Cherry-pick 278159@main (ed28635). https://bugs.webkit.org/show_bug.c…

…gi?id=273177

    [GTK][WPE] Don't allow depth test and stencil clipping if packed depth stencil is not supported
    https://bugs.webkit.org/show_bug.cgi?id=273177

    Reviewed by Carlos Garcia Campos.

    Use a packed depth stencil format when available, which allows depth testing
    and stencil clipping at the same time. If packed depth stencil is not
    supported, use separate buffers for depth and stencil. In the latter case,
    if both buffers are requested at the same time, the stencil buffer won't
    be created.

    * Source/WebCore/platform/graphics/egl/GLContext.cpp:
    (WebCore::GLContext::glExtensions const):
    * Source/WebCore/platform/graphics/egl/GLContext.h:
    * Source/WebCore/platform/graphics/texmap/BitmapTexture.cpp:
    (WebCore::depthBufferFormat):
    (WebCore::BitmapTexture::initializeStencil):
    (WebCore::BitmapTexture::initializeDepthBuffer):
    (WebCore::BitmapTexture::~BitmapTexture):
    * Source/WebCore/platform/graphics/texmap/BitmapTexture.h:

    Canonical link: https://commits.webkit.org/278159@main

Canonical link: https://commits.webkit.org/274313.193@webkitglib/2.44

Source/WebCore/platform/graphics/egl/GLContext.cpp

@@ -520,6 +520,7 @@ const GLContext::GLExtensions& GLContext::glExtensions() const
         const char* extensionsString = reinterpret_cast<const char*>(glGetString(GL_EXTENSIONS));
         m_glExtensions.OES_texture_npot = isExtensionSupported(extensionsString, "GL_OES_texture_npot");
         m_glExtensions.EXT_unpack_subimage = isExtensionSupported(extensionsString, "GL_EXT_unpack_subimage");
+        m_glExtensions.OES_packed_depth_stencil = isExtensionSupported(extensionsString, "GL_OES_packed_depth_stencil");
     });
     return m_glExtensions;
 }

Source/WebCore/platform/graphics/egl/GLContext.h

@@ -75,6 +75,7 @@ class GLContext {
     struct GLExtensions {
         bool OES_texture_npot { false };
         bool EXT_unpack_subimage { false };
+        bool OES_packed_depth_stencil { false };
     };
     const GLExtensions& glExtensions() const;
 

Source/WebCore/platform/graphics/texmap/BitmapTexture.cpp

@@ -51,8 +51,26 @@ static const GLenum s_pixelDataType = GL_UNSIGNED_INT_8_8_8_8_REV;
 static const GLenum s_pixelDataType = GL_UNSIGNED_BYTE;
 #endif
 
+// On GLES3, the format we want for packed depth stencil is GL_DEPTH24_STENCIL8, but when added through
+// the extension this format is called GL_DEPTH24_STENCIL8_OES. In any case they hold the same value 0x88F0
+// so we can just use the first one.
+// These definitions may not exist if this is a GLES1/2 context without the GL_OES_packed_depth_stencil
+// extension. We need to define the one we want to use in order to build on every case.
+#ifndef GL_DEPTH24_STENCIL8
+#define GL_DEPTH24_STENCIL8 0x88F0
+#endif
+
 namespace WebCore {
 
+GLenum depthBufferFormat()
+{
+    auto* glContext = GLContext::current();
+    if (glContext->version() >= 300 || glContext->glExtensions().OES_packed_depth_stencil)
+        return GL_DEPTH24_STENCIL8;
+
+    return GL_DEPTH_COMPONENT16;
+}
+
 BitmapTexture::BitmapTexture(const IntSize& size, OptionSet<Flags> flags, GLint internalFormat)
     : m_flags(flags)
     , m_size(size)
@@ -185,34 +203,39 @@ void BitmapTexture::updateContents(GraphicsLayer* sourceLayer, const IntRect& ta
 
 void BitmapTexture::initializeStencil()
 {
-#if !USE(TEXMAP_DEPTH_STENCIL_BUFFER)
-    if (m_rbo)
+    if (m_flags.contains(Flags::DepthBuffer)) {
+        // We have a depth buffer and we're asked to have a stencil buffer as well. This is only
+        // possible if packed depth stencil is available. If that's the case, just bind the depth
+        // buffer as the stencil one if haven't done so. If packed depth stencil is not available
+        // don't do anything, which will cause stencil clips on this surface to fail.
+        if (depthBufferFormat() == GL_DEPTH24_STENCIL8 && !m_stencilBound) {
+            glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_STENCIL_ATTACHMENT, GL_RENDERBUFFER, m_depthBufferObject);
+            m_stencilBound = true;
+        }
         return;
+    }
 
