sine wave animation? - BlitzCoder.net

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Socoder -> Blitz -> sine wave animation?
Wed, 02 Apr 2008, 06:48
spinal	Does anyone have an example of a simple sine wave animation, something like the psp background? It does not need to be anywhere near as good as that, just a wiggling line across the screen. -=-=- Check out my excellent homepage!
Wed, 02 Apr 2008, 07:06
mike_g	This is about as crude as you can get, but with a little work you could probably turn it into something that looks nice: #include "SDL/SDL.h" #include <math.h> #define GRAPHICS_WIDTH 256 #define GRAPHICS_HEIGHT 256 #define BITDEPTH 32 #define DEG_TO_RAD 0.0174532925 #define FRAME_LIMIT 1000 / 20 SDL_Surface screen = NULL; SDL_Event event; void WritePixel(int x, int y, Uint32 col) { Uint32 pix; pix=screen->pixels+(x+yGRAPHICS_WIDTH)4; pix=col; } int main() { if(SDL_Init(SDL_INIT_VIDEO) !=0) return 1; screen = SDL_SetVideoMode(GRAPHICS_WIDTH, GRAPHICS_HEIGHT, BITDEPTH, 0); if(screen == NULL) return 1; int x; int quit = 0; int anim = 0; unsigned timer; //This is the main loop that runs until the program ends while(!quit) { timer = SDL_GetTicks(); SDL_FillRect(screen, NULL, 0); //Draw Sinewave for(x=0; x<GRAPHICS_WIDTH; x++) WritePixel(x, 128+cos(xDEG_TO_RAD+anim)*100, 0xFFFFFFFF); if(SDL_Flip(screen)==-1) return 1; while(SDL_PollEvent(&event)) if(event.type==SDL_KEYDOWN) quit=1; if(++anim > 359) anim = 0; timer = SDL_GetTicks()-timer; if(timer < FRAME_LIMIT) SDL_Delay(FRAME_LIMIT-timer); } SDL_Quit(); return 0; } --v
Wed, 02 Apr 2008, 07:24
Phoenix	If you want a PSP-style background, you're probably better off pre-making it in some image editing program. In addition to Mike's solution, here's a quick Blitz example: Const gfxW = 600 Const gfxH = 400 Graphics(gfxW, gfxH, 0, 2) SetBuffer(BackBuffer()) waveOffset = 200 waveAmplitude = 50 speed = 2 While(Not KeyHit(1)) a = a + speed ; Change this to change speed LockBuffer() For i = 0 To gfxW WritePixelFast i,Sin(a+i)(Sin(a)waveAmplitude)+waveOffset, $FFFFFF Next UnlockBuffer() Flip Cls Wend End --v
Wed, 02 Apr 2008, 07:51
Jayenkai	Or an even more wibbly wobbly thing... Global CanDrawLocked=1 ; Switch to 0 if you don't see anything! Graphics 768,576,32,2 Graphics 256,192,32,3 SetBuffer BackBuffer() Dim aty#(257) ; 256 slots + 1 'cos C's like that, if you're copying over. Global r#,g#,b# ; color Global rg#,gg#,bg# ; color Go!! r=Rand(255):b=Rand(255):g=Rand(255) rg=Rnd(0.1,1.5):gg=Rnd(0.1,1.5):bg=Rnd(0.1,1.5) For x=0 To 256:aty(x)=96:Next ; preset to middle Global ang# Repeat ;Cls ; <-- try with, try without... ; Sort out colors r=r+rg If r<0 Then r=0:rg=Rnd(0.1,1.5) If r>255 Then r=255:rg=-Rnd(0.1,1.5) g=g+gg If g<0 Then g=0:gg=Rnd(0.1,1.5) If g>255 Then g=255:gg=-Rnd(0.1,1.5) b=b+bg If b<0 Then b=0:bg=Rnd(0.1,1.5) If b>255 Then b=255:bg=-Rnd(0.1,1.5) ; Do drawing If candrawlocked=1 Then LockBuffer BackBuffer() For x=0 To 255 aty(x)=aty(x+1) ; Move everything -1 pixel aty(x)=aty(x)+(Sin((ang+x)2)) ; Shift all pixels about using sin wave Color r/4,g/4,b/4 ; Draw Line x,aty(x)-10,x,aty(x)+10 Color r/2,g/2,b/2 Line x,aty(x)-5,x,aty(x)+5 Color r,g,b Line x,aty(x)-1,x,aty(x)+1 Next If candrawlocked=1 Then UnlockBuffer BackBuffer() ; Do end point work.. ang=ang+0.5 aty(256)=(Sin(ang)32)+96 ;Set end point ;Or, in fact, if you wanted something a little less "sin wave" you can stick anything into aty(256) ;eg ;aty(256)=(Sin(ang)16)+96+(Cos(ang8)20) ; <-- This one's my fave.. ;aty(256)=(Sin(ang)16)+96+(Cos(ang2)20)+(Tan(ang0.2)16) Flip Until KeyDown(1) --v -=-=- ''Load, Next List!''
