feat: add pbr support

destrum/assets_src/shaders/materials.glsl

@@ -3,14 +3,19 @@
 
 #extension GL_EXT_buffer_reference : require
 
+// Must match MaterialData in Material.h
 struct MaterialData {
     vec4 baseColor;
-    vec4 metallicRoughnessEmissive;
+    vec4 emissiveColor;
+    vec4 metallicRoughnessNormalOcclusion;
     uint textureFilteringMode;
     uint diffuseTex;
     uint normalTex;
-    uint metallicRoughnessTex;
+    uint metallicTex;
+    uint roughnessTex;
+    uint occlusionTex;
     uint emissiveTex;
+    uint _pad0;
 };
 
 layout (buffer_reference, std430) readonly buffer MaterialsBuffer {