The following example illustrates masking.
It is an adaptation of NeHe Lesson 20: http://nehe.gamedev.net/data/lessons/lesson.asp?lesson=20
' SED_PBWIN - Use the PBWIN compiler
#COMPILE EXE
#DIM ALL
#INCLUDE "GLU.INC"
#INCLUDE "GDIPLUS.INC"
#INCLUDE "GDIPUTILS.INC"
$WindowCaption = "NeHe Lesson 20"
%GL_WINDOWWIDTH = 640 ' Window width
%GL_WINDOWHEIGHT = 480 ' Window height
%GL_BITSPERPEL = 16 ' Color resolution in bits per pixel
%GL_DEPTHBITS = 16 ' Depth of the depth (z-axis) buffer
GLOBAL hDC AS LONG ' Device context handle
GLOBAL TextureHandles() AS DWORD ' Texture handles
GLOBAL masking AS LONG ' Masking on/off
GLOBAL scene AS LONG ' Which scene to draw
GLOBAL roll AS SINGLE ' Rolling texture
' =======================================================================================
' All the setup goes here
' =======================================================================================
SUB SetupScene (BYVAL hwnd AS DWORD, BYVAL nWidth AS LONG, BYVAL nHeight AS LONG)
LOCAL hr AS LONG
LOCAL i AS LONG
DIM TextureHandles(4) AS DWORD
DIM TextureWidth(4) AS LONG
DIM TextureHeight(4) AS LONG
DIM strTextureData(4) AS STRING
masking = %TRUE
' Load textures from disk
hr = GdiPlusLoadTexture("logo.bmp", TextureWidth(0), TextureHeight(0), strTextureData(0), %TRUE)
hr = GdiPlusLoadTexture("mask1.bmp", TextureWidth(1), TextureHeight(1), strTextureData(1), %TRUE)
hr = GdiPlusLoadTexture("image1.bmp", TextureWidth(2), TextureHeight(2), strTextureData(2), %TRUE)
hr = GdiPlusLoadTexture("mask2.bmp", TextureWidth(3), TextureHeight(3), strTextureData(3), %TRUE)
hr = GdiPlusLoadTexture("image2.bmp", TextureWidth(4), TextureHeight(4), strTextureData(4), %TRUE)
' Create two textures
glGenTextures 5, TextureHandles(0)
FOR i = 0 TO 4
glBindTexture %GL_TEXTURE_2D, TextureHandles(i)
glTexParameteri %GL_TEXTURE_2D, %GL_TEXTURE_MAG_FILTER, %GL_LINEAR
glTexParameteri %GL_TEXTURE_2D, %GL_TEXTURE_MIN_FILTER, %GL_LINEAR
glTexImage2D %GL_TEXTURE_2D, 0, 3, TextureWidth(i), TextureHeight(i), 0, _
%GL_RGBA, %GL_UNSIGNED_BYTE, BYVAL STRPTR(strTextureData(i))
NEXT
' Specify clear values for the color buffers
glClearColor 0.0!, 0.0!, 0.0!, 0.0!
' Enables clearing of the depth buffer
glClearDepth 1.0!
' Enable depth testing
glEnable %GL_DEPTH_TEST
' Enables smooth color shading
glShadeModel %GL_SMOOTH
' Enable 2D texture mapping
glEnable %GL_TEXTURE_2D
END SUB
' =======================================================================================
' =======================================================================================
' Resize the scene
' =======================================================================================
SUB ResizeScene (BYVAL hwnd AS DWORD, BYVAL nWidth AS LONG, BYVAL nHeight AS LONG)
' Prevent divide by zero making height equal one
IF nHeight = 0 THEN nHeight = 1
' Reset the current viewport
glViewport 0, 0, nWidth, nHeight
' Select the projection matrix
glMatrixMode %GL_PROJECTION
' Reset the projection matrix
glLoadIdentity
' Calculate the aspect ratio of the window
gluPerspective 45.0!, nWidth / nHeight, 0.1!, 100.0!
' Select the model view matrix
glMatrixMode %GL_MODELVIEW
' Reset the model view matrix
glLoadIdentity
END SUB
' =======================================================================================
' =======================================================================================
' Draw the scene
' =======================================================================================
SUB DrawScene (BYVAL hwnd AS DWORD, BYVAL nWidth AS LONG, BYVAL nHeight AS LONG)
' Clear the screen buffer
glClear %GL_COLOR_BUFFER_BIT OR %GL_DEPTH_BUFFER_BIT
' Reset the view
glLoadIdentity
' Move into the screen 5 units
glTranslatef 0.0!, 0.0!, -2.0!
' Select the logo texture
glBindTexture %GL_TEXTURE_2D, TextureHandles(0)
' Start drawing a textured quad
glBegin %GL_QUADS
glTexCoord2f 0.0!, - roll + 0.0! : glVertex3f -1.1!, -1.1!, 0.0! ' Bottom left
glTexCoord2f 3.0!, - roll + 0.0! : glVertex3f 1.1!, -1.1!, 0.0! ' Bottom right
glTexCoord2f 3.0!, - roll + 3.0! : glVertex3f 1.1!, 1.1!, 0.0! ' Top right
glTexCoord2f 0.0!, - roll + 3.0! : glVertex3f -1.1!, 1.1!, 0.0! ' Top left
glEnd
glEnable %GL_BLEND ' Enable blending
glDisable %GL_DEPTH_TEST ' Disable depth testing
IF masking THEN ' Is masking enabled?
glBlendFunc %GL_DST_COLOR, %GL_ZERO ' Blend screen color with zero (black)
END IF
IF scene THEN ' Are we drawing the second scene?
