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_MAPTRIANGLE
Samuel Gomes edited this page Nov 8, 2022
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1 revision
The _MAPTRIANGLE statement maps a triangular portion of an image onto a destination image or screen page.
_MAPTRIANGLE [{_SEAMLESS}] ( sx1 , sy1 )-( sx2 , sy2 )-( sx3 , sy3 ), source& TO ( dx1 , dy1 )-( dx2 , dy2 )-( dx3 , dy3 )[, destination&][{_SMOOTH|_SMOOTHSHRUNK|_SMOOTHSTRETCHED}]]
_MAPTRIANGLE [{_CLOCKWISE|_ANTICLOCKWISE}] [{_SEAMLESS}] ( sx1 , sy1 )-( sx2 , sy2 )-( sx3 , sy3 ), source& TO ( dx1 , dy1 , dz1 )-( dx2 , dy2 , dz2 )-( dx3 , dy3 , dz3 ) [, destination&][{_SMOOTH|_SMOOTHSHRUNK|_SMOOTHSTRETCHED}]]
- The _SEAMLESS option makes the triangle skip the right-most and bottom-most pixels of the triangle. When you make larger objects using several triangles, there can be a "seam" where they overlap when using alpha transparency and the seam would be twice as bright. _SEAMLESS is ignored when rendering 3D content and is not yet supported when drawing 2D hardware images.**
- For 3D drawing use the _CLOCKWISE and _ANTICLOCKWISE arguments to only draw triangles in the correct direction. See Example 4.
- Coordinates are SINGLE values where whole numbers represent the exact center of a pixel of the source texture.
- source& and optional destination& are LONG image or screen page handles.
- Supports an optional final argument _SMOOTH which applies linear filtering. See Example 3.
- Use _SMOOTHSTRETCHED or _SMOOTHSHRUNK for when a pixelated/smooth effect is desirable but not both.
- This statement is used similar to _PUTIMAGE to place triangular sections of an image, but is more flexible.
- The STEP keyword can be used to for coordinates relative to the last graphic coordinates used.
- For 2D drawing, the destination coordinates are pixel coordinates either on-screen or on the destination image.
- For 3D drawing, the destination coordinates represent left (-x) to right (+x), bottom (-y) to top (+y) & furthest (-z) to nearest (z=-1). The center of the screen is therefore (0,0,-1). Note that a z value of 0 will result in off-screen content. The furthest visible z value is -10,000.
- When drawing software images coordinate positions are limited from -16383 to 16383
- The source coordinates can be positioned outside the boundary of the source image to achieve a tiled effect.
- If the destination& image handle is the current SCREEN page, _DEST or hardware layer, then it can be omitted.
- Hardware images (created using mode 33 via _LOADIMAGE or _COPYIMAGE) can be used as the source or destination.
Rotating an image using a rotation and zoom SUB with _MAPTRIANGLE.
SCREEN _NEWIMAGE(800, 600, 32)
Image& = _LOADIMAGE("qb64_trans.png") 'replace with your own image
DO
CLS
RotoZoom 400, 300, Image&, 1.5 + SIN(zoom), angle
LOCATE 1, 1: PRINT "Angle:"; CINT(angle)
PRINT "Zoom"; USING "##.###"; 1.5 + SIN(zoom)
_DISPLAY
angle = angle + .5: IF angle >= 360 THEN angle = angle - 360
zoom = zoom + .01
LOOP UNTIL INKEY$ <> ""
END
SUB RotoZoom (X AS LONG, Y AS LONG, Image AS LONG, Scale AS SINGLE, Rotation AS SINGLE)
DIM px(3) AS SINGLE: DIM py(3) AS SINGLE
W& = _WIDTH(Image&): H& = _HEIGHT(Image&)
px(0) = -W& / 2: py(0) = -H& / 2: px(1) = -W& / 2:py(1) = H& / 2
px(2) = W& / 2: py(2) = H& / 2: px(3) = W& / 2: py(3) = -H& / 2
sinr! = SIN(-Rotation / 57.2957795131): cosr! = COS(-Rotation / 57.2957795131)
FOR i& = 0 TO 3
x2& = (px(i&) * cosr! + sinr! * py(i&)) * Scale + X: y2& = (py(i&) * cosr! - px(i&) * sinr!) * Scale + Y
px(i&) = x2&: py(i&) = y2&
NEXT
_MAPTRIANGLE (0, 0)-(0, H& - 1)-(W& - 1, H& - 1), Image& TO(px(0), py(0))-(px(1), py(1))-(px(2), py(2))
_MAPTRIANGLE (0, 0)-(W& - 1, 0)-(W& - 1, H& - 1), Image& TO(px(0), py(0))-(px(3), py(3))-(px(2), py(2))
END SUB
**Triangle sections of image in code above __ **
**|\2|**
** 1→|_\|**
A 3D Spinning Cube demo using a software image and _MAPTRIANGLE:
' Copyright (C) 2011 by Andrew L. Ayers
DIM OBJECT(9, 9, 4, 2) AS LONG
' OBJECTS DEFINED AS FOLLOWS:
' (#OBJECTS,#PLANES PER OBJECT,#POINTS PER PLANE, XYZ TRIPLE)
DIM DPLANE2D(4, 1) AS LONG ' SCREEN PLANE COORDINATES
' DPLANE2D DEFINED AS FOLLOWS:
' (#POINTS PER PLANE, XY DOUBLE)
DIM DPLANE3D(4, 2) AS LONG ' 3D PLANE COORDINATES
' DPLANE3D DEFINED AS FOLLOWS:
' (#POINTS PER PLANE, XYZ TRIPLE)
DIM PLANECOL(9) AS INTEGER
DIM STAB(359), CTAB(359) ' SINE/COSINE TABLES
D& = 400: MX& = 0: MY& = 0: MZ& = -100
'
' COMPUTE SINE/COSINE TABLES
FOR t& = 0 TO 359
STAB(t&) = SIN((6.282 / 360) * t&)
CTAB(t&) = COS((6.282 / 360) * t&)
NEXT
'
' BUILD CUBE IN OBJECT ARRAY
' PLANE 0
OBJECT(0, 0, 0, 0) = -30: OBJECT(0, 0, 0, 1) = 30: OBJECT(0, 0, 0, 2) = -30
OBJECT(0, 0, 1, 0) = -30: OBJECT(0, 0, 1, 1) = -30: OBJECT(0, 0, 1, 2) = -30
OBJECT(0, 0, 2, 0) = 30: OBJECT(0, 0, 2, 1) = -30: OBJECT(0, 0, 2, 2) = -30
OBJECT(0, 0, 3, 0) = 30: OBJECT(0, 0, 3, 1) = 30: OBJECT(0, 0, 3, 2) = -30
OBJECT(0, 0, 4, 0) = 0: OBJECT(0, 0, 4, 1) = 0: OBJECT(0, 0, 4, 2) = -30
' PLANE 1
OBJECT(0, 1, 0, 0) = 30: OBJECT(0, 1, 0, 1) = 30: OBJECT(0, 1, 0, 2) = -30
OBJECT(0, 1, 1, 0) = 30: OBJECT(0, 1, 1, 1) = -30: OBJECT(0, 1, 1, 2) = -30
OBJECT(0, 1, 2, 0) = 30: OBJECT(0, 1, 2, 1) = -30: OBJECT(0, 1, 2, 2) = 30
OBJECT(0, 1, 3, 0) = 30: OBJECT(0, 1, 3, 1) = 30: OBJECT(0, 1, 3, 2) = 30
OBJECT(0, 1, 4, 0) = 30: OBJECT(0, 1, 4, 1) = 0: OBJECT(0, 1, 4, 2) = 0
' PLANE 2
OBJECT(0, 2, 0, 0) = 30: OBJECT(0, 2, 0, 1) = 30: OBJECT(0, 2, 0, 2) = 30
OBJECT(0, 2, 1, 0) = 30: OBJECT(0, 2, 1, 1) = -30: OBJECT(0, 2, 1, 2) = 30
OBJECT(0, 2, 2, 0) = -30: OBJECT(0, 2, 2, 1) = -30: OBJECT(0, 2, 2, 2) = 30
OBJECT(0, 2, 3, 0) = -30: OBJECT(0, 2, 3, 1) = 30: OBJECT(0, 2, 3, 2) = 30
OBJECT(0, 2, 4, 0) = 0: OBJECT(0, 2, 4, 1) = 0: OBJECT(0, 2, 4, 2) = 30
' PLANE 3
OBJECT(0, 3, 0, 0) = -30: OBJECT(0, 3, 0, 1) = 30: OBJECT(0, 3, 0, 2) = 30
OBJECT(0, 3, 1, 0) = -30: OBJECT(0, 3, 1, 1) = -30: OBJECT(0, 3, 1, 2) = 30
OBJECT(0, 3, 2, 0) = -30: OBJECT(0, 3, 2, 1) = -30: OBJECT(0, 3, 2, 2) = -30
OBJECT(0, 3, 3, 0) = -30: OBJECT(0, 3, 3, 1) = 30: OBJECT(0, 3, 3, 2) = -30
OBJECT(0, 3, 4, 0) = -30: OBJECT(0, 3, 4, 1) = 0: OBJECT(0, 3, 4, 2) = 0
' PLANE 4
OBJECT(0, 4, 0, 0) = -30: OBJECT(0, 4, 0, 1) = -30: OBJECT(0, 4, 0, 2) = -30
OBJECT(0, 4, 1, 0) = -30: OBJECT(0, 4, 1, 1) = -30: OBJECT(0, 4, 1, 2) = 30
OBJECT(0, 4, 2, 0) = 30: OBJECT(0, 4, 2, 1) = -30: OBJECT(0, 4, 2, 2) = 30
OBJECT(0, 4, 3, 0) = 30: OBJECT(0, 4, 3, 1) = -30: OBJECT(0, 4, 3, 2) = -30
OBJECT(0, 4, 4, 0) = 0: OBJECT(0, 4, 4, 1) = -30: OBJECT(0, 4, 4, 2) = 0
' PLANE 5
OBJECT(0, 5, 0, 0) = -30: OBJECT(0, 5, 0, 1) = 30: OBJECT(0, 5, 0, 2) = -30
OBJECT(0, 5, 1, 0) = 30: OBJECT(0, 5, 1, 1) = 30: OBJECT(0, 5, 1, 2) = -30
OBJECT(0, 5, 2, 0) = 30: OBJECT(0, 5, 2, 1) = 30: OBJECT(0, 5, 2, 2) = 30
OBJECT(0, 5, 3, 0) = -30: OBJECT(0, 5, 3, 1) = 30: OBJECT(0, 5, 3, 2) = 30
OBJECT(0, 5, 4, 0) = 0: OBJECT(0, 5, 4, 1) = 30: OBJECT(0, 5, 4, 2) = 0
' SET UP PLANE COLORS ON CUBE
'
PLANECOL(0) = 3
PLANECOL(1) = 4
PLANECOL(2) = 5
PLANECOL(3) = 6
PLANECOL(4) = 7
PLANECOL(5) = 8
'
_TITLE "QB64 _MAPTRIANGLE CUBE DEMO"
SCREEN _NEWIMAGE(800, 600, 32)
TextureImage& = _LOADIMAGE("qb64_trans.png") **'<<<< **replace with your own image
'_PUTIMAGE , Image&
DO
' LIMIT TO 25 FPS
_LIMIT 25
' ERASE LAST IMAGE
CLS
' CALCULATE POSITION OF NEW IMAGE
FOR OB& = 0 TO 0 ' UP TO 9 OBJECTS
SP = STAB(PIT(OB&)): CP = CTAB(PIT(OB&))
SY = STAB(YAW(OB&)): CY = CTAB(YAW(OB&))
SR = STAB(ROL(OB&)): CR = CTAB(ROL(OB&))
FOR PL& = 0 TO 5 ' CONSISTING OF UP TO 9 PLANES
'
FOR PN& = 0 TO 3 ' EACH PLANE WITH UP TO 4 POINTS (#5 TO PAINT)
'
' TRANSLATE, THEN ROTATE
TX& = OBJECT(OB&, PL&, PN&, 0)
TY& = OBJECT(OB&, PL&, PN&, 1)
TZ& = OBJECT(OB&, PL&, PN&, 2)
RX& = (TZ& * CP - TY& * SP) * SY - ((TZ& * SP + TY& * CP) * SR + TX& * CR) * CY
RY& = (TZ& * SP + TY& * CP) * CR - TX& * SR
RZ& = (TZ& * CP - TY& * SP) * CY + ((TZ& * SP + TY& * CP) * SR + TX& * CR) * SY
'
' ROTATE, THEN TRANSLATE
RX& = RX& + MX&
RY& = RY& + MY&
RZ& = RZ& + MZ&
'
DPLANE3D(PN&, 0) = RX&: DPLANE3D(PN&, 1) = RY&: DPLANE3D(PN&, 2) = RZ&
DPLANE2D(PN&, 0) = 399 + (D& * RX& / RZ&)
DPLANE2D(PN&, 1) = 299 + (D& * RY& / RZ&)
NEXT
'
' CHECK TO SEE IF PLANE IS VISIBLE
x1& = DPLANE3D(0, 0): y1& = DPLANE3D(0, 1): Z1& = DPLANE3D(0, 2)
