gmio_stl: add utility function gmio_stl_triangle_compute_normal()

src/gmio_core/internal/vecgeom_utils.h

@@ -0,0 +1,74 @@
+/****************************************************************************
+** gmio
+** Copyright Fougue (2 Mar. 2015)
+** contact@fougue.pro
+**
+** This software is a reusable library whose purpose is to provide complete
+** I/O support for various CAD file formats (eg. STL)
+**
+** This software is governed by the CeCILL-B license under French law and
+** abiding by the rules of distribution of free software.  You can  use,
+** modify and/ or redistribute the software under the terms of the CeCILL-B
+** license as circulated by CEA, CNRS and INRIA at the following URL
+** "http://www.cecill.info/licences/Licence_CeCILL-B_V1-en.html".
+****************************************************************************/
+
+#ifndef GMIO_INTERNAL_VECGEOM_UTILS_H
+#define GMIO_INTERNAL_VECGEOM_UTILS_H
+
+#include "../global.h"
+
+/*! Cross product of float32 vectors (ux,uy,uz) and (vx,vy,vz) */
+GMIO_INLINE void gmio_cross_product_f32(
+        float ux, float uy, float uz,
+        float vx, float vy, float vz,
+        float* nx, float* ny, float* nz);
+
+/*! Cross product of float64 vectors (ux,uy,uz) and (vx,vy,vz) */
+GMIO_INLINE void gmio_cross_product_f64(
+        double ux, double uy, double uz,
+        double vx, double vy, double vz,
+        double* nx, double* ny, double* nz);
+
+
+/*
+ *  Implementation
+ */
+
+void gmio_cross_product_f32(
+        float ux, float uy, float uz,
+        float vx, float vy, float vz,
+        float* nx, float* ny, float* nz)
+{
+    *nx = uy*vz - uz*vx;
+    *ny = uz*vx - ux*vz;
+    *nz = ux*vy - uy*vx;
+    {
+        const float d = (float)sqrt((*nx)*(*nx) + (*ny)*(*ny) + (*nz)*(*nz));
+        if (d > 0.f) {
+            *nx /= d;
+            *ny /= d;
+            *nz /= d;
+        }
+    }
+}
+
+void gmio_cross_product_f64(
+        double ux, double uy, double uz,
+        double vx, double vy, double vz,
+        double* nx, double* ny, double* nz)
+{
+    *nx = uy*vz - uz*vx;
+    *ny = uz*vx - ux*vz;
+    *nz = ux*vy - uy*vx;
+    {
+        const double d = sqrt((*nx)*(*nx) + (*ny)*(*ny) + (*nz)*(*nz));
+        if (d > 0.) {
+            *nx /= d;
+            *ny /= d;
+            *nz /= d;
+        }
+    }
+}
+
+#endif /* GMIO_INTERNAL_VECGEOM_UTILS_H */

src/gmio_stl/stl_triangle.c

@@ -0,0 +1,36 @@
+/****************************************************************************
+** gmio
+** Copyright Fougue (2 Mar. 2015)
+** contact@fougue.pro
+**
+** This software is a reusable library whose purpose is to provide complete
+** I/O support for various CAD file formats (eg. STL)
+**
+** This software is governed by the CeCILL-B license under French law and
+** abiding by the rules of distribution of free software.  You can  use,
+** modify and/ or redistribute the software under the terms of the CeCILL-B
+** license as circulated by CEA, CNRS and INRIA at the following URL
+** "http://www.cecill.info/licences/Licence_CeCILL-B_V1-en.html".
+****************************************************************************/
+
+#include "stl_triangle.h"
+
+#include "../gmio_core/internal/vecgeom_utils.h"
+
+GMIO_INLINE struct gmio_stl_coords gmio_stl_coords_diff(
+        const struct gmio_stl_coords* u, const struct gmio_stl_coords* v)
+{
+    struct gmio_stl_coords diff;
+    diff.x = u->x - v->x;
+    diff.y = u->y - v->y;
+    diff.z = u->z - v->z;
+    return diff;
+}
+
+void gmio_stl_triangle_compute_normal(struct gmio_stl_triangle* tri)
+{
+    const struct gmio_stl_coords u = gmio_stl_coords_diff(&tri->v2, &tri->v1);
+    const struct gmio_stl_coords v = gmio_stl_coords_diff(&tri->v3, &tri->v1);
+    struct gmio_stl_coords* n = &tri->n;
+    gmio_cross_product_f32(u.x, u.y, u.z, v.x, v.y, v.z, &n->x, &n->y, &n->z);
+}

src/gmio_stl/stl_triangle.h

@@ -45,5 +45,13 @@ struct gmio_stl_triangle
     uint16_t attribute_byte_count; /*!< Useful only for STL binary format */
 };
 
