- x6 = ((ref[0][0] - ref[1][0] - ref[2][0] + ref[3][0]) *
- (ref[2][1] - ref[3][1]) -
- ( ref[0][1] - ref[1][1] - ref[2][1] + ref[3][1]) *
- (ref[2][0] - ref[3][0])) * h;
- x7 = ((ref[0][1] - ref[1][1] - ref[2][1] + ref[3][1]) *
- (ref[1][0] - ref[3][0]) -
- ( ref[0][0] - ref[1][0] - ref[2][0] + ref[3][0]) *
- (ref[1][1] - ref[3][1])) * w;
- q = ( ref[1][0] - ref[3][0]) * (ref[2][1] - ref[3][1]) -
- ( ref[2][0] - ref[3][0]) * (ref[1][1] - ref[3][1]);
-
- x0 = q * (ref[1][0] - ref[0][0]) * h + x6 * ref[1][0];
- x1 = q * (ref[2][0] - ref[0][0]) * w + x7 * ref[2][0];
- x2 = q * ref[0][0] * w * h;
- x3 = q * (ref[1][1] - ref[0][1]) * h + x6 * ref[1][1];
- x4 = q * (ref[2][1] - ref[0][1]) * w + x7 * ref[2][1];
- x5 = q * ref[0][1] * w * h;
+ switch (s->sense) {
+ case PERSPECTIVE_SENSE_SOURCE:
+ x6 = ((ref[0][0] - ref[1][0] - ref[2][0] + ref[3][0]) *
+ (ref[2][1] - ref[3][1]) -
+ ( ref[0][1] - ref[1][1] - ref[2][1] + ref[3][1]) *
+ (ref[2][0] - ref[3][0])) * h;
+ x7 = ((ref[0][1] - ref[1][1] - ref[2][1] + ref[3][1]) *
+ (ref[1][0] - ref[3][0]) -
+ ( ref[0][0] - ref[1][0] - ref[2][0] + ref[3][0]) *
+ (ref[1][1] - ref[3][1])) * w;
+ q = ( ref[1][0] - ref[3][0]) * (ref[2][1] - ref[3][1]) -
+ ( ref[2][0] - ref[3][0]) * (ref[1][1] - ref[3][1]);
+
+ x0 = q * (ref[1][0] - ref[0][0]) * h + x6 * ref[1][0];
+ x1 = q * (ref[2][0] - ref[0][0]) * w + x7 * ref[2][0];
+ x2 = q * ref[0][0] * w * h;
+ x3 = q * (ref[1][1] - ref[0][1]) * h + x6 * ref[1][1];
+ x4 = q * (ref[2][1] - ref[0][1]) * w + x7 * ref[2][1];
+ x5 = q * ref[0][1] * w * h;
+ x8 = q * w * h;
+ break;
+ case PERSPECTIVE_SENSE_DESTINATION:
+ t0 = ref[0][0] * (ref[3][1] - ref[1][1]) +
+ ref[1][0] * (ref[0][1] - ref[3][1]) +
+ ref[3][0] * (ref[1][1] - ref[0][1]);
+ t1 = ref[1][0] * (ref[2][1] - ref[3][1]) +
+ ref[2][0] * (ref[3][1] - ref[1][1]) +
+ ref[3][0] * (ref[1][1] - ref[2][1]);
+ t2 = ref[0][0] * (ref[3][1] - ref[2][1]) +
+ ref[2][0] * (ref[0][1] - ref[3][1]) +
+ ref[3][0] * (ref[2][1] - ref[0][1]);
+ t3 = ref[0][0] * (ref[1][1] - ref[2][1]) +
+ ref[1][0] * (ref[2][1] - ref[0][1]) +
+ ref[2][0] * (ref[0][1] - ref[1][1]);
+
+ x0 = t0 * t1 * w * (ref[2][1] - ref[0][1]);
+ x1 = t0 * t1 * w * (ref[0][0] - ref[2][0]);
+ x2 = t0 * t1 * w * (ref[0][1] * ref[2][0] - ref[0][0] * ref[2][1]);
+ x3 = t1 * t2 * h * (ref[1][1] - ref[0][1]);
+ x4 = t1 * t2 * h * (ref[0][0] - ref[1][0]);
+ x5 = t1 * t2 * h * (ref[0][1] * ref[1][0] - ref[0][0] * ref[1][1]);
+ x6 = t1 * t2 * (ref[1][1] - ref[0][1]) +
+ t0 * t3 * (ref[2][1] - ref[3][1]);
+ x7 = t1 * t2 * (ref[0][0] - ref[1][0]) +
+ t0 * t3 * (ref[3][0] - ref[2][0]);
+ x8 = t1 * t2 * (ref[0][1] * ref[1][0] - ref[0][0] * ref[1][1]) +
+ t0 * t3 * (ref[2][0] * ref[3][1] - ref[2][1] * ref[3][0]);
+ break;
+ }