feat: add pbr support

destrum/include/destrum/Assets/ModelFile.h

@@ -11,7 +11,7 @@
 #include <destrum/Util/ModelDoc.h>
 
 namespace ModelFile {
-    inline constexpr std::uint32_t Version = 1;
+    inline constexpr std::uint32_t Version = 2;
     inline constexpr std::string_view Extension = ".dmodel";
 
     inline constexpr ModelDoc::LoadOptions CookOptions{};

destrum/include/destrum/Graphics/Caches/MaterialCache.h

@@ -50,6 +50,8 @@ public:
     void updateMaterialGPU(MaterialID id);
 
 private:
+    [[nodiscard]] MaterialData toMaterialData(const Material& material) const;
+
     std::vector<Material> materials;
     std::vector<std::string> materialKeys;
 

destrum/include/destrum/Graphics/Material.h

@@ -5,17 +5,23 @@
 #include <utility>
 #include <glm/glm.hpp>
 #include <destrum/Assets/AssetReference.h>
+#include <destrum/Graphics/ids.h>
 
+// Must match MaterialData in materials.glsl
 struct alignas(16) MaterialData {
     alignas(16) glm::vec4 baseColor;
-    alignas(16) glm::vec4 metalRoughnessEmissive;
+    alignas(16) glm::vec4 emissiveColor;
+    alignas(16) glm::vec4 metallicRoughnessNormalOcclusion;
     uint32_t textureFilteringMode;
     uint32_t diffuseTex;
     uint32_t normalTex;
-    uint32_t metallicRoughnessTex;
+    uint32_t metallicTex;
+    uint32_t roughnessTex;
+    uint32_t occlusionTex;
     uint32_t emissiveTex;
-    uint32_t _pad0, _pad1, _pad2; // explicit to 64 bytes
+    uint32_t _pad0;
 };
+static_assert(sizeof(MaterialData) == 80);
 
 enum class TextureFilteringMode : std::uint32_t {
     Nearest,
@@ -23,6 +29,9 @@ enum class TextureFilteringMode : std::uint32_t {
     Anisotropic,
 };
 
+// Metallic / roughness workflow, matching glTF:
+// metallic is read from the blue channel, roughness from green and occlusion from red,
+// so a packed (occlusion)metallicRoughness texture can be used for all three slots.
 struct Material {
     [[nodiscard]] static Material SimpleColor(
         glm::vec3 color,
@@ -32,22 +41,32 @@ struct Material {
         material.baseColor = color;
         material.metallicFactor = 0.0f;
         material.roughnessFactor = 1.0f;
-        material.emissiveFactor = 0.0f;
         material.name = std::move(materialName);
         return material;
     }
 
+    [[nodiscard]] bool UsesTexture(ImageID id) const
+    {
+        return id != NULL_IMAGE_ID &&
+               (diffuseTexture == id || normalTexture == id || metallicTexture == id ||
+                roughnessTexture == id || occlusionTexture == id || emissiveTexture == id);
+    }
+
     glm::vec3 baseColor{1.f, 1.f, 1.f};
     float metallicFactor{0.f};
     float roughnessFactor{0.7f};
-    float emissiveFactor{0.f};
+    glm::vec3 emissiveColor{0.f};
+    float normalScale{1.f};
+    float occlusionStrength{1.f};
 
     TextureFilteringMode textureFilteringMode{TextureFilteringMode::Linear};
 
     ImageID diffuseTexture{NULL_IMAGE_ID};
-    // ImageId normalMapTexture{NULL_IMAGE_ID};
-    // ImageId metallicRoughnessTexture{NULL_IMAGE_ID};
-    // ImageId emissiveTexture{NULL_IMAGE_ID};
+    ImageID normalTexture{NULL_IMAGE_ID};
+    ImageID metallicTexture{NULL_IMAGE_ID};
+    ImageID roughnessTexture{NULL_IMAGE_ID};
+    ImageID occlusionTexture{NULL_IMAGE_ID};
+    ImageID emissiveTexture{NULL_IMAGE_ID};
 
     std::string name;
     AssetReference assetReference;

destrum/include/destrum/Graphics/RenderResources.h

@@ -11,6 +11,8 @@
 #include <memory>
 #include <string_view>
 
+namespace ModelDoc { struct MaterialInfo; }
+
 class GfxDevice;
 
 class RenderResources {
@@ -40,7 +42,7 @@ public:
         GfxDevice& gfxDevice,
         const std::filesystem::path& path,
         VkImageUsageFlags usage = VK_IMAGE_USAGE_SAMPLED_BIT,
-        bool mipMap = false,
+        bool mipMap = true,
         TextureIntent intent = TextureIntent::ColorSrgb);
 
     ImageID addImageToCache(GPUImage image);
@@ -49,6 +51,9 @@ public:
     // References are keyed as "source#subresource" in the resource caches.
     void loadModelAsset(GfxDevice& gfxDevice, std::string_view sourceReference);
 
+    // Creates a PBR material from an imported model material, loading its texture maps.
+    MaterialID addModelMaterial(GfxDevice& gfxDevice, const ModelDoc::MaterialInfo& sourceMaterial);
+
     [[nodiscard]] const GPUImage& getImage(ImageID id) const;
 
     [[nodiscard]] ImageID getWhiteTextureID() const { return whiteImageId; }

destrum/include/destrum/Util/ModelDoc.h

@@ -369,6 +369,9 @@ static MaterialInfo LoadMaterialInfo(const aiScene* scene,
                             TextureSemantic::Roughness, out.textures);
     AddMaterialTextureSlots(scene, material, modelDir, aiTextureType_AMBIENT_OCCLUSION,
                             TextureSemantic::AmbientOcclusion, out.textures);
+    // glTF occlusion maps are imported as lightmaps
+    AddMaterialTextureSlots(scene, material, modelDir, aiTextureType_LIGHTMAP,
+                            TextureSemantic::AmbientOcclusion, out.textures);
     AddMaterialTextureSlots(scene, material, modelDir, aiTextureType_EMISSION_COLOR,
                             TextureSemantic::Emissive, out.textures);