x2& = DPLANE3D(1, 0): y2& = DPLANE3D(1, 1): Z2& = DPLANE3D(1, 2)
x3& = DPLANE3D(2, 0): y3& = DPLANE3D(2, 1): Z3& = DPLANE3D(2, 2)
T1& = -x1& * (y2& * Z3& - y3& * Z2&)
T2& = x2& * (y3& * Z1& - y1& * Z3&)
T3& = x3& * (y1& * Z2& - y2& * Z1&)
'
VISIBLE& = T1& - T2& - T3&
IF VISIBLE& > 0 THEN
' DRAW PLANE
xx1% = DPLANE2D(0, 0): yy1% = DPLANE2D(0, 1)
xx2% = DPLANE2D(1, 0): yy2% = DPLANE2D(1, 1)
xx3% = DPLANE2D(2, 0): yy3% = DPLANE2D(2, 1)
col% = PLANECOL(PL&)
_MAPTRIANGLE (0, 0)-(0, 255)-(255, 255), TextureImage& TO(xx3%, yy3%)-(xx2%, yy2%)-(xx1%, yy1%)
' CALL DrawTriangle(xx1%, yy1%, xx2%, yy2%, xx3%, yy3%, col%)
xx1% = DPLANE2D(0, 0): yy1% = DPLANE2D(0, 1)
xx3% = DPLANE2D(2, 0): yy3% = DPLANE2D(2, 1)
xx4% = DPLANE2D(3, 0): yy4% = DPLANE2D(3, 1)
_MAPTRIANGLE (0, 0)-(255, 255)-(255, 0), TextureImage& TO(xx3%, yy3%)-(xx1%, yy1%)-(xx4%, yy4%)
'CALL DrawTriangle(xx1%, yy1%, xx3%, yy3%, xx4%, yy4%, col%)
END IF
NEXT
'
' ROTATE OBJECT
PIT(OB&) = PIT(OB&) + 5
IF PIT(OB&) > 359 THEN PIT(OB&) = 0
YAW(OB&) = YAW(OB&) + 7
IF YAW(OB&) > 359 THEN YAW(OB&) = 0
ROL(OB&) = ROL(OB&) + 9
IF ROL(OB&) > 359 THEN ROL(OB&) = 0
NEXT
'
' Calculate Frames per Second
frames% = frames% + 1
IF oldtime$ <> TIME$ THEN
fps% = frames%
frames% = 1
oldtime$ = TIME$
END IF
COLOR _RGB(255, 255, 255): LOCATE 1, 1: PRINT "FPS :"; fps%
'
' Show Image on Screen
_DISPLAY
LOOP UNTIL INKEY$ <> ""
WIDTH 80: SCREEN 0: CLS
SUB DrawHline (fromx%, tox%, yy%, col%)
'DEF SEG = &HA000
'IF fromx% > tox% THEN SWAP fromx%, tox%
'yyy& = yy%
'sloc& = yyy& * 320 + fromx%
'eloc& = sloc& + (tox% - fromx%)
'FOR t& = sloc& TO eloc&
' POKE t&, col%
'NEXT
'DEF SEG
LINE (fromx%, yy%)-(tox%, yy%), _RGB(255, 255, 255) 'col%
END SUB
SUB DrawTriangle (x1%, y1%, x2%, y2%, x3%, y3%, col%)
DO
sflag% = 0
IF y1% > y2% THEN
sflag% = 1
SWAP y1%, y2%
SWAP x1%, x2%
END IF
IF y2% > y3% THEN
sflag% = 1
SWAP y2%, y3%
SWAP x2%, x3%
END IF
LOOP UNTIL sflag% = 0
'
IF y2% = y3% THEN
' Draw a flat bottomed triangle
ydiff1% = y2% - y1%
ydiff2% = y3% - y1%
IF ydiff1% <> 0 THEN
slope1! = (x2% - x1%) / ydiff1%
ELSE
slope1! = 0
END IF
IF ydiff2% <> 0 THEN
slope2! = (x3% - x1%) / ydiff2%
ELSE
slope2! = 0
END IF
sx! = x1%: ex! = x1%
FOR y% = y1% TO y2%
CALL DrawHline(CINT(sx!), CINT(ex!), y%, col%)
sx! = sx! + slope1!
ex! = ex! + slope2!
NEXT
EXIT SUB
ELSE
IF y1% = y2% THEN
'
' Draw a flat topped triangle
ydiff1% = y3% - y1%
ydiff2% = y3% - y2%
IF ydiff1% <> 0 THEN
slope1! = (x3% - x1%) / ydiff1%
ELSE
slope1! = 0
END IF
IF ydiff2% <> 0 THEN
slope2! = (x3% - x2%) / ydiff2%
ELSE
slope2! = 0
END IF
sx! = x1%: ex! = x2%
FOR y% = y1% TO y3%
CALL DrawHline(CINT(sx!), CINT(ex!), y%, col%)
sx! = sx! + slope1!
ex! = ex! + slope2!
NEXT
x1% = sx!: x2% = ex!