glTranslatef 0.0!, 0.0!, -1.0! ' Translate into the screen one unit
glRotatef roll * 360, 0.0!, 0.0!, 1.0! ' Rotate on the z axis 360 degrees
IF masking THEN ' Is masking on?
glBindTexture %GL_TEXTURE_2D, TextureHandles(3) ' Select the second mask texture
glBegin %GL_QUADS ' Start drawing a textured quad
glTexCoord2f 0.0!, 0.0! : glVertex3f -1.1!, -1.1!, 0.0! ' Bottom left
glTexCoord2f 1.0!, 0.0! : glVertex3f 1.1!, -1.1!, 0.0! ' Bottom right
glTexCoord2f 1.0!, 1.0! : glVertex3f 1.1!, 1.1!, 0.0! ' Top right
glTexCoord2f 0.0!, 1.0! : glVertex3f -1.1!, 1.1!, 0.0! ' Top left
glEnd ' Done Drawing The Quad
END IF
glBlendFunc %GL_ONE, %GL_ONE ' Copy image 2 color to the screen
glBindTexture %GL_TEXTURE_2D, TextureHandles(4) ' Select the second image texture
glBegin %GL_QUADS ' Start drawing a textured quad
glTexCoord2f 0.0!, 0.0! : glVertex3f -1.1!, -1.1!, 0.0! ' Bottom left
glTexCoord2f 1.0!, 0.0! : glVertex3f 1.1!, -1.1!, 0.0! ' Bottom right
glTexCoord2f 1.0!, 1.0! : glVertex3f 1.1!, 1.1!, 0.0! ' Top right
glTexCoord2f 0.0!, 1.0! : glVertex3f -1.1!, 1.1!, 0.0! ' Top left
glEnd ' Done Drawing The Quad
ELSE
IF masking THEN ' Is masking on?
glBindTexture %GL_TEXTURE_2D, TextureHandles(1) ' Select the first mask texture
glBegin %GL_QUADS ' Start drawing a textured quad
glTexCoord2f roll + 0.0!, 0.0! : glVertex3f -1.1!, -1.1!, 0.0! ' Bottom left
glTexCoord2f roll + 4.0!, 0.0! : glVertex3f 1.1!, -1.1!, 0.0! ' Bottom right
glTexCoord2f roll + 4.0!, 4.0! : glVertex3f 1.1!, 1.1!, 0.0! ' Top right
glTexCoord2f roll + 0.0!, 4.0! : glVertex3f -1.1!, 1.1!, 0.0! ' Top left
glEnd ' Done drawing the quad
END IF
glBlendFunc %GL_ONE, %GL_ONE ' Copy image 1 color to the screen
glBindTexture %GL_TEXTURE_2D, TexTureHandles(2) ' Select the first image texture
glBegin %GL_QUADS ' Start drawing a textured quad
glTexCoord2f roll + 0.0!, 0.0! : glVertex3f -1.1!, -1.1!, 0.0! ' Bottom left
glTexCoord2f roll + 4.0!, 0.0! : glVertex3f 1.1!, -1.1!, 0.0! ' Bottom right
glTexCoord2f roll + 4.0!, 4.0! : glVertex3f 1.1!, 1.1!, 0.0! ' Top right
glTexCoord2f roll + 0.0!, 4.0! : glVertex3f -1.1!, 1.1!, 0.0! ' Top left
glEnd ' Done drawing the quad
END IF
glEnable %GL_DEPTH_TEST ' Enable depth testing
glDisable %GL_BLEND ' Disable blending
roll = roll + 0.002! ' Increase our texture roll bariable
IF roll > 1.0! THEN ' Is roll greater than one
roll = roll - 1.0! ' Subtract 1 from roll
END IF
END SUB
' =======================================================================================
' =======================================================================================
' Cleanup
' =======================================================================================
SUB Cleanup (BYVAL hwnd AS DWORD)
' Delete the textures
glDeleteTextures(5, TextureHandles(0))
END SUB
' =======================================================================================
' =======================================================================================
' Processes keystrokes
' Parameters:
' * hwnd = Window hande
' * vKeyCode = Virtual key code
' * bKeyDown = %TRUE if key is pressed; %FALSE if it is released
' =======================================================================================
SUB ProcessKeystrokes (BYVAL hwnd AS DWORD, BYVAL vKeyCode AS LONG, BYVAL bKeyDown AS LONG)
STATIC mp, sp AS LONG
SELECT CASE AS LONG vKeyCode
CASE %VK_ESCAPE
' Quit if Esc key pressed
SendMessage hwnd, %WM_CLOSE, 0, 0
CASE %VK_SPACE
IF ISTRUE bKeyDown AND ISFALSE sp THEN
sp = %TRUE
scene = NOT scene
END IF
IF ISFALSE bKeyDown THEN sp = %FALSE
CASE %VK_M
IF ISTRUE bKeyDown AND ISFALSE mp THEN
mp = %TRUE
IF ISTRUE masking THEN masking = %FALSE ELSE masking = %TRUE
END IF
IF ISFALSE bKeyDown THEN mp = %FALSE
END SELECT
END SUB
' =======================================================================================
' =======================================================================================
' Main
' =======================================================================================
FUNCTION WINMAIN (BYVAL hInstance AS DWORD, BYVAL hPrevInstance AS DWORD, BYVAL lpszCmdLine AS ASCIIZ PTR, BYVAL nCmdShow AS LONG) AS LONG
LOCAL hwnd AS DWORD
LOCAL wcex AS WNDCLASSEX
LOCAL szClassName AS ASCIIZ * 256
LOCAL szCaption AS ASCIIZ * 256
LOCAL msg AS tagMSG
LOCAL rc AS RECT
LOCAL bDone AS LONG
LOCAL nLeft AS LONG
LOCAL nTop AS LONG
LOCAL nWidth AS LONG
LOCAL nHeight AS LONG
LOCAL dwStyle AS DWORD
LOCAL dwStyleEx AS DWORD
STATIC vKeyCode AS LONG
STATIC bKeyDown AS LONG
LOCAL t AS DOUBLE
LOCAL t0 AS DOUBLE
LOCAL fps AS DOUBLE
LOCAL nFrames AS LONG
LOCAL dm AS DEVMODE
LOCAL bFullScreen AS LONG
LOCAL lResult AS LONG
' Register the window class
szClassName = "PBOPENGL"
wcex.cbSize = SIZEOF(wcex)
wcex.style = %CS_HREDRAW OR %CS_VREDRAW OR %CS_OWNDC
wcex.lpfnWndProc = CODEPTR(WndProc)
wcex.cbClsExtra = 0
wcex.cbWndExtra = 0
wcex.hInstance = hInstance
wcex.hCursor = LoadCursor (%NULL, BYVAL %IDC_ARROW)
wcex.hbrBackground = %NULL
wcex.lpszMenuName = %NULL
wcex.lpszClassName = VARPTR(szClassName)
wcex.hIcon = LoadIcon (%NULL, BYVAL %IDI_APPLICATION) ' Sample, if resource icon: LoadIcon(hInst, "APPICON")
wcex.hIconSm = LoadIcon (%NULL, BYVAL %IDI_APPLICATION) ' Remember to set small icon too..
