Extract and render colors for mesh

src/nol/core.clj

@@ -1,6 +1,6 @@
 (ns nol.core
   (:require [clojure.math])
-  (:import [org.lwjgl.assimp Assimp AIFace AIMaterial AIMesh AIScene AIVector3D]
+  (:import [org.lwjgl.assimp AIColor4D AIFace AIMaterial AIMaterial$Buffer AIMesh AIScene AIVector3D Assimp]
            [org.lwjgl.glfw GLFW GLFWErrorCallbackI GLFWKeyCallbackI]
            [org.lwjgl.opengl GL GL11 GL15 GL20 GL33 GL30 GL45]
            [org.lwjgl.system MemoryUtil MemoryStack]
@@ -43,10 +43,6 @@
       (throw (RuntimeException. (str "Program link error: " (GL20/glGetProgramInfoLog program)))))
     program))
 
-(defn load-model [path]
-  (Assimp/aiImportFile path (bit-or Assimp/aiProcess_Triangulate
-                                    Assimp/aiProcess_FlipUVs)))
-
 (def vertices (float-array [0.0   1.0 0.0
                             -1.0 -1.0 0.0
                             1.0  -1.0 0.0]))
@@ -62,6 +58,18 @@
     (GL11/glClear GL11/GL_COLOR_BUFFER_BIT)
 
     (swap! state assoc :last-time t)
+    (do
+      (GL20/glUseProgram program)
+
+      (let [color-loc (GL20/glGetUniformLocation program "uColor")]
+        (doseq [m meshes
+                :let [[r g b a] (:color (:mesh m))]]
+          (GL20/glUniform4f color-loc r g b a)
+          (GL30/glBindVertexArray (:vao m))
+          (GL11/glDrawElements GL11/GL_TRIANGLES (:indices-count m) GL11/GL_UNSIGNED_INT 0)))
+
+      (GL30/glBindVertexArray 0)
+      (GL20/glUseProgram 0))
 
     (GLFW/glfwSwapBuffers window)))
 
@@ -78,7 +86,7 @@
   (GLFW/glfwWindowHint GLFW/GLFW_CONTEXT_VERSION_MINOR 5)
   (GLFW/glfwWindowHint GLFW/GLFW_OPENGL_PROFILE GLFW/GLFW_OPENGL_CORE_PROFILE)
 
-  (let [window (GLFW/glfwCreateWindow 960 300 #_592 "NOL" MemoryUtil/NULL MemoryUtil/NULL)]
+  (let [window (GLFW/glfwCreateWindow 960 #_1900 300 #_1100 "NOL" MemoryUtil/NULL MemoryUtil/NULL)]
     (when (= window MemoryUtil/NULL)
       (GLFW/glfwTerminate)
       (throw (RuntimeException. "Failed to create window")))
@@ -126,15 +134,69 @@
       (.setDaemon true)
       (.start))))
 
+(defn extract-mesh [^AIScene scene idx]
+  (let [meshes (.mMeshes scene)]
+    (let [mesh (AIMesh/create (long (.get meshes idx)))
+          mat-idx (.mMaterialIndex mesh)
+          mat-ptr ^long (.get (.mMaterials scene) mat-idx)
+          material (AIMaterial/create (long mat-ptr))
+          mat-color (AIColor4D/create)
+          _ (Assimp/aiGetMaterialColor material Assimp/AI_MATKEY_COLOR_DIFFUSE 0 0 ^AIColor4D mat-color)
+          verts (.mVertices mesh)
+          n (.mNumVertices mesh)
+          vert-arr (float-array (* 3 n))
+          faces (.mFaces mesh)
+          nf (.mNumFaces mesh)
+          idx-arr (int-array (* 3 nf))]
+      (dotimes [i n]
+        (let [v (.get verts i)]
+          (aset vert-arr (+ (* i 3) 0) (.x v))
+          (aset vert-arr (+ (* i 3) 1) (.y v))
+          (aset vert-arr (+ (* i 3) 2) (.z v))))
+      (dotimes [i nf]
+        (let [face (.get faces i)
+              idxs (.mIndices face)]
+          (aset idx-arr (+ (* i 3) 0) (.get idxs 0))
+          (aset idx-arr (+ (* i 3) 1) (.get idxs 1))
+          (aset idx-arr (+ (* i 3) 2) (.get idxs 2))))
+      {:verts vert-arr :indices idx-arr :mat-idx (.mMaterialIndex mesh)
+       :color (let [color [(.r mat-color) (.g mat-color) (.b mat-color) (.a mat-color)]]
+                (if (= color [1.0 1.0 1.0 1.0])
+                  [(rand) (rand) (rand) 1.0]
+                  color))})))
+
+(defn load-model [path]
+  (let [flags (bit-or Assimp/aiProcess_Triangulate
+                      Assimp/aiProcess_FlipUVs)]
+    (Assimp/aiImportFile path flags)))
+
 (comment
   (start!)
   (stop!)
   (def ^AIScene scene (load-model "assets/model.glb"))
-  (.mNumMeshes scene) ;; 54
-  (.mNumMaterials scene) ;; 17
+
+  (def meshes (with-gl
+                (doall
+                  (for [i (range (.mNumMeshes scene))]
+                    (let [mesh (extract-mesh scene i)
+                          vbo (GL45/glCreateBuffers)
+                          ebo (GL45/glCreateBuffers)
+                          vao (GL45/glCreateVertexArrays)]
+                      (GL45/glNamedBufferStorage vbo (:verts mesh)   GL45/GL_DYNAMIC_STORAGE_BIT)
+                      (GL45/glNamedBufferStorage ebo (:indices mesh) GL45/GL_DYNAMIC_STORAGE_BIT)
+                      (GL45/glVertexArrayElementBuffer vao ebo)
+                      (GL45/glVertexArrayVertexBuffer vao 0 vbo 0 (* 3 Float/BYTES))
+                      (GL45/glVertexArrayAttribFormat vao 0 3 GL11/GL_FLOAT false 0)
+                      (GL45/glVertexArrayAttribBinding vao 0 0)
+                      (GL45/glEnableVertexArrayAttrib vao 0)
+                      {:vbo vbo :vao vao :ebo ebo
+                       :mesh mesh
+                       :indices-count (alength (:indices mesh))})))))
 
   (with-gl
     (GL11/glClearColor 0.392 0.584 0.929 1.0))
+  (with-gl
+    (GL11/glClearColor 0.0 0.0 0.0 1.0))
 
   (with-gl
     (GL45/glNamedBufferSubData (:vbo @state) 0 ^floats (float-array [ 0.0   0.5 0.0