Fix shadowmap example for Metal

examples/rhi/shadowmap/buildshaders.bat

 qsb --glsl 120 --hlsl 50 --msl 12 -c shadowmap.vert -o shadowmap.vert.qsb
 qsb --glsl 120 --hlsl 50 --msl 12 -c shadowmap.frag -o shadowmap.frag.qsb
-qsb --glsl 120 --hlsl 50 --msl 12 -c light.vert -o light.vert.qsb
-qsb --glsl 120 --hlsl 50 --msl 12 -c light.frag -o light.frag.qsb
+qsb --glsl 120 --hlsl 50 --msl 12 -c main.vert -o main.vert.qsb
+qsb --glsl 120 --hlsl 50 --msl 12 -c main.frag -o main.frag.qsb

examples/rhi/shadowmap/buildshaders.sh

+qsb --glsl 120 --hlsl 50 --msl 12 shadowmap.vert -o shadowmap.vert.qsb
+qsb --glsl 120 --hlsl 50 --msl 12 shadowmap.frag -o shadowmap.frag.qsb
+qsb --glsl 120 --hlsl 50 --msl 12 main.vert -o main.vert.qsb
+qsb --glsl 120 --hlsl 50 --msl 12 main.frag -o main.frag.qsb

examples/rhi/shadowmap/light.frag → examples/rhi/shadowmap/main.frag

@@ -17,7 +17,11 @@ void main()
 {
     vec4 adjustedLcVertPos = vLCVertPos;
     adjustedLcVertPos.z -= 0.0001; // bias to avoid acne
-    float sc = textureProj(shadowMap, adjustedLcVertPos);
+
+    // no textureProj, that seems to end up not doing the perspective divide for z (?)
+    vec3 v = adjustedLcVertPos.xyz / adjustedLcVertPos.w;
+    float sc = texture(shadowMap, v); // sampler is comparison enabled so compares to z
+
     float shadowFactor = 0.2;
     if (sc > 0 || ubuf.useShadow == 0)
         shadowFactor = 1.0;

examples/rhi/shadowmap/shadowmap.cpp

@@ -128,8 +128,8 @@ void Window::customInit()
     d.ps = m_r->newGraphicsPipeline();
     d.releasePool << d.ps;
     d.ps->setShaderStages({
-        { QRhiGraphicsShaderStage::Vertex, getShader(QLatin1String(":/light.vert.qsb")) },
-        { QRhiGraphicsShaderStage::Fragment, getShader(QLatin1String(":/light.frag.qsb")) }
+        { QRhiGraphicsShaderStage::Vertex, getShader(QLatin1String(":/main.vert.qsb")) },
+        { QRhiGraphicsShaderStage::Fragment, getShader(QLatin1String(":/main.frag.qsb")) }
     });
     d.ps->setDepthTest(true);
     d.ps->setDepthWrite(true);
@@ -225,7 +225,7 @@ void Window::customRender()
     if (m_r->isClipDepthZeroToOne()) {
         // convert x, y [-1, 1] -> [0, 1]
         *sbp++ = 0.5f; *sbp++ = 0.0f; *sbp++ = 0.0f; *sbp++ = 0.0f;
-        *sbp++ = 0.0f; *sbp++ = 0.5f; *sbp++ = 0.0f; *sbp++ = 0.0f;
+        *sbp++ = 0.0f; *sbp++ = m_r->isYUpInNDC() ? -0.5f : 0.5f; *sbp++ = 0.0f; *sbp++ = 0.0f;
         *sbp++ = 0.0f; *sbp++ = 0.0f; *sbp++ = 1.0f; *sbp++ = 0.0f;
         *sbp++ = 0.5f; *sbp++ = 0.5f; *sbp++ = 0.0f; *sbp++ = 1.0f;
     } else {

examples/rhi/shadowmap/shadowmap.qrc

@@ -2,7 +2,7 @@
   <qresource>
     <file>shadowmap.vert.qsb</file>
     <file>shadowmap.frag.qsb</file>
-    <file>light.vert.qsb</file>
-    <file>light.frag.qsb</file>
+    <file>main.vert.qsb</file>
+    <file>main.frag.qsb</file>
 </qresource>
 </RCC>