RegisterClassEx wcex
' Ask the user which screen mode he prefers
lResult = MessageBox(%NULL, "Would you like to run in fullscreen mode?", _
"Start fullScreen?", %MB_YESNOCANCEL OR %MB_ICONQUESTION)
SELECT CASE lResult
CASE %IDCANCEL : EXIT FUNCTION
CASE %IDYES : bFullScreen = %TRUE
CASE %IDNO : bFullScreen = %FALSE
END SELECT
' Window size
nWidth = %GL_WINDOWWIDTH
nHeight = %GL_WINDOWHEIGHT
IF bFullScreen THEN
' Change display settings
dm.dmSize = SIZEOF(dm)
dm.dmPelsWidth = nWidth
dm.dmPelsHeight = nHeight
dm.dmBitsPerPel = %GL_BITSPERPEL
dm.dmFields = %DM_BITSPERPEL OR %DM_PELSWIDTH OR %DM_PELSHEIGHT
IF ChangeDisplaySettings(dm, %CDS_FULLSCREEN) = 0 THEN ShowCursor %FALSE
END IF
' Window caption
szCaption = $WindowCaption
' Window styles
IF ISFALSE bFullScreen THEN
dwStyle = %WS_OVERLAPPEDWINDOW
dwStyleEx = %WS_EX_APPWINDOW OR %WS_EX_WINDOWEDGE
ELSE
dwStyle = %WS_POPUP
dwStyleEx = %WS_EX_APPWINDOW
END IF
' Create the window
hwnd = CreateWindowEx( _
dwStyleEx, _ ' extended styles
szClassName, _ ' window class name
szCaption, _ ' window caption
dwStyle, _ ' window style
nLeft, _ ' initial x position
nTop, _ ' initial y position
nWidth, _ ' initial x size
nHeight, _ ' initial y size
%NULL, _ ' parent window handle
0, _ ' window menu handle
hInstance, _ ' program instance handle
BYVAL %NULL) ' creation parameters
' Retrieve the coordinates of the window's client area
GetClientRect hwnd, rc
' Initialize the new OpenGl window
SetupScene hwnd, rc.nRight - rc.nLeft, rc.nBottom - rc.nTop
' Show the window
ShowWindow hwnd, nCmdShow
UpdateWindow hwnd
DO UNTIL bDone
' Windows message pump
DO WHILE PeekMessage(msg, %NULL, 0, 0, %PM_REMOVE)
IF msg.message = %WM_QUIT THEN
bDone = %TRUE
ELSE
IF msg.message = %WM_KEYDOWN THEN
vKeyCode = msg.wParam
bKeyDown = %TRUE
ELSEIF msg.message = %WM_KEYUP THEN
vKeyCode = msg.wParam
bKeyDown = %FALSE
END IF
TranslateMessage msg
DispatchMessage msg
END IF
LOOP
IF ISFALSE bFullScreen THEN
' Get time and mouse position
t = INT(TIMER)
' Calculate and display FPS (frames per second)
IF t > t0 OR nFrames = 0 THEN
fps = nFrames \ (t - t0)
wsprintf szCaption, $WindowCaption & " (%i FPS)", BYVAL fps
SetWindowText hwnd, szCaption
t0 = t
nFrames = 0
END IF
nFrames = nFrames + 1
END IF
' Draw the scene
DrawScene hwnd, nWidth, nHeight
' Exchange the front and back buffers
SwapBuffers hDC
' Process the keystrokes
IF vKeyCode THEN
ProcessKeystrokes hwnd, vKeyCode, bKeyDown
vKeyCode = 0
END IF
LOOP
' Retore defaults
IF bFullScreen THEN
ChangeDisplaySettings BYVAL %NULL, 0
ShowCursor %TRUE
END IF
FUNCTION = msg.wParam
END FUNCTION
' =======================================================================================
' =======================================================================================
' Main window procedure
' =======================================================================================
FUNCTION WndProc (BYVAL hwnd AS DWORD, BYVAL wMsg AS DWORD, BYVAL wParam AS DWORD, BYVAL lParam AS LONG) AS LONG
LOCAL pf AS LONG
LOCAL pfd AS PIXELFORMATDESCRIPTOR
STATIC hRC AS LONG
SELECT CASE wMsg
CASE %WM_SYSCOMMAND
' Disable the Windows screensaver
IF (wParam AND &HFFF0) = %SC_SCREENSAVE THEN EXIT FUNCTION
' Close the window
IF (wParam AND &HFFF0) = %SC_CLOSE THEN
SendMessage hwnd, %WM_CLOSE, 0, 0
EXIT FUNCTION
END IF
CASE %WM_CREATE
' Retrieve the device context handle
hDC = GetDC(hwnd)
' Fill the PIXELFORMATDESCRIPTOR structure
pfd.nSize = SIZEOF(PIXELFORMATDESCRIPTOR) ' Size of the structure
pfd.nVersion = 1 ' Version number
pfd.dwFlags = %PFD_DRAW_TO_WINDOW _ ' Format must support window
OR %PFD_SUPPORT_OPENGL _ ' Format must support OpenGL
OR %PFD_DOUBLEBUFFER ' Format must support double buffering
pfd.iPixelType = %PFD_TYPE_RGBA ' Request an RGBA format
pfd.cColorBits = %GL_BITSPERPEL ' Number of color bitplanes in each color buffer
pfd.cRedBits = 0 ' Number of red bitplanes in each RGBA color buffer.
