rhi: Enhance line width and point size support

...but this will vary between backends, or in some cases
even between implementations of the same API.

Point size is settable only via the vertex shader (gl_PointSize).
It is silently ignored with D3D and HLSL.

Line widths other than 1 are supported only on OpenGL and Vulkan.
(but this is in fact deprecated with GL and optional with Vulkan)

Add QRhi::Feature values for both.

The line width is now settable on QRhiGraphicsPipeline. It is not a
dynamic state since the static, per-pipeline width is good enough for
most cases. (and the feature is not supported on half of the backends
anyways so it will get limited use in practice).

Change-Id: I6d3a32269527c452b794b2cb8b0f03101eab40b2
Reviewed-by: Lars Knoll <lars.knoll@qt.io>

1 files changed, 4 insertions, 0 deletions

diff --git a/src/gui/rhi/qrhimetal.mm b/src/gui/rhi/qrhimetal.mm
index 214374e0c6..09b80c831d 100644
--- a/src/gui/rhi/qrhimetal.mm
+++ b/src/gui/rhi/qrhimetal.mm
@@ -523,6 +523,10 @@ bool QRhiMetal::isFeatureSupported(QRhi::Feature feature) const
         return true;
     case QRhi::Compute:
         return true;
+    case QRhi::WideLines:
+        return false;
+    case QRhi::VertexShaderPointSize:
+        return true;
     default:
         Q_UNREACHABLE();
         return false;