// Spin rotates the current direction by the given number degrees around each
// axis. Generally this is called with one direction change at a time.
func (p *pov) Spin(x, y, z float64) {
if x != 0 {
rotation := lin.NewQ().SetAa(1, 0, 0, lin.Rad(x))
p.dir.Mult(rotation, p.dir)
}
if y != 0 {
rotation := lin.NewQ().SetAa(0, 1, 0, lin.Rad(y))
p.dir.Mult(p.dir, rotation)
}
if z != 0 {
rotation := lin.NewQ().SetAa(0, 0, 1, lin.Rad(z))
p.dir.Mult(rotation, p.dir)
}
}
// drawScene renders the 3D models consisting of one VAO
func (tag *trtag) drawScene() {
gl.Clear(gl.COLOR_BUFFER_BIT | gl.DEPTH_BUFFER_BIT)
tag.checkError("gl.Clear")
gl.UseProgram(tag.shaders)
tag.checkError("gl.UseProgram")
gl.BindVertexArray(tag.vao)
tag.checkError("gl.BindVertexArray")
// Use a modelview matrix and quaternion to rotate the 3D object.
tag.mvp64.SetQ(lin.NewQ().SetAa(0, 1, 0, lin.Rad(-tag.rotateAngle)))
tag.mvp64.TranslateMT(0, 0, -4)
tag.mvp64.Mult(tag.mvp64, tag.persp)
tag.mvp32 = renderMatrix(tag.mvp64, tag.mvp32)
gl.UniformMatrix4fv(tag.mvpRef, 1, false, tag.mvp32.Pointer())
if err := gl.GetError(); err != 0 {
fmt.Printf("gl.UniformMatrix error %d\n", err)
}
gl.DrawElements(gl.TRIANGLES, int32(len(tag.faces)), gl.UNSIGNED_BYTE, gl.Pointer(nil))
if err := gl.GetError(); err != 0 {
fmt.Printf("gl.DrawElements error %d\n", err)
}
// cleanup
gl.UseProgram(0)
tag.checkError("gl.UseProgram-0")
gl.BindVertexArray(0)
tag.checkError("gl.BindVertexArray-0")
// rotate based on time... not on how fast the computer runs.
if time.Now().Sub(tag.lastTime).Seconds() > 0.01 {
tag.rotateAngle += 1
tag.lastTime = time.Now()
}
}
// Update is the regular engine callback.
func (cm *cmtag) Update(input *vu.Input) {
if input.Resized {
cm.resize()
}
// own the rotation.
dir := lin.NewQ().SetAa(0, 1, 0, lin.Rad(cm.turn))
cm.bod.SetRotation(dir.GetS())
if cm.switchCam {
// apply physics location to the camera.
x, y, z := cm.bod.Location()
cm.scene.SetViewLocation(x, y, z)
cm.scene.SetViewRotation(dir.GetS())
cm.scene.SetViewTilt(-cm.look)
} else {
// keep camera at a fixed location.
cm.scene.SetViewLocation(0, 10, 25)
cm.scene.SetViewRotation(0, 0, 0, 1)
cm.scene.SetViewTilt(0)
}
// handle user requests.
for press, rel := range input.Down {
switch press {
case "W":
cm.move(zaxis, -1, rel < 0) // back and forth.
case "S":
cm.move(zaxis, 1, rel < 0)
case "A":
cm.move(xaxis, -1, rel < 0) // left and right
case "D":
cm.move(xaxis, 1, rel < 0)
// switch camera between first and fixed third person.
case "C":
if time.Now().After(cm.last.Add(cm.holdoff)) {
cm.switchCam = !cm.switchCam
cm.last = time.Now()
}
}
}
// apply rotation based on mouse changes.
xdiff := cm.pmx - input.Mx
ydiff := cm.pmy - input.My
cm.spin(yaxis, xdiff) // rotate left/right (around y-axis)
cm.spin(xaxis, ydiff) // rotate up/down (around x-axis)
cm.pmx, cm.pmy = input.Mx, input.My
}
// xz_xy view transform implementation.
func xz_xy(v *view, vm *lin.M4) *lin.M4 {
rot := v.q0.SetAa(1, 0, 0, -lin.Rad(90))
return vm.SetQ(rot).ScaleMS(1, 1, 0).TranslateTM(-v.loc.X, -v.loc.Y, -v.loc.Z)
}
// vf view transform implementation.
func vf(v *view, vm *lin.M4) *lin.M4 {
rot := v.q0.SetAa(1, 0, 0, lin.Rad(-v.up))
rot.Mult(rot, v.dir)
return vm.SetQ(rot).TranslateTM(-v.loc.X, -v.loc.Y, -v.loc.Z)
}