pfd.cRedShift = 0 ' Shift count for red bitplanes in each RGBA color buffer.
pfd.cGreenBits = 0 ' Number of green bitplanes in each RGBA color buffer.
pfd.cGreenShift = 0 ' Shift count for green bitplanes in each RGBA color buffer.
pfd.cBlueBits = 0 ' Number of blue bitplanes in each RGBA color buffer.
pfd.cBlueShift = 0 ' Shift count for blue bitplanes in each RGBA color buffer.
pfd.cAlphaBits = 0 ' Number of alpha bitplanes in each RGBA color buffer
pfd.cAlphaShift = 0 ' Shift count for alpha bitplanes in each RGBA color buffer.
pfd.cAccumBits = 0 ' Total number of bitplanes in the accumulation buffer.
pfd.cAccumRedBits = 0 ' Number of red bitplanes in the accumulation buffer.
pfd.cAccumGreenBits = 0 ' Number of gree bitplanes in the accumulation buffer.
pfd.cAccumBlueBits = 0 ' Number of blue bitplanes in the accumulation buffer.
pfd.cAccumAlphaBits = 0 ' Number of alpha bitplanes in the accumulation buffer.
pfd.cDepthBits = %GL_DEPTHBITS ' Depth of the depth (z-axis) buffer.
pfd.cStencilBits = 0 ' Depth of the stencil buffer.
pfd.cAuxBuffers = 0 ' Number of auxiliary buffers.
pfd.iLayerType = %PFD_MAIN_PLANE ' Ignored. Earlier implementations of OpenGL used this member, but it is no longer used.
pfd.bReserved = 0 ' Number of overlay and underlay planes.
pfd.dwLayerMask = 0 ' Ignored. Earlier implementations of OpenGL used this member, but it is no longer used.
pfd.dwVisibleMask = 0 ' Transparent color or index of an underlay plane.
pfd.dwDamageMask = 0 ' Ignored. Earlier implementations of OpenGL used this member, but it is no longer used.
' Find a matching pixel format
pf = ChoosePixelFormat(hDC, pfd)
IF ISFALSE pf THEN
MessageBox hwnd, "Can't find a suitable pixel format", _
"Error", %MB_OK OR %MB_ICONEXCLAMATION
SendMessage hwnd, %WM_CLOSE, 0, 0
EXIT FUNCTION
END IF
' Set the pixel format
IF ISFALSE SetPixelFormat(hDC, pf, pfd) THEN
MessageBox hwnd, "Can't set the pixel format", _
"Error", %MB_OK OR %MB_ICONEXCLAMATION
SendMessage hwnd, %WM_CLOSE, 0, 0
EXIT FUNCTION
END IF
' Create a new OpenGL rendering context
hRC = wglCreateContext(hDC)
IF ISFALSE hRC THEN
MessageBox hwnd, "Can't create an OpenGL rendering context", _
"Error", %MB_OK OR %MB_ICONEXCLAMATION
SendMessage hwnd, %WM_CLOSE, 0, 0
EXIT FUNCTION
END IF
' Make it current
IF ISFALSE wglMakeCurrent(hDC,hRC) THEN
MessageBox hwnd, "Can't activate the OpenGL rendering context", _
"Error", %MB_OK OR %MB_ICONEXCLAMATION
SendMessage hwnd, %WM_CLOSE, 0, 0
EXIT FUNCTION
END IF
EXIT FUNCTION
CASE %WM_DESTROY
' Clear resources
Cleanup hwnd
' Release the device and rendering contexts
wglMakeCurrent hDC, 0
' Make the rendering context no longer current
wglDeleteContext hRC
' Release the device context
ReleaseDC hwnd, hDC
' Post an WM_QUIT message
PostQuitMessage 0
EXIT FUNCTION
CASE %WM_SIZE
ResizeScene hwnd, LO(WORD, lParam), HI(WORD, lParam)
EXIT FUNCTION
END SELECT
' Call the default window procedure to process unhandled messages
FUNCTION = DefWindowProc(hwnd, wMsg, wParam, lParam)
END FUNCTION
' =======================================================================================
(http://www.jose.it-berater.org/captures/EX_NeHe_Lesson_20.jpg)
The following example illustrates masking.