-    glGenRenderbuffers(1, &m_rbo);
-    glBindRenderbuffer(GL_RENDERBUFFER, m_rbo);
+    // We don't have a depth buffer. Use a stencil only buffer.
+    if (m_stencilBufferObject)
+        return;
+
+    glGenRenderbuffers(1, &m_stencilBufferObject);
+    glBindRenderbuffer(GL_RENDERBUFFER, m_stencilBufferObject);
     glRenderbufferStorage(GL_RENDERBUFFER, GL_STENCIL_INDEX8, m_size.width(), m_size.height());
     glBindRenderbuffer(GL_RENDERBUFFER, 0);
-    glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_STENCIL_ATTACHMENT, GL_RENDERBUFFER, m_rbo);
+    glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_STENCIL_ATTACHMENT, GL_RENDERBUFFER, m_stencilBufferObject);
     glClearStencil(0);
     glClear(GL_STENCIL_BUFFER_BIT);
-#endif
 }
 
 void BitmapTexture::initializeDepthBuffer()
 {
     if (m_depthBufferObject)
         return;
 
-#if USE(TEXMAP_DEPTH_STENCIL_BUFFER)
-    GLenum format = GL_DEPTH24_STENCIL8_OES;
-#else
-    GLenum format = GL_DEPTH_COMPONENT16;
-#endif
-
     glGenRenderbuffers(1, &m_depthBufferObject);
     glBindRenderbuffer(GL_RENDERBUFFER, m_depthBufferObject);
-    glRenderbufferStorage(GL_RENDERBUFFER, format, m_size.width(), m_size.height());
+    glRenderbufferStorage(GL_RENDERBUFFER, depthBufferFormat(), m_size.width(), m_size.height());
     glBindRenderbuffer(GL_RENDERBUFFER, 0);
     glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_DEPTH_ATTACHMENT, GL_RENDERBUFFER, m_depthBufferObject);
 }
@@ -264,13 +287,11 @@ BitmapTexture::~BitmapTexture()
     if (m_fbo)
         glDeleteFramebuffers(1, &m_fbo);
 
-#if !USE(TEXMAP_DEPTH_STENCIL_BUFFER)
-    if (m_rbo)
-        glDeleteRenderbuffers(1, &m_rbo);
-#endif
-
     if (m_depthBufferObject)
         glDeleteRenderbuffers(1, &m_depthBufferObject);
+
+    if (m_stencilBufferObject)
+        glDeleteRenderbuffers(1, &m_stencilBufferObject);
 }
 
 void BitmapTexture::copyFromExternalTexture(GLuint sourceTextureID)

Source/WebCore/platform/graphics/texmap/BitmapTexture.h

@@ -43,12 +43,6 @@ class NativeImage;
 class TextureMapper;
 enum class TextureMapperFlags : uint16_t;
 
-#if OS(WINDOWS)
-#define USE_TEXMAP_DEPTH_STENCIL_BUFFER 1
-#else
-#define USE_TEXMAP_DEPTH_STENCIL_BUFFER 0
-#endif
-
 class BitmapTexture final : public RefCounted<BitmapTexture> {
 public:
     enum class Flags : uint8_t {
@@ -100,10 +94,9 @@ class BitmapTexture final : public RefCounted<BitmapTexture> {
     IntSize m_size;
     GLuint m_id { 0 };
     GLuint m_fbo { 0 };
-#if !USE(TEXMAP_DEPTH_STENCIL_BUFFER)
-    GLuint m_rbo { 0 };
-#endif
     GLuint m_depthBufferObject { 0 };
+    GLuint m_stencilBufferObject { 0 };
+    bool m_stencilBound { false };
     bool m_shouldClear { true };
     ClipStack m_clipStack;
     OptionSet<TextureMapperFlags> m_colorConvertFlags;