Add the graphics api independent scenegraph port

Opt in via environment variables:
QSG_RHI=1 -> enable using QRhi instead of GL
QSG_RHI_BACKEND -> set to vulkan, metal, d3d11, gl to override the default
(the default is d3d11 on Windows, metal on Mac, gl elsewhere)

Or force a given rhi backend via the existing
QQuickWindow::setSceneGraphBackend().

Otherwise the default behavior is the same as before, the rhi code path
is never active by default.

-no-opengl builds are supported in the sense that they work and default
to the software backend. However, the rhi code path cannot currently be
used in such builds, even though QRhi from qtbase is fully functional
with Vulkan, D3D, or Metal even when qtbase was configured with
-no-opengl. This cannot be utilized by Quick atm due to OpenGL usage
being all over the place in the sources corresponding to the default
backend, and those host the rhi code path as well. This will be cleaned up
hopefully in Qt 6, with the removal all direct OpenGL usage.

Other env.vars.:
QSG_RHI_DEBUG_LAYER=1 -> enable D3D debug or Vulkan validation layer
(assuming the system is set up for this)
QSG_RHI_SHADEREFFECT_DEBUG=1 -> print stuff from ShaderEffect
QSG_SAMPLES=1,2,4,... -> MSAA sample count (but QSurfaceFormat works too)
QT_D3D_ADAPTER_INDEX=0,1,... -> D3D adapter index
QT_VK_PHYSICAL_DEVICE_INDEX=0,1,... -> Vulkan physical device index
QSG_RHI_UINT32_INDEX=1 -> always use uint index data (both
merged/unmerged, convert when needed - with some rhi backends this is
implicit)
QSG_RENDER_LOOP -> to override the render loop as usual. The default
with RHI is threaded for Metal, threaded for Vulkan on Windows, basic
for Vulkan on Linux and Android (to be checked later), while the existing
rules apply for OpenGL.

Not supported when running with QRhi:
  - particles
  - compressed atlases (though this is transparent to the apps)
  - QSGRenderNode
  - QQuickRenderControl
  - QQuickFramebufferObject
  - certain QQuickWindow functionality that depends directly on OpenGL
  - anisotropic filtering for textures
  - native text may lack some gamma correction
  - QSGEngine applicability unclear
  - some QML profiler logs may be incorrect or irrelevant

Change-Id: I7822e99ad79e342e4166275da6e9e66498d76521
Reviewed-by: Lars Knoll <lars.knoll@qt.io>

