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Entity - Entity handle Blend - Blend mode of the entity. 1: Alpha (default) 2: Multiply 3: Add |
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Sets the blending mode of an entity. This blending mode determines the way in which the new RGBA of the pixel being rendered is combined with the RGB of the background. To calculate the new RGBA of the pixel being rendered, the texture RGBA for the pixel (see dxTextureBlend for more information on how the texture RGBA is calculated) is taken, its alpha component multiplied by the entities/brushes (where applicable) alpha value and its dxColor compentent multiplied by the entities/brushes colour. This is the RGBA which will then be blended into the background pixel, and how this is done depends on the dxEntityBlend value. Alpha: This blends the pixels according to the Alpha value. This is rougly done to the formula: Rr = ( An * Rn ) + ( ( 1.0 - An ) * Ro ) Gr = ( An * Gn ) + ( ( 1.0 - An ) * Go ) Br = ( An * Bn ) + ( ( 1.0 - An ) * Bo ) Where R = Red, G = Green, B = Blue, n = new pixel colour values, r = resultant colour values, o = old pixel colour values. Alpha blending is the default blending mode and is used with most world objects. Multiply: This blend mode will darken the underlying pixels. If you think of each RGB value as being on a scale from 0% to 100%, where 0 = 0% and 255 = 100%, the multiply blend mode will multiply the red, green and blue values individually together in order to get the new RGB value, roughly according to: Rr = ( ( Rn / 255.0 ) * ( Ro / 255.0 ) ) * 255.0 Gr = ( ( Gn / 255.0 ) * ( Go / 255.0 ) ) * 255.0 Br = ( ( Bn / 255.0 ) * ( Bo / 255.0 ) ) * 255.0 The alpha value has no effect with multiplicative blending. Blending a RGB value of 255, 255, 255 will make no difference, while an RGB value of 128, 128, 128 will darken the pixels by a factor of 2 and an RGB value of 0, 0, 0 will completely blacken out the resultant pixels. An RGB value of 0, 255, 255 will remove the red component of the underlying pixel while leaving the other dxColor values untouched. Multiply blending is most often used for lightmaps, shadows or anything else that needs to 'darken' the resultant pixels. Add: Additive blending will add the new dxColor values to the old, roughly according to: Rr = ( Rn * An ) + Ro Gr = ( Gn * An ) + Go Br = ( Bn * An ) + Bo The resultant RGB values are clipped out at 255, meaning that multiple additive effects can quickly cause visible banding from smooth gradients. Additive blending is extremely useful for effects such as laser shots and fire. See also: dxTextureBlend, dxEntityAlpha. |
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dxGraphics3D 640,480 dxSetBuffer dxBackBuffer() dxSeedRnd MilliSecs() ; create camera camera=dxCreateCamera() dxCameraClsColor camera,160,160,160 dxPositionEntity camera,0,0,-30 middle=dxCreatePivot() dxEntityParent camera,middle ; create add texture - white cirlce on a black background For n=0 To 50 dxColor 5+(n*5),5+(n*5),5+(n*5) dxOval 10+n,10+n,236-(n*2),236-(n*2),1 Next blob_tex=dxCreateTexture(256,256) blob=dxCreateImage(256,256) GrabImage blob,0,0 dxCopyRect 0,0,256,256,0,0,dxImageBuffer(blob),dxTextureBuffer(blob_tex) dxFreeImage blob max_blobs=100 ; create blobs using add blend mode Dim blobs(max_blobs) ; blob sprites Dim xyblobs#(max_blobs,2) ; blob vector For n=0 To max_blobs blobs(n)=dxCreateSprite() dxEntityFX blobs(n),1 dxEntityBlend blobs(n),3 ;set blend mode to add dxEntityTexture blobs(n),blob_tex xyblobs(n,0)=dxRnd(-.1,.1) xyblobs(n,1)=dxRnd(-.1,.1) xyblobs(n,2)=dxRnd(-.1,.1) dxEntityColor blobs(n),dxRand(0,255),dxRand(0,255),dxRand(0,255) ;give it a colour Next ; create cube texture dxColor 255,255,255 dxRect 0,0,256,256,1 For n=0 To 7 If n=0 Then dxColor 0,0,0 If n=1 Then dxColor 0,0,255 If n=2 Then dxColor 0,255,0 If n=3 Then dxColor 0,255,255 If n=4 Then dxColor 255,0,0 If n=5 Then dxColor 255,0,255 If n=6 Then dxColor 255,255,0 If n=7 Then dxColor 255,255,255 dxRect n*32,n*32,32,32,1 Next dxColor 0,0,0 For n=0 To 255 Step 32 dxLine 0,n,255,n dxLine n,0,n,255 Next cube_tex=dxCreateTexture(256,256) cube=dxCreateImage(256,256) GrabImage cube,0,0 dxCopyRect 0,0,256,256,0,0,dxImageBuffer(cube),dxTextureBuffer(cube_tex) dxFreeImage cube ; create cube cube=dxCreateCube() dxScaleEntity cube,11,11,11 dxEntityTexture cube,cube_tex dxEntityFX cube,17 ;set fullbright and 2 sided textures dxEntityBlend cube,2 ;set multiply blend Repeat ; move the blobs around For n=0 To max_blobs dxMoveEntity blobs(n),xyblobs(n,0),xyblobs(n,1),xyblobs(n,2) ;bounce off sides If dxEntityX(blobs(n))<-10 Or dxEntityX(blobs(n))>10 Then xyblobs(n,0)=-xyblobs(n,0) If dxEntityY(blobs(n))<-10 Or dxEntityY(blobs(n))>10 Then xyblobs(n,1)=-xyblobs(n,1) If dxEntityZ(blobs(n))<-10 Or dxEntityZ(blobs(n))>10 Then xyblobs(n,2)=-xyblobs(n,2) Next ; turn camera dxTurnEntity middle,.1,.2,.3 dxUpdateWorld dxRenderWorld dxFlip Until dxKeyHit(1) |