+GMIO_C_LINKAGE_BEGIN
+
+/*! Computes the normal vector of triangle \p tri */
+GMIO_LIBSTL_EXPORT
+void gmio_stl_triangle_compute_normal(struct gmio_stl_triangle* tri);
+
+GMIO_C_LINKAGE_END
+
 #endif /* GMIO_STL_TRIANGLE_H */
 /*! @} */

tests/CMakeLists.txt

@@ -53,8 +53,9 @@ file(COPY ${CMAKE_CURRENT_SOURCE_DIR}/models
 set(GMIO_TEST_STL_SRC
         main_test_stl.c
         test_stl_internal.c
-        test_stl_io.c
         test_stl_infos.c
+        test_stl_io.c
+        test_stl_triangle.c
         test_stlb_header.c
         core_utils.c
         stl_utils.c)

tests/main_test_core.c

@@ -28,7 +28,6 @@ const char* test_internal__stringstream();
 const char* test_internal__string_utils();
 const char* test_internal__benchmark_gmio_fast_atof();
 
-const char* test_platform__alignment();
 const char* test_platform__global_h();
 const char* test_platform__compiler();
 
@@ -49,7 +48,6 @@ const char* all_tests()
     UTEST_RUN(test_internal__string_utils);
     UTEST_RUN(test_internal__benchmark_gmio_fast_atof);
 
-    UTEST_RUN(test_platform__alignment);
     UTEST_RUN(test_platform__global_h);
     UTEST_RUN(test_platform__compiler);
 

tests/main_test_stl.c

@@ -15,6 +15,10 @@
 
 #include "utest_lib.h"
 
+const char* test_stl_coords_packing();
+const char* test_stl_triangle_packing();
+const char* test_stl_triangle_compute_normal();
+
 const char* test_stl_internal__rw_common();
 
 const char* test_stl_infos();
@@ -31,13 +35,19 @@ const char* all_tests()
 {
     UTEST_SUITE_START();
 
+    UTEST_RUN(test_stl_coords_packing);
+    UTEST_RUN(test_stl_triangle_packing);
+    UTEST_RUN(test_stl_triangle_compute_normal);
+
     UTEST_RUN(test_stl_internal__rw_common);
 
     UTEST_RUN(test_stl_infos);
+
     UTEST_RUN(test_stl_read);
     UTEST_RUN(test_stla_write);
     UTEST_RUN(test_stlb_write_header);
     UTEST_RUN(test_stlb_write);
+
     UTEST_RUN(test_stlb_header_str);
     UTEST_RUN(test_stlb_header_to_printable_str);
 

tests/test_core_platform.c

@@ -17,8 +17,6 @@
 
 #include "../src/gmio_core/global.h"
 #include "../src/gmio_core/stream.h"
-#include "../src/gmio_stl/stl_constants.h"
-#include "../src/gmio_stl/stl_triangle.h"
 
 #include <stddef.h>
 #include <string.h>
@@ -26,23 +24,6 @@
 /* Disable MSVC warning "conditional expression is constant" */
 GMIO_PRAGMA_MSVC_WARNING_PUSH_AND_DISABLE(4127)
 
