Code archives/Graphics/TextureQuad
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| This is an attempt -- still in progress -- to render any image onto an arbitrary quad, in something at least approaching a reasonable speed (not 'in-game' speed, though). Any improvements welcome, particularly in fixing the holes! EDIT: Whoa! 3 times faster in BlitzPlus!!! :) EDIT 2: Some pictures crash in BlitzPlus but not '3D... investigation needed! Just try another picture if it crashes :) | |||||
; ----------------------------------------------------------------------------- ; 2D quad texturer by james @ hi - toro . com ; ----------------------------------------------------------------------------- ; ----------------------------------------------------------------------------- ; **** CHANGE THIS BEFORE RUNNING!!! **** ; ----------------------------------------------------------------------------- picture$ = "boing.bmp" ; An image on your hard drive... ; ----------------------------------------------------------------------------- ; Note: picture size is irrelevant in speed terms; only quad size matters. ; ----------------------------------------------------------------------------- ; Note also that you can see a very simple demo by uncommenting the appropriate ; line at the top of the demo section (the simple demo source is at the bottom). ; ----------------------------------------------------------------------------- ; ----------------------------------------------------------------------------- ; Current 'issues'... ; ----------------------------------------------------------------------------- ; Holes in rendered image due to line algorithm. Got some ideas, though feel ; free to beat me to it. Looking for any speedups too! ; ----------------------------------------------------------------------------- ; Slight problem with right/bottom edges with certain image sizes. Should be ; able to sort this! ; ----------------------------------------------------------------------------- ; ----------------------------------------------------------------------------- ; Globals and constants required... ; ----------------------------------------------------------------------------- Global GfxWidth, GfxHeight Const RenderDEBUG = True ; ----------------------------------------------------------------------------- ; Types required... ; ----------------------------------------------------------------------------- Type Quad Field x [3] Field y [3] End Type ; ----------------------------------------------------------------------------- ; Functions required... ; ----------------------------------------------------------------------------- Function InitRenderer () GfxWidth = GraphicsWidth () - 1 GfxHeight = GraphicsHeight () - 1 End Function ; BELOW: x0, y0, etc, are the x/y positions of each corner of the quad. Define ; them in clockwise order... Function CreateQuad.Quad (x0, y0, x1, y1, x2, y2, x3, y3) q.Quad = New Quad q\x[0] = x0: q\y[0] = y0 q\x[1] = x1: q\y[1] = y1 q\x[2] = x2: q\y[2] = y2 q\x[3] = x3: q\y[3] = y3 Return q End Function Function Dist# (x0#, y0#, x1#, y1#) Return Sqr (((x1 - x0) * (x1 - x0)) + ((y1 - y0) * (y1 - y0))) End Function Function TextureQuad (q.Quad, image) ; ---------------------------------------------------------------------------- ; Check globals have been set... ; ---------------------------------------------------------------------------- ; NOTE: RenderDEBUG is a constant set at top of code. Setting it to False will ; result in this part of the code not being compiled, so you can leave it in... :) If RenderDEBUG If (Not GfxWidth) Or (Not GfxHeight) RuntimeError "Programmer error!" + Chr (10) + Chr (10) + "You need to call InitRenderer () after setting graphics mode!" EndIf EndIf ; ---------------------------------------------------------------------------- ; A quad, with a long side and a short side, points marked... ; ---------------------------------------------------------------------------- ; o--------------- ; |0 ------------ ; | ------------o ; | |1 ; | | ; | | ; | | ; | | ; | | ; | | ; | | ; | | ; | | ; | | ; | | ; | | ; | ------------o ; | -------- 2 ; | -------- ; o----------- ; 3 ; ---------------------------------------------------------------------------- ; ---------------------------------------------------------------------------- ; Cache image information... ; ---------------------------------------------------------------------------- IW = ImageWidth (image) - 1 IH = ImageHeight (image) - 1 IB = ImageBuffer (image) ; ---------------------------------------------------------------------------- ; Compare lengths of left side and right side... ; ---------------------------------------------------------------------------- leftside# = Dist (q\x[0], q\y[0], q\x[3], q\y[3]) rightside# = Dist (q\x[1], q\y[1], q\x[2], q\y[2]) ; ---------------------------------------------------------------------------- ; Get index numbers for points making up each side... ; ---------------------------------------------------------------------------- If leftside > rightside ; Left side longer... long1 = 0 long2 = 3 short1 = 1 short2 = 2 plotdir = 1 Else ; Right side longer... long1 = 1 long2 = 2 short1 = 0 short2 = 3 plotdir = -1 EndIf ; ---------------------------------------------------------------------------- ; The 'plotdir' variable above corrects mirroring that occurs when right side ; is longer (don't ask)... ; ---------------------------------------------------------------------------- ; ---------------------------------------------------------------------------- ; OK, now we step down both sides of the quad, using the step size according to ; the longer of the two sides... ; ---------------------------------------------------------------------------- ; ---------------------------------------------------------------------------- ; Taking the long side, the division used to step down it (stepper) ; is 1 / length of line. This is used to move down both sides... ; ---------------------------------------------------------------------------- ystepper# = 1.0 / Dist (q\x[long1], q\y[long1], q\x[long2], q\y[long2]) ; ---------------------------------------------------------------------------- ; Since the step size is variable, can't use For... Next, so I use ; While... Wend to count up to this value... ; ---------------------------------------------------------------------------- ylimit# = 1.0 + ystepper ; ---------------------------------------------------------------------------- ; Current position down the sides (will be from 0.0 to 1.0 along the line length)... ; ---------------------------------------------------------------------------- ypos# = 0 ; ---------------------------------------------------------------------------- ; Lock back buffer and image buffer ready for Read/WritePixelFast action... ; ---------------------------------------------------------------------------- LockBuffer BackBuffer () LockBuffer IB ; ---------------------------------------------------------------------------- ; OK, going down both sides... ; ---------------------------------------------------------------------------- While ypos < ylimit ; ------------------------------------------------------------------------ ; Get x and y position of current point on long side... ; ------------------------------------------------------------------------ xlong# = (q\x[long1] * (1 - ypos) + q\x[long2] * ypos) ylong# = (q\y[long1] * (1 - ypos) + q\y[long2] * ypos) ; ------------------------------------------------------------------------ ; Get x and y position of current point on short side... ; ------------------------------------------------------------------------ xshort# = (q\x[short1] * (1 - ypos) + q\x[short2] * ypos) yshort# = (q\y[short1] * (1 - ypos) + q\y[short2] * ypos) ; ------------------------------------------------------------------------ ; Now we need to get the step size to traverse horizontally between the side points... ; ------------------------------------------------------------------------ xstepper# = 1.0 / Dist (xlong, ylong, xshort, yshort) ; ------------------------------------------------------------------------ ; Since the step size is variable, can't use For... Next, so I use ; While... Wend to count up to this value... ; ------------------------------------------------------------------------ xlimit# = 1.0 + xstepper ; ------------------------------------------------------------------------ ; Current position between the sides (will be from 0.0 to 1.0 along the line length)... ; ------------------------------------------------------------------------ xpos# = 0 ; ------------------------------------------------------------------------ ; OK, go across between the two current side points... ; ------------------------------------------------------------------------ While xpos < xlimit ; -------------------------------------------------------------------- ; Get current x and y position on horizontal line... ; -------------------------------------------------------------------- If plotdir = 1 plotx = ((xlong * (1 - xpos)) + (xshort * xpos)) ploty = ((ylong * (1 - xpos)) + (yshort * xpos)) Else plotx = ((xshort * (1 - xpos)) + (xlong * xpos)) ploty = ((yshort * (1 - xpos)) + (ylong * xpos)) EndIf ; -------------------------------------------------------------------- ; Check the point is on the screen (NOTE GLOBALS GW AND GH)... ; -------------------------------------------------------------------- If (plotx > 0) And (ploty > 0) If (plotx < GfxWidth) And (ploty < GfxHeight) ; ------------------------------------------------------------ ; Plot pixel from