It is an adaptation of NeHe Lesson 20: http://nehe.gamedev.net/data/lessons/lesson.asp?lesson=20
' SED_PBWIN - Use the PBWIN compiler
#COMPILE EXE
#DIM ALL
#INCLUDE "SDL.INC"
#INCLUDE "GLU.INC"
#INCLUDE "GDIPUTILS.INC"
$WindowCaption = "NeHe Lesson 20"
GLOBAL hDC AS LONG ' Device context handle
GLOBAL TextureHandles() AS DWORD ' Texture handles
GLOBAL masking AS LONG ' Masking on/off
GLOBAL scene AS LONG ' Which scene to draw
GLOBAL roll AS SINGLE ' Rolling texture
' =======================================================================================
' All the setup goes here
' =======================================================================================
SUB SetupScene ()
LOCAL hr AS LONG
LOCAL i AS LONG
DIM TextureHandles(4) AS DWORD
DIM TextureWidth(4) AS LONG
DIM TextureHeight(4) AS LONG
DIM strTextureData(4) AS STRING
masking = %TRUE
' Load textures from disk
hr = GdiPlusLoadTexture("logo.bmp", TextureWidth(0), TextureHeight(0), strTextureData(0), %TRUE)
hr = GdiPlusLoadTexture("mask1.bmp", TextureWidth(1), TextureHeight(1), strTextureData(1), %TRUE)
hr = GdiPlusLoadTexture("image1.bmp", TextureWidth(2), TextureHeight(2), strTextureData(2), %TRUE)
hr = GdiPlusLoadTexture("mask2.bmp", TextureWidth(3), TextureHeight(3), strTextureData(3), %TRUE)
hr = GdiPlusLoadTexture("image2.bmp", TextureWidth(4), TextureHeight(4), strTextureData(4), %TRUE)
' Create two textures
glGenTextures 5, TextureHandles(0)
FOR i = 0 TO 4
glBindTexture %GL_TEXTURE_2D, TextureHandles(i)
glTexParameteri %GL_TEXTURE_2D, %GL_TEXTURE_MAG_FILTER, %GL_LINEAR
glTexParameteri %GL_TEXTURE_2D, %GL_TEXTURE_MIN_FILTER, %GL_LINEAR
glTexImage2D %GL_TEXTURE_2D, 0, 3, TextureWidth(i), TextureHeight(i), 0, _
%GL_RGBA, %GL_UNSIGNED_BYTE, BYVAL STRPTR(strTextureData(i))
NEXT
' Specify clear values for the color buffers
glClearColor 0.0!, 0.0!, 0.0!, 0.0!
' Enables clearing of the depth buffer
glClearDepth 1.0!
' Enable depth testing
glEnable %GL_DEPTH_TEST
' Enables smooth color shading
glShadeModel %GL_SMOOTH
' Enable 2D texture mapping
glEnable %GL_TEXTURE_2D
END SUB
' =======================================================================================
' =======================================================================================
' Draw the scene
' =======================================================================================
SUB DrawScene (BYVAL nWidth AS LONG, BYVAL nHeight AS LONG)
LOCAL i AS LONG
LOCAL sx, sy, sz AS SINGLE
' Clear the screen buffer
glClear %GL_COLOR_BUFFER_BIT OR %GL_DEPTH_BUFFER_BIT
' Select and setup the projection matrix
glMatrixMode %GL_PROJECTION
glLoadIdentity
' Prevent divide by zero making height equal one
IF nHeight = 0 THEN nHeight = 1
' Calculate the aspect ratio of the window
gluPerspective 45.0!, nWidth/nHeight, 1.0!, 100.0!
' Select and setup the modelview matrix
glMatrixMode %GL_MODELVIEW
glLoadIdentity
' Move into the screen 5 units
glTranslatef 0.0!, 0.0!, -2.0!
' Select the logo texture
glBindTexture %GL_TEXTURE_2D, TextureHandles(0)
' Start drawing a textured quad
glBegin %GL_QUADS
glTexCoord2f 0.0!, - roll + 0.0! : glVertex3f -1.1!, -1.1!, 0.0! ' Bottom left
glTexCoord2f 3.0!, - roll + 0.0! : glVertex3f 1.1!, -1.1!, 0.0! ' Bottom right
glTexCoord2f 3.0!, - roll + 3.0! : glVertex3f 1.1!, 1.1!, 0.0! ' Top right
glTexCoord2f 0.0!, - roll + 3.0! : glVertex3f -1.1!, 1.1!, 0.0! ' Top left
glEnd
glEnable %GL_BLEND ' Enable blending
glDisable %GL_DEPTH_TEST ' Disable depth testing
IF masking THEN ' Is masking enabled?
glBlendFunc %GL_DST_COLOR, %GL_ZERO ' Blend screen color with zero (black)
END IF
IF scene THEN ' Are we drawing the second scene?
glTranslatef 0.0!, 0.0!, -1.0! ' Translate into the screen one unit
glRotatef roll * 360, 0.0!, 0.0!, 1.0! ' Rotate on the z axis 360 degrees
IF masking THEN ' Is masking on?