-const char* test_platform__alignment()
-{
-    UTEST_ASSERT(offsetof(struct gmio_stl_coords, x) == 0);
-    UTEST_ASSERT(offsetof(struct gmio_stl_coords, y) == 4);
-    UTEST_ASSERT(offsetof(struct gmio_stl_coords, z) == 8);
-    UTEST_ASSERT(sizeof(struct gmio_stl_coords) == GMIO_STL_COORDS_RAWSIZE);
-
-    UTEST_ASSERT(offsetof(struct gmio_stl_triangle, n) == 0);
-    UTEST_ASSERT(offsetof(struct gmio_stl_triangle, v1) == GMIO_STL_COORDS_RAWSIZE);
-    UTEST_ASSERT(offsetof(struct gmio_stl_triangle, v2) == 2*GMIO_STL_COORDS_RAWSIZE);
-    UTEST_ASSERT(offsetof(struct gmio_stl_triangle, v3) == 3*GMIO_STL_COORDS_RAWSIZE);
-    UTEST_ASSERT(offsetof(struct gmio_stl_triangle, attribute_byte_count) == 4*GMIO_STL_COORDS_RAWSIZE);
-    UTEST_ASSERT(sizeof(struct gmio_stl_triangle) >= GMIO_STLB_TRIANGLE_RAWSIZE);
-
-    return NULL;
-}
-
 const char* test_platform__global_h()
 {
     UTEST_ASSERT(sizeof(int8_t) == 1);

tests/test_stl_triangle.c

@@ -0,0 +1,59 @@
+/****************************************************************************
+** gmio
+** Copyright Fougue (2 Mar. 2015)
+** contact@fougue.pro
+**
+** This software is a reusable library whose purpose is to provide complete
+** I/O support for various CAD file formats (eg. STL)
+**
+** This software is governed by the CeCILL-B license under French law and
+** abiding by the rules of distribution of free software.  You can  use,
+** modify and/ or redistribute the software under the terms of the CeCILL-B
+** license as circulated by CEA, CNRS and INRIA at the following URL
+** "http://www.cecill.info/licences/Licence_CeCILL-B_V1-en.html".
+****************************************************************************/
+
+#include "utest_assert.h"
+
+#include "../src/gmio_stl/stl_constants.h"
+#include "../src/gmio_stl/stl_triangle.h"
+
+#include <stddef.h>
+#include <string.h>
+
+/* Disable MSVC warning "conditional expression is constant" */
+GMIO_PRAGMA_MSVC_WARNING_PUSH_AND_DISABLE(4127)
+
+const char* test_stl_coords_packing()
+{
+    UTEST_COMPARE_UINT(0, offsetof(struct gmio_stl_coords, x));
+    UTEST_COMPARE_UINT(4, offsetof(struct gmio_stl_coords, y));
+    UTEST_COMPARE_UINT(8, offsetof(struct gmio_stl_coords, z));
+    UTEST_COMPARE_UINT(GMIO_STL_COORDS_RAWSIZE, sizeof(struct gmio_stl_coords));
+    return NULL;
+}
+
+const char* test_stl_triangle_packing()
+{
+    UTEST_COMPARE_UINT(0, offsetof(struct gmio_stl_triangle, n));
+    UTEST_COMPARE_UINT(GMIO_STL_COORDS_RAWSIZE, offsetof(struct gmio_stl_triangle, v1));
+    UTEST_COMPARE_UINT(2*GMIO_STL_COORDS_RAWSIZE, offsetof(struct gmio_stl_triangle, v2));
+    UTEST_COMPARE_UINT(3*GMIO_STL_COORDS_RAWSIZE, offsetof(struct gmio_stl_triangle, v3));
+    UTEST_COMPARE_UINT(4*GMIO_STL_COORDS_RAWSIZE, offsetof(struct gmio_stl_triangle, attribute_byte_count));
+    UTEST_ASSERT(sizeof(struct gmio_stl_triangle) >= GMIO_STLB_TRIANGLE_RAWSIZE);
+    return NULL;
+}
+
+const char* test_stl_triangle_compute_normal()
+{
+    { /* Doesn't fail on invalid facet */
+        const struct gmio_stl_coords null_coords = {0};
+        struct gmio_stl_triangle tri = {0};
+        gmio_stl_triangle_compute_normal(&tri);
+        UTEST_ASSERT(memcmp(&tri.n, &null_coords, sizeof(struct gmio_stl_triangle))
+                     == 0);
+    }
+    return NULL;
+}
+
+GMIO_PRAGMA_MSVC_WARNING_POP()