Add support to export the 3d scene as OBJ file

README.md

@@ -61,16 +61,17 @@ Some notes on differences with respect to other implementations.
 Workstation numbers can be in the range from 0 to 99.
 
 ### Workstation types
-* 0 PWST_OUTPUT_TRUE                 Output only on GL display
-* 1 PWST_OUTIN_TRUE                  Input/Output on GL display
-* 2 PWST_OUTPUT_TRUE_DB              Output only on GL, buffered
-* 3 PWST_OUTIN_TRUE_DB               Input/Output on GL display, buffered
-* 4 PWST_HCOPY_TRUE_TGA              Hardcopy to file as TGA
-* 5 PWST_HCOPY_TRUE_RGB_PNG          Hardcopy to file as PNG RGB only
-* 6 PWST_HCOPY_TRUE_RGBA_PNG         Hardcopy to file as PNG with Alpha channel
-* 7 PWST_HCOPY_TRUE_EPS              Hardcopy to file as Encapsulated PostScript, no shaders
-* 8 PWST_HCOPY_TRUE_PDF              Hardcopy to file as PDF, no shaders
-* 9 PWST_HCOPY_TRUE_SVG              Hardcopy to file as SVG, no shaders
+* 0  PWST_OUTPUT_TRUE                 Output only on GL display
+* 1  PWST_OUTIN_TRUE                  Input/Output on GL display
+* 2  PWST_OUTPUT_TRUE_DB              Output only on GL, buffered
+* 3  PWST_OUTIN_TRUE_DB               Input/Output on GL display, buffered
+* 4  PWST_HCOPY_TRUE_TGA              Hardcopy to file as TGA
+* 5  PWST_HCOPY_TRUE_RGB_PNG          Hardcopy to file as PNG RGB only
+* 6  PWST_HCOPY_TRUE_RGBA_PNG         Hardcopy to file as PNG with Alpha channel
+* 7  PWST_HCOPY_TRUE_EPS              Hardcopy to file as Encapsulated PostScript, no shaders
+* 8  PWST_HCOPY_TRUE_PDF              Hardcopy to file as PDF, no shaders
+* 9  PWST_HCOPY_TRUE_SVG              Hardcopy to file as SVG, no shaders
+* 10 PWST_HCOPY_TRUE_OBJ              Export geometry as OBJ
 
 Notes:
  * There is no support for PostScript at the moment.

phigs.def

@@ -57,3 +57,10 @@ Workstation example for output svg
 %wp 0.0 1.0 0.0 1.    position
 %hs 1.                scale factor for hardcopy
 %bg 0. 0. 0.          Background color R G B
+
+Workstation example for output obj
+%wk 93                Workstation for hardcopy
+%wg 2480 2480 0 0 1   Window width height px py border
+%wp 0.0 1.0 0.0 1.    position
+%hs 1.                scale factor for hardcopy
+%bg 0. 0. 0.          Background color R G B

src/include/phigs/phigs.h

@@ -2,7 +2,7 @@
 
 Copyright (c) 1989, 1990, 1991  X Consortium
 Copyright (c) 2014 Surplus Users Ham Society
-Copyright (c) 2022-2023 CERN
+Copyright (c) 2022-2025 CERN
 
 Permission is hereby granted, free of charge, to any person obtaining a copy
 of this software and associated documentation files (the "Software"), to deal
@@ -163,7 +163,8 @@ typedef enum {
    PCAT_PNGA,
    PCAT_EPS,
    PCAT_PDF,
-   PCAT_SVG
+   PCAT_SVG,
+   PCAT_OBJ
 } Pws_cat;
 
 typedef enum {

src/include/phigs/private/wsglP.h

@@ -3,7 +3,7 @@
 *
 *   This file is part of Open PHIGS
 *   Copyright (C) 2014 Surplus Users Ham Society
-*             (C) 2022-2023 CERN
+*             (C) 2022-2025 CERN
 *
 *   Open PHIGS is free software: you can redistribute it and/or modify
 *   it under the terms of the GNU Lesser General Public License as published by
@@ -119,6 +119,80 @@ typedef struct _Wsgl {
    Ws_dev_st       dev_st;
 } Wsgl;
 
