[bb] Filled Quad by starfox [ 1+ years ago ]

[BlitzBot]

Title : Filled Quad
Author : starfox
Posted : 1+ years ago

Description : Takes four points (any position) and fills it with a quadrilateral, useful for pseudo 3d stuff. Also comes with an optional parameter gridprecise to determine how precise to make the quad (smaller the more precise, but slower). This function is pretty fast.

Code :

Code: BlitzBasic

1. Function FilledQuad(p1x,p1y,p2x,p2y,p3x,p3y,p4x,p4y,gridprecise=2)
2. Local farleftx,farlefty ;Find the point farthest to the left
3. Local farrightx,farrighty ;Find the point farthest to the right
4. Local mid1x,mid1y ;Find the point second farthest to the left
5. Local mid2x,mid2y ;Find the point second farthest to the right
6. Local farleftid,farrightid,mid1id,mid2id
7.  
8. ;Find parallel points
9. par1x = p1x
10. par1y = p1y
11. par2x = p4x
12. par2y = p4y
13.  
14. If Abs(par1x-p1x) < 2
15. count = count + 1
16. EndIf
17. If Abs(par1x-p2x) < 2
18. count = count + 1
19. EndIf
20. If Abs(par1x-p3x) < 2
21. count = count + 1
22. EndIf
23. If Abs(par1x-p4x) < 2
24. count = count + 1
25. EndIf
26. If count >= 3 Then Return ;Can't do anything to that!
27. count=0
28. If Abs(par2x-p1x) < 2
29. count = count + 1
30. EndIf
31. If Abs(par2x-p2x) < 2
32. count = count + 1
33. EndIf
34. If Abs(par2x-p3x) < 2
35. count = count + 1
36. EndIf
37. If Abs(par2x-p4x) < 2
38. count = count + 1
39. EndIf
40. If count >= 3 Then Return ;Can't do anything to that!
41. count=0
42. If Abs(par1y-p1y) < 2
43. count = count + 1
44. EndIf
45. If Abs(par1y-p2y) < 2
46. count = count + 1
47. EndIf
48. If Abs(par1y-p3y) < 2
49. count = count + 1
50. EndIf
51. If Abs(par1y-p4y) < 2
52. count = count + 1
53. EndIf
54. If count >= 3 Then Return ;Can't do anything to that!
55. count=0
56. If Abs(par2y-p1y) < 2
57. count = count + 1
58. EndIf
59. If Abs(par2y-p2y) < 2
60. count = count + 1
61. EndIf
62. If Abs(par2y-p3y) < 2
63. count = count + 1
64. EndIf
65. If Abs(par2y-p4y) < 2
66. count = count + 1
67. EndIf
68. If count >= 3 Then Return ;Can't do anything to that!
69.  
70. ;Long unneccesary function to detect locations:p
71.  
72. farleftx = p1x
73. farlefty = p1y
74. farleftid=1
75.  
76. If farleftx > p2x
77. farleftx = p2x
78. farlefty = p2y
79. farleftid=2
80. EndIf
81.  
82. If farleftx > p3x
83. farleftx = p3x
84. farlefty = p3y
85. farleftid=3
86. EndIf
87.  
88. If farleftx > p4x
89. farleftx = p4x
90. farlefty = p4y
91. farleftid=4
92. EndIf
93.  
94. farrightx = p1x
95. farrighty = p1y
96. farrightid=1
97.  
98. If farrightx < p2x
99. farrightx = p2x
100. farrighty = p2y
101. farrightid=2
102. EndIf
103.  
104. If farrightx < p3x
105. farrightx = p3x
106. farrighty = p3y
107. farrightid=3
108. EndIf
109.  
110. If farrightx < p4x
111. farrightx = p4x
112. farrighty = p4y
113. farrightid=4
114. EndIf
115.  
116. If farleftid <> 1 And farrightid <> 1
117. mid1x = p1x
118. mid1y = p1y
119. mid1id=1
120. EndIf
121.  
122. If farleftid <> 2 And farrightid <> 2
123. If mid1id <> 0
124. mid2x = p2x
125. mid2y = p2y
126. mid2id=2
127. Else
128. mid1x = p2x
129. mid1y = p2y
130. Mid1id = 2
131. EndIf
132. EndIf
133.  
134. If farleftid <> 3 And farrightid <> 3
135. If mid1id <> 0
136. mid2x = p3x
137. mid2y = p3y
138. mid2id=3
139. Else
140. mid1x = p3x
141. mid1y = p3y
142. Mid1id = 3
143. EndIf
144. EndIf
145.  
146. If farleftid <> 4 And farrightid <> 4
147. If mid1id <> 0
148. mid2x = p4x
149. mid2y = p4y
150. mid2id=4
151. Else
152. mid1x = p4x
153. mid1y = p4y
154. Mid1id = 4
155. EndIf
156. EndIf
157.  
158. col = ray2dintersect(farleftx,farlefty,mid1x,mid1y,mid2x,mid2y,farrightx,farrighty)
159. If col = 1 Then changdir=1
160. col = ray2dintersect(farleftx,farlefty,mid2x,mid2y,mid1x,mid1y,farrightx,farrighty)
161. If col = 1 Then changdir=2
162.  
163. ;2D vectors
164. Local vec1x#,vec1y#,vec1step#
165. Local vec2x#,vec2y#,vec2step#
166.  
167. ;Quad Picture
168. ;   O---------O
169. ;  /         /
170. ; /         /
171. ;O---------O
172.  
173. vec1x = farleftx:vec1y = farlefty
174. vec2x = farleftx:vec2y = farlefty
175.  
176.  
177. dist1# = Abs(mid1x-farleftx)
178. If dist1 = 0 Then dist1 = 1
179. dist2# = Abs(mid2x-farleftx)
180. If dist2 = 0 Then dist2 = 1
181. alldist = Abs(farrightx-farleftx)
182.  
183. vec1step = (mid1y-farlefty)/(dist1)
184. vec2step = (mid2y-farlefty)/(dist2)
185.  
186. If mid1x-farleftx = 0
187. vec1y = vec1y + vec1step
188. EndIf
189.  
190. If mid2x-farleftx = 0
191. vec2y = vec2y + vec2step
192. EndIf
193.  
194. If changdir = 2
195. dist2# = Abs(farrightx-farleftx)
196. If dist2 = 0 Then dist2 = 1
197. vec2step = (farrighty-farlefty)/(dist2)
198.  
199. If farrightx-farleftx = 0
200. vec2y = vec2y + vec2step
201. EndIf
202.  
203. ElseIf changdir = 1
204. dist1# = Abs(farrightx-farleftx)
205. If dist1 = 0 Then dist1 = 1
206. vec1step = (farrighty-farlefty)/(dist1)
207.  
208. If farrightx-farleftx = 0
209. vec1y = vec1y + vec1step
210. EndIf
211.  
212. EndIf
213.  
214. starttea = farleftx
215. endtea = farrightx
216.  
217. For tea =  starttea To endtea
218.  
219. If tea Mod gridprecise = 0
220. If vec1y < vec2y
221.  
222.         If tea >= 0 And tea <= 640
223.         If vec1y >= 0 And vec1y <= 480
224.         Rect(tea,vec1y,gridprecise,vec2y-vec1y+1)
225.         EndIf
226.         EndIf
227. Else
228.         If tea >= 0 And tea <= 640
229.         If vec2y >= 0 And vec2y <= 480
230.         Rect(tea,vec2y,gridprecise,vec1y-vec2y+1)
231.         EndIf
232.         EndIf
233. EndIf
234. EndIf
235.  
236.         If tea >= mid1x And gotomid1=0
237.         If changdir=0
238.         dist1# = (farrightx-mid1x)
239.         If dist1 = 0 Then dist1 = 1
240.         vec1step = (farrighty-mid1y)/(dist1)
241.         ElseIf changdir = 2
242.                 dist1# = (mid2x-mid1x)
243.                 If dist1 = 0 Then dist1 = 1
244.                 vec1step = (mid2y-mid1y)/(dist1)
245.         ElseIf changdir = 1
246.                 dist2# = (farrightx-mid1x)
247.                 If dist2 = 0 Then dist2 = 1
248.                 vec2step = (farrighty-mid1y)/(dist2)
249.         EndIf
250.         gotomid1=1
251.         EndIf
252.        
253.         If tea >= mid2x And gotomid2=0
254.         If changdir=0
255.         dist2# = (farrightx-mid2x)
256.         If dist2 = 0 Then dist2 = 1
257.         vec2step = (farrighty-mid2y)/(dist2)
258.         ElseIf changdir=2
259.                 dist1# = (farrightx-mid2x)
260.                 If dist1 = 0 Then dist1 = 1
261.                 vec1step = (farrighty-mid2y)/(dist1)
262.         ElseIf changdir=1
263.                 dist2# = (mid1x-mid2x)
264.                 If dist2 = 0 Then dist2 = 1
265.                 vec2step = (mid1y-mid2y)/(dist2)
266.         EndIf
267.         gotomid2=1
268.         EndIf
269.        
270.         vec1y = vec1y + vec1step
271.         vec2y = vec2y + vec2step
272.        
273. Next
274.  
275.  
276. End Function

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