' ########################################################################################
' Microsoft Windows
' File: GLCTX_SpinningTriangle.bas
' Contents: OpenGL example
' Description: Renders a spinning colored triangle controlled with both the TIMER function and the mouse.
' This version uses the CWindow class and the GlCtx graphic control
' Compilers: PBWIN 10+, PBCC 6+
' Headers: Windows API headers 2.02+
' Copyright (c) 2011 José Roca. Freeware. Use at your own risk
' Adapted from ogl_primitive_types.cpp, by Kevin Harris, 1 Feb 2005,
' downloadable at http://www.codesampler.com/oglsrc/oglsrc_1.htm#ogl_primitive_types
' ########################################################################################
#COMPILE EXE
#DIM ALL
%UNICODE = 1
' // Header files for imported files
%USEGLCTX = 1
#INCLUDE ONCE "CWindow.inc" ' // CWindow class
#INCLUDE ONCE "GlCtx.inc" ' // OpenGL control
$WindowCaption = "OpenGL - Spinning Triangle"
%IDC_GLCTX = 1001
GLOBAL pGL AS ISpinningTrianle
' =======================================================================================
' Spinning triangle class
' =======================================================================================
CLASS CSpinningTrianle
INTERFACE ISpinningTrianle : INHERIT IUnknown
' ====================================================================================
' All the setup goes here
' ====================================================================================
METHOD SetupScene
' // Specify clear values for the color buffers
glClearColor 0.0!, 0.0!, 0.0!, 0.0!
END METHOD
' ====================================================================================
' ====================================================================================
' Resizes the scene
' ====================================================================================
METHOD ResizeScene (BYVAL hCtl AS DWORD)
' // Get the dimensions of the window
LOCAL nWidth, nHeight AS LONG
AfxGetWindowSize(hCtl, nWidth, nHeight)
' // 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 65.0!, nWidth / nHeight, 1.0!, 100.0!
' // Select the model view matrix
glMatrixMode %GL_MODELVIEW
' // Reset the model view matrix
glLoadIdentity
END METHOD
' ====================================================================================
' ====================================================================================
' Draws the scene
' ====================================================================================
METHOD DrawScene (BYVAL hCtl AS DWORD)
' // Get the dimensions of the window
LOCAL nWidth, nHeight AS LONG
AfxGetWindowSize(hCtