Enforce lightmap material uniqueness and fix other issues

Two problems were fixed here:
- Materials were always exported unconditionally, meaning that we were
wasting time processing the same data over and over. This could have
generated "interesting" data (eg multiple hsGMaterials and friends with
the same name) that Plasma would have barfed on.
- Lightmaps were being applied to the incorrect materials

korman/exporter/material.py

@@ -178,9 +178,23 @@ class MaterialConverter:
 
     def export_material(self, bo, bm):
         """Exports a Blender Material as an hsGMaterial"""
-        self._report.msg("Exporting Material '{}'", bm.name, indent=1)
 
-        hsgmat = self._mgr.add_object(hsGMaterial, name=bm.name, bl=bo)
+        # Sometimes, a material might need to be single-use. Right now, the most apparent example
+        # of that situation is when a lightmap image is baked. Wavesets are in the same boat, but
+        # that's a special case as of the writing of this code.
+        single_user = self._requires_single_user_material(bo, bm)
+        if single_user:
+            mat_name = "{}_{}".format(bo.name, bm.name)
+            self._report.msg("Exporting Material '{}' as single user '{}'", bm.name, mat_name, indent=1)
+            hgmat = None
+        else:
+            mat_name = bm.name
+            self._report.msg("Exporting Material '{}'", mat_name, indent=1)
+            hsgmat = self._mgr.find_key(hsGMaterial, name=mat_name, bl=bo)
+            if hsgmat is not None:
+                return hsgmat
+
+        hsgmat = self._mgr.add_object(hsGMaterial, name=mat_name, bl=bo)
         slots = [(idx, slot) for idx, slot in enumerate(bm.texture_slots) if self._can_export_texslot(slot)]
 
         # There is a major difference in how Blender and Plasma handle stencils.
@@ -227,7 +241,7 @@ class MaterialConverter:
                     curr_stencils = len(stencils)
                     for i in range(curr_stencils):
                         stencil_idx, stencil = stencils[i]
-                        stencil_name = "STENCILGEN_{}@{}_{}".format(stencil.name, bm.name, slot.name)
+                        stencil_name = "STENCILGEN_{}@{}_{}".format(stencil.name, hsgmat.key.name, slot.name)
                         stencil_layer = self.export_texture_slot(bo, bm, hsgmat, stencil, stencil_idx, name=stencil_name)
                         if i+1 < curr_stencils:
                             stencil_layer.state.miscFlags |= hsGMatState.kMiscBindNext
@@ -236,7 +250,7 @@ class MaterialConverter:
         # Plasma makes several assumptions that every hsGMaterial has at least one layer. If this
         # material had no Textures, we will need to initialize a default layer
         if not hsgmat.layers:
-            layer = self._mgr.add_object(plLayer, name="{}_AutoLayer".format(bm.name), bl=bo)
+            layer = self._mgr.add_object(plLayer, name="{}_AutoLayer".format(mat_name), bl=bo)
             self._propagate_material_settings(bm, layer)
             hsgmat.addLayer(layer.key)
 
@@ -266,7 +280,7 @@ class MaterialConverter:
         return hsgmat.key
 
     def export_bumpmap_slot(self, bo, bm, hsgmat, slot, idx):
-        name = "{}_{}".format(bm.name if bm is not None else bo.name, slot.name)
+        name = "{}_{}".format(hsgmat.key.name, slot.name)
         self._report.msg("Exporting Plasma Bumpmap Layers for '{}'", name, indent=2)
 
         # Okay, now we need to make 3 layers for the Du, Dw, and Dv
@@ -315,7 +329,7 @@ class MaterialConverter:
 
     def export_texture_slot(self, bo, bm, hsgmat, slot, idx, name=None, blend_flags=True):
         if name is None:
-            name = "{}_{}".format(bm.name if bm is not None else bo.name, slot.name)
+            name = "{}_{}".format(hsgmat.key.name, slot.name)
         self._report.msg("Exporting Plasma Layer '{}'", name, indent=2)
         layer = self._mgr.add_object(plLayer, name=name, bl=bo)
         if bm is not None and not slot.use_map_normal:
@@ -973,7 +987,10 @@ class MaterialConverter:
         if not tex_name in bm.texture_slots:
             raise ExportError("Texture '{}' not used in Material '{}'".format(bm.name, tex_name))
 
-        name = "{}_{}_LayerAnim".format(bm.name, tex_name)
+        if self._requires_single_user_material(bo, bm):
+            name = "{}_{}_{}_LayerAnim".format(bo.name, bm.name, tex_name)
+        else:
+            name = "{}_{}_LayerAnim".format(bm.name, tex_name)
         layer = texture.plasma_layer
         pClass = plLayerSDLAnimation if layer.anim_sdl_var else plLayerAnimation
         return self._mgr.find_create_key(pClass, bl=bo, name=name)
@@ -1016,6 +1033,14 @@ class MaterialConverter:
     def _report(self):
         return self._exporter().report
 
+    def _requires_single_user_material(self, bo, bm):
+        modifiers = bo.plasma_modifiers
+        if modifiers.lightmap.bake_lightmap:
+            return True
+        if modifiers.water_basic.enabled:
+            return True
+        return False
+
     def _test_image_alpha(self, image):
         """Tests to see if this image has any alpha data"""