// raycast checks which grid tile is selected on a mouse click. It gets
// the picking ray direction and then intersect the ray against the
// geometry in world space.
func (rc *rctag) raycast(mx, my int) {
rx, ry, rz := rc.cam.Ray(mx, my, rc.ww, rc.wh)
ray := vu.NewRay(rx, ry, rz)
ray.World().SetLoc(rc.cam.Location()) // camera is ray origin.
// collide the ray with the plane and get the world-space contact point on hit.
if hit, x, y, z := vu.Cast(ray, rc.floor.Body()); hit {
bot := &lin.V3{X: -rc.fsize, Y: -rc.fsize, Z: 0}
top := &lin.V3{X: rc.fsize, Y: rc.fsize, Z: 0}
// check if the plane hit was within the floor area.
if x >= bot.X && x <= top.X && y >= bot.Y && y <= top.Y {
// place a marker where the mouse hit.
rc.hilite.SetLocation(x, y, z)
rc.hilite.SetVisible(true)
rc.banner.SetVisible(true)
if model := rc.banner.Model(); model != nil {
// adjust and display grid coordinates. Map x, y to 0:31
xsize, ysize := top.X-bot.X, top.Y-bot.Y
gx := int(((x * 2 / xsize) + 1) / 2 * rc.gsize)
gy := int(((y * 2 / ysize) + 1) / 2 * rc.gsize)
model.SetPhrase(fmt.Sprintf("%d:%d", gx, gy))
}
} else {
rc.hilite.SetVisible(false) // missed the grid.
rc.banner.SetVisible(false)
}
} else {
println("missed plane")
rc.hilite.SetVisible(false) // missed the plane entirely.
rc.banner.SetVisible(false)
}
}
// hovercast checks the sphere each update and turns the spheres a different
// colour when the mouse is over them.
func (rc *rctag) hovercast(mx, my int) {
rx, ry, rz := rc.cam.Ray(mx, my, rc.ww, rc.wh)
ray := vu.NewRay(rx, ry, rz)
ray.World().SetLoc(rc.cam.Location())
parts := []vu.Pov{rc.s0, rc.s1, rc.s2, rc.s3}
colors := []rgb{rgb{1, 0, 0}, rgb{0, 1, 0}, rgb{0, 0, 1}, rgb{1, 1, 0}}
for cnt, p := range parts {
if hit, _, _, _ := vu.Cast(ray, p.Body()); hit {
p.Model().SetUniform("kd", 1, 1, 1)
} else {
rgb := colors[cnt]
p.Model().SetUniform("kd", rgb.R, rgb.G, rgb.B)
}
}
}