+/* record geometry */
+typedef enum {
+    GEOM_LINE,
+    GEOM_FACE
+} GeomType;
+
+typedef struct {
+    GeomType type;
+    int* indices;
+    int* norms;
+    int count;
+} Geometry;
+
+extern Ppoint3 * vertices;
+extern Ppoint3 * normals;
+extern int vertex_count;
+extern int normal_count;
+
+extern Geometry* geometries;
+extern int geom_count;
+extern Ppoint3 current_normal;
+
+extern int record_geom;
+extern int record_geom_fill;
+extern int normal_valid;
+
+#define MAX_VERTICES 10000
+/*******************************************************************************
+ * wsgl_set_current_normal(float x, float y, float z)
+ *
+ * DESCR:       add 3d vertex
+ * RETURNS:     Non zero or zero on error
+ */
+  void wsgl_set_current_normal(float x, float y, float z);
+
+/*******************************************************************************
+ * wsgl_add_vertex(float x, float y, float z)
+ *
+ * DESCR:       add 3d vertex
+ * RETURNS:     Non zero or zero on error
+ */
+  int wsgl_add_vertex(float x, float y, float z);
+
+/*******************************************************************************
+ * wsgl_add_normal(float x, float y, float z)
+ *
+ * DESCR:       add 3d vertex
+ * RETURNS:     Non zero or zero on error
+ */
+  int wsgl_add_normal(float x, float y, float z);
+
+/*******************************************************************************
+ * wsgl_add_geometry(GeomType type, const int* verts, const int* norms, int count)
+ *
+ * DESCR:       add 3d geometry
+ * RETURNS:     Non zero or zero on error
+ */
+  void wsgl_add_geometry(GeomType type, const int* verts, const int* norms, int count);
+
+/*******************************************************************************
+ * wsgl_export_obj(const char* filename, const char* title)
+ * DESCR:       export as OBJ file
+ * RETURNS:     Non zero or zero on error
+ */
+
+  void wsgl_export_obj(const char* filename, const char* title);
+/*******************************************************************************
+ * wsgl_clear_geometry()
+ *
+ * DESCR:       cleanup geometry records
+ * RETURNS:     Non zero or zero on error
+ */
+  void wsgl_clear_geometry();
+
 /*******************************************************************************
  * wsgl_init
  *
@@ -1209,8 +1283,7 @@ void wsgl_anno_text_rel(
  * DESCR:	Initialise shaders
  * RETURNS:	N/A
  */
-
-  void wsgl_shaders(Ws * ws);
+void wsgl_shaders(Ws * ws);
 
 extern Phg_font *fnt_fonts[];
 extern unsigned char *wsgl_hatch_tbl[];

src/include/phigs/ws_type.h

@@ -2,7 +2,7 @@
 
 Copyright (c) 1989, 1990, 1991  X Consortium
 Copyright (c) 2014 Surplus Users Ham Society
-Copyright (c) 2022-2023 CERN
+Copyright (c) 2022-2025 CERN
 
 Permission is hereby granted, free of charge, to any person obtaining a copy
 of this software and associated documentation files (the "Software"), to deal
@@ -67,6 +67,7 @@ extern "C" {
 #define PWST_HCOPY_TRUE_EPS              7
 #define PWST_HCOPY_TRUE_PDF              8
 #define PWST_HCOPY_TRUE_SVG              9
+#define PWST_HCOPY_TRUE_OBJ              10
 
 /* Default tables */
 #define WST_MIN_PREDEF_LINE_REPS         1

src/libphigs/CMakeLists.txt

@@ -81,6 +81,7 @@ SET(P_WSGL_SRCS
   wsgl/wsgl_light.c
   wsgl/wsgl_line.c
   wsgl/wsgl_marker.c
+  wsgl/wsgl_obj.c
   wsgl/wsgl_shaders.c
   wsgl/wsgl_sofas3clear.c
   wsgl/wsgl_sofas3edge.c

src/libphigs/c_binding/cb_lite.c

@@ -70,6 +70,7 @@ void pinq_light_src_rep( ws_id, index, type, err_ind, rep)
              dt->ws_category == PCAT_EPS ||
              dt->ws_category == PCAT_PDF ||
              dt->ws_category == PCAT_SVG ||
+             dt->ws_category == PCAT_OBJ ||
              dt->ws_category == PCAT_OUTIN ||
              dt->ws_category == PCAT_MO) ) {
         *err_ind = ERR59;

src/libphigs/c_binding/cb_phg.c

@@ -110,6 +110,7 @@ void popen_phigs(
    phg_wst_add_ws_type(PCAT_EPS, 0);
    phg_wst_add_ws_type(PCAT_PDF, 0);
    phg_wst_add_ws_type(PCAT_SVG, 0);
+   phg_wst_add_ws_type(PCAT_OBJ, 0);
 
    PHG_WS_LIST = (Ws_handle *) malloc(sizeof(Ws_handle) * MAX_NO_OPEN_WS);
    if (PHG_WS_LIST == NULL) {