Text doens't alpha..

Blitz3D Forums/Blitz3D Programming/Text doens't alpha..

Liberator (Posted 2005) [#1]

Quick questions.... in the example: ; TextureBuffer Example ; --------------------- Graphics3D 640,480 SetBuffer BackBuffer() camera=CreateCamera() light=CreateLight() RotateEntity light,90,0,0 cube=CreateCube() PositionEntity cube,0,0,5 ; Create texture of size 256x256 tex=CreateTexture(256,256) ; Set buffer - texture buffer SetBuffer TextureBuffer(tex) ; Clear texture buffer with background white color ClsColor 255,255,255 Cls ; Draw text on texture font=LoadFont("arial",24) SetFont font Color 0,0,0 Text 0,0,"This texture" Text 0,40,"was created using" : Color 0,0,255 Text 0,80,"CreateTexture()" : Color 0,0,0 Text 0,120,"and drawn to using" : Color 0,0,255 Text 0,160,"SetBuffer TextureBuffer()" ; Texture cube with texture EntityTexture cube,tex ; Set buffer - backbuffer SetBuffer BackBuffer() While Not KeyDown( 1 ) pitch#=0 yaw#=0 roll#=0 If KeyDown( 208 )=True Then pitch#=-1 If KeyDown( 200 )=True Then pitch#=1 If KeyDown( 203 )=True Then yaw#=-1 If KeyDown( 205 )=True Then yaw#=1 If KeyDown( 45 )=True Then roll#=-1 If KeyDown( 44 )=True Then roll#=1 TurnEntity cube,pitch#,yaw#,roll# RenderWorld Flip Wend End ------------------------------- Try creating the 'tex' texture with the masked flag so it says "tex=CreateTexture(256,256,1+4)". Now why does nothing show up? Shoulden't the text be transparent? Or is there somthing about the way textures work that I'm simply not understanding....

Beaker (Posted 2005) [#2]

Take a look here: http://www.blitzbasic.com/codearcs/codearcs.php?code=548

RGR (Posted 2005) [#3]

@Liberator I made the same as you did, months ago and someone pointed me into the right direction. After you make CLS the alpha values are still 0 at each pixel - so you have to poke the alphavalues on each pixel of the texture. Another way would be to create an image, save it and load it as Texture with Flags. Naturally better would be to have a Command ClsColor(R,G,B,A#=1.0)

jfk EO-11110 (Posted 2005) [#4]

If I remember correctly, you can TEXT to a texturebuffer exactly one time, IF the alpha-channel is already set. To prevent slow writepixel commands you may create a dummy texture of the same size, set its alpha bytes to zero (using writepixelfast) and then COPYRECT (instead of CLS) from this dummy texture to the target texture whenever you plan to write some new TEXT to the target texture.