diff options
Diffstat (limited to 'examples/graphics/hdtv/lookat.c')
| -rw-r--r-- | examples/graphics/hdtv/lookat.c | 40 |
1 files changed, 40 insertions, 0 deletions
diff --git a/examples/graphics/hdtv/lookat.c b/examples/graphics/hdtv/lookat.c new file mode 100644 index 0000000..d7c9ce4 --- /dev/null +++ b/examples/graphics/hdtv/lookat.c @@ -0,0 +1,40 @@ +// LookAt matrix code (may be implemented into libpsxgte soon) + +#include "lookat.h" + +void crossProduct(SVECTOR *v0, SVECTOR *v1, VECTOR *out) { + + out->vx = ((v0->vy*v1->vz)-(v0->vz*v1->vy))>>12; + out->vy = ((v0->vz*v1->vx)-(v0->vx*v1->vz))>>12; + out->vz = ((v0->vx*v1->vy)-(v0->vy*v1->vx))>>12; + +} + +void LookAt(VECTOR *eye, VECTOR *at, SVECTOR *up, MATRIX *mtx) { + + VECTOR taxis; + SVECTOR zaxis; + SVECTOR xaxis; + SVECTOR yaxis; + VECTOR pos; + VECTOR vec; + + setVector(&taxis, at->vx-eye->vx, at->vy-eye->vy, at->vz-eye->vz); + VectorNormalS(&taxis, &zaxis); + crossProduct(&zaxis, up, &taxis); + VectorNormalS(&taxis, &xaxis); + crossProduct(&zaxis, &xaxis, &taxis); + VectorNormalS(&taxis, &yaxis); + + mtx->m[0][0] = xaxis.vx; mtx->m[1][0] = yaxis.vx; mtx->m[2][0] = zaxis.vx; + mtx->m[0][1] = xaxis.vy; mtx->m[1][1] = yaxis.vy; mtx->m[2][1] = zaxis.vy; + mtx->m[0][2] = xaxis.vz; mtx->m[1][2] = yaxis.vz; mtx->m[2][2] = zaxis.vz; + + pos.vx = -eye->vx;; + pos.vy = -eye->vy;; + pos.vz = -eye->vz;; + + ApplyMatrixLV(mtx, &pos, &vec); + TransMatrix(mtx, &vec); + +}
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