From 60b9692af28a353c4e5813d1723422477e31f433 Mon Sep 17 00:00:00 2001
From: Chuyan Zhang <me@zcy.moe>
Date: Sun, 6 Oct 2024 11:43:15 -0700
Subject: Add material texture load

---
 src/gltf_loader.cpp | 52 +++++++++++++++++++++++++++++++++++++++++++++++++---
 src/render_assets.h | 23 +++++++++++++++++++++++
 2 files changed, 72 insertions(+), 3 deletions(-)

(limited to 'src')

diff --git a/src/gltf_loader.cpp b/src/gltf_loader.cpp
index 684fa7f..a692e93 100644
--- a/src/gltf_loader.cpp
+++ b/src/gltf_loader.cpp
@@ -1,6 +1,7 @@
 #include "gltf_loader.h"
 #include "render_assets.h"
 #include "spdlog/spdlog.h"
+#include "tiny_gltf.h"
 #include <cstdint>
 
 enum class SceneFileType {
@@ -214,6 +215,47 @@ bool load_gltf(const std::string_view path, iris::Scene &scene) {
         }
     }
 
+    std::vector<iris::Image> images;
+    images.reserve(model.images.size());
+    for (const tinygltf::Image &image : model.images) {
+        images.emplace_back(iris::Image {
+            .data = image.image,
+            .extent = glm::uvec3(image.width, image.height, image.component),
+            .bits_per_channel = image.bits,
+        });
+    }
+
+    std::vector<iris::Sampler2D> samplers;
+    samplers.reserve(model.samplers.size());
+    for (const tinygltf::Sampler &sampler : model.samplers) {
+        samplers.emplace_back(iris::Sampler2D {
+            .min_filter = sampler.minFilter,
+            .mag_filter = sampler.magFilter,
+            .wrap_s = sampler.wrapS,
+            .wrap_t = sampler.wrapT,
+        });
+    }
+
+    // load textures
+    for (const tinygltf::Texture &texture : model.textures) {
+        const std::string texture_name = texture.name == "" ? "texture" : texture.name;
+        if (texture.source < 0 || unsigned(texture.source) >= images.size()) {
+            spdlog::error("Invalid texture source index: {}", texture.source);
+            return false;
+        }
+        if (texture.sampler < 0 || unsigned(texture.sampler) >= samplers.size()) {
+            spdlog::error("Invalid texture sampler index: {}", texture.sampler);
+            return false;
+        }
+        
+        iris::Texture iris_texture {
+            .name = texture_name,
+            .image = images[texture.source],
+            .sampler = samplers[texture.sampler],
+        };
+        spdlog::info("Texture: {}", texture_name);
+    }
+
     for (const tinygltf::Material &material : model.materials) {
         const std::string material_name = material.name == "" ? "material" : material.name;
         const auto &pbr = material.pbrMetallicRoughness;
@@ -227,13 +269,17 @@ bool load_gltf(const std::string_view path, iris::Scene &scene) {
             .metallic = float(pbr.metallicFactor),
             .roughness = float(pbr.roughnessFactor),
         };
-        
+        // Where to detect if the texture is valid? Can we early intercept?
+        iris_material.base_color_texture = pbr.baseColorTexture.index;
+        iris_material.metallic_roughness_texture = pbr.metallicRoughnessTexture.index;
+        iris_material.normal_texture = material.normalTexture.index;
+        iris_material.occulsion_texture = material.occlusionTexture.index;
+        iris_material.emissive_texture = material.emissiveTexture.index;
+
         // TODO: load texture information, skip for now
         spdlog::info("Material: {}", material_name);
     }
 
-    // TODO load materials and textures
-
     for (const tinygltf::Camera &camera : model.cameras) {
         iris::Camera iris_camera {
             .position = glm::vec3(0.0f),
diff --git a/src/render_assets.h b/src/render_assets.h
index 113084a..1819271 100644
--- a/src/render_assets.h
+++ b/src/render_assets.h
@@ -27,9 +27,32 @@ struct Material {
     glm::vec4 base_color;
     float metallic;
     float roughness;
+
+    int32_t base_color_texture;
+    int32_t metallic_roughness_texture;
+    int32_t normal_texture;
+    int32_t occulsion_texture;
+    int32_t emissive_texture;
+};
+
+
+struct Image {
+    std::vector<uint8_t> data;
+    glm::uvec3 extent;
+    int32_t bits_per_channel;
+};
+
+struct Sampler2D {
+    int32_t min_filter;
+    int32_t mag_filter;
+    int32_t wrap_s;
+    int32_t wrap_t;
 };
 
 struct Texture {
+    std::string name;
+    Image image;
+    Sampler2D sampler;
 };
 
 struct Camera {
-- 
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