WebAssembly for QtBase

This is the squashed diff from wip/webassembly to dev.

Done-with: Peng Wu <peng.wu@intopalo.com>
Done-with: Sami Enne <sami.enne@intopalo.com>
Done-with: Morten Johan Sørvig <morten.sorvig@qt.io>
Started-by: Andrew Knight <andrew.knight@intopalo.com>
Change-Id: I6562433c0a38d6ec49ab675e0f104f2665f3392d
Reviewed-by: Lorn Potter <lorn.potter@gmail.com>
Reviewed-by: Eskil Abrahamsen Blomfeldt <eskil.abrahamsen-blomfeldt@qt.io>

1 files changed, 45 insertions, 0 deletions

diff --git a/src/gui/opengl/qopenglframebufferobject.cpp b/src/gui/opengl/qopenglframebufferobject.cpp
index 6486a447ee..cae3d516c4 100644
--- a/src/gui/opengl/qopenglframebufferobject.cpp
+++ b/src/gui/opengl/qopenglframebufferobject.cpp
@@ -142,6 +142,14 @@ QT_BEGIN_NAMESPACE
 #define GL_CONTEXT_LOST                   0x0507
 #endif
 
+#ifndef GL_DEPTH_STENCIL_ATTACHMENT
+#define GL_DEPTH_STENCIL_ATTACHMENT       0x821A
+#endif
+
+#ifndef GL_DEPTH_STENCIL
+#define GL_DEPTH_STENCIL                  0x84F9
+#endif
+
 
 
 /*!
@@ -619,7 +627,11 @@ void QOpenGLFramebufferObjectPrivate::initDepthStencilAttachments(QOpenGLContext
 
     // free existing attachments
     if (depth_buffer_guard) {
+#ifdef Q_OS_WASM
+        funcs.glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_DEPTH_STENCIL_ATTACHMENT, GL_RENDERBUFFER, 0);
+#else
         funcs.glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_DEPTH_ATTACHMENT, GL_RENDERBUFFER, 0);
+#endif
         depth_buffer_guard->free();
     }
     if (stencil_buffer_guard) {
@@ -637,7 +649,35 @@ void QOpenGLFramebufferObjectPrivate::initDepthStencilAttachments(QOpenGLContext
     // In practice, a combined depth-stencil buffer is supported by all desktop platforms, while a
     // separate stencil buffer is not. On embedded devices however, a combined depth-stencil buffer
     // might not be supported while separate buffers are, according to QTBUG-12861.
+#ifdef Q_OS_WASM
+    // WebGL doesn't allow separately attach buffers to
+    // STENCIL_ATTACHMENT and DEPTH_ATTACHMENT
+    // QTBUG-69913
+    if (attachment == QOpenGLFramebufferObject::CombinedDepthStencil) {
+        funcs.glGenRenderbuffers(1, &depth_buffer);
+        funcs.glBindRenderbuffer(GL_RENDERBUFFER, depth_buffer);
+        Q_ASSERT(funcs.glIsRenderbuffer(depth_buffer));
+
+        GLenum storageFormat = GL_DEPTH_STENCIL;
+
+        if (samples != 0 ) {
+            funcs.glRenderbufferStorageMultisample(GL_RENDERBUFFER, samples,
+                                                   storageFormat, dsSize.width(), dsSize.height());
+        } else {
+            funcs.glRenderbufferStorage(GL_RENDERBUFFER, storageFormat,
+                                        dsSize.width(), dsSize.height());
+        }
+
+        funcs.glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_DEPTH_STENCIL_ATTACHMENT,
+                                        GL_RENDERBUFFER, depth_buffer);
 
+        valid = checkFramebufferStatus(ctx);
+        if (!valid) {
+            funcs.glDeleteRenderbuffers(1, &depth_buffer);
+            depth_buffer = 0;
+        }
+    }
+#else
     if (attachment == QOpenGLFramebufferObject::CombinedDepthStencil
         && funcs.hasOpenGLExtension(QOpenGLExtensions::PackedDepthStencil))
     {
@@ -729,11 +769,16 @@ void QOpenGLFramebufferObjectPrivate::initDepthStencilAttachments(QOpenGLContext
             stencil_buffer = 0;
         }
     }
+#endif //Q_OS_WASM
 
     // The FBO might have become valid after removing the depth or stencil buffer.
     valid = checkFramebufferStatus(ctx);
 
+#ifdef Q_OS_WASM
+    if (depth_buffer) {
+#else
     if (depth_buffer && stencil_buffer) {
+#endif
         fbo_attachment = QOpenGLFramebufferObject::CombinedDepthStencil;
     } else if (depth_buffer) {
         fbo_attachment = QOpenGLFramebufferObject::Depth;