the original image by reading from the fractional ; position across/down the image (xpos and ypos are from 0.0 to 1.0, ; remember)... ; ------------------------------------------------------------ WritePixelFast plotx, ploty, ReadPixelFast (IW * xpos, IH * ypos, IB) EndIf EndIf ; -------------------------------------------------------------------- ; Move across current line... ; -------------------------------------------------------------------- xpos = xpos + xstepper Wend ; ------------------------------------------------------------------------ ; Move down sides... ; ------------------------------------------------------------------------ ypos = ypos + ystepper Wend ; ---------------------------------------------------------------------------- ; Unlock buffers... ; ---------------------------------------------------------------------------- UnlockBuffer IB UnlockBuffer BackBuffer () End Function ; Goto SimpleDemo ; Uncomment for bare-minimum demo (see bottom of source code)... ; ----------------------------------------------------------------------------- ; Demo... ; ----------------------------------------------------------------------------- AppTitle "Grab the circles to move the corners..." Graphics 640, 480, 0, 2 SetBuffer BackBuffer () InitRenderer () image = LoadImage (picture$) ; Drawing a 256 x 256 image actual size, though this part isn't important! poly.Quad = CreateQuad (100, 100, 356, 100, 356, 356, 100, 356) ClsColor 64, 96, 128 mousepointsize = 16 Repeat If MouseDown (1) If movepoint = False For p = 0 To 3 If Dist (MouseX (), MouseY (), poly\x[p], poly\y[p]) < mousepointsize movepoint = True point = p EndIf Next EndIf Else movepoint = False EndIf If movepoint poly\x[point] = MouseX () poly\y[point] = MouseY () EndIf Cls drawtime = MilliSecs () TextureQuad (poly, image) drawtime = MilliSecs () - drawtime For p = 0 To 3 Oval poly\x[p] - mousepointsize / 2, poly\y[p] - mousepointsize / 2, mousepointsize, mousepointsize, 0 Text poly\x[p] + mousepointsize, poly\y[p] + mousepointsize, "Point " + p Next Text 20, 20, "Render time (millisecs): " + drawtime Flip Until KeyHit (1) End .SimpleDemo ; ----------------------------------------------------------------------------- ; Simpler demo (bare minimum usage)... ; ----------------------------------------------------------------------------- Graphics 640, 480, 0, 2 SetBuffer BackBuffer () InitRenderer () poly.Quad = CreateQuad (100, 150, 500, 50, 300, 400, 150, 300) image = LoadImage (picture$) Repeat Cls TextureQuad (poly, image) Flip Until KeyHit (1) End |
Comments
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| Great function! Here is the Blitzmax version with a bug fix: Type tQuad Field X%[4] Field Y%[4] End Type Function CreateQuad:tQuad(x0%, y0%, x1%, y1%, x2%, y2%, x3%, y3%) Local q:tquad = New tquad q.x[0] = x0; q.y[0] = y0 q.x[1] = x1; q.y[1] = y1 q.x[2] = x2; q.y[2] = y2 q.x[3] = x3; q.y[3] = y3 Return q End Function Function Dist# (x0#, y0#, x1#, y1#) Return Sqr (((x1 - x0) * (x1 - x0)) + ((y1 - y0) * (y1 - y0))) End Function Function DrawTexturedQuad(q:tquad,Source:TPixmap,Dest:TPixmap) If Not source Then Return If Not dest Then Return Local IW% = source.width - 1 Local IH% = source.height - 1 'Local IB% = ImageBuffer (image) Local leftside# = Dist (q.x[0], q.y[0], q.x[3], q.y[3]) Local rightside# = Dist (q.x[1], q.y[1], q.x[2], q.y[2]) Local long1% Local long2% Local short1% Local short2% Local plotdir% If leftside > rightside ' Left side longer... long1 = 0 long2 = 3 short1 = 1 short2 = 2 plotdir = 1 Else ' Right side longer... long1 = 1 long2 = 2 short1 = 0 short2 = 3 plotdir = -1 EndIf Local ystepper# = 1.0 / Dist (q.x[long1], q.y[long1], q.x[long2], q.y[long2]) Local ylimit# = 1.0 + ystepper Local ypos# = 0 Local plotx%,Ploty% While ypos < ylimit Local xlong# = (q.x[long1] * (1 - ypos) + q.x[long2] * ypos) Local ylong# = (q.y[long1] * (1 - ypos) + q.y[long2] * ypos) Local xshort# = (q.x[short1] * (1 - ypos) + q.x[short2] * ypos) Local yshort# = (q.y[short1] * (1 - ypos) + q.y[short2] * ypos) Local xstepper# = 1.0 / Dist (xlong, ylong, xshort, yshort) Local xlimit# = 1.0 + xstepper Local xpos# = 0 While xpos < xlimit If plotdir = 1 plotx = ((xlong * (1 - xpos)) + (xshort * xpos)) ploty = ((ylong * (1 - xpos)) + (yshort * xpos)) Else plotx = ((xshort * (1 - xpos)) + (xlong * xpos)) ploty = ((yshort * (1 - xpos)) + (ylong * xpos)) EndIf If (plotx > 0) And (ploty > 0) If (plotx < dest.width) And (ploty < dest.height) And Int(IW * xpos) < IW And Int(IH * ypos) < IH Then dest.WritePixel(plotx, ploty, source.ReadPixel(Int(IW * xpos), Int(IH * ypos)) ) 'WritePixelFast plotx, ploty, ReadPixelFast (IW * xpos, IH * ypos, IB EndIf EndIf xpos = xpos + xstepper Wend ypos = ypos + ystepper Wend End Function |
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