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implemented hidden line removal

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This commit is contained in:
Irmen de Jong 2020-09-18 23:04:18 +02:00
parent 63a653cdf0
commit c376e42092
1 changed files with 18 additions and 30 deletions
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48
examples/cx16/cobramk3-gfx.p8
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@ -2,6 +2,8 @@
%import cx16lib
%import conv
; TODO add all other Elite's ships, show their name, advance to next ship on keypress
main {
; storage for rotated coordinates
@ -9,10 +11,6 @@ main {
word[shipdata.totalNumberOfPoints] rotatedy
word[shipdata.totalNumberOfPoints] rotatedz
; TODO hidden surface removal - this needs surfaces data and surface normal calculations.
; TODO add all other Elite's ships, show their name, advance to next ship on keypress
sub start() {
uword anglex
uword angley
@ -25,7 +23,6 @@ main {
cx16.GRAPH_clear()
print_ship_name()
repeat {
rotate_vertices(msb(anglex), msb(angley), msb(anglez))
@ -41,8 +38,8 @@ main {
draw_lines_hiddenremoval()
;draw_lines()
anglex -= 505
angley += 217
anglex += 217
angley -= 505
anglez += 452
}
}
@ -145,10 +142,8 @@ main {
}
sub draw_lines_hiddenremoval() {
; complex routine that draws the ship model based on its faces
; complex drawing routine that draws the ship model based on its faces,
; where it uses the surface normals to determine visibility.
; TODO use a pointer to the edges and points instead of indexing
memset(edgestodraw, shipdata.totalNumberOfEdges, true)
ubyte @zp edgeIdx = 0
ubyte @zp pointIdx = 0
@ -195,26 +190,19 @@ main {
}
sub facing_away(ubyte edgePointsIdx) -> ubyte {
; todo hidden line removal check
; ubyte p1x = shipdata.
;
; word normal_z
;
; def normal_z(self, points: Tuple) -> float:
; p1 = self.rotated_coords[points[0]]
; p2 = self.rotated_coords[points[1]]
; p3 = self.rotated_coords[points[2]]
; # So for a triangle p1, p2, p3, if the vector U = p2 - p1 and the vector V = p3 - p1
; # then the normal N = U * V and can be calculated by:
; # Nx = UyVz - UzVy
; # Ny = UzVx - UxVz
; # Nz = UxVy - UyVx
; ux = p2[0]-p3[0]
; uy = p2[1]-p3[1]
; vx = p1[0]-p3[0]
; vy = p1[1]-p3[1]
; return ux*vy - uy*vx
return 0
; simplistic visibility determination by checking the Z component of the surface normal
ubyte p1 = shipdata.facesPoints[edgePointsIdx]
edgePointsIdx++
ubyte p2 = shipdata.facesPoints[edgePointsIdx]
edgePointsIdx++
ubyte p3 = shipdata.facesPoints[edgePointsIdx]
word p1x = rotatedx[p1] / 128
word p1y = rotatedy[p1] / 128
word p2x = rotatedx[p2] / 128
word p2y = rotatedy[p2] / 128
word p3x = rotatedx[p3] / 128
word p3y = rotatedy[p3] / 128
return (p2x-p3x)*(p1y-p3y) - (p2y-p3y)*(p1x-p3x) > 0
}
ubyte[shipdata.totalNumberOfEdges] edgestodraw