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//*Start with OpenGLSurface1 sized and locked to window edges
//*and picture dragged into project and renamed "myPic"

//--------- window events
Sub Open()
  genTexBank(0)          //create bank for 1 texture (0 based)
  storeImage(0, myPic)   //put an image in the bank
  OpenGLSurface1.Render  //ready to draw
End Sub

Sub Resizing()
  OpenGLSurface1.Render
End Sub

//-------- OpenGLSurface1 event
Function Render() As Boolean
  initGLDrawing(me)   //setup projection and clear buffers
  
  OpenGL.glEnable(OpenGL.GL_TEXTURE_2D)
  bindTo(0)   //bind to image in first bank
  
  OpenGL.glBegin(OpenGL.GL_QUADS)  //draw quad
  
  OpenGL.glTexCoord2f(1, 1)
  OpenGL.glVertex3f(-1, -1, 0)
  OpenGL.glTexCoord2f(1, 0)
  OpenGL.glVertex3f(-1,  1, 0)
  OpenGL.glTexCoord2f(0, 0)
  OpenGL.glVertex3f( 1,  1, 0)
  OpenGL.glTexCoord2f(0, 1)
  OpenGL.glVertex3f( 1, -1, 0)
  
  OpenGL.glEnd
End Function



//======================== texture helpers (window property and methods)

texNames(-1) As Integer  //stores list of generated bank 'names'

Sub genTexBank(lastBankIdx As integer)
  dim count As integer = lastBankIdx + 1
  
  dim m As new MemoryBlock(count * 4) //array of 4 byte integers
  
  OpenGL.glGenTextures(count, m) //retrieve ids
  
  redim texNames(lastBankIdx) //scan values into easier to use int array
  for i As integer = 0 to lastBankIdx
    texNames(i) = m.Int32Value(i * 4)
  next
End Sub

Sub storeImage(bankIdx As integer, p As Picture)
  dim imgW As integer = p.Width
  dim imgH As integer = p.Height
  dim memImg As new MemoryBlock(imgW * imgH * 3)
  
  dim surf As RGBSurface = p.RGBSurface
  
  if surf = nil then //need a new pic with a surface
    dim p2 As new Picture(imgW, imgH, 32)
    p2.Graphics.DrawPicture p, 0, 0
    p = p2 'repoint cause p2 goes out of scope, not necessary tho
    surf = p.RGBSurface 'grab surf now, should be good
  end
  
  dim x, y, offset As integer 'scan surf into memoryblock
  for y = 0 to imgH - 1
    for x = 0 to imgW - 1
      memImg.ColorValue(offset, 24) = surf.Pixel(x, y)
      offset = offset + 3
    next
  next
  
  OpenGL.glBindTexture(OpenGL.GL_TEXTURE_2D, texNames(bankIdx))
  
  OpenGL.glTexParameteri(OpenGL.GL_TEXTURE_2D, OpenGL.GL_TEXTURE_WRAP_S,     OpenGL.GL_REPEAT)
  OpenGL.glTexParameteri(OpenGL.GL_TEXTURE_2D, OpenGL.GL_TEXTURE_WRAP_T,     OpenGL.GL_REPEAT)
  OpenGL.glTexParameteri(OpenGL.GL_TEXTURE_2D, OpenGL.GL_TEXTURE_MAG_FILTER, OpenGL.GL_LINEAR)'NEAREST)
  OpenGL.glTexParameteri(OpenGL.GL_TEXTURE_2D, OpenGL.GL_TEXTURE_MIN_FILTER, OpenGL.GL_LINEAR)'GL_NEAREST)
  
  OpenGL.glPixelStorei(OpenGL.GL_UNPACK_ALIGNMENT, 1)
  OpenGL.glTexImage2D(OpenGL.GL_TEXTURE_2D, 0, OpenGL.GL_RGBA, imgW, imgH, 0, OpenGL.GL_BGR, OpenGL.GL_UNSIGNED_BYTE, memImg)
End Sub

Sub bindTo(bankIdx As integer)
  OpenGL.glBindTexture(OpenGL.GL_TEXTURE_2D, texNames(bankIdx))
End Sub


//======================= setup drawing (window method)

Sub initGLDrawing(disp As OpenGLSurface)
  //viewport
  OpenGL.glViewport 0, 0, disp.Width, disp.Height
  
  //projection transform (camera)
  OpenGL.glMatrixMode(OpenGL.GL_PROJECTION)
  OpenGL.glLoadIdentity
  dim imageRatio As single = disp.Width / disp.Height //fix for fov in x
  OpenGL.gluPerspective 55 / imageRatio, imageRatio, 0.1, 100
  Soft Declare sub gluLookAt lib "OpenGL.framework" (eyeX as Double, eyeY as Double, eyeZ as Double, centerX as Double, centerY as Double, centerZ as Double, upX as Double, upY as Double, upZ as Double)
  gluLookAt 2, 1.5, -5,    0, 0, 0,    0, 1, 0 //cam position, lookat point, up vector
  //model transform
  OpenGL.glMatrixMode(OpenGL.GL_MODELVIEW)
  OpenGL.glLoadIdentity
  
  //clear
  OpenGL.glClearColor 1, 1, 0, 0  'yellow
  OpenGL.glClear      OpenGL.GL_COLOR_BUFFER_BIT + OpenGL.GL_DEPTH_BUFFER_BIT
  OpenGL.glEnable     OpenGL.GL_DEPTH_TEST
End Sub

OpenGL.glClearColor(1,1,1,1) 'White Background
OpenGL.glClear(OpenGL.GL_COLOR_BUFFER_BIT) 'Clear Colour buffer
OpenGL.glClear(OpenGL.GL_DEPTH_BUFFER_BIT) 'Clear Depth buffer
OpenGL.glEnable(OpenGL.GL_DOUBLEBUFFER) 'Make the scene move quicker
OpenGL.glEnable(OpenGL.GL_DEPTH_TEST) 'Enables 3d depth testing

Call Camera

OpenGL.glDisable OpenGL.GL_CULL_FACE

OpenGL.glPushMatrix()
OpenGL.glTranslated(XPosition, YPosition, ZPosition) //center on camera eye
OpenGL.glColor3d(1,1,1)
drawSkybox(50) 'draw environment cube
OpenGL.glPopMatrix()

OpenGL.glCullFace OpenGL.GL_BACK 'Only draw quads facing us
OpenGL.glEnable OpenGL.GL_CULL_FACE 'Ignore quads away from us

OpenGL.glPushMatrix()
OpenGL.glScaled(0.35,0.35,0.35) ' scale at 35%
call DrawCube 'Draw a hundered cubes
OpenGL.glPopMatrix()