+
+/** XXX need a SIMD version of this */
+static unsigned
+choose_cube_face(float rx, float ry, float rz, float *newS, float *newT)
+{
+ /*
+ major axis
+ direction target sc tc ma
+ ---------- ------------------------------- --- --- ---
+ +rx TEXTURE_CUBE_MAP_POSITIVE_X_EXT -rz -ry rx
+ -rx TEXTURE_CUBE_MAP_NEGATIVE_X_EXT +rz -ry rx
+ +ry TEXTURE_CUBE_MAP_POSITIVE_Y_EXT +rx +rz ry
+ -ry TEXTURE_CUBE_MAP_NEGATIVE_Y_EXT +rx -rz ry
+ +rz TEXTURE_CUBE_MAP_POSITIVE_Z_EXT +rx -ry rz
+ -rz TEXTURE_CUBE_MAP_NEGATIVE_Z_EXT -rx -ry rz
+ */
+ const float arx = fabsf(rx);
+ const float ary = fabsf(ry);
+ const float arz = fabsf(rz);
+ unsigned face;
+ float sc, tc, ma;
+
+ if (arx > ary && arx > arz) {
+ if (rx >= 0.0F) {
+ face = PIPE_TEX_FACE_POS_X;
+ sc = -rz;
+ tc = -ry;
+ ma = arx;
+ }
+ else {
+ face = PIPE_TEX_FACE_NEG_X;
+ sc = rz;
+ tc = -ry;
+ ma = arx;
+ }
+ }
+ else if (ary > arx && ary > arz) {
+ if (ry >= 0.0F) {
+ face = PIPE_TEX_FACE_POS_Y;
+ sc = rx;
+ tc = rz;
+ ma = ary;
+ }
+ else {
+ face = PIPE_TEX_FACE_NEG_Y;
+ sc = rx;
+ tc = -rz;
+ ma = ary;
+ }
+ }
+ else {
+ if (rz > 0.0F) {
+ face = PIPE_TEX_FACE_POS_Z;
+ sc = rx;
+ tc = -ry;
+ ma = arz;
+ }
+ else {
+ face = PIPE_TEX_FACE_NEG_Z;
+ sc = -rx;
+ tc = -ry;
+ ma = arz;
+ }
+ }
+
+ *newS = (sc / ma + 1.0F) * 0.5F;
+ *newT = (tc / ma + 1.0F) * 0.5F;
+
+ return face;
+}
+
+
+
+void
+sample_texture4_cube(vector float s, vector float t,
+ vector float r, vector float q,
+ uint unit, uint level, int face_ignored,
+ vector float colors[4])
+{
+ static const vector float zero = {0.0f, 0.0f, 0.0f, 0.0f};
+ uint p, faces[4];
+ float newS[4], newT[4];
+
+ /* Compute cube face referenced by the four sets of texcoords.
+ * XXX we should SIMD-ize this.
+ */
+ for (p = 0; p < 4; p++) {
+ float rx = spu_extract(s, p);
+ float ry = spu_extract(t, p);
+ float rz = spu_extract(r, p);
+ faces[p] = choose_cube_face(rx, ry, rz, &newS[p], &newT[p]);
+ }
+
+ if (faces[0] == faces[1] &&
+ faces[0] == faces[2] &&
+ faces[0] == faces[3]) {
+ /* GOOD! All four texcoords refer to the same cube face */
+ s = (vector float) {newS[0], newS[1], newS[2], newS[3]};
+ t = (vector float) {newT[0], newT[1], newT[2], newT[3]};
+ sample_texture4_nearest(s, t, zero, zero, unit, level, faces[0], colors);
+ }
+ else {
+ /* BAD! The four texcoords refer to different faces */
+ for (p = 0; p < 4; p++) {
+ vector float c[4];
+
+ sample_texture4_nearest(spu_splats(newS[p]), spu_splats(newT[p]),
+ zero, zero, unit, level, faces[p], c);
+
+ float red = spu_extract(c[0], p);
+ float green = spu_extract(c[1], p);
+ float blue = spu_extract(c[2], p);
+ float alpha = spu_extract(c[3], p);
+
+ colors[0] = spu_insert(red, colors[0], p);
+ colors[1] = spu_insert(green, colors[1], p);
+ colors[2] = spu_insert(blue, colors[2], p);
+ colors[3] = spu_insert(alpha, colors[3], p);
+ }
+ }
+}