Refactor TextureCube face information functions with lookup tables

diff --git a/source/texturecube.cpp b/source/texturecube.cpp
index e767423fe539f9ee92fd10dd5af8f1beaa6eebb4..833ef28f0ebd78add08ccfae4c8555df87dff288 100644 (file)
--- a/source/texturecube.cpp
+++ b/source/texturecube.cpp
@@ -13,6 +13,16 @@ using namespace std;
 namespace Msp {
 namespace GL {
 
+TextureCubeFace TextureCube::face_order[6] =
+{
+       POSITIVE_X,
+       NEGATIVE_X,
+       POSITIVE_Y,
+       NEGATIVE_Y,
+       POSITIVE_Z,
+       NEGATIVE_Z
+};
+
 Vector3 TextureCube::directions[6] =
 {
        Vector3(1, 0, 0),
@@ -23,6 +33,16 @@ Vector3 TextureCube::directions[6] =
        Vector3(0, 0, -1)
 };
 
+unsigned TextureCube::orientations[12] =
+{
+       5, 3,
+       4, 3,
+       0, 4,
+       0, 5,
+       0, 3,
+       1, 3
+};
+
 TextureCube::TextureCube():
        Texture(GL_TEXTURE_CUBE_MAP),
        ifmt(RGB),
@@ -166,58 +186,38 @@ unsigned TextureCube::get_level_size(unsigned level) const
 
 TextureCubeFace TextureCube::enumerate_faces(unsigned i)
 {
-       switch(i)
-       {
-       case 0: return POSITIVE_X;
-       case 1: return NEGATIVE_X;
-       case 2: return POSITIVE_Y;
-       case 3: return NEGATIVE_Y;
-       case 4: return POSITIVE_Z;
-       case 5: return NEGATIVE_Z;
-       default: throw out_of_range("TextureCube::enumerate_faces");
-       }
+       if(i>=6)
+               throw out_of_range("TextureCube::enumerate_faces");
+       return face_order[i];
 }
 
-const Vector3 &TextureCube::get_face_direction(TextureCubeFace face)
+unsigned TextureCube::get_face_index(TextureCubeFace face)
 {
        switch(face)
        {
-       case POSITIVE_X: return directions[0];
-       case NEGATIVE_X: return directions[1];
-       case POSITIVE_Y: return directions[2];
-       case NEGATIVE_Y: return directions[3];
-       case POSITIVE_Z: return directions[4];
-       case NEGATIVE_Z: return directions[5];
-       default: throw invalid_argument("TextureCube::get_face_direction");
+       case POSITIVE_X: return 0;
+       case NEGATIVE_X: return 1;
+       case POSITIVE_Y: return 2;
+       case NEGATIVE_Y: return 3;
+       case POSITIVE_Z: return 4;
+       case NEGATIVE_Z: return 5;
+       default: throw invalid_argument("TextureCube::get_face_index");
        }
 }
 
+const Vector3 &TextureCube::get_face_direction(TextureCubeFace face)
+{
+       return directions[get_face_index(face)];
+}
+
 const Vector3 &TextureCube::get_s_direction(TextureCubeFace face)
 {
-       switch(face)
-       {
-       case POSITIVE_X: return directions[5];
-       case NEGATIVE_X: return directions[4];
-       case POSITIVE_Y: return directions[0];
-       case NEGATIVE_Y: return directions[0];
-       case POSITIVE_Z: return directions[0];
-       case NEGATIVE_Z: return directions[1];
-       default: throw invalid_argument("TextureCube::get_s_direction");
-       }
+       return directions[orientations[get_face_index(face)*2]];
 }
 
 const Vector3 &TextureCube::get_t_direction(TextureCubeFace face)
 {
-       switch(face)
-       {
-       case POSITIVE_X: return directions[3];
-       case NEGATIVE_X: return directions[3];
-       case POSITIVE_Y: return directions[4];
-       case NEGATIVE_Y: return directions[5];
-       case POSITIVE_Z: return directions[3];
-       case NEGATIVE_Z: return directions[3];
-       default: throw invalid_argument("TextureCube::get_t_direction");
-       }
+       return directions[orientations[get_face_index(face)*2+1]];
 }
 
 Vector3 TextureCube::get_texel_direction(TextureCubeFace face, unsigned u, unsigned v)

diff --git a/source/texturecube.h b/source/texturecube.h
index 62f1189aa541426ff86d0cdcb5593604155a2dea..9ce216fdd1db1e79e164769f9d6017984de15f46 100644 (file)
--- a/source/texturecube.h
+++ b/source/texturecube.h
@@ -53,7 +53,9 @@ private:
        unsigned size;
        unsigned allocated;
 
+       static TextureCubeFace face_order[6];
        static Vector3 directions[6];
+       static unsigned orientations[12];
 
 public:
        TextureCube();
@@ -93,6 +95,8 @@ public:
        and 5, inclusive. */
        static TextureCubeFace enumerate_faces(unsigned);
 
+       static unsigned get_face_index(TextureCubeFace);
+
        /** Returns a vector pointing out of the face. */
        static const Vector3 &get_face_direction(TextureCubeFace);