glBindTexture %GL_TEXTURE_2D, TextureHandles(3) ' Select the second mask texture
glBegin %GL_QUADS ' Start drawing a textured quad
glTexCoord2f 0.0!, 0.0! : glVertex3f -1.1!, -1.1!, 0.0! ' Bottom left
glTexCoord2f 1.0!, 0.0! : glVertex3f 1.1!, -1.1!, 0.0! ' Bottom right
glTexCoord2f 1.0!, 1.0! : glVertex3f 1.1!, 1.1!, 0.0! ' Top right
glTexCoord2f 0.0!, 1.0! : glVertex3f -1.1!, 1.1!, 0.0! ' Top left
glEnd ' Done Drawing The Quad
END IF
glBlendFunc %GL_ONE, %GL_ONE ' Copy image 2 color to the screen
glBindTexture %GL_TEXTURE_2D, TextureHandles(4) ' Select the second image texture
glBegin %GL_QUADS ' Start drawing a textured quad
glTexCoord2f 0.0!, 0.0! : glVertex3f -1.1!, -1.1!, 0.0! ' Bottom left
glTexCoord2f 1.0!, 0.0! : glVertex3f 1.1!, -1.1!, 0.0! ' Bottom right
glTexCoord2f 1.0!, 1.0! : glVertex3f 1.1!, 1.1!, 0.0! ' Top right
glTexCoord2f 0.0!, 1.0! : glVertex3f -1.1!, 1.1!, 0.0! ' Top left
glEnd ' Done Drawing The Quad
ELSE
IF masking THEN ' Is masking on?
glBindTexture %GL_TEXTURE_2D, TextureHandles(1) ' Select the first mask texture
glBegin %GL_QUADS ' Start drawing a textured quad
glTexCoord2f roll + 0.0!, 0.0! : glVertex3f -1.1!, -1.1!, 0.0! ' Bottom left
glTexCoord2f roll + 4.0!, 0.0! : glVertex3f 1.1!, -1.1!, 0.0! ' Bottom right
glTexCoord2f roll + 4.0!, 4.0! : glVertex3f 1.1!, 1.1!, 0.0! ' Top right
glTexCoord2f roll + 0.0!, 4.0! : glVertex3f -1.1!, 1.1!, 0.0! ' Top left
glEnd ' Done drawing the quad
END IF
glBlendFunc %GL_ONE, %GL_ONE ' Copy image 1 color to the screen
glBindTexture %GL_TEXTURE_2D, TexTureHandles(2) ' Select the first image texture
glBegin %GL_QUADS ' Start drawing a textured quad
glTexCoord2f roll + 0.0!, 0.0! : glVertex3f -1.1!, -1.1!, 0.0! ' Bottom left
glTexCoord2f roll + 4.0!, 0.0! : glVertex3f 1.1!, -1.1!, 0.0! ' Bottom right
glTexCoord2f roll + 4.0!, 4.0! : glVertex3f 1.1!, 1.1!, 0.0! ' Top right
glTexCoord2f roll + 0.0!, 4.0! : glVertex3f -1.1!, 1.1!, 0.0! ' Top left
glEnd ' Done drawing the quad
END IF
glEnable %GL_DEPTH_TEST ' Enable depth testing
glDisable %GL_BLEND ' Disable blending
roll = roll + 0.002! ' Increase our texture roll bariable
IF roll > 1.0! THEN ' Is roll greater than one
roll = roll - 1.0! ' Subtract 1 from roll
END IF
' // Swap buffers
SDL_GL_SwapBuffers
END SUB
' =======================================================================================
' =======================================================================================
' Main
' =======================================================================================
FUNCTION PBMAIN () AS LONG
LOCAL pscreen AS SDL_Surface PTR
LOCAL nWidth, nHeight, bpp AS LONG
LOCAL lResult, bFullScreen AS LONG
LOCAL szCaption AS ASCIIZ * 256
LOCAL dwFlags AS DWORD
LOCAL t, t0, fps AS DOUBLE
LOCAL nFrames AS LONG
LOCAL mp, sp AS LONG
szCaption = $WindowCaption ' Window caption
' Ask the user which screen mode he prefers
lResult = MessageBox(%NULL, "Would you like to run in fullscreen mode?", _
"Start fullScreen?", %MB_YESNOCANCEL OR %MB_ICONQUESTION)
SELECT CASE lResult
CASE %IDCANCEL : EXIT FUNCTION
CASE %IDYES : bFullScreen = %TRUE
CASE %IDNO : bFullScreen = %FALSE
END SELECT
' // Initialize SDL's subsystems - in this case, only video.
IF SDL_Init(%SDL_INIT_VIDEO) < 0 THEN
MSGBOX "Unable to init SDL: " & SDL_GetError()
EXIT FUNCTION
END IF
' // Attempt to create a 640x480 window
nWidth = 640 : nHeight = 480 : bpp = 16
IF bFullScreen THEN
dwFlags = %SDL_OPENGL OR %SDL_FULLSCREEN
ELSE
dwFlags = %SDL_OPENGL
END IF
pscreen = SDL_SetVideoMode(nWidth, nHeight, bpp, dwFlags)
SDL_WM_SetCaption szCaption, ""
' // If we fail, return error.
IF pscreen = %NULL THEN
SDL_Quit
MSGBOX "Unable to set the video mode: " & SDL_GetError()
EXIT FUNCTION
END IF
' // Set up the scene
SetupScene
' Enable keyboard repeat
SDL_EnableKeyRepeat %SDL_DEFAULT_REPEAT_DELAY, %SDL_DEFAULT_REPEAT_INTERVAL
' // Main loop
LOCAL done AS LONG
LOCAL uevent AS SDL_Event
WHILE done = %FALSE
' // Poll for events, and handle the ones we care about.
