diff options
Diffstat (limited to 'src/quick/items/qquickshadereffect.cpp')
| -rw-r--r-- | src/quick/items/qquickshadereffect.cpp | 30 |
1 files changed, 26 insertions, 4 deletions
diff --git a/src/quick/items/qquickshadereffect.cpp b/src/quick/items/qquickshadereffect.cpp index f7fc7880ed..4f1a9a28ec 100644 --- a/src/quick/items/qquickshadereffect.cpp +++ b/src/quick/items/qquickshadereffect.cpp @@ -209,11 +209,33 @@ QT_BEGIN_NAMESPACE it is the textures that map to properties referencing \l Image or \l ShaderEffectSource items. - Unlike with OpenGL, runtime compilation of shader source code may not be - supported. Backends for modern APIs are likely to prefer offline + Unlike OpenGL, backends for modern APIs will typically prefer offline compilation and shipping pre-compiled bytecode with applications instead of - inlined shader source strings. To check what is expected at runtime, use the - GraphicsInfo.shaderSourceType and GraphicsInfo.shaderCompilationType properties. + inlined shader source strings. In this case the string properties for + vertex and fragment shaders are treated as URLs referring to local files or + files shipped via the Qt resource system. + + To check at runtime what is supported, use the + GraphicsInfo.shaderSourceType and GraphicsInfo.shaderCompilationType + properties. Note that these are bitmasks, because some backends may support + multiple approaches. + + In case of Direct3D 12, both bytecode in files and HLSL source strings are + supported. If the vertexShader and fragmentShader properties form a valid + URL with the \c file or \c qrc schema, the bytecode is read from the + specified file. Otherwise, the string is treated as HLSL source code and is + compiled at runtime, assuming Shader Model 5.0 and an entry point of + \c{"main"}. This allows dynamically constructing shader strings. However, + whenever the shader source code is static, it is strongly recommended to + pre-compile to bytecode using the \c fxc tool and refer to these files from + QML. This will be a lot more efficient at runtime and allows catching + syntax errors in the shaders at compile time. + + Unlike OpenGL, the Direct3D backend is able to perform runtime shader + compilation on dedicated threads. This is managed transparently to the + applications, and means that ShaderEffect items that contain HLSL source + strings do not block the rendering or other parts of the application until + the bytecode is ready. \table 70% \row |