13 files changed, 191 insertions, 0 deletions

diff --git a/examples/quick/shadereffects/content/shaders/+qsb/blur.frag b/examples/quick/shadereffects/content/shaders/+qsb/blur.frag
new file mode 100644
index 0000000000..1c79359297
--- /dev/null
+++ b/examples/quick/shadereffects/content/shaders/+qsb/blur.frag
diff --git a/examples/quick/shadereffects/content/shaders/+qsb/colorize.frag b/examples/quick/shadereffects/content/shaders/+qsb/colorize.frag
new file mode 100644
index 0000000000..45c5301f31
--- /dev/null
+++ b/examples/quick/shadereffects/content/shaders/+qsb/colorize.frag
diff --git a/examples/quick/shadereffects/content/shaders/+qsb/genie.vert b/examples/quick/shadereffects/content/shaders/+qsb/genie.vert
new file mode 100644
index 0000000000..dd94129cf7
--- /dev/null
+++ b/examples/quick/shadereffects/content/shaders/+qsb/genie.vert
diff --git a/examples/quick/shadereffects/content/shaders/+qsb/outline.frag b/examples/quick/shadereffects/content/shaders/+qsb/outline.frag
new file mode 100644
index 0000000000..470e2bd6e6
--- /dev/null
+++ b/examples/quick/shadereffects/content/shaders/+qsb/outline.frag
diff --git a/examples/quick/shadereffects/content/shaders/+qsb/shadow.frag b/examples/quick/shadereffects/content/shaders/+qsb/shadow.frag
new file mode 100644
index 0000000000..128af21daa
--- /dev/null
+++ b/examples/quick/shadereffects/content/shaders/+qsb/shadow.frag
diff --git a/examples/quick/shadereffects/content/shaders/+qsb/wobble.frag b/examples/quick/shadereffects/content/shaders/+qsb/wobble.frag
new file mode 100644
index 0000000000..9b27ae87cb
--- /dev/null
+++ b/examples/quick/shadereffects/content/shaders/+qsb/wobble.frag
diff --git a/examples/quick/shadereffects/content/shaders/rhi/blur.frag b/examples/quick/shadereffects/content/shaders/rhi/blur.frag
new file mode 100644
index 0000000000..0c914d4244
--- /dev/null
+++ b/examples/quick/shadereffects/content/shaders/rhi/blur.frag
@@ -0,0 +1,21 @@
+#version 440
+
+layout(location = 0) in vec2 qt_TexCoord0;
+layout(location = 0) out vec4 fragColor;
+
+layout(binding = 1) uniform sampler2D source;
+
+layout(std140, binding = 0) uniform buf {
+    mat4 qt_Matrix;
+    float qt_Opacity;
+    vec2 delta;
+} ubuf;
+
+void main()
+{
+    fragColor =(0.0538 * texture(source, qt_TexCoord0 - 3.182 * ubuf.delta)
+                + 0.3229 * texture(source, qt_TexCoord0 - 1.364 * ubuf.delta)
+                + 0.2466 * texture(source, qt_TexCoord0)
+                + 0.3229 * texture(source, qt_TexCoord0 + 1.364 * ubuf.delta)
+                + 0.0538 * texture(source, qt_TexCoord0 + 3.182 * ubuf.delta)) * ubuf.qt_Opacity;
+}
diff --git a/examples/quick/shadereffects/content/shaders/rhi/colorize.frag b/examples/quick/shadereffects/content/shaders/rhi/colorize.frag
new file mode 100644
index 0000000000..bc8067cc8c
--- /dev/null
+++ b/examples/quick/shadereffects/content/shaders/rhi/colorize.frag
@@ -0,0 +1,20 @@
+#version 440
+
+layout(location = 0) in vec2 qt_TexCoord0;
+layout(location = 0) out vec4 fragColor;
+
+layout(binding = 1) uniform sampler2D source;
+
+layout(std140, binding = 0) uniform buf {
+    mat4 qt_Matrix;
+    float qt_Opacity;
+    vec4 tint;
+} ubuf;
+
+void main()
+{
+    vec4 c = texture(source, qt_TexCoord0);
+    float lo = min(min(c.x, c.y), c.z);
+    float hi = max(max(c.x, c.y), c.z);
+    fragColor = ubuf.qt_Opacity * vec4(mix(vec3(lo), vec3(hi), ubuf.tint.xyz), c.w);
+}
diff --git a/examples/quick/shadereffects/content/shaders/rhi/compile.bat b/examples/quick/shadereffects/content/shaders/rhi/compile.bat
new file mode 100755
index 0000000000..93dfb7b2a9
--- /dev/null
+++ b/examples/quick/shadereffects/content/shaders/rhi/compile.bat
@@ -0,0 +1,56 @@
+:::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::
+::
+:: Copyright (C) 2019 The Qt Company Ltd.
+:: Contact: https://www.qt.io/licensing/
+::
+:: This file is part of the examples of the Qt Toolkit.
+::
+:: $QT_BEGIN_LICENSE:BSD$
+:: Commercial License Usage
+:: Licensees holding valid commercial Qt licenses may use this file in
+:: accordance with the commercial license agreement provided with the
+:: Software or, alternatively, in accordance with the terms contained in
+:: a written agreement between you and The Qt Company. For licensing terms
+:: and conditions see https://www.qt.io/terms-conditions. For further
+:: information use the contact form at https://www.qt.io/contact-us.
+::
+:: BSD License Usage
+:: Alternatively, you may use this file under the terms of the BSD license
+:: as follows:
+::
+:: "Redistribution and use in source and binary forms, with or without
+:: modification, are permitted provided that the following conditions are
+:: met:
+::   * Redistributions of source code must retain the above copyright
+::     notice, this list of conditions and the following disclaimer.
+::   * Redistributions in binary form must reproduce the above copyright
+::     notice, this list of conditions and the following disclaimer in
+::     the documentation and/or other materials provided with the
+::     distribution.