EXIT SUB
ELSE
' Draw a general purpose triangle
' First draw the flat bottom portion (top half)
ydiff1% = y2% - y1%
ydiff2% = y3% - y1%
IF ydiff1% <> 0 THEN
slope1! = (x2% - x1%) / ydiff1%
ELSE
slope1! = 0
END IF
IF ydiff2% <> 0 THEN
slope2! = (x3% - x1%) / ydiff2%
ELSE
slope2! = 0
END IF
sx! = x1%: ex! = x1%
FOR y% = y1% TO y2%
CALL DrawHline(CINT(sx!), CINT(ex!), y%, col%)
sx! = sx! + slope1!
ex! = ex! + slope2!
NEXT
' Then draw the flat topped portion (bottom half)
x1% = x2%
x2% = ex!
y1% = y2%
ydiff1% = y3% - y1%
ydiff2% = y3% - y2%
IF ydiff1% <> 0 THEN
slope1! = (x3% - x1%) / ydiff1%
ELSE
slope1! = 0
END IF
IF ydiff2% <> 0 THEN
slope2! = (x3% - x2%) / ydiff2%
ELSE
slope2! = 0
END IF
sx! = x1%: ex! = x2%
FOR y% = y1% TO y3%
CALL DrawHline(CINT(sx!), CINT(ex!), y%, col%)
sx! = sx! + slope1!
ex! = ex! + slope2!
NEXT
x1% = sx!: x2% = ex!
END IF
END IF
'
END SUB
A 3D Spinning Cube demo using a hardware image and QB64GL hardware acceleration with _MAPTRIANGLE:
' Copyright (C) 2011 by Andrew L. Ayers
DIM OBJECT(9, 9, 4, 2) AS LONG
' OBJECTS DEFINED AS FOLLOWS:
' (#OBJECTS,#PLANES PER OBJECT,#POINTS PER PLANE, XYZ TRIPLE)
DIM DPLANE2D(4, 1) AS LONG ' SCREEN PLANE COORDINATES
' DPLANE2D DEFINED AS FOLLOWS:
' (#POINTS PER PLANE, XY DOUBLE)
DIM DPLANE3D(4, 2) AS LONG ' 3D PLANE COORDINATES
' DPLANE3D DEFINED AS FOLLOWS:
' (#POINTS PER PLANE, XYZ TRIPLE)
DIM PLANECOL(9) AS INTEGER
DIM STAB(359), CTAB(359) ' SINE/COSINE TABLES
D& = 400: MX& = 0: MY& = 0: MZ& = -100
'
' COMPUTE SINE/COSINE TABLES
FOR t& = 0 TO 359
STAB(t&) = SIN((6.282 / 360) * t&)
CTAB(t&) = COS((6.282 / 360) * t&)
NEXT
'
' BUILD CUBE IN OBJECT ARRAY
' PLANE 0
OBJECT(0, 0, 0, 0) = -30: OBJECT(0, 0, 0, 1) = 30: OBJECT(0, 0, 0, 2) = -30
OBJECT(0, 0, 1, 0) = -30: OBJECT(0, 0, 1, 1) = -30: OBJECT(0, 0, 1, 2) = -30
OBJECT(0, 0, 2, 0) = 30: OBJECT(0, 0, 2, 1) = -30: OBJECT(0, 0, 2, 2) = -30
OBJECT(0, 0, 3, 0) = 30: OBJECT(0, 0, 3, 1) = 30: OBJECT(0, 0, 3, 2) = -30
OBJECT(0, 0, 4, 0) = 0: OBJECT(0, 0, 4, 1) = 0: OBJECT(0, 0, 4, 2) = -30
' PLANE 1
OBJECT(0, 1, 0, 0) = 30: OBJECT(0, 1, 0, 1) = 30: OBJECT(0, 1, 0, 2) = -30
OBJECT(0, 1, 1, 0) = 30: OBJECT(0, 1, 1, 1) = -30: OBJECT(0, 1, 1, 2) = -30
OBJECT(0, 1, 2, 0) = 30: OBJECT(0, 1, 2, 1) = -30: OBJECT(0, 1, 2, 2) = 30
OBJECT(0, 1, 3, 0) = 30: OBJECT(0, 1, 3, 1) = 30: OBJECT(0, 1, 3, 2) = 30
OBJECT(0, 1, 4, 0) = 30: OBJECT(0, 1, 4, 1) = 0: OBJECT(0, 1, 4, 2) = 0
' PLANE 2
OBJECT(0, 2, 0, 0) = 30: OBJECT(0, 2, 0, 1) = 30: OBJECT(0, 2, 0, 2) = 30
OBJECT(0, 2, 1, 0) = 30: OBJECT(0, 2, 1, 1) = -30: OBJECT(0, 2, 1, 2) = 30
OBJECT(0, 2, 2, 0) = -30: OBJECT(0, 2, 2, 1) = -30: OBJECT(0, 2, 2, 2) = 30
OBJECT(0, 2, 3, 0) = -30: OBJECT(0, 2, 3, 1) = 30: OBJECT(0, 2, 3, 2) = 30
OBJECT(0, 2, 4, 0) = 0: OBJECT(0, 2, 4, 1) = 0: OBJECT(0, 2, 4, 2) = 30
' PLANE 3
OBJECT(0, 3, 0, 0) = -30: OBJECT(0, 3, 0, 1) = 30: OBJECT(0, 3, 0, 2) = 30
OBJECT(0, 3, 1, 0) = -30: OBJECT(0, 3, 1, 1) = -30: OBJECT(0, 3, 1, 2) = 30
OBJECT(0, 3, 2, 0) = -30: OBJECT(0, 3, 2, 1) = -30: OBJECT(0, 3, 2, 2) = -30
OBJECT(0, 3, 3, 0) = -30: OBJECT(0, 3, 3, 1) = 30: OBJECT(0, 3, 3, 2) = -30
OBJECT(0, 3, 4, 0) = -30: OBJECT(0, 3, 4, 1) = 0: OBJECT(0, 3, 4, 2) = 0
' PLANE 4
OBJECT(0, 4, 0, 0) = -30: OBJECT(0, 4, 0, 1) = -30: OBJECT(0, 4, 0, 2) = -30
OBJECT(0, 4, 1, 0) = -30: OBJECT(0, 4, 1, 1) = -30: OBJECT(0, 4, 1, 2) = 30
OBJECT(0, 4, 2, 0) = 30: OBJECT(0, 4, 2, 1) = -30: OBJECT(0, 4, 2, 2) = 30
OBJECT(0, 4, 3, 0) = 30: OBJECT(0, 4, 3, 1) = -30: OBJECT(0, 4, 3, 2) = -30
OBJECT(0, 4, 4, 0) = 0: OBJECT(0, 4, 4, 1) = -30: OBJECT(0, 4, 4, 2) = 0
' PLANE 5
OBJECT(0, 5, 0, 0) = -30: OBJECT(0, 5, 0, 1) = 30: OBJECT(0, 5, 0, 2) = -30
OBJECT(0, 5, 1, 0) = 30: OBJECT(0, 5, 1, 1) = 30: OBJECT(0, 5, 1, 2) = -30
OBJECT(0, 5, 2, 0) = 30: OBJECT(0, 5, 2, 1) = 30: OBJECT(0, 5, 2, 2) = 30
OBJECT(0, 5, 3, 0) = -30: OBJECT(0, 5, 3, 1) = 30: OBJECT(0, 5, 3, 2) = 30
OBJECT(0, 5, 4, 0) = 0: OBJECT(0, 5, 4, 1) = 30: OBJECT(0, 5, 4, 2) = 0
' SET UP PLANE COLORS ON CUBE
'
PLANECOL(0) = 3
PLANECOL(1) = 4
PLANECOL(2) = 5
PLANECOL(3) = 6
PLANECOL(4) = 7
PLANECOL(5) = 8
'
_TITLE "QB64 _MAPTRIANGLE CUBE DEMO"
SCREEN _NEWIMAGE(800, 600, 32)
TextureImage& = _LOADIMAGE("qb64_trans.png", 32)'replace with your own image
_SETALPHA 128, , TextureImage&
TextureImage& = _COPYIMAGE(TextureImage&, 33)'copy of hardware image
'_PUTIMAGE , Image&
DO
' LIMIT TO 25 FPS
'_LIMIT 25
' ERASE LAST IMAGE
'CLS , _RGB(0, 0, 160)
' CALCULATE POSITION OF NEW IMAGE
FOR OB& = 0 TO 0 ' UP TO 9 OBJECTS
SP = STAB(PIT(OB&)): CP = CTAB(PIT(OB&))
SY = STAB(YAW(OB&)): CY = CTAB(YAW(OB&))
SR = STAB(ROL(OB&)): CR = CTAB(ROL(OB&))
FOR PL& = 0 TO 5 ' CONSISTING OF UP TO 9 PLANES
'
FOR PN& = 0 TO 3 ' EACH PLANE WITH UP TO 4 POINTS (#5 TO PAINT)
'
' TRANSLATE, THEN ROTATE
TX& = OBJECT(OB&, PL&, PN&, 0)
TY& = OBJECT(OB&, PL&, PN&, 1)
TZ& = OBJECT(OB&, PL&, PN&, 2)
RX& = (TZ& * CP - TY& * SP) * SY - ((TZ& * SP + TY& * CP) * SR + TX& * CR) * CY
RY& = (TZ& * SP + TY& * CP) * CR - TX& * SR
RZ& = (TZ& * CP - TY& * SP) * CY + ((TZ& * SP + TY& * CP) * SR + TX& * CR) * SY
'
' ROTATE, THEN TRANSLATE
RX& = RX& + MX&
RY& = RY& + MY&
RZ& = RZ& + MZ&
'
