TextureMapper: Calculate zFar and zNear for the projection matrix

https://bugs.webkit.org/show_bug.cgi?id=244564 Reviewed by Darin Adler. TextureMapper was using fixed zFar and zNear values, (-99999, 9999999). These were too big for 16 bits depth buffer on Linux. <https://bugs.webkit.org/show_bug.cgi?id=244526#c2> Changed TextureMapperLayer::computeTransformsRecursive to calculate zFar and zNear. * LayoutTests/platform/glib/TestExpectations: Unmarked imported/w3c/web-platform-tests/css/css-transforms/perspective-split-by-zero-w.html * Source/WebCore/platform/graphics/texmap/TextureMapper.h: (WebCore::TextureMapper::setDepthRange): * Source/WebCore/platform/graphics/texmap/TextureMapperGL.cpp: (WebCore::createProjectionMatrix): (WebCore::TextureMapperGL::bindDefaultSurface): (WebCore::TextureMapperGL::bindSurface): (WebCore::TextureMapperGL::setDepthRange): * Source/WebCore/platform/graphics/texmap/TextureMapperGL.h: * Source/WebCore/platform/graphics/texmap/TextureMapperLayer.cpp: (WebCore::TextureMapperComputeTransformData::updateDepthRange): (WebCore::TextureMapperLayer::computeTransformsRecursive): (WebCore::TextureMapperLayer::paint): * Source/WebCore/platform/graphics/texmap/TextureMapperLayer.h: Canonical link: https://commits.webkit.org/254897@main
WebKit · Sep 27, 2022 · 922f8f0 · 922f8f0
1 parent 7605a55
commit 922f8f0
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Showing 5 changed files with 63 additions and 18 deletions.
diff --git a/Source/WebCore/platform/graphics/texmap/TextureMapper.h b/Source/WebCore/platform/graphics/texmap/TextureMapper.h
@@ -83,6 +83,7 @@ class TextureMapper {
     virtual void endPreserves3D() { };
     virtual Ref<BitmapTexture> createTexture() = 0;
     virtual Ref<BitmapTexture> createTexture(int internalFormat) = 0;
+    virtual void setDepthRange(double zNear, double zFar) = 0;
 
     virtual void beginPainting(PaintFlags = 0) { }
     virtual void endPainting() { }

diff --git a/Source/WebCore/platform/graphics/texmap/TextureMapperGL.cpp b/Source/WebCore/platform/graphics/texmap/TextureMapperGL.cpp
@@ -72,6 +72,8 @@ class TextureMapperGLData {
     GLint previousDepthState { 0 };
     GLint viewport[4] { 0, };
     GLint previousScissor[4] { 0, };
+    double zNear { 0 };
+    double zFar { 0 };
     RefPtr<BitmapTexture> currentSurface;
     const BitmapTextureGL::FilterInfo* filterInfo { nullptr };
 
@@ -867,15 +869,14 @@ void TextureMapperGL::drawFiltered(const BitmapTexture& sampler, const BitmapTex
     drawTexturedQuadWithProgram(program.get(), static_cast<const BitmapTextureGL&>(sampler).id(), 0, targetRect, TransformationMatrix(), 1);
 }
 
-static inline TransformationMatrix createProjectionMatrix(const IntSize& size, bool mirrored)
+static inline TransformationMatrix createProjectionMatrix(const IntSize& size, bool mirrored, double zNear, double zFar)
 {
-    const float nearValue = -99999;
-    const float farValue = 9999999;
-
-    return TransformationMatrix(2.0 / float(size.width()), 0, 0, 0,
-                                0, (mirrored ? 2.0 : -2.0) / float(size.height()), 0, 0,
-                                0, 0, -2.f / (farValue - nearValue), 0,
-                                -1, mirrored ? -1 : 1, -(farValue + nearValue) / (farValue - nearValue), 1);
+    const double nearValue = std::min(zNear + 1, 9999999.0);
+    const double farValue = std::max(zFar - 1, -99999.0);
+    return TransformationMatrix(2.0 / size.width(), 0, 0, 0,
+        0, (mirrored ? 2.0 : -2.0) / size.height(), 0, 0,
+        0, 0, 2.0 / (farValue - nearValue), 0,
+        -1, mirrored ? -1 : 1, -(farValue + nearValue) / (farValue - nearValue), 1);
 }
 
 TextureMapperGL::~TextureMapperGL()
@@ -887,7 +888,7 @@ void TextureMapperGL::bindDefaultSurface()
 {
     glBindFramebuffer(GL_FRAMEBUFFER, data().targetFrameBuffer);
     auto& viewport = data().viewport;
-    data().projectionMatrix = createProjectionMatrix(IntSize(viewport[2], viewport[3]), data().PaintFlags & PaintingMirrored);
+    data().projectionMatrix = createProjectionMatrix(IntSize(viewport[2], viewport[3]), data().PaintFlags & PaintingMirrored, data().zNear, data().zFar);
     glViewport(viewport[0], viewport[1], viewport[2], viewport[3]);
     m_clipStack.apply();
     data().currentSurface = nullptr;
@@ -901,7 +902,7 @@ void TextureMapperGL::bindSurface(BitmapTexture *surface)
     }
 
     static_cast<BitmapTextureGL*>(surface)->bindAsSurface();
-    data().projectionMatrix = createProjectionMatrix(surface->size(), true /* mirrored */);
+    data().projectionMatrix = createProjectionMatrix(surface->size(), true /* mirrored */, data().zNear, data().zFar);
     data().currentSurface = surface;
 }
 
