hi there!
i know that there is a giant discusion about stencil shadows and shadow volumes... so i decidet to show you my shadow volume creation code!
it is a mod of the version of this thread: http://www.blitzbasic.com/Community/posts.php?topic=58767
and i have modifyed it up to this(it is VERY MUCH OPTIMIZED!!!):
Graphics3D 1024, 768, 32, 2
SetBuffer BackBuffer()
;Globs
Dim Edge#(65000, 7)
;Camera
Cam = CreateCamera()
;Caster
Cube = CreateSphere()
PositionEntity Cube, 0, 0, 7
;Light
Light = CreateLight()
PositionEntity Light, 3, 3, 7
PointEntity Light, Cube
While Not KeyHit(1)
TurnEntity Cube, 1, .5, 1.5
vol = CreateVolume(Cube, Light)
RenderWorld
FreeEntity vol
Flip
Wend
End
Function CreateVolume(model, light, volume_lenght = 1000000)
VolumeMesh = CreateMesh()
VolumeSurface = CreateSurface(VolumeMesh)
EntityAlpha VolumeMesh, .5
EntityColor VolumeMesh, 255, 0, 0
EntityFX VolumeMesh, 1
light_x# = EntityX(light)
light_y# = EntityY(light)
light_z# = EntityZ(light)
For n = 1 To CountSurfaces(model)
surf = GetSurface(model, n)
dwNumFaces = CountTriangles(surf) - 1
For v = 0 To dwNumFaces
vert0 = TriangleVertex(surf, v, 0)
vert1 = TriangleVertex(surf, v, 1)
vert2 = TriangleVertex(surf, v, 2)
TFormPoint VertexX(surf, vert0), VertexY(surf, vert0), VertexZ(surf, vert0), model, 0
v1_x# = TFormedX()
v1_y# = TFormedY()
v1_z# = TFormedZ()
TFormPoint VertexX(surf, vert1), VertexY(surf, vert1), VertexZ(surf, vert1), model, 0
v2_x# = TFormedX()
v2_y# = TFormedY()
v2_z# = TFormedZ()
TFormPoint VertexX(surf, vert2), VertexY(surf, vert2), VertexZ(surf, vert2), model, 0
v3_x# = TFormedX()
v3_y# = TFormedY()
v3_z# = TFormedZ()
aa_x# = v3_x# - v2_x#
aa_y# = v3_y# - v2_y#
aa_z# = v3_z# - v2_z#
bb_x# = v2_x# - v1_x#
bb_y# = v2_y# - v1_y#
bb_z# = v2_z# - v1_z#
norm_x# = aa_y# * bb_z# - aa_z# * bb_y#
norm_y# = aa_z# * bb_x# - aa_x# * bb_z#
norm_z# = aa_x# * bb_y# - aa_y# * bb_x#
normlight_x# = (v1_x# + v2_x# + v3_x#) / 3 - light_x#
normlight_y# = (v1_y# + v2_y# + v3_y#) / 3 - light_y#
normlight_z# = (v1_z# + v2_z# + v3_z#) / 3 - light_z#
If (norm_x# * normlight_x# + norm_y# * normlight_y# + norm_z# * normlight_z#) * (1.0 / Float(Sqr(norm_x# * norm_x# + norm_y# * norm_y# + norm_z# * norm_z#))) * (1.0 / Float(Sqr(normlight_x# * normlight_x# + normlight_y# * normlight_y# + normlight_z# * normlight_z#))) => 0 Then
Edge(CNTFront, 0) = surf
Edge(CNTFront, 1) = tri
Edge(CNTFront, 2) = v1_x#
Edge(CNTFront, 3) = v1_y#
Edge(CNTFront, 4) = v1_z#
Edge(CNTFront, 5) = v2_x#
Edge(CNTFront, 6) = v2_y#
Edge(CNTFront, 7) = v2_z#
CNTFront = CNTFront + 1
Edge(CNTFront, 0) = surf
Edge(CNTFront, 1) = tri
Edge(CNTFront, 2) = v2_x#
Edge(CNTFront, 3) = v2_y#
Edge(CNTFront, 4) = v2_z#
Edge(CNTFront, 5) = v3_x#
Edge(CNTFront, 6) = v3_y#
Edge(CNTFront, 7) = v3_z#
CNTFront = CNTFront + 1
Edge(CNTFront, 0) = surf
Edge(CNTFront, 1) = tri
Edge(CNTFront, 2) = v3_x#
Edge(CNTFront, 3) = v3_y#
Edge(CNTFront, 4) = v3_z#
Edge(CNTFront, 5) = v1_x#
Edge(CNTFront, 6) = v1_y#
Edge(CNTFront, 7) = v1_z#
CNTFront = CNTFront + 1
EndIf
Next
Next
For a = 0 To CNTFront
If Edge(a, 0) > 0 Then
Diverso = True
p0_x# = Edge(a, 2)
p0_y# = Edge(a, 3)
p0_z# = Edge(a, 4)
p1_x# = Edge(a, 5)
p1_y# = Edge(a, 6)
p1_z# = Edge(a, 7)
For b = a + 1 To CNTFront
p0_2_x# = Edge(b, 2)
p0_2_y# = Edge(b, 3)
p0_2_z# = Edge(b, 4)
p1_2_x# = Edge(b, 5)
p1_2_y# = Edge(b, 6)
p1_2_z# = Edge(b, 7)
If Edge(b, 0) > 0 Then
If (p0_x# = p0_2_x# And p0_y# = p0_2_y# And p0_z# = p0_2_z# And p1_x# = p1_2_x# And p1_y# = p1_2_y# And p1_z# = p1_2_z#) = False Then
If p0_x# = p1_2_x# And p0_y# = p1_2_y# And p0_z# = p1_2_z# And p1_x# = p0_2_x# And p1_y# = p0_2_y# And p1_z# = p0_2_z# Then
Edge(a, 0) = surf = 0
Edge(b, 0) = surf = 0
Diverso = False
Exit
EndIf
EndIf
EndIf
Next
If Diverso Then
pe0_x# = p0_x# - light_x#
pe0_y# = p0_y# - light_y#
pe0_z# = p0_z# - light_z#
do# = 1.0 / Float(Sqr(pe0_x# * pe0_x# + pe0_y# * pe0_y# + pe0_z# * pe0_z#))
pe0_x# = pe0_x# * do# * volume_lenght + p0_x#
pe0_y# = pe0_y# * do# * volume_lenght + p0_y#
pe0_z# = pe0_z# * do# * volume_lenght + p0_z#
pe1_x# = (p1_x# - light_x#) * volume_lenght + p1_x#
pe1_y# = (p1_y# - light_y#) * volume_lenght + p1_y#
pe1_z# = (p1_z# - light_z#) * volume_lenght + p1_z#
va = AddVertex(VolumeSurface, p0_x#, p0_y#, p0_z#)
vb = AddVertex(VolumeSurface, pe1_x#, pe1_y#, pe1_z#)
AddTriangle(VolumeSurface, va, AddVertex(VolumeSurface, pe0_x#, pe0_y#, pe0_z#), vb)
AddTriangle(VolumeSurface, va, vb, AddVertex(VolumeSurface, p1_x#, p1_y#, p1_z#))
Edge(a, 0) = 0
EndIf
EndIf
Next
Return VolumeMesh
End Function
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