DPLANE3D(PN&, 0) = RX&: DPLANE3D(PN&, 1) = RY&: DPLANE3D(PN&, 2) = RZ&
DPLANE2D(PN&, 0) = 399 + (D& * RX& / RZ&)
DPLANE2D(PN&, 1) = 299 + (D& * RY& / RZ&)
NEXT
'
' CHECK TO SEE IF PLANE IS VISIBLE
x1& = DPLANE3D(0, 0): y1& = DPLANE3D(0, 1): Z1& = DPLANE3D(0, 2)
x2& = DPLANE3D(1, 0): y2& = DPLANE3D(1, 1): Z2& = DPLANE3D(1, 2)
x3& = DPLANE3D(2, 0): y3& = DPLANE3D(2, 1): Z3& = DPLANE3D(2, 2)
T1& = -x1& * (y2& * Z3& - y3& * Z2&)
T2& = x2& * (y3& * Z1& - y1& * Z3&)
T3& = x3& * (y1& * Z2& - y2& * Z1&)
'
VISIBLE& = T1& - T2& - T3&
IF VISIBLE& > 0 THEN
' DRAW PLANE
xx1% = DPLANE2D(0, 0): yy1% = DPLANE2D(0, 1)
xx2% = DPLANE2D(1, 0): yy2% = DPLANE2D(1, 1)
xx3% = DPLANE2D(2, 0): yy3% = DPLANE2D(2, 1)
col% = PLANECOL(PL&)
_BLEND TextureImage&
_MAPTRIANGLE (0, 0)-(0, 255)-(255, 255), TextureImage& TO(xx1%, yy1%)-(xx2%, yy2%)-(xx3%, yy3%)
' CALL DrawTriangle(xx1%, yy1%, xx2%, yy2%, xx3%, yy3%, col%)
xx1% = DPLANE2D(0, 0): yy1% = DPLANE2D(0, 1)
xx3% = DPLANE2D(2, 0): yy3% = DPLANE2D(2, 1)
xx4% = DPLANE2D(3, 0): yy4% = DPLANE2D(3, 1)
_DONTBLEND TextureImage&
_MAPTRIANGLE (0, 0)-(255, 255)-(255, 0), TextureImage& TO(xx3%, yy3%)-(xx1%, yy1%)-(xx4%, yy4%), , _SMOOTH
'CALL DrawTriangle(xx1%, yy1%, xx3%, yy3%, xx4%, yy4%, col%)
END IF
NEXT
'
' ROTATE OBJECT
PIT(OB&) = PIT(OB&) + 5
IF PIT(OB&) > 359 THEN PIT(OB&) = 0
YAW(OB&) = YAW(OB&) + 7
IF YAW(OB&) > 359 THEN YAW(OB&) = 0
ROL(OB&) = ROL(OB&) + 9
IF ROL(OB&) > 359 THEN ROL(OB&) = 0
NEXT
'
' Calculate Frames per Second
frames% = frames% + 1
IF oldtime$ <> TIME$ THEN
fps% = frames%
frames% = 1
oldtime$ = TIME$
END IF
COLOR _RGB(255, 255, 255): LOCATE 1, 1: PRINT "FPS :"; fps%
'
' Show Image on Screen
_DISPLAY
LOOP UNTIL INKEY$ <> ""
WIDTH 80: SCREEN 0: CLS
SUB DrawHline (fromx%, tox%, yy%, col%)
'DEF SEG = &HA000
'IF fromx% > tox% THEN SWAP fromx%, tox%
'yyy& = yy%
'sloc& = yyy& * 320 + fromx%
'eloc& = sloc& + (tox% - fromx%)
'FOR t& = sloc& TO eloc&
' POKE t&, col%
'NEXT
'DEF SEG
LINE (fromx%, yy%)-(tox%, yy%), _RGB(255, 255, 255) 'col%
END SUB
SUB DrawTriangle (x1%, y1%, x2%, y2%, x3%, y3%, col%)
DO
sflag% = 0
IF y1% > y2% THEN
sflag% = 1
SWAP y1%, y2%
SWAP x1%, x2%
END IF
IF y2% > y3% THEN
sflag% = 1
SWAP y2%, y3%
SWAP x2%, x3%
END IF
LOOP UNTIL sflag% = 0
'
IF y2% = y3% THEN
' Draw a flat bottomed triangle
ydiff1% = y2% - y1%
ydiff2% = y3% - y1%
IF ydiff1% <> 0 THEN
slope1! = (x2% - x1%) / ydiff1%
ELSE
slope1! = 0
END IF
IF ydiff2% <> 0 THEN
slope2! = (x3% - x1%) / ydiff2%
ELSE
slope2! = 0
END IF
sx! = x1%: ex! = x1%
FOR y% = y1% TO y2%
CALL DrawHline(CINT(sx!), CINT(ex!), y%, col%)
sx! = sx! + slope1!
ex! = ex! + slope2!
