scenegraph: Add plumbing for enabling multiview

This will be used in RenderMode3D only in practice, where Qt Quick 3D
is going to pass in multiple matrices to the QSGRenderer.

Task-number: QTBUG-114871
Change-Id: Icae7f05958729d9e51948e1f38621ec4a541192d
Reviewed-by: Andy Nichols <andy.nichols@qt.io>

1 files changed, 19 insertions, 9 deletions

diff --git a/src/quick/scenegraph/shaders_ng/smoothcolor.vert b/src/quick/scenegraph/shaders_ng/smoothcolor.vert
index 03a3ff8975..6ec10a7e70 100644
--- a/src/quick/scenegraph/shaders_ng/smoothcolor.vert
+++ b/src/quick/scenegraph/shaders_ng/smoothcolor.vert
@@ -7,22 +7,32 @@ layout(location = 2) in vec4 vertexOffset;
 layout(location = 0) out vec4 color;
 
 layout(std140, binding = 0) uniform buf {
+#if QSHADER_VIEW_COUNT >= 2
+    mat4 matrix[QSHADER_VIEW_COUNT];
+#else
     mat4 matrix;
+#endif
     vec2 pixelSize;
     float opacity;
-} ubuf;
-
-out gl_PerVertex { vec4 gl_Position; };
+};
 
 void main()
 {
-    vec4 pos = ubuf.matrix * vertex;
+#if QSHADER_VIEW_COUNT >= 2
+    vec4 pos = matrix[gl_ViewIndex] * vertex;
+    vec4 m0 = matrix[gl_ViewIndex][0];
+    vec4 m1 = matrix[gl_ViewIndex][1];
+#else
+    vec4 pos = matrix * vertex;
+    vec4 m0 = matrix[0];
+    vec4 m1 = matrix[1];
+#endif
     gl_Position = pos;
 
     if (vertexOffset.x != 0.) {
-        vec4 delta = ubuf.matrix[0] * vertexOffset.x;
+        vec4 delta = m0 * vertexOffset.x;
         vec2 dir = delta.xy * pos.w - pos.xy * delta.w;
-        vec2 ndir = .5 * ubuf.pixelSize * normalize(dir / ubuf.pixelSize);
+        vec2 ndir = .5 * pixelSize * normalize(dir / pixelSize);
         dir -= ndir * delta.w * pos.w;
         float numerator = dot(dir, ndir * pos.w * pos.w);
         float scale = 0.0;
@@ -34,9 +44,9 @@ void main()
     }
 
     if (vertexOffset.y != 0.) {
-        vec4 delta = ubuf.matrix[1] * vertexOffset.y;
+        vec4 delta = m1 * vertexOffset.y;
         vec2 dir = delta.xy * pos.w - pos.xy * delta.w;
-        vec2 ndir = .5 * ubuf.pixelSize * normalize(dir / ubuf.pixelSize);
+        vec2 ndir = .5 * pixelSize * normalize(dir / pixelSize);
         dir -= ndir * delta.w * pos.w;
         float numerator = dot(dir, ndir * pos.w * pos.w);
         float scale = 0.0;
@@ -47,5 +57,5 @@ void main()
         gl_Position += scale * delta;
     }
 
-    color = vertexColor * ubuf.opacity;
+    color = vertexColor * opacity;
 }