Shadowing

[bplus]

Back when I made the "tree house" game, a few years ago. It's 3D and you can only walk around. At that time, I remember Galleon rewrote the program and added something to the display part to shade the textures. Everything got darker in proportion to the distance. I didn't understand then. I looked for the code, but I couldn't find it, and the old forum is not available. Since then, I have solved the distance-proportional darkening of games by generating lots of textures. That's a lot of memory, and it doesn't work on a large surface, because if one vertex of a triangle is close to you and another vertex is far away, then what shade should it get? So it's only good for displaying small textures.

In the past few days, I've been thinking about how Galleon solved the problem of placing a texture of any size on the screen in any way. Then he told me that a black mask with an alpha distance proportional to the texture should be drawn. That's when I understood that by switching _depthbuffer on and off, it can be solved by dragging the alpha texture after each texture. And I understood why I didn't use it then. Very good, fast, practical, only switching the z-buffer on and off slows down the program significantly.

I was wondering how it could be solved without switching on the z-buffer.

Suppose _maptriangle gets a 3d point. be x,y,z. it should be 20,10,30. This point in the plane will be where, for example, 200,100,300 or 2,1,3 or 40,20,60. This simple realization helped. Simply, after drawing the texture, x,y,z must be multiplied by 0.999999, and then the mask can be drawn on it. That way, you don't have to switch on the z-buffer.
I thank Galleon several times already! If it doesn't show it then, I won't think about how it could be operated faster.

Code: (Select All)

picture$ = "" '<-------- enter an image or leave the field blank



'texture
If _FileExists(picture$) Then
    text = _LoadImage(picture$, 33)
Else
    temp = _NewImage(1, 1, 32): _Dest temp: Cls , _RGB32(255, 255, 255): text = _CopyImage(temp, 33): _FreeImage temp
End If

'window
monx = 800: mony = Int(monx / _DesktopWidth * _DesktopHeight): monm = monx * .008: mon = _NewImage(monx, mony, 32): Screen mon: _FullScreen: _DisplayOrder _Hardware , _Software

Const pip180 = 3.141592 / 180
Dim Shared me(9), cosrotz, sinrotz, cosrotx, sinrotx, sinrot_cs, cosrot_cs

'cube locations, sizes
Randomize Timer
cube_res = 1000: cube_deep = 1000
temp = _NewImage(cube_res - 1, cube_deep - 1, 32): _Dest temp: For t = 0 To cube_res - 1: For t2 = 0 To cube_deep - 1
    PSet (t, t2), _RGBA32(0, 0, 0, Int(255 / (cube_deep - 1) * t2) - 3)
Next t2, t: cube_text = _CopyImage(temp, 33): _FreeImage temp

'mask distance behind texture
Dim shdw_m(15000): For t = 0 To 15000: shdw_m(t) = Interpolate(.999, .97, 1 / 15000 * t): Next t


mapdim = 1000

'make cubes
obj_c = 200
Dim obj(obj_c - 1, 9): _Source deep_text: For t = 0 To obj_c - 2: For t2 = 0 To 2: obj(t, t2) = mapdim * Rnd: obj(t, t2 + 3) = 10 + 40 * Rnd: Next t2, t

For t = 0 To 2: obj(obj_c - 1, 3 + t) = mapdim / 2: obj(obj_c - 1, t) = mapdim / 2: Next t
For t = 0 To 2: me(t) = mapdim / 2: Next t: light = .2: me(4) = -.2: ut_me4 = -.2: ylook_limit = 80 'radian

_Dest mon
Locate 1, 1: Print "moving:WASD       looking:mouse        light adjust : mousewheel"
Dim p(3, 2), p2(3, 2), pc(7, 9)
Do: _Limit 30
    'control
    mouse_sens_xy = .01: mouse_sens_z = .01
    mousex = 0: mousey = 0: mousew = 0: While _MouseInput: mousex = mousex + _MouseMovementX: mousey = mousey + _MouseMovementY: mousew = mousew + _MouseWheel: Wend
    me(3) = me(3) + mousex * mouse_sens_xy: me(4) = me(4) + mousey * mouse_sens_z