+::   * Neither the name of The Qt Company Ltd nor the names of its
+::     contributors may be used to endorse or promote products derived
+::     from this software without specific prior written permission.
+::
+::
+:: THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+:: "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+:: LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+:: A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+:: OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+:: SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+:: LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+:: DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+:: THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+:: (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+:: OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE."
+::
+:: $QT_END_LICENSE$
+::
+:::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::
+
+qsb --glsl "150,120,100 es" --hlsl 50 --msl 12 -o ../+qsb/blur.frag blur.frag
+qsb --glsl "150,120,100 es" --hlsl 50 --msl 12 -o ../+qsb/colorize.frag colorize.frag
+qsb --glsl "150,120,100 es" --hlsl 50 --msl 12 -o ../+qsb/outline.frag outline.frag
+qsb --glsl "150,120,100 es" --hlsl 50 --msl 12 -o ../+qsb/shadow.frag shadow.frag
+qsb --glsl "150,120,100 es" --hlsl 50 --msl 12 -o ../+qsb/wobble.frag wobble.frag
+qsb -b --glsl "150,120,100 es" --hlsl 50 --msl 12 -o ../+qsb/genie.vert genie.vert
diff --git a/examples/quick/shadereffects/content/shaders/rhi/genie.vert b/examples/quick/shadereffects/content/shaders/rhi/genie.vert
new file mode 100644
index 0000000000..2cb1e71046
--- /dev/null
+++ b/examples/quick/shadereffects/content/shaders/rhi/genie.vert
@@ -0,0 +1,29 @@
+#version 440
+
+layout(location = 0) in vec4 qt_Vertex;
+layout(location = 1) in vec2 qt_MultiTexCoord0;
+
+layout(location = 0) out vec2 qt_TexCoord0;
+
+layout(std140, binding = 0) uniform buf {
+    mat4 qt_Matrix;
+    float qt_Opacity;
+    float bend;
+    float minimize;
+    float side;
+    float width;
+    float height;
+} ubuf;
+
+out gl_PerVertex { vec4 gl_Position; };
+
+void main()
+{
+    qt_TexCoord0 = qt_MultiTexCoord0;
+    vec4 pos = qt_Vertex;
+    pos.y = mix(qt_Vertex.y, ubuf.height, ubuf.minimize);
+    float t = pos.y / ubuf.height;
+    t = (3. - 2. * t) * t * t;
+    pos.x = mix(qt_Vertex.x, ubuf.side * ubuf.width, t * ubuf.bend);
+    gl_Position = ubuf.qt_Matrix * pos;
+}
diff --git a/examples/quick/shadereffects/content/shaders/rhi/outline.frag b/examples/quick/shadereffects/content/shaders/rhi/outline.frag
new file mode 100644
index 0000000000..26df69c5fe
--- /dev/null
+++ b/examples/quick/shadereffects/content/shaders/rhi/outline.frag
@@ -0,0 +1,24 @@
+#version 440
+
+layout(location = 0) in vec2 qt_TexCoord0;
+layout(location = 0) out vec4 fragColor;
+
+layout(binding = 1) uniform sampler2D source;
+
+layout(std140, binding = 0) uniform buf {
+    mat4 qt_Matrix;
+    float qt_Opacity;
+    vec2 delta;
+} ubuf;
+
+void main()
+{
+    vec4 tl = texture(source, qt_TexCoord0 - ubuf.delta);
+    vec4 tr = texture(source, qt_TexCoord0 + vec2(ubuf.delta.x, -ubuf.delta.y));
+    vec4 bl = texture(source, qt_TexCoord0 - vec2(ubuf.delta.x, -ubuf.delta.y));
+    vec4 br = texture(source, qt_TexCoord0 + ubuf.delta);
+    vec4 gx = (tl + bl) - (tr + br);
+    vec4 gy = (tl + tr) - (bl + br);
+    fragColor.xyz = vec3(0.);
+    fragColor.w = clamp(dot(sqrt(gx * gx + gy * gy), vec4(1.)), 0., 1.) * ubuf.qt_Opacity;
+}
diff --git a/examples/quick/shadereffects/content/shaders/rhi/shadow.frag b/examples/quick/shadereffects/content/shaders/rhi/shadow.frag
new file mode 100644
index 0000000000..8247517b6d
--- /dev/null
+++ b/examples/quick/shadereffects/content/shaders/rhi/shadow.frag
@@ -0,0 +1,21 @@
+#version 440
+
+layout(location = 0) in vec2 qt_TexCoord0;
+layout(location = 0) out vec4 fragColor;
+
+layout(binding = 1) uniform sampler2D source;
+layout(binding = 2) uniform sampler2D shadow;
+
+layout(std140, binding = 0) uniform buf {
+    mat4 qt_Matrix;
+    float qt_Opacity;
+    float darkness;
+    vec2 delta;
+} ubuf;
+
+void main()
+{
+    vec4 fg = texture(source, qt_TexCoord0);
+    vec4 bg = texture(shadow, qt_TexCoord0 + ubuf.delta);
+    fragColor = (fg + vec4(0., 0., 0., ubuf.darkness * bg.a) * (1. - fg.a)) * ubuf.qt_Opacity;
+}
diff --git a/examples/quick/shadereffects/content/shaders/rhi/wobble.frag b/examples/quick/shadereffects/content/shaders/rhi/wobble.frag
new file mode 100644
index 0000000000..a34481c2f2
--- /dev/null
+++ b/examples/quick/shadereffects/content/shaders/rhi/wobble.frag
@@ -0,0 +1,20 @@
+#version 440
+
+layout(location = 0) in vec2 qt_TexCoord0;
+layout(location = 0) out vec4 fragColor;
+
+layout(binding = 1) uniform sampler2D source;
+
+layout(std140, binding = 0) uniform buf {
+    mat4 qt_Matrix;
+    float qt_Opacity;
+    float amplitude;
+    float frequency;
+    float time;
+} ubuf;
+
+void main()
+{
+    vec2 p = sin(ubuf.time + ubuf.frequency * qt_TexCoord0);
+    fragColor = texture(source, qt_TexCoord0 + ubuf.amplitude * vec2(p.y, -p.x)) * ubuf.qt_Opacity;
+}