WHILE SDL_PollEvent(VARPTR(uevent))
SELECT CASE uevent.type
CASE %SDL_KEYDOWN
SELECT CASE uevent.key.keysym.sym
CASE %SDLK_SPACE
IF ISFALSE sp THEN
sp = %TRUE
scene = NOT scene
END IF
CASE %SDLK_M
IF ISFALSE mp THEN
mp = %TRUE
IF ISTRUE masking THEN masking = %FALSE ELSE masking = %TRUE
END IF
END SELECT
CASE %SDL_KEYUP
' // Quit if escape is pressed
IF uevent.key.keysym.sym = %SDLK_ESCAPE THEN
done = %TRUE
EXIT LOOP
END IF
' Reset flags
mp = %FALSE
sp = %FALSE
CASE %SDL_QUIT
done = %TRUE
EXIT LOOP
END SELECT
WEND
IF ISFALSE bFullScreen THEN
' Get time and mouse position
t = INT(TIMER)
' Calculate and display FPS (frames per second)
IF t > t0 OR nFrames = 0 THEN
fps = nFrames \ (t - t0)
wsprintf szCaption, $WindowCaption & " (%i FPS)", BYVAL fps
SDL_WM_SetCaption szCaption, szCaption
t0 = t
nFrames = 0
END IF
nFrames = nFrames + 1
END IF
' // Draw the scene
DrawScene nWidth, nHeight
WEND
' Delete the textures
glDeleteTextures(5, TextureHandles(0))
' Shut down SDL
SDL_Quit
END FUNCTION
' =======================================================================================
The following example illustrates masking.
It is an adaptation of NeHe Lesson 20: http://nehe.gamedev.net/data/lessons/lesson.asp?lesson=20
' SED_PBWIN - Use the PBWIN compiler
#COMPILE EXE
#DIM ALL
#INCLUDE ONCE "GLFW.INC"
#INCLUDE ONCE "GDIPUTILS.INC"
FUNCTION PBMAIN () AS LONG
LOCAL nWidth, nHeight, running, frames, x, y AS LONG
LOCAL t, t0, fps AS DOUBLE
LOCAL szTitlestr AS ASCIIZ * 200
LOCAL hr, i AS LONG
LOCAL masking AS LONG ' Masking on/off
LOCAL mp AS LONG ' M pressed?
LOCAL sp AS LONG ' Space pressed?
LOCAL scene AS LONG ' Which scene to draw
LOCAL roll AS SINGLE ' Rolling texture
DIM TextureHandles(4) AS DWORD
DIM TextureWidth(4) AS LONG
DIM TextureHeight(4) AS LONG
DIM strTextureData(4) AS STRING
masking = %TRUE
' Initialize GLFW
glfwInit
' Open OpenGL window
IF ISFALSE glfwOpenWindow(640, 480, 0, 0, 0, 0, 16, 0, %GLFW_WINDOW) THEN
glfwTerminate
EXIT FUNCTION
END IF
' Load textures from disk
hr = GdiPlusLoadTexture("logo.bmp", TextureWidth(0), TextureHeight(0), strTextureData(0), %TRUE)
hr = GdiPlusLoadTexture("mask1.bmp", TextureWidth(1), TextureHeight(1), strTextureData(1), %TRUE)
hr = GdiPlusLoadTexture("image1.bmp", TextureWidth(2), TextureHeight(2), strTextureData(2), %TRUE)
hr = GdiPlusLoadTexture("mask2.bmp", TextureWidth(3), TextureHeight(3), strTextureData(3), %TRUE)
hr = GdiPlusLoadTexture("image2.bmp", TextureWidth(4), TextureHeight(4), strTextureData(4), %TRUE)
' Create two textures
glGenTextures 5, TextureHandles(0)
FOR i = 0 TO 4
glBindTexture %GL_TEXTURE_2D, TextureHandles(i)
glTexParameteri %GL_TEXTURE_2D, %GL_TEXTURE_MAG_FILTER, %GL_LINEAR
glTexParameteri %GL_TEXTURE_2D, %GL_TEXTURE_MIN_FILTER, %GL_LINEAR
glTexImage2D %GL_TEXTURE_2D, 0, 3, TextureWidth(i), TextureHeight(i), 0, _
%GL_RGBA, %GL_UNSIGNED_BYTE, BYVAL STRPTR(strTextureData(i))
NEXT
' Specify clear values for the color buffers
glClearColor 0.0!, 0.0!, 0.0!, 0.0!
' Enables clearing of the depth buffer
glClearDepth 1.0!
' Enable depth testing
glEnable %GL_DEPTH_TEST
' Enables smooth color shading
glShadeModel %GL_SMOOTH
' Enable 2D texture mapping
glEnable %GL_TEXTURE_2D
' Main loop
running = %TRUE
frames = 0
t0 = glfwGetTime
DO WHILE running
' Get time and mouse position
t = glfwGetTime
glfwGetMousePos x, y
' Calculate and display FPS (frames per second)
IF t - t0 > 1.0! OR frames = 0 THEN
fps = frames / (t-t0)
wsprintf szTitlestr, "NEHE Lesson 20 (%i FPS)", BYVAL fps
glfwSetWindowTitle szTitlestr
t0 = t
frames = 0
END IF
frames = frames + 1
' Get window size (may be different than the requested size)
glfwGetWindowSize nWidth, nHeight
IF nHeight <= 0 THEN nHeight = 1
' Set viewport
glViewport 0, 0, nWidth, nHeight
' Clear the screen and depth buffers
glClear %GL_COLOR_BUFFER_BIT OR %GL_DEPTH_BUFFER_BIT
' Select and setup the projection matrix
glMatrixMode %GL_PROJECTION
glLoadIdentity
' Calculate the aspect ratio of the window
gluPerspective 45.0!, nWidth/nHeight, 1.0!, 100.0!
' Select and setup the modelview matrix
glMatrixMode %GL_MODELVIEW
glLoadIdentity
' Move into the screen 5 units
glTranslatef 0.0!, 0.0!, -2.0!