Wed, 02 Apr 2008, 09:53
JL235	As usual a really nice effect by Jay. Thanks, I might use that.
Wed, 02 Apr 2008, 16:13
spinal	took peonix's and tweaked it a little... you need line.gif should be bmp but jay's thinumy cant upload bmps. Const gfxW = 800 Const gfxH = 300 Graphics(gfxW, gfxH, 0, 2) SetBuffer(BackBuffer()) lin = LoadImage("line.bmp") waveAmplitude = 30 speed = 2 While(Not KeyHit(1)) a = a + Rnd(2,3) ; Change this to change speed b = b + Rnd(1,3) ; Change this to change speed For i = 0 To gfxW Step 2 DrawBlock lin,i ,Sin(a+i/3)(Sin(a)waveAmplitude) DrawBlock lin,i+1,Sin(b+i/3)(Sin(b)waveAmplitude) Next Flip Wend End --v I cheated a little with the transparency. also, can someone think of a better way to do this... Const gfxW = 800 Const gfxH = 300 Graphics(gfxW, gfxH, 0, 2) SetBuffer(BackBuffer()) lin = LoadImage("line.bmp") waveAmplitude = 30 speed = 2 a=0 : b=0 : c=60: d=36 While(Not KeyHit(1)) a = a + Rnd(2,3) ; Change this to change speed b = b + Rnd(1,3) ; Change this to change speed c = c + Rnd(2,3) ; Change this to change speed d = d + Rnd(1,3) ; Change this to change speed For i = 0 To gfxW Step 2 If frame=0 Then DrawBlock lin,i ,Sin(a+i/3)(Sin(a)waveAmplitude)+50 DrawBlock lin,i+1,Sin(b+i/3)(Sin(b)waveAmplitude)+50 Else DrawBlock lin,i ,Sin(c+i/3)(Sin(c)waveAmplitude)-20 DrawBlock lin,i+1,Sin(d+i/3)(Sin(d)waveAmplitude)-20 End If Next frame=1-frame Flip 1 Wend End --v -=-=- Check out my excellent homepage!
Wed, 02 Apr 2008, 16:34
Jayenkai	Const gfxW = 800 Const gfxH = 300 Graphics(gfxW, gfxH, 0, 2) ;lin = LoadImage("line.bmp") lin=CreateImage(1,300) SetBuffer ImageBuffer(lin) For y=0 To 300 d=y1.5 If d>200 Then d=y/2 Color d,d,150+d/2 Plot 0,y Next lin2=CreateImage(1,300) SetBuffer ImageBuffer(lin2) For y=0 To 300 Step 2 d=y1.5 If d>200 Then d=y/2 Color d,d,150+d/2 Plot 0,y Next SetBuffer(BackBuffer()) waveAmplitude = 30 speed = 2 While(Not KeyHit(1)) a = a + Rnd(2,3) ; Change this to change speed b = b + Rnd(1,3) ; Change this to change speed c = c + Rnd(2,3) ; Change this to change speed d = d + Rnd(1,3) ; Change this to change speed For i = 0 To gfxW Step 2 DrawBlock lin,i , Sin(a+i/3)(Sin(a)waveAmplitude) DrawBlock lin,i+1 , Sin(b+i/3)(Sin(b)waveAmplitude) DrawImage lin2,i , Int(Sin(c+i/3)(Sin(c)waveAmplitude1.5)/2)2 DrawImage lin2,i+1 , (Int(Sin(d+i/3)(Sin(d)waveAmplitude1.5)/2)2)+1 Next Flip Wend End --v Extra dithering allows for a 3rd and 4th wave, but due to it doing drawimage rather than drawblock, it has slowed it down somewhat.. -=-=- ''Load, Next List!''
Sun, 06 Apr 2008, 14:29
JL235	Here is my version which I am planning to use. It doesn't draw the whole line on everyframe and instead draws say half or a quarter of it. The lines which are missed are then drawn on the next frame, the one after, and so on. This spreads the load across multiple frames, but reduces quality. In this example I think I have it set to skip every 12 lines, but it draws 4 of them (1 for each wave). So it's only drawing a third of the screen (12 / 4) on each frame. This is also needed as I generate a whole new line for each frame with a new colour. In order to do that quickly I precalculate double values stored into an array for each pixel in the line. I then just multiple the r/g/b values for the whole line by the double for that pixel and so can create the gradient very quickly. I also made a SinWave object so it'd be easy for me to have them change speed and size over time too, which I might add. Enjoy!
Sun, 06 Apr 2008, 14:48
Jayenkai	V.cool! Shame it took 3 weeks for Java to start before I saw it running, but otherwise very good! -=-=- ''Load, Next List!''
Sun, 06 Apr 2008, 15:23
JL235	Java works really well in Opera, I'm impressed!