From 279b472d96c8bbe3edb18f1bd3998bb39b65324b Mon Sep 17 00:00:00 2001
From: Javier Sancho <jsf@jsancho.org>
Date: Fri, 23 May 2014 09:12:21 +0200
Subject: [PATCH] Improving ways for accessing data structs

---
 src/assimp.scm | 119 +++++++++++++++++++++++++++++++++++++++++++------
 src/test.c     |  18 ++++++++
 2 files changed, 124 insertions(+), 13 deletions(-)
 create mode 100644 src/test.c

diff --git a/src/assimp.scm b/src/assimp.scm
index 4ecbcf4..e4d8f8e 100644
--- a/src/assimp.scm
+++ b/src/assimp.scm
@@ -26,24 +26,117 @@
 		      (dynamic-func "aiImportFile" libassimp)
 		      (list '* unsigned-int)))
 
-(define-wrapped-pointer-type scene
-  scene?
-  wrap-scene unwrap-scene
-  (lambda (s p)
-    (format p "#<scene ~x>"
-	    (pointer-address (unwrap-scene s)))))
+
+;;; Type Generation
+
+(define-syntax define-type
+  (lambda (x)
+    (define (mk-string . args)
+      (string-concatenate
+       (map (lambda (a)
+	      (if (string? a)
+		  a
+		  (symbol->string (syntax->datum a))))
+	    args)))
+    (define (mk-symbol . args)
+      (datum->syntax x
+        (string->symbol
+	 (apply mk-string args))))
+    (syntax-case x ()
+      ((_ name (field field-proc) ...)
+       (with-syntax ((type? (mk-symbol #'name "?"))
+		     (wrap-type (mk-symbol "wrap-" #'name))
+		     (unwrap-type (mk-symbol "unwrap-" #'name))
+		     (output-string (mk-string "#<" #'name " ~x>"))
+		     (type-contents (mk-symbol #'name "-contents")))
+         #'(begin
+	     (define-wrapped-pointer-type name
+	       type?
+	       wrap-type unwrap-type
+	       (lambda (x p)
+		 (format p output-string
+			 (pointer-address (unwrap-type x)))))
+	     (define (type-contents wrapped)
+	       (let ((unwrapped (unwrap-type wrapped)))
+		 (cond ((= (pointer-address unwrapped) 0)
+			'())
+		       (else
+			(filter
+			 (lambda (f)
+			   (not (null? (cdr f))))
+			 (list (cons 'field (field-proc unwrapped))
+			       ...))))))))))))
+
+
+(define (bv-uint-ref pointer index)
+  (bytevector-uint-ref
+   (pointer->bytevector pointer 4 index)
+   0
+   (native-endianness)
+   4))
+
+(define* (get-pointer-of-pointers-procedure num-index root-index #:optional wrap-proc)
+  (lambda (pointer)
+    (let* ((num (bv-uint-ref pointer num-index))
+	   (rootp (make-pointer (bv-uint-ref pointer root-index))))
+      (let loop ((i 0))
+	(cond ((= i num)
+	       '())
+	      (else
+	       (let* ((p (make-pointer (bv-uint-ref rootp (* 4 i))))
+		      (wp (if wrap-proc (wrap-proc p) p)))
+		 (cons wp (loop (+ i 1))))))))))
+
+;;; Scenes
+
+(define-type scene
+  (flags (lambda (p) (bv-uint-ref p 0)))
+  (root-node (lambda (p) (wrap-node (make-pointer (bv-uint-ref p 4)))))
+  (meshes (get-pointer-of-pointers-procedure 8 12 wrap-mesh))
+  (materials (get-pointer-of-pointers-procedure 16 20))
+  (animations (get-pointer-of-pointers-procedure 24 28))
+  (textures (get-pointer-of-pointers-procedure 32 36))
+  (lights (get-pointer-of-pointers-procedure 40 44))
+  (cameras (get-pointer-of-pointers-procedure 48 52)))
 
 (define (load-scene filename flags)
   (wrap-scene
    (aiImportFile (string->pointer filename)
 		 flags)))
 
-(bytevector-uint-ref (pointer->bytevector numptob (sizeof long))
-                     0 (native-endianness)
-                     (sizeof long))
+(export load-scene
+	unwrap-scene
+	scene?
+	scene-contents)
+
+
+;;; Nodes
+
+(define-type node
+  (name (lambda (p) (bv-uint-ref p 0))) ;check, it's a struct
+  (transformation (lambda (p) (bv-uint-ref p 1028))) ;check, it's a struct
+  (parent (lambda (p) (bv-uint-ref p 1092)))
+  (children (get-pointer-of-pointers-procedure 1096 1100))
+  (meshes (get-pointer-of-pointers-procedure 1104 1108)))
+
+(export node?
+	node-contents)
+
+
+;;; Meshes
 
-(define (scene-contents scene)
-  (bytevector-uint-ref (pointer->bytevector (unwrap-scene scene) 16)
-		       0 (native-endiannes) 4))
+(define-type mesh
+  (num-primitive-types (lambda (p) (bv-uint-ref p 0)))
+  (vertices (get-pointer-of-pointers-procedure 4 12))
+  (faces (get-pointer-of-pointers-procedure 8 124))
+  (normals (lambda (p) (bv-uint-ref p 16)))
+  (tangents (lambda (p) (bv-uint-ref p 20)))
+  (bitangents (lambda (p) (bv-uint-ref p 24)))
+  (colors (lambda (p) (bv-uint-ref p 28))) ;AI_MAX_NUMBER_OF_COLOR_SETS
+  (texture-coords (lambda (p) (bv-uint-ref p 60))) ;AI_MAX_NUMBER_OF_TEXTURECOORDS
+  (num-uv-components (lambda (p) (bv-uint-ref p 92))) ;AI_MAX_NUMBER_OF_TEXTURECOORDS
+  (bones (get-pointer-of-pointers-procedure 128 132))
+  (material-index (lambda (p) (bv-uint-ref p 136))))
 
-(export load-scene)
+(export mesh?
+	mesh-contents)
diff --git a/src/test.c b/src/test.c
new file mode 100644
index 0000000..d93d72e
--- /dev/null
+++ b/src/test.c
@@ -0,0 +1,18 @@
+#include <stdlib.h>
+#include <stdio.h>
+
+#include <GL/glut.h>
+
+#include <assimp/cimport.h>
+#include <assimp/scene.h>
+#include <assimp/postprocess.h>
+
+int main(int argc, char **argv)
+{
+  const struct aiScene* scene = NULL;
+  const struct aiNode* node = NULL;
+
+  scene = aiImportFile("/home/jsancho/Imágenes/fleurOptonl.blend", aiProcessPreset_TargetRealtime_MaxQuality);
+  node = scene->mRootNode;
+  printf("Node:\n  parent: %d\n  children: %d\n  meshes: %d\n", node->mParent, node->mNumChildren, node->mNumMeshes);
+}
-- 
2.39.2