Revise an incorrect QVulkanWindow doc note

Applying the transformation in question has no effect on the winding
order. Rewrite that section.

While all the examples are correct, clarify the rules for the geometry
they use since the winding order varies. Fix up the triangle example code
to use front=CCW for clarity (even though it does not matter much since
culling is off there).

Change-Id: Icb968c76cc9fa918a5608d3c66b4fccd5668175e
Reviewed-by: Christian Stromme <christian.stromme@qt.io>

3 files changed, 4 insertions, 4 deletions

diff --git a/examples/vulkan/hellovulkancubes/renderer.cpp b/examples/vulkan/hellovulkancubes/renderer.cpp
index 2e913bcae8..5ada79ce79 100644
--- a/examples/vulkan/hellovulkancubes/renderer.cpp
+++ b/examples/vulkan/hellovulkancubes/renderer.cpp
@@ -53,7 +53,7 @@
 #include <QtConcurrentRun>
 #include <QTime>
 
-static float quadVert[] = {
+static float quadVert[] = { // Y up, front = CW
     -1, -1, 0,
     -1,  1, 0,
      1, -1, 0,
diff --git a/examples/vulkan/hellovulkantexture/hellovulkantexture.cpp b/examples/vulkan/hellovulkantexture/hellovulkantexture.cpp
index ffe1a31442..67ae0ca5dc 100644
--- a/examples/vulkan/hellovulkantexture/hellovulkantexture.cpp
+++ b/examples/vulkan/hellovulkantexture/hellovulkantexture.cpp
@@ -59,7 +59,7 @@
 // Vulkan Y is negated in clip space and the near/far plane is at 0/1 instead
 // of -1/1. These will be corrected for by an extra transformation when
 // calculating the modelview-projection matrix.
-static float vertexData[] = {
+static float vertexData[] = { // Y up, front = CW
     // x, y, z, u, v
     -1, -1, 0, 0, 1,
     -1,  1, 0, 0, 0,
diff --git a/examples/vulkan/shared/trianglerenderer.cpp b/examples/vulkan/shared/trianglerenderer.cpp
index 6ed7e65ff9..b48f564003 100644
--- a/examples/vulkan/shared/trianglerenderer.cpp
+++ b/examples/vulkan/shared/trianglerenderer.cpp
@@ -56,7 +56,7 @@
 // Vulkan Y is negated in clip space and the near/far plane is at 0/1 instead
 // of -1/1. These will be corrected for by an extra transformation when
 // calculating the modelview-projection matrix.
-static float vertexData[] = {
+static float vertexData[] = { // Y up, front = CCW
      0.0f,   0.5f,   1.0f, 0.0f, 0.0f,
     -0.5f,  -0.5f,   0.0f, 1.0f, 0.0f,
      0.5f,  -0.5f,   0.0f, 0.0f, 1.0f
@@ -337,7 +337,7 @@ void TriangleRenderer::initResources()
     rs.sType = VK_STRUCTURE_TYPE_PIPELINE_RASTERIZATION_STATE_CREATE_INFO;
     rs.polygonMode = VK_POLYGON_MODE_FILL;
     rs.cullMode = VK_CULL_MODE_NONE; // we want the back face as well
-    rs.frontFace = VK_FRONT_FACE_CLOCKWISE;
+    rs.frontFace = VK_FRONT_FACE_COUNTER_CLOCKWISE;
     rs.lineWidth = 1.0f;
     pipelineInfo.pRasterizationState = &rs;