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cogl/matrix: Look-at using graphene matrices

Browse Source 
https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1439
This commit is contained in:
Georges Basile Stavracas Neto 2020-09-10 10:52:38 -03:00
parent 2b7a73e0c3
commit 0dbd6d3a80
1 changed files with 10 additions and 42 deletions
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52
cogl/cogl/cogl-matrix.c
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@ -1946,54 +1946,22 @@ cogl_matrix_look_at (CoglMatrix *matrix,
float world_up_y,
float world_up_z)
{
CoglMatrix tmp;
graphene_vec3_t forward;
graphene_vec3_t side;
graphene_matrix_t m;
graphene_vec3_t eye;
graphene_vec3_t center;
graphene_vec3_t up;
CoglMatrix look_at;
/* Get a unit viewing direction vector */
graphene_vec3_init (&forward,
object_x - eye_position_x,
object_y - eye_position_y,
object_z - eye_position_z);
graphene_vec3_normalize (&forward, &forward);
graphene_vec3_init (&eye, eye_position_x, eye_position_y, eye_position_z);
graphene_vec3_init (&center, object_x, object_y, object_z);
graphene_vec3_init (&up, world_up_x, world_up_y, world_up_z);
/* Take the sideways direction as being perpendicular to the viewing
* direction and the word up vector. */
graphene_vec3_cross (&forward, &up, &side);
graphene_vec3_normalize (&side, &side);
graphene_matrix_init_look_at (&m, &eye, &center, &up);
/* Now we have unit sideways and forward-direction vectors calculate
* a new mutually perpendicular up vector. */
graphene_vec3_cross (&side, &forward, &up);
graphene_matrix_to_cogl_matrix (&m, &look_at);
look_at.flags = MAT_FLAG_GENERAL_3D | MAT_DIRTY_TYPE | MAT_DIRTY_INVERSE;
tmp.xx = graphene_vec3_get_x (&side);
tmp.yx = graphene_vec3_get_y (&side);
tmp.zx = graphene_vec3_get_z (&side);
tmp.wx = 0;
tmp.xy = graphene_vec3_get_x (&up);
tmp.yy = graphene_vec3_get_y (&up);
tmp.zy = graphene_vec3_get_z (&up);
tmp.wy = 0;
tmp.xz = -graphene_vec3_get_x (&forward);
tmp.yz = -graphene_vec3_get_y (&forward);
tmp.zz = -graphene_vec3_get_z (&forward);
tmp.wz = 0;
tmp.xw = 0;
tmp.yw = 0;
tmp.zw = 0;
tmp.ww = 1;
tmp.flags = (MAT_FLAG_GENERAL_3D | MAT_DIRTY_TYPE | MAT_DIRTY_INVERSE);
cogl_matrix_translate (&tmp, -eye_position_x, -eye_position_y, -eye_position_z);
cogl_matrix_multiply (matrix, matrix, &tmp);
cogl_matrix_multiply (matrix, matrix, &look_at);
}
void