0
0  *  v - h = a
1

camera.z - h = a

mousedir*((camera.z-h)/mousedir.z)+camera.xyz = position

#include <acknex.h>

<<<INCLUDE LINE-PLANE INTERSECTION TEST CODE HERE>>>

void main()
{
    level_load(NULL);
    mouse_mode = 4;
    
    vec_set(camera.x, vector(-200,0,300));
    camera.tilt = -45;
    
    // Create a simple floor.
    ENTITY *cube = ent_create(CUBE_MDL, NULLVECTOR, NULL);
    cube.z -= cube.max_z;
    vec_set(cube.scale_x, vector(8,8,1));
    
    while(1)
    {
        VECTOR to;
        vec_set(to,mouse_dir3d);
        vec_add(to,mouse_pos3d);
    
        // Get the intersection between the mouse ray and the floor.
        VECTOR *ip = get_line_plane_intersection(mouse_pos3d, to, NULLVECTOR,
            vector(0,0,1), NULL);

        if (ip) // Draw intersection point.
            draw_point3d(ip, COLOR_RED, 100, 6);
            
        wait(1);
    }
}