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QB64 Discussion / Re: Practicing Coding Game
« Last post by bplus on Today at 04:05:59 PM »I must say, most people would grab images and manipulate them. But I admire the brave soul who chooses to draw by code! :)
Here is quad drawing tools. Basically you need a triangle fill routine and then draw 2 triangles that share an edge.
I constructed parallelograms, random quad and rhombus from central point. I am afraid the level for that is a little high too.
Fortunately you don't need allot of math to get 4 points for the quad but you do have to watch that the shared edge is line x2, y2 to x4, y4 for quad sub.
Here is quad drawing tools. Basically you need a triangle fill routine and then draw 2 triangles that share an edge.
I constructed parallelograms, random quad and rhombus from central point. I am afraid the level for that is a little high too.
Fortunately you don't need allot of math to get 4 points for the quad but you do have to watch that the shared edge is line x2, y2 to x4, y4 for quad sub.
Code: [Select]
_TITLE "A draw quad tool, white = parallelogram, red = random quad, blue = rhombus" 'B+ started 2019-03-21
RANDOMIZE TIMER
CONST white = &HFFFFFFFF
CONST red = &HFFFF0000
CONST blue = &HFF0000FF
'a quad is 4 points about a center, squares, rectangles, rhombus, parallelogram, trapizoids are special cases
SCREEN _NEWIMAGE(800, 600, 32)
_SCREENMOVE 300, 40
WHILE _KEYDOWN(27) = 0
CLS
'try paralleogram white
'pick a random point not too close to edge of screen (50 away) to be center of parallelogram
x0 = (_WIDTH - 100) * RND + 50: y0 = (_HEIGHT - 100) * RND + 50
'pick a random radius from center, all are equal for parellel
r = RND * 40 + 10
'pick an angle between 0 and 180 degrees =_PI radians
a = RND * _PI
'a par o gram has 2 angles that sum to 180 = _PI
p1 = RND * PI(11 / 6) + _PI(1 / 6): p2 = _PI - p1
a1 = a + p1
a2 = a1 + p2
a3 = a2 + p1
x1 = x0 + r * COS(a): y1 = y0 + r * SIN(a)
x2 = x0 + r * COS(a1): y2 = y0 + r * SIN(a1)
x3 = x0 + r * COS(a2): y3 = y0 + r * SIN(a2)
x4 = x0 + r * COS(a3): y4 = y0 + r * SIN(a3)
fquad x1, y1, x2, y2, x3, y3, x4, y4, white
'random quad
' or lets say all the angles are 90 more than last but use random radius from center point
x0 = (_WIDTH - 100) * RND + 50: y0 = (_HEIGHT - 100) * RND + 50
a = _PI(.25) * RND 'start point angle from center
r = 10 + 40 * RND
x1 = x0 + r * COS(a): y1 = y0 + r * SIN(a)
r = 10 + 40 * RND
x2 = x0 + r * COS(a + _PI(.5)): y2 = y0 + r * SIN(a + _PI(.5)) 'plus 90 degree = pi/2 = .5*pi
r = 10 + 40 * RND
x3 = x0 + r * COS(a + _PI): y3 = y0 + r * SIN(a + _PI) 'plus 180 degrees = pi
r = 10 + 40 * RND
x4 = x0 + r * COS(a + _PI(1.5)): y4 = y0 + r * SIN(a + _PI(1.5)) 'plus 270 degrees = 3/2*pi
fquad x1, y1, x2, y2, x3, y3, x4, y4, red
'PSET (x0, y0), white
'LINE (x0, y0)-(x1, y1), white
'LINE (x0, y0)-(x2, y2), blue
'LINE (x0, y0)-(x3, y3), white
'LINE (x0, y0)-(x4, y4), blue
'rhombus like ellipse 2 radii
r1 = RND * 35 + 15: r2 = RND * 35 + 15
x0 = (_WIDTH - 100) * RND + 50: y0 = (_HEIGHT - 100) * RND + 50
a = _PI(.25) * RND 'start point angle from center
x1 = x0 + r1 * COS(a): y1 = y0 + r1 * SIN(a)
x2 = x0 + r2 * COS(a + _PI(.5)): y2 = y0 + r2 * SIN(a + _PI(.5)) 'plus 90 degree = pi/2 = .5*pi
x3 = x0 + r1 * COS(a + _PI): y3 = y0 + r1 * SIN(a + _PI) 'plus 180 degrees = pi
x4 = x0 + r2 * COS(a + _PI(1.5)): y4 = y0 + r2 * SIN(a + _PI(1.5)) 'plus 270 degrees = 3/2*pi
fquad x1, y1, x2, y2, x3, y3, x4, y4, blue
_DISPLAY
_LIMIT 1
WEND
' if you connect 2 points that are not adjacent but opposite each other you divide a quad to 2 triangle
' So if we have code to draw a filled triangle we have to just draw 2 filled triangles.
'need 4 non linear points (not all on 1 line) list them clockwise so x2, y2 is opposite of x4, y4
SUB fquad (x1, y1, x2, y2, x3, y3, x4, y4, K AS _UNSIGNED LONG)
ftri x1, y1, x2, y2, x4, y4, K
ftri x3, y3, x2, y2, x4, y4, K
END SUB
'Very Handy code to draw a filled triangle
SUB ftri (x1, y1, x2, y2, x3, y3, K AS _UNSIGNED LONG)
a& = _NEWIMAGE(1, 1, 32)
_DEST a&
PSET (0, 0), K
_DEST 0
_MAPTRIANGLE _SEAMLESS(0, 0)-(0, 0)-(0, 0), a& TO(x1, y1)-(x2, y2)-(x3, y3)
_FREEIMAGE a& '<<< this is important!
END SUB