@@ -1041,6 +1042,12 @@ Ref<BitmapTexture> TextureMapperGL::createTexture(GLint internalFormat)
     return BitmapTextureGL::create(m_contextAttributes, internalFormat);
 }
 
+void TextureMapperGL::setDepthRange(double zNear, double zFar)
+{
+    data().zNear = zNear;
+    data().zFar = zFar;
+}
+
 std::unique_ptr<TextureMapper> TextureMapper::platformCreateAccelerated()
 {
     return makeUnique<TextureMapperGL>();

diff --git a/Source/WebCore/platform/graphics/texmap/TextureMapperGL.h b/Source/WebCore/platform/graphics/texmap/TextureMapperGL.h
@@ -85,6 +85,7 @@ class TextureMapperGL : public TextureMapper {
     IntSize maxTextureSize() const override { return IntSize(2000, 2000); }
     Ref<BitmapTexture> createTexture() override { return createTexture(GL_DONT_CARE); }
     Ref<BitmapTexture> createTexture(GLint internalFormat) override;
+    void setDepthRange(double zNear, double zFar) override;
 
     void drawFiltered(const BitmapTexture& sourceTexture, const BitmapTexture* contentTexture, const FilterOperation&, int pass);
 

diff --git a/Source/WebCore/platform/graphics/texmap/TextureMapperLayer.cpp b/Source/WebCore/platform/graphics/texmap/TextureMapperLayer.cpp
@@ -44,6 +44,19 @@ class TextureMapperPaintOptions {
     bool preserves3D { false };
 };
 
+struct TextureMapperLayer::ComputeTransformData {
+    double zNear { 0 };
+    double zFar { 0 };
+
+    void updateDepthRange(double z)
+    {
+        if (zNear < z)
+            zNear = z;
+        else if (zFar > z)
+            zFar = z;
+    }
+};
+
 TextureMapperLayer::TextureMapperLayer() = default;
 
 TextureMapperLayer::~TextureMapperLayer()
@@ -54,7 +67,7 @@ TextureMapperLayer::~TextureMapperLayer()
     removeFromParent();
 }
 
-void TextureMapperLayer::computeTransformsRecursive()
+void TextureMapperLayer::computeTransformsRecursive(ComputeTransformData& data)
 {
     if (m_state.size.isEmpty() && m_state.masksToBounds)
         return;
@@ -111,18 +124,37 @@ void TextureMapperLayer::computeTransformsRecursive()
 
     m_state.visible = m_state.backfaceVisibility || !m_layerTransforms.combined.isBackFaceVisible();
 
+    auto calculateZ = [&](double x, double y) -> double {
+        double z = 0;
+        double w = 1;
+        m_layerTransforms.combined.map4ComponentPoint(x, y, z, w);
+        if (w <= 0) {
+            if (!z)
+                return 0;
+            if (z < 0)
+                return -std::numeric_limits<double>::infinity();
+            return std::numeric_limits<double>::infinity();
+        }
+        return z / w;
+    };
+
+    data.updateDepthRange(calculateZ(0, 0));
+    data.updateDepthRange(calculateZ(m_state.size.width(), 0));
+    data.updateDepthRange(calculateZ(0, m_state.size.height()));
+    data.updateDepthRange(calculateZ(m_state.size.width(), m_state.size.height()));
+
     if (m_parent && m_parent->m_state.preserves3D)
-        m_centerZ = m_layerTransforms.combined.mapPoint(FloatPoint3D(m_state.size.width() / 2, m_state.size.height() / 2, 0)).z();
+        m_centerZ = calculateZ(m_state.size.width() / 2, m_state.size.height() / 2);
 
     if (m_state.maskLayer)
-        m_state.maskLayer->computeTransformsRecursive();
+        m_state.maskLayer->computeTransformsRecursive(data);
     if (m_state.replicaLayer)
-        m_state.replicaLayer->computeTransformsRecursive();
+        m_state.replicaLayer->computeTransformsRecursive(data);
     if (m_state.backdropLayer)
-        m_state.backdropLayer->computeTransformsRecursive();
+        m_state.backdropLayer->computeTransformsRecursive(data);
     for (auto* child : m_children) {
         ASSERT(child->m_parent == this);
-        child->computeTransformsRecursive();
+        child->computeTransformsRecursive(data);
     }
 
     // Reorder children if needed on the way back up.
@@ -137,7 +169,9 @@ void TextureMapperLayer::computeTransformsRecursive()
 
 void TextureMapperLayer::paint(TextureMapper& textureMapper)
 {
-    computeTransformsRecursive();
+    ComputeTransformData data;
+    computeTransformsRecursive(data);
+    textureMapper.setDepthRange(data.zNear, data.zFar);
 
     TextureMapperPaintOptions options(textureMapper);
     options.textureMapper.bindSurface(0);

diff --git a/Source/WebCore/platform/graphics/texmap/TextureMapperLayer.h b/Source/WebCore/platform/graphics/texmap/TextureMapperLayer.h
@@ -111,7 +111,9 @@ class WEBCORE_EXPORT TextureMapperLayer : public CanMakeWeakPtr<TextureMapperLay
             return m_parent->rootLayer();
         return const_cast<TextureMapperLayer&>(*this);
     }
-    void computeTransformsRecursive();
+
+    struct ComputeTransformData;
+    void computeTransformsRecursive(ComputeTransformData&);
 
     static void sortByZOrder(Vector<TextureMapperLayer* >& array);