' Select the logo texture
glBindTexture %GL_TEXTURE_2D, TextureHandles(0)
' Start drawing a textured quad
glBegin %GL_QUADS
glTexCoord2f 0.0!, - roll + 0.0! : glVertex3f -1.1!, -1.1!, 0.0! ' Bottom left
glTexCoord2f 3.0!, - roll + 0.0! : glVertex3f 1.1!, -1.1!, 0.0! ' Bottom right
glTexCoord2f 3.0!, - roll + 3.0! : glVertex3f 1.1!, 1.1!, 0.0! ' Top right
glTexCoord2f 0.0!, - roll + 3.0! : glVertex3f -1.1!, 1.1!, 0.0! ' Top left
glEnd
glEnable %GL_BLEND ' Enable blending
glDisable %GL_DEPTH_TEST ' Disable depth testing
IF masking THEN ' Is masking enabled?
glBlendFunc %GL_DST_COLOR, %GL_ZERO ' Blend screen color with zero (black)
END IF
IF scene THEN ' Are we drawing the second scene?
glTranslatef 0.0!, 0.0!, -1.0! ' Translate into the screen one unit
glRotatef roll * 360, 0.0!, 0.0!, 1.0! ' Rotate on the z axis 360 degrees
IF masking THEN ' Is masking on?
glBindTexture %GL_TEXTURE_2D, TextureHandles(3) ' Select the second mask texture
glBegin %GL_QUADS ' Start drawing a textured quad
glTexCoord2f 0.0!, 0.0! : glVertex3f -1.1!, -1.1!, 0.0! ' Bottom left
glTexCoord2f 1.0!, 0.0! : glVertex3f 1.1!, -1.1!, 0.0! ' Bottom right
glTexCoord2f 1.0!, 1.0! : glVertex3f 1.1!, 1.1!, 0.0! ' Top right
glTexCoord2f 0.0!, 1.0! : glVertex3f -1.1!, 1.1!, 0.0! ' Top left
glEnd ' Done Drawing The Quad
END IF
glBlendFunc %GL_ONE, %GL_ONE ' Copy image 2 color to the screen
glBindTexture %GL_TEXTURE_2D, TextureHandles(4) ' Select the second image texture
glBegin %GL_QUADS ' Start drawing a textured quad
glTexCoord2f 0.0!, 0.0! : glVertex3f -1.1!, -1.1!, 0.0! ' Bottom left
glTexCoord2f 1.0!, 0.0! : glVertex3f 1.1!, -1.1!, 0.0! ' Bottom right
glTexCoord2f 1.0!, 1.0! : glVertex3f 1.1!, 1.1!, 0.0! ' Top right
glTexCoord2f 0.0!, 1.0! : glVertex3f -1.1!, 1.1!, 0.0! ' Top left
glEnd ' Done Drawing The Quad
ELSE
IF masking THEN ' Is masking on?
glBindTexture %GL_TEXTURE_2D, TextureHandles(1) ' Select the first mask texture
glBegin %GL_QUADS ' Start drawing a textured quad
glTexCoord2f roll + 0.0!, 0.0! : glVertex3f -1.1!, -1.1!, 0.0! ' Bottom left
glTexCoord2f roll + 4.0!, 0.0! : glVertex3f 1.1!, -1.1!, 0.0! ' Bottom right
glTexCoord2f roll + 4.0!, 4.0! : glVertex3f 1.1!, 1.1!, 0.0! ' Top right
glTexCoord2f roll + 0.0!, 4.0! : glVertex3f -1.1!, 1.1!, 0.0! ' Top left
glEnd ' Done drawing the quad
END IF
glBlendFunc %GL_ONE, %GL_ONE ' Copy image 1 color to the screen
glBindTexture %GL_TEXTURE_2D, TexTureHandles(2) ' Select the first image texture
glBegin %GL_QUADS ' Start drawing a textured quad
glTexCoord2f roll + 0.0!, 0.0! : glVertex3f -1.1!, -1.1!, 0.0! ' Bottom left
glTexCoord2f roll + 4.0!, 0.0! : glVertex3f 1.1!, -1.1!, 0.0! ' Bottom right
glTexCoord2f roll + 4.0!, 4.0! : glVertex3f 1.1!, 1.1!, 0.0! ' Top right
glTexCoord2f roll + 0.0!, 4.0! : glVertex3f -1.1!, 1.1!, 0.0! ' Top left
glEnd ' Done drawing the quad
END IF
glEnable %GL_DEPTH_TEST ' Enable depth testing
glDisable %GL_BLEND ' Disable blending
roll = roll + 0.002! ' Increase our texture roll bariable
IF roll > 1.0! THEN ' Is roll greater than one
roll = roll - 1.0! ' Subtract 1 from roll
END IF
' Swap buffers
glfwSwapBuffers
' Space
IF glfwGetKey(32) = %GLFW_PRESS AND ISFALSE sp THEN
sp = %TRUE
scene = NOT scene
END IF
IF glfwGetKey(32) <> %GLFW_PRESS THEN sp = %FALSE
' M key
IF glfwGetKey(77) = %GLFW_PRESS AND ISFALSE mp THEN
mp = %TRUE
IF ISTRUE masking THEN masking = %FALSE ELSE masking = %TRUE
END IF
IF glfwGetKey(77) <> %GLFW_PRESS THEN mp = %FALSE
' Check if the ESC key was pressed or the window was closed
running = NOT glfwGetKey(%GLFW_KEY_ESC) AND glfwGetWindowParam(%GLFW_OPENED)
LOOP
' Delete the textures
glDeleteTextures(5, TextureHandles(0))
' Close OpenGL window and terminate GLFW
glfwTerminate
END FUNCTION