Shaders: simplify a bunch of repeated checks in shader code.

src/Magnum/Shaders/MeshVisualizer.cpp

@@ -111,7 +111,6 @@ GL::Version MeshVisualizerBase::setupShaders(GL::Shader& vert, GL::Shader& frag,
     frag = Implementation::createCompatibilityShader(rs, version, GL::Shader::Type::Fragment);
 
     vert.addSource(_flags & FlagBase::Wireframe ? "#define WIREFRAME_RENDERING\n" : "")
-        .addSource(_flags & FlagBase::NoGeometryShader ? "#define NO_GEOMETRY_SHADER\n" : "")
         #ifndef MAGNUM_TARGET_GLES2
         .addSource(_flags & FlagBase::InstancedObjectId ? "#define INSTANCED_OBJECT_ID\n" : "")
         .addSource(_flags >= FlagBase::PrimitiveIdFromVertexId ? "#define PRIMITIVE_ID_FROM_VERTEX_ID\n" : "")
@@ -196,6 +195,11 @@ MeshVisualizer2D::MeshVisualizer2D(const Flags flags): Implementation::MeshVisua
     const GL::Version version = setupShaders(vert, frag, rs);
 
     vert.addSource("#define TWO_DIMENSIONS\n")
+        /* Pass NO_GEOMETRY_SHADER not only when NoGeometryShader but also when
+           nothing actually needs it, as that makes checks much simpler in
+           the vertex shader code */
+        .addSource((flags & Flag::NoGeometryShader) || !(flags & Flag::Wireframe) ?
+            "#define NO_GEOMETRY_SHADER\n" : "")
         .addSource(rs.get("generic.glsl"))
         .addSource(rs.get("MeshVisualizer.vert"));
     frag.addSource(rs.get("generic.glsl"))
@@ -352,6 +356,14 @@ MeshVisualizer3D::MeshVisualizer3D(const Flags flags): Implementation::MeshVisua
     #endif
 
     vert.addSource("#define THREE_DIMENSIONS\n")
+        /* Pass NO_GEOMETRY_SHADER not only when NoGeometryShader but also when
+           nothing actually needs it, as that makes checks much simpler in
+           the vertex shader code */
+        .addSource((flags & Flag::NoGeometryShader) || !(flags & (Flag::Wireframe
+            #if !defined(MAGNUM_TARGET_GLES2) && !defined(MAGNUM_TARGET_WEBGL)
+            |Flag::TangentDirection|Flag::BitangentDirection|Flag::BitangentFromTangentDirection|Flag::NormalDirection
+            #endif
+            )) ? "#define NO_GEOMETRY_SHADER\n" : "")
         #if !defined(MAGNUM_TARGET_GLES2) && !defined(MAGNUM_TARGET_WEBGL)
         .addSource(flags & Flag::TangentDirection ? "#define TANGENT_DIRECTION\n" : "")
         .addSource(flags & Flag::BitangentFromTangentDirection ? "#define BITANGENT_FROM_TANGENT_DIRECTION\n" : "")

src/Magnum/Shaders/MeshVisualizer.vert

@@ -132,7 +132,7 @@ layout(location = OBJECT_ID_ATTRIBUTE_LOCATION)
 #endif
 in highp uint instanceObjectId;
 
-#if defined(NO_GEOMETRY_SHADER) || (!defined(WIREFRAME_RENDERING) && !defined(TANGENT_DIRECTION) && !defined(BITANGENT_DIRECTION) && !defined(BITANGENT_FROM_TANGENT_DIRECTION) && !defined(NORMAL_DIRECTION))
+#ifdef NO_GEOMETRY_SHADER
 flat out highp uint interpolatedInstanceObjectId;
 #else
 flat out highp uint interpolatedVsInstanceObjectId;
@@ -140,7 +140,7 @@ flat out highp uint interpolatedVsInstanceObjectId;
 #endif
 
 #ifdef PRIMITIVE_ID_FROM_VERTEX_ID
-#if defined(NO_GEOMETRY_SHADER) || (!defined(WIREFRAME_RENDERING) && !defined(TANGENT_DIRECTION) && !defined(BITANGENT_DIRECTION) && !defined(BITANGENT_FROM_TANGENT_DIRECTION) && !defined(NORMAL_DIRECTION))
+#ifdef NO_GEOMETRY_SHADER
 flat out highp uint interpolatedPrimitiveId;
 #else
 flat out highp uint interpolatedVsPrimitiveId;
@@ -199,7 +199,7 @@ void main() {
     #endif
 
     #ifdef INSTANCED_OBJECT_ID
-    #if defined(NO_GEOMETRY_SHADER) || (!defined(WIREFRAME_RENDERING) && !defined(TANGENT_DIRECTION) && !defined(BITANGENT_DIRECTION) && !defined(BITANGENT_FROM_TANGENT_DIRECTION) && !defined(NORMAL_DIRECTION))
+    #ifdef NO_GEOMETRY_SHADER
     interpolatedInstanceObjectId
     #else
     interpolatedVsInstanceObjectId
@@ -207,7 +207,7 @@ void main() {
         = instanceObjectId;
     #endif
     #ifdef PRIMITIVE_ID_FROM_VERTEX_ID
-    #if defined(NO_GEOMETRY_SHADER) || (!defined(WIREFRAME_RENDERING) && !defined(TANGENT_DIRECTION) && !defined(BITANGENT_DIRECTION) && !defined(BITANGENT_FROM_TANGENT_DIRECTION) && !defined(NORMAL_DIRECTION))
+    #ifdef NO_GEOMETRY_SHADER
     interpolatedPrimitiveId
     #else
     interpolatedVsPrimitiveId