    ylook_deg = ((me(4) / pip180) + 90): If Abs(ylook_deg) > ylook_limit Then me(4) = ut_me4 Else ut_me4 = me(4)
    rot_cs = (rot_cs + mousex * .001 * Abs(Sin(me(4)))) * .9
    light = light - mousew * 0.005: If light < 0 Then light = 0 Else If light > 1 Then light = 1
    Locate 2, 1: Print "light:"; Int(light * 100); "%   "
    position_speed = 5
    kw = _KeyDown(119): ks = _KeyDown(115): ka = _KeyDown(97): kd = _KeyDown(100): new_direction = (Abs(ka Or kd Or kw) Or -Abs(ks)) * position_speed
    deg_XY = -90 * Abs(ka) + 90 * Abs(kd): szog_xy = me(3) + deg_XY * pip180: szog_z = me(4)
    me(0) = me(0) - Sin(szog_xy) * (1 - Cos(szog_z)) * new_direction
    me(1) = me(1) - Cos(szog_xy) * (1 - Cos(szog_z)) * new_direction
    me(2) = me(2) - Cos(szog_z + _Pi) * new_direction

    cosrotz = Cos(me(3)): sinrotz = Sin(me(3)): cosrotx = Cos(me(4)): sinrotx = Sin(me(4)): cosrot_cs = Cos(rot_cs): sinrot_cs = Sin(rot_cs) 'to rotating angles

    'draw cubes
    px1 = cube_res / 2: px2 = cube_res - 2
    dl = cube_deep - 3: c_dis = Interpolate(50, 2500, light): temp = cube_deep / c_dis
    For a_obj = 0 To obj_c - 1: For t = 0 To 7
        For t2 = 0 To 2: pc(t, t2) = (obj(a_obj, 3 + t2) * (Sgn(t And 2 ^ t2) * 2 - 1) + (obj(a_obj, t2) - me(t2))): Next t2
            rotate pc(t, 0), pc(t, 1), pc(t, 2)
            pc(t, 3) = Sqr(pc(t, 0) * pc(t, 0) + pc(t, 1) * pc(t, 1) + pc(t, 2) * pc(t, 2))
            sm = shdw_m(Abs(Int(pc(t, 2))))
            For t2 = 0 To 2: pc(t, 4 + t2) = pc(t, t2) * sm: Next t2
        Next t

        For t = 0 To 5: For t2 = 0 To 3: side(t2) = Val(Mid$("024623673175105445670123", 1 + t * 4 + t2, 1)): For t3 = 0 To 2: p(t2, t3) = pc(side(t2), t3): p2(t2, t3) = pc(side(t2), t3 + 4): Next t3, t2

            'texture
            _MapTriangle (0, 0)-(_Width(text) - 1, 0)-(0, _Height(text)), text To(p(0, 0), p(0, 1), p(0, 2))-(p(1, 0), p(1, 1), p(1, 2))-(p(2, 0), p(2, 1), p(2, 2)), , _Smooth
            _MapTriangle (_Width(text), _Height(text))-(_Width(text) - 1, 0)-(0, _Height(text)), text To(p(3, 0), p(3, 1), p(3, 2))-(p(1, 0), p(1, 1), p(1, 2))-(p(2, 0), p(2, 1), p(2, 2)), , _Smooth

            'shadow mask
            For t2 = 0 To 3: py(t2) = Int(temp * pc(side(t2), 3)): If py(t2) > dl Then py(t2) = dl
            Next t2
            _MapTriangle (1, py(0))-(px1, py(1))-(px2, py(2)), cube_text To(p2(0, 0), p2(0, 1), p2(0, 2))-(p2(1, 0), p2(1, 1), p2(1, 2))-(p2(2, 0), p2(2, 1), p2(2, 2)), , _Smooth
            _MapTriangle (1, py(3))-(px1, py(1))-(px2, py(2)), cube_text To(p2(3, 0), p2(3, 1), p2(3, 2))-(p2(1, 0), p2(1, 1), p2(1, 2))-(p2(2, 0), p2(2, 1), p2(2, 2)), , _Smooth
    Next t, a_obj

    _Display

Loop
Function Interpolate (a, b, x): Interpolate = a + (b - a) * x: End Function
Sub rotate (px, py, pz2): px3 = px * cosrotz - py * sinrotz: py2 = px * sinrotz + py * cosrotz: py3 = py2 * cosrotx - pz2 * sinrotx: pz3 = py2 * sinrotx + pz2 * cosrotx
px4 = px3 * cosrot_cs - py3 * sinrot_cs: py4 = px3 * sinrot_cs + py3 * cosrot_cs: px = -px4: py = -py4: pz2 = -pz3: End Sub

cool!