Fix undefined gl_ClipDistance and use uint for std140 bool

Change `bool clipEnabled` to `uint clipEnabled` in the default-material
shader UBO. GLSL bool has implementation-defined std140 layout; uint is
portable and matches the SPIR-V decompiled output.

Add an else-branch writing `gl_ClipDistance[0] = 1.0` when clipping is
disabled. Without this, gl_ClipDistance is undefined and some drivers
cull geometry unexpectedly.

Author: laanwj

code/graphics/shaders/compiled/default-material.vert.spv.glsl

@@ -37,5 +37,9 @@ void main()
     {
         gl_ClipDistance[0] = dot(_22.clipEquation, _22.modelMatrix * vertPosition);
     }
+    else
+    {
+        gl_ClipDistance[0] = 1.0;
+    }
 }
 

code/graphics/shaders/default-material.frag

@@ -22,7 +22,7 @@ layout (binding = 1, std140) uniform genericData {
 
 	float intensity;
 	float alphaThreshold;
-	bool clipEnabled;
+	uint clipEnabled;
 };
 
 layout(binding = 2) uniform sampler2DArray baseMap;

code/graphics/shaders/default-material.vert

@@ -27,7 +27,7 @@ layout (binding = 1, std140) uniform genericData {
 
 	float intensity;
 	float alphaThreshold;
-	bool clipEnabled;
+	uint clipEnabled;
 };
 
 void main()
@@ -36,7 +36,9 @@ void main()
 	fragColor = vertColor * color;
 	gl_Position = projMatrix * modelViewMatrix * vertPosition;
 
-	if (clipEnabled) {
+	if (clipEnabled != 0u) {
 		gl_ClipDistance[0] = dot(clipEquation, modelMatrix * vertPosition);
+	} else {
+		gl_ClipDistance[0] = 1.0;
 	}
 }