// Clear the alpha channel in the color buffer
func ClearAlpha(alpha_value gl.GLclampf) {
With(Attrib{gl.COLOR_BUFFER_BIT}, func() {
gl.ColorMask(false, false, false, true)
gl.ClearColor(0, 0, 0, alpha_value)
gl.Clear(gl.COLOR_BUFFER_BIT)
})
}
func fill(canv *Canvas, alphaTex *glh.Texture, paint *Paint) {
gGl.GlColorConfig.SetColor(paint.fillColor)
defer gGl.GlColorConfig.Reset()
gGl.Activate(gGl.FillDrawer)
gl.ColorMask(true, true, true, true)
gl.StencilMask(0x3)
gl.StencilFunc(gl.LESS, 0, 0xff)
w, h := canv.W, canv.H
p := canv.toGLPoints([]Point{
iPt(0, 0),
iPt(w, 0),
iPt(w, h),
iPt(0, h),
})
vertices := []float32{
p[0].X, p[0].Y, 0, 1,
p[1].X, p[1].Y, 1, 1,
p[2].X, p[2].Y, 1, 0,
p[3].X, p[3].Y, 0, 0,
}
gl.BufferData(gl.ARRAY_BUFFER, len(vertices)*4, vertices, gl.STATIC_DRAW)
elements := []uint32{
0, 1, 2,
2, 3, 0,
}
gl.BufferData(gl.ELEMENT_ARRAY_BUFFER, len(elements)*4, elements, gl.STATIC_DRAW)
glh.With(alphaTex, func() {
gl.DrawElements(gl.TRIANGLES, 6, gl.UNSIGNED_INT, nil)
})
}
func (p *Path) draw(canv *Canvas, alphaBuffer *glh.Framebuffer, clrStencil bool) {
gGl.QuadraticDrawConfig.SetExcludeTransluFrags(false)
glh.With(alphaBuffer, func() {
gl.ClearColor(0, 0, 0, 0)
gl.Clear(gl.COLOR_BUFFER_BIT)
p.glDraw(canv)
})
if clrStencil {
gl.StencilMask(0x3)
gl.ClearStencil(0x0)
gl.Clear(gl.STENCIL_BUFFER_BIT)
}
gl.ColorMask(false, false, false, false)
gl.StencilMask(0x3)
gl.StencilFunc(gl.ALWAYS, 0, 0xff)
gl.StencilOp(gl.KEEP, gl.KEEP, gl.INVERT)
p.glDraw(canv)
gl.StencilMask(0x1)
gGl.QuadraticDrawConfig.SetExcludeTransluFrags(true)
p.glDraw(canv)
}
func main() {
var err error
if err = glfw.Init(); err != nil {
fmt.Fprintf(os.Stderr, "[e] %v\n", err)
return
}
defer glfw.Terminate()
w, h := 1980, 1080
// w, h := 1280, 768
if err = glfw.OpenWindow(w, h, 8, 8, 8, 16, 0, 32, glfw.Fullscreen); err != nil {
fmt.Fprintf(os.Stderr, "[e] %v\n", err)
return
}
defer glfw.CloseWindow()
glfw.SetSwapInterval(1)
glfw.SetWindowTitle("Debris")
quadric = glu.NewQuadric()
gl.Enable(gl.CULL_FACE)
gl.Enable(gl.DEPTH_TEST)
gl.DepthFunc(gl.LEQUAL)
gl.Enable(gl.NORMALIZE)
gl.Enable(gl.BLEND)
gl.BlendFunc(gl.SRC_ALPHA, gl.ONE_MINUS_SRC_ALPHA)
gl.ShadeModel(gl.SMOOTH)
gl.Enable(gl.LIGHTING)
var (
ambient = []float32{0.1, 0.3, 0.6, 1}
diffuse = []float32{1, 1, 0.5, 1}
specular = []float32{0.4, 0.4, 0.4, 1}
light_position = []float32{1, 0, 0, 0}
// mat_specular []float32 = []float32{1, 1, 0.5, 1}
mat_specular = []float32{1, 1, 0.75, 1}
mat_shininess = float32(120)
// light_position []float32 = []float32{0.0, 0.0, 1.0, 0.0}
)
const (
fov = 1.1 // degrees
znear = 145
zfar = 155
camera_z_offset = -150
camera_x_rotation = 0 // degrees
// camera_x_rotation = 20 // degrees
starfield_fov = 45
faces = 1000
earth_radius = 1
)
gl.Lightfv(gl.LIGHT1, gl.AMBIENT, ambient)
gl.Lightfv(gl.LIGHT1, gl.DIFFUSE, diffuse)
gl.Lightfv(gl.LIGHT1, gl.SPECULAR, specular)
gl.Lightfv(gl.LIGHT1, gl.POSITION, light_position)
gl.Enable(gl.LIGHT1)
mat_emission := []float32{0, 0, 0.1, 1}
gl.Materialfv(gl.FRONT_AND_BACK, gl.EMISSION, mat_emission)