NEXT
EXIT SUB
ELSE
IF y1% = y2% THEN
'
' Draw a flat topped triangle
ydiff1% = y3% - y1%
ydiff2% = y3% - y2%
IF ydiff1% <> 0 THEN
slope1! = (x3% - x1%) / ydiff1%
ELSE
slope1! = 0
END IF
IF ydiff2% <> 0 THEN
slope2! = (x3% - x2%) / ydiff2%
ELSE
slope2! = 0
END IF
sx! = x1%: ex! = x2%
FOR y% = y1% TO y3%
CALL DrawHline(CINT(sx!), CINT(ex!), y%, col%)
sx! = sx! + slope1!
ex! = ex! + slope2!
NEXT
x1% = sx!: x2% = ex!
EXIT SUB
ELSE
' Draw a general purpose triangle
' First draw the flat bottom portion (top half)
ydiff1% = y2% - y1%
ydiff2% = y3% - y1%
IF ydiff1% <> 0 THEN
slope1! = (x2% - x1%) / ydiff1%
ELSE
slope1! = 0
END IF
IF ydiff2% <> 0 THEN
slope2! = (x3% - x1%) / ydiff2%
ELSE
slope2! = 0
END IF
sx! = x1%: ex! = x1%
FOR y% = y1% TO y2%
CALL DrawHline(CINT(sx!), CINT(ex!), y%, col%)
sx! = sx! + slope1!
ex! = ex! + slope2!
NEXT
' Then draw the flat topped portion (bottom half)
x1% = x2%
x2% = ex!
y1% = y2%
ydiff1% = y3% - y1%
ydiff2% = y3% - y2%
IF ydiff1% <> 0 THEN
slope1! = (x3% - x1%) / ydiff1%
ELSE
slope1! = 0
END IF
IF ydiff2% <> 0 THEN
slope2! = (x3% - x2%) / ydiff2%
ELSE
slope2! = 0
END IF
sx! = x1%: ex! = x2%
FOR y% = y1% TO y3%
CALL DrawHline(CINT(sx!), CINT(ex!), y%, col%)
sx! = sx! + slope1!
ex! = ex! + slope2!
NEXT
x1% = sx!: x2% = ex!
END IF
END IF
'
END SUB
Using a desktop image with _MAPTRIANGLE _ANTICLOCKWISE rendering.
SCREEN _NEWIMAGE(800, 600, 32)
ss32 = _SCREENIMAGE 'take a 32bit software screenshot
_SETALPHA 128, , ss32 'make it a bit transparent
ss33 = _COPYIMAGE(ss32, 33) 'convert it to a hardware image (mode 33)
_FREEIMAGE ss32 'we don't need this anymore
DO
CLS , _RGB(0, 128, 255) 'use our software screen as a blue backdrop
'rotate our destination points
'the QB64 3D co-ordinate system is the same as OpenGL's:
' negative z is in front of you, if it doesn't have a negative z value you won't see it!
' x goes from left to right, 0 is the middle of the screen
' y goes from bottom to top, 0 is the middle of the screen
scale = 10
dist = -10
angle = angle + 0.1
x1 = SIN(angle) * scale
z1 = COS(angle) * scale
x2 = SIN(angle + 3.14) * scale 'adding 3.14 adds 180 degrees
z2 = COS(angle + 3.14) * scale
'what we performed above is a 2D/horizontal rotation of points
'(3D rotations are beyond the scope of this example)
'draw the triangle
'_ANTICLOCKWISE makes it only draw when our triangle is facing the correct direction
'_SMOOTH applies linear filtering to avoid a pixelated look
_MAPTRIANGLE **_ANTICLOCKWISE** (_WIDTH(ss33) / 2, 0)-(0, _HEIGHT(ss33))-(_WIDTH(ss33),_
_HEIGHT(ss33)), ss33 TO(0, scale, dist)-(x1, -scale, z1 + dist)-(x2, -scale, z2 + dist), , **_SMOOTH**
_LIMIT 30
_DISPLAY
LOOP
Tip: If you are using Linux you might want to replace "_SCREENIMAGE" with a _LOADIMAGE command if you don't see anything.