStencilBits(&stencilBits)) { // Depends on current draw framebuffer.
+        const GLuint stencilRefMask = (1 << stencilBits) - 1;
+
+        AssertMaskedUintParamCorrect(gl, LOCAL_GL_STENCIL_REF,      stencilRefMask, mStencilRefFront);
+        AssertMaskedUintParamCorrect(gl, LOCAL_GL_STENCIL_BACK_REF, stencilRefMask, mStencilRefBack);
+    }
+
+    // Program
     GLuint bound = mCurrentProgram ? mCurrentProgram->mGLName : 0;
     AssertUintParamCorrect(gl, LOCAL_GL_CURRENT_PROGRAM, bound);
 
@@ -730,7 +739,7 @@ WebGLContext::AssertCachedBindings()
 }
 
 void
-WebGLContext::AssertCachedState()
+WebGLContext::AssertCachedGlobalState()
 {
 #ifdef DEBUG
     MakeContextCurrent();
@@ -771,14 +780,6 @@ WebGLContext::AssertCachedState()
 
     AssertUintParamCorrect(gl, LOCAL_GL_STENCIL_CLEAR_VALUE, mStencilClearValue);
 
-    GLint stencilBits = 0;
-    if (GetStencilBits(&stencilBits)) {
-        const GLuint stencilRefMask = (1 << stencilBits) - 1;
-
-        AssertMaskedUintParamCorrect(gl, LOCAL_GL_STENCIL_REF,      stencilRefMask, mStencilRefFront);
-        AssertMaskedUintParamCorrect(gl, LOCAL_GL_STENCIL_BACK_REF, stencilRefMask, mStencilRefBack);
-    }
-
     // GLES 3.0.4, $4.1.4, p177:
     //   [...] the front and back stencil mask are both set to the value `2^s - 1`, where
     //   `s` is greater than or equal to the number of bits in the deepest stencil buffer