gl.Materialfv(gl.FRONT_AND_BACK, gl.SPECULAR, mat_specular)
gl.Materialf(gl.FRONT_AND_BACK, gl.SHININESS, mat_shininess)
gl.ClearColor(0.02, 0.02, 0.02, 1)
gl.ClearDepth(1)
gl.ClearStencil(0)
gl.Clear(gl.COLOR_BUFFER_BIT | gl.DEPTH_BUFFER_BIT)
b := createBuffer()
planetoids := []*Planetoid{}
for i := 0; i < 1000; i++ {
p := &Planetoid{
apogee: 1.2 + rand.Float64()*0.7,
perigee: 1.5,
// inclination: 45,
inclination: rand.Float64()*20 - 10,
// inclination: 0,
phase0: rand.Float64() * 360,
rising_node: rand.Float64() * 10,
phase: 0,
// radius: rand.Float32()*0.05 + 0.01, //float32(r),
radius: rand.Float32()*0.0125 + 0.005, //float32(r),
// quadric: glu.NewQuadric(),
circle: b,
}
planetoids = append(planetoids, p)
}
// Initial projection matrix:
var aspect float64
glfw.SetWindowSizeCallback(func(w, h int) {
gl.Viewport(0, 0, w, h)
gl.MatrixMode(gl.PROJECTION)
gl.LoadIdentity()
aspect = float64(w) / float64(h)
glu.Perspective(fov, aspect, znear, zfar)
})
d := float64(0)
wireframe := false
atmosphere := false
polar := false
rotating := false
front := false
earth := true
cone := true
shadowing := true
tilt := false
running := true
glfw.SetKeyCallback(func(key, state int) {
if state != glfw.KeyPress {
// Don't act on key coming up
return
}
switch key {
case 'A':
atmosphere = !atmosphere
case 'C':
cone = !cone
case 'E':
earth = !earth
case 'R':
rotating = !rotating
case 'F':
front = !front
if front {
gl.FrontFace(gl.CW)
} else {
gl.FrontFace(gl.CCW)
}
case 'S':
shadowing = !shadowing
case 'T':
tilt = !tilt
case 'W':
wireframe = !wireframe
method := gl.GLenum(gl.FILL)
if wireframe {
method = gl.LINE
}
gl.PolygonMode(gl.FRONT_AND_BACK, method)
case glfw.KeyF2:
println("Screenshot captured")
// glh.CaptureToPng("screenshot.png")
w, h := glh.GetViewportWH()
im := image.NewRGBA(image.Rect(0, 0, w, h))
glh.ClearAlpha(1)
gl.Flush()
glh.CaptureRGBA(im)
go func() {
fd, err := os.Create("screenshot.png")
if err != nil {
panic("Unable to open file")
}
defer fd.Close()
png.Encode(fd, im)
}()
case 'Q', glfw.KeyEsc:
running = !running
case glfw.KeySpace:
polar = !polar
}
})
_ = rand.Float64
stars := glh.NewMeshBuffer(
glh.RenderArrays,
glh.NewPositionAttr(3, gl.DOUBLE, gl.STATIC_DRAW),
glh.NewColorAttr(3, gl.DOUBLE, gl.STATIC_DRAW))
const Nstars = 50000
points := make([]float64, 3*Nstars)
colors := make([]float64, 3*Nstars)
for i := 0; i < Nstars; i++ {
const R = 1
phi := rand.Float64() * 2 * math.Pi
z := R * (2*rand.Float64() - 1)
theta := math.Asin(z / R)
points[i*3+0] = R * math.Cos(theta) * math.Cos(phi)
points[i*3+1] = R * math.Cos(theta) * math.Sin(phi)
points[i*3+2] = z
const r = 0.8
v := rand.Float64()*r + (1 - r)
colors[i*3+0] = v
colors[i*3+1] = v
colors[i*3+2] = v
}
stars.Add(points, colors)
render_stars := func() {
glh.With(glh.Attrib{gl.DEPTH_BUFFER_BIT | gl.ENABLE_BIT}, func() {
gl.Disable(gl.LIGHTING)
gl.PointSize(1)
gl.Color4f(1, 1, 1, 1)
gl.Disable(gl.DEPTH_TEST)
gl.DepthMask(false)
stars.Render(gl.POINTS)
})
}
render_scene := func() {
// Update light position (sensitive to current modelview matrix)
gl.Lightfv(gl.LIGHT1, gl.POSITION, light_position)
gl.Lightfv(gl.LIGHT2, gl.POSITION, light_position)
if earth {
Sphere(earth_radius, faces)
}
unlit_points := glh.Compound(glh.Disable(gl.LIGHTING), glh.Primitive{gl.POINTS})
glh.With(unlit_points, func() {
gl.Vertex3d(1, 0, 0)
})
for _, p := range planetoids {
const dt = 0.1 // TODO: Frame update
p.Render(dt)
}
glh.With(glh.Disable(gl.LIGHTING), func() {
// Atmosphere
gl.Color4f(0.25, 0.25, 1, 0.1)
if atmosphere && earth {
Sphere(earth_radius*1.025, 100)
}
gl.PointSize(10)
glh.With(glh.Primitive{gl.POINTS}, func() {
gl.Color4f(1.75, 0.75, 0.75, 1)
gl.Vertex3d(-1.04, 0, 0)
})
})
}
render_shadow_volume := func() {
glh.With(glh.Attrib{
gl.COLOR_BUFFER_BIT | gl.DEPTH_BUFFER_BIT | gl.ENABLE_BIT |
gl.POLYGON_BIT | gl.STENCIL_BUFFER_BIT,
}, func() {
gl.Disable(gl.LIGHTING)
if shadowing {
// gl.Disable(gl.DEPTH_TEST)
gl.DepthMask(false)
gl.DepthFunc(gl.LEQUAL)
gl.Enable(gl.STENCIL_TEST)
gl.ColorMask(false, false, false, false)
gl.StencilFunc(gl.ALWAYS, 1, 0xffffffff)
}
shadow_volume := func() {
const sv_length = 2
const sv_granularity = 100
const sv_radius = earth_radius * 1.001
// Shadow cone
glh.With(glh.Matrix{gl.MODELVIEW}, func() {
gl.Rotatef(90, 1, 0, 0)
gl.Rotatef(90, 0, -1, 0)
gl.Color4f(0.5, 0.5, 0.5, 1)
glu.Cylinder(quadric, sv_radius, sv_radius*1.05,
sv_length, sv_granularity, 1)
glu.Disk(quadric, 0, sv_radius, sv_granularity, 1)
glh.With(glh.Matrix{gl.MODELVIEW}, func() {
gl.Translated(0, 0, sv_length)
glu.Disk(quadric, 0, sv_radius*1.05, sv_granularity, 1)
})
})
for _, p := range planetoids {
p.RenderShadowVolume()
}
}
if cone {
gl.FrontFace(gl.CCW)
gl.StencilOp(gl.KEEP, gl.KEEP, gl.INCR)
shadow_volume()
gl.FrontFace(gl.CW)
gl.StencilOp(gl.KEEP, gl.KEEP, gl.DECR)
shadow_volume()
}
if shadowing {
gl.StencilFunc(gl.NOTEQUAL, 0, 0xffffffff)
gl.StencilOp(gl.KEEP, gl.KEEP, gl.KEEP)
gl.ColorMask(true, true, true, true)
// gl.Disable(gl.STENCIL_TEST)
gl.Disable(gl.DEPTH_TEST)
gl.FrontFace(gl.CCW)
// gl.Color4f(1, 0, 0, 0.75)
gl.Color4f(0, 0, 0, 0.75)
// gl.Color4f(1, 1, 1, 0.75)
gl.LoadIdentity()
gl.Translated(0, 0, camera_z_offset)
// TODO: Figure out why this doesn't draw over the whole screen
glh.With(glh.Disable(gl.LIGHTING), func() {
glh.DrawQuadd(-10, -10, 20, 20)
})
// gl.FrontFace(gl.CW)
// gl.Enable(gl.LIGHTING)
// gl.Disable(gl.LIGHT1)
// render_scene()
// gl.Enable(gl.LIGHT1)
}
})
}
_ = render_stars
for running {
running = glfw.WindowParam(glfw.Opened) == 1
glfw.SwapBuffers()
gl.Clear(gl.COLOR_BUFFER_BIT | gl.DEPTH_BUFFER_BIT | gl.STENCIL_BUFFER_BIT)
rotation := func() {
if tilt {
gl.Rotated(20, 1, 0, 0)
}
if polar {
gl.Rotated(90, 1, 0, 0)
}
gl.Rotated(d, 0, -1, 0)
}
// Star field
glh.With(glh.Matrix{gl.PROJECTION}, func() {
gl.LoadIdentity()
glu.Perspective(starfield_fov, aspect, 0, 1)
glh.With(glh.Matrix{gl.MODELVIEW}, func() {
gl.LoadIdentity()
rotation()
render_stars()
})
})
gl.MatrixMode(gl.MODELVIEW)
gl.LoadIdentity()
gl.Translated(0, 0, camera_z_offset)
rotation()
if rotating {
d += 0.2
}
_ = render_scene
render_scene()
_ = render_shadow_volume
render_shadow_volume()
}
}