Rotate view?
BlitzMax Forums/OpenGL Module/Rotate view?
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| I have some text scrolling up the screen but I would like to give it the starwars intro effect. Can I rotate the camera view to get perspective whilst still using Max2D for the majority of the code? Any help appreciated. |
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| I think that you cannot use Max2D abd rotate the angle of the view. Because Max2D uses (I think) strictly GluOrtho2D or glOrtho. |
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| I don't see any reason why you can't call glOrtho2D or whatever any number of times in your code, ie before you render stuff, to give you a perspective projection. |
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| Correct, Daniel. Cracked it last nite. You can reset the projection in your code. |
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| It's pretty handy too - basically you are moving the camera and it lets you zoom, rotate and fly your game screen around in three dimensions pretty easily. |
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| Yeah I like it but I'm slow getting to grips with OGL. It works but I don't know if I'm doing things 'the right way' |
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| So, how about posting your code? Because this would be totally sweet to see used in the middle of a game :) |
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graphics 800,600,32
starfont=loadimagefont("Jedi Normal")
'glPushmatrix()
SetImageFont starfont
Const text_row_h=70
'MY STUFF HERE
fin=0
ystart#=450.00
SetBlend ALPHABLEND
ncount=0
ndelay=1
glMatrixMode(GL_PROJECTION)
glLoadIdentity()
gluPerspective(20.0,-8.0/6.0,1.0,100000.0)
glrotatef(180.0,0,0,1)
'glrotatef (180.0,0.0,0.0,1.0)
glEnable(GL_FOG)
Local fcols:Float[]=[0.0,0.0,0.0,0.0]
Local colptr:Float Ptr=VarPtr fcols[0]
glFogfv(GL_FOG_COLOUR,colptr)
glFogf(GL_FOG_START,500)
glFogf(GL_FOG_END,1000)
glFogi(GL_FOG_MODE,GL_LINEAR)
xpos=-108
angg#=80.0
dist=-836.0
scaley#=1.29599917
scalex#=0.113999963
Cls
Flip
Repeat
Cls
glMatrixMode(GL_MODELVIEW)
glLoadidentity()
SetOrigin xpos,ystart
glTranslatef(0,0,dist)
glrotatef(angg,1,0,0)
SetScale scalex,scaley
SetColor Rand(0,255),Rand(0,255),Rand(0,255)
DrawText " ***********************************",0.0,text_row_h
DrawText " * your text here!! *",0.0,text_row_h*2
DrawText " **********************************",0.0,text_row_h*3
DrawText " * ************** *",0.0,text_row_h*4
DrawText " *************04/05*************",0.0,text_row_h*5
EndIf
ncount:+1
If ncount>ndelay Then ncount=0
If ncount=0 Then ystart:-1
Flip
Until KeyHit(KEY_ESCAPE) Or ystart<-2000.0
glMatrixMode GL_PROJECTION
glLoadidentity()
glOrtho 0,800,600,0,-1,1
SetScale(1,1)
SetColor 255,255,255
SetAlpha 1.0
glMatrixMode GL_MODELVIEW
glLoadIdentity
SetOrigin 0,0
glDisable(GL_FOG)
'glPopmatrix()
Cls
Flip
Here you go - I've tried to make a couple of mods so you can run it straight off the bat - untested - you'll need to download a font called 'Jedi Normal' to see it as intended - this is on a website called "2200 free fonts" - available in Mac or PC format. Make sure the font filename is correct in the code above. |
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| compile errors! "endif" without "if missing parameter "size" in line 2 had to go at that point, hope that helps |
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Graphics 800,600,32
starfont=LoadImageFont("Jedi Normal",48)
'glPushmatrix()
SetImageFont starfont
Const text_row_h=70
'MY STUFF HERE
fin=0
ystart#=450.00
SetBlend ALPHABLEND
ncount=0
ndelay=1
glMatrixMode(GL_PROJECTION)
glLoadIdentity()
gluPerspective(20.0,-8.0/6.0,1.0,100000.0)
glrotatef(180.0,0,0,1)
'glrotatef (180.0,0.0,0.0,1.0)
glEnable(GL_FOG)
Local fcols:Float[]=[0.0,0.0,0.0,0.0]
Local colptr:Float Ptr=VarPtr fcols[0]
glFogfv(GL_FOG_COLOUR,colptr)
glFogf(GL_FOG_START,500)
glFogf(GL_FOG_END,1000)
glFogi(GL_FOG_MODE,GL_LINEAR)
xpos=-108
angg#=80.0
dist=-836.0
scaley#=1.29599917
scalex#=0.113999963
Cls
Flip
Repeat
Cls
glMatrixMode(GL_MODELVIEW)
glLoadidentity()
SetOrigin xpos,ystart
glTranslatef(0,0,dist)
glrotatef(angg,1,0,0)
SetScale scalex,scaley
SetColor Rand(0,255),Rand(0,255),Rand(0,255)
DrawText " ***********************************",0.0,text_row_h
DrawText " * your text here!! *",0.0,text_row_h*2
DrawText " **********************************",0.0,text_row_h*3
DrawText " * ************** *",0.0,text_row_h*4
DrawText " *************04/05*************",0.0,text_row_h*5
DrawText "BLAH BLAH etc ",0,text_row_h*6
DrawText "* *",0,text_row_h*7
DrawText "* *",0,text_row_h*8
DrawText "* *",0,text_row_h*9
ncount:+1
If ncount>ndelay Then ncount=0
If ncount=0 Then ystart:-1
Flip
Until KeyHit(KEY_ESCAPE) Or ystart<-2000.0
glMatrixMode GL_PROJECTION
glLoadidentity()
glOrtho 0,800,600,0,-1,1
SetScale(1,1)
SetColor 255,255,255
SetAlpha 1.0
glMatrixMode GL_MODELVIEW
glLoadIdentity
SetOrigin 0,0
glDisable(GL_FOG)
'glPopmatrix()
Cls
Flip
OK- snapped out of the bout of laziness. This is tested. Just need the font in the same dir. |
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| Thanks. I've used this for some awesome in-game transitions...fade out and spin, then spin back in real fast :) One more thing - how do I set the origin of rotation? opengl noob speaking here. Thanks. |
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| Erm - I'm an OGL noob, too. Did most of this by 'fiddling about'. Look at the GLtranslatef() and the GLrotatef() in the main loop - these tell OpenGL to translate so far along the x,y,z axes [GLtranslate (distx,disty,distz)] then from that centre rotate n degrees about vector 'A' [GLrotatef(angle,Ax,Ay,Az)] - before drawing the text - try fiddling with these. |
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| Yes, that's all well and good, but then how do I move the camera back before rendering? |
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| You don't - you move the scene forward using a GLtranslatef(). |
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