quads get distorted when i draw more than one

BlitzMax Forums/OpenGL Module/quads get distorted when i draw more than one
slenkar
(Posted 2009) [#1]
why does the 2nd image look distorted?
Strict

Import Pub.OpenGL
Import brl.GLGraphics
' Setup a 2D projection
Const XSize = 800, YSize = 600
Const screendepth=0
Global Texname:Int
DebugLog "huh?"

'Global checkimage:Byte[129,129,4]
DebugLog "array"
GLGraphics(xsize,ysize,ScreenDepth,0,GRAPHICS_BACKBUFFER|GRAPHICS_DEPTHBUFFER) '| BGL_FULLSCREEN

DebugLog "2"

glMatrixMode (GL_PROJECTION)
glLoadIdentity ()

glOrtho (0, XSize, YSize, 0, 0, 1)
glDisable(GL_DEPTH_TEST)
glMatrixMode (GL_MODELVIEW)
glLoadIdentity()
' Displacement trick for exact pixelization
glTranslatef(0.375, 0.375, 0)
 DebugLog "3"
' Variables
Local angle#, x1, y1, x2, y2, radius#
Local  i
 Local Framecounter_counter
Local framecounter_time
Local Framecounter_framerate
DebugLog "load texture"

		glEnable(GL_BLEND)
glEnable(GL_TEXTURE_2D)


'glBlendFunc(GL_SRC_ALPHA, GL_ONE)
     '         //activate blending mode
'glBlendFunc(GL_DST_COLOR, GL_SRC_ALPHA)
glblendfunc(GL_SRC_ALPHA,GL_ONE_MINUS_SRC_ALPHA)
Local pix:TPixmap=LoadPixmap("bmxlogo.tga")
'MaskPixmap(pix,255,255,255)



Local tex=GLTexFromPixmap(pix)
'Eric Desrosiers
While Not KeyHit( KEY_ESCAPE ) And Not AppTerminate() 
' Draw a scene
glClearColor(.3, .3, .3, 0)
glClear(GL_COLOR_BUFFER_BIT)
	'glEnable(GL_ALPHA_TEST)
'glDepthMask(true)

'	glDisable(GL_DEPTH_TEST)
'glEnable(GL_CULL_FACE)
'

'//To enable my_own_blend effect
'glEnable(GL_COLOR_MATERIAL)

'glBlendFunc(GL_SRC_ALPHA, GL_ONE)
'glEnable(GL_BLEND)

HollowRectangle (0,0,620,460) 
Line (0,0,620,0) 
Rectangle (0,40,620, 80) 
Line (580,460,620,420) 

For i = 1 To 5000
x1 = Rand(0,xsize)
y1 = Rand(0,ysize)
 Point(x1,y1)
Next

Circle(320,240,20)
HollowCircle(320,240,30 )
HollowCircle ( 320, 240, 60)
HollowCircle( 320, 240, 40)
'glBindTexture GL_TEXTURE_2D,Texname
glEnable(GL_TEXTURE_2D)
	glBindTexture GL_TEXTURE_2D,Tex

'For Local x=0 To xsize Step 128
'For Local y=0 To ysize Step 128
quad(300,300,128,128)
'Next
'Next

quad(528,300,128,128)
'quad(300,400,128,128)
	glDisable(GL_TEXTURE_2D)
	glColor3f(1.0,1.0,1.0)

	'Framecounter--------------------------------------------
	Framecounter_counter=Framecounter_counter+1
	If Framecounter_time=0 Then Framecounter_time=MilliSecs()
	If Framecounter_time+1001 <MilliSecs() Then
		Framecounter_framerate=Framecounter_counter
		Framecounter_counter=0
		Framecounter_time=MilliSecs()
		DebugLog("FPS : "+Framecounter_framerate)
	EndIf



Flip
Wend
 
Function Point(x1,y1)
glBegin(GL_POINTS)
glVertex2f(x1 + 0.5, y1 + 0.5)
glEnd()
EndFunction
 
Function Line(x1,y1,x2,y2) 
glBegin(GL_LINES)
glVertex2f(x1, y1)
glVertex2f(x2, y2)
glEnd()
EndFunction
 
Function Rectangle(x1,y1,x2,y2)
glBegin(GL_QUADS)
glVertex2f(x1, y1)
 glVertex2f(x2, y1)
 glVertex2f(x2, y2)
 glVertex2f(x1, y2)
glEnd()
EndFunction
 
Function HollowRectangle(x1,y1,x2,y2)
glBegin(GL_LINE_LOOP)
glVertex2f(x1, y1)
 glVertex2f(x2, y1)
 glVertex2f(x2, y2)
 glVertex2f(x1, y2)
glEnd()
EndFunction

Function quad(x,y,width,height)


glBegin(GL_QUADS)
glTexCoord2f(0,1)
glVertex2f(x, y+height)
glTexCoord2f(1,1)
glVertex2f( x+width, x+height)
glTexCoord2f(1,0)
glVertex2f( x+width,y)
glTexCoord2f(0,0)
glVertex2f(x,y)
glEnd()


Rem
		glTexCoord2f(0,0)
		glVertex2f(x, y)
		glTexCoord2f(0, tex_height)
		glVertex2f(x, height)
		glTexCoord2f(tex_Width,tex_Height)
		glVertex2f(width,height)
		glTexCoord2f(tex_Width, 0)
		glVertex2f(width,y)
EndRem
EndFunction
Function Circle(x1,y1,radius#)
glBegin(GL_TRIANGLE_FAN)
glVertex2f(x1, y1)
For Local angle# = 0 To 360 Step 5
glVertex2f(x1 + Sin(angle#) * radius#, y1 + Cos(angle#) * radius#)
Next
glEnd()
EndFunction
 
Function HollowCircle(x1,y1,radius#)
glBegin(GL_LINE_LOOP)
For Local angle# = 0 To 360 Step 5
glVertex2f(x1 + Sin(angle#) * radius#, y1 + Cos(angle#) * radius#)
Next
glEnd()
EndFunction
(use an image that is 128x128)
Floyd
(Posted 2009) [#2]
It's a typo in the quad function; x+height should be y+height.
slenkar
(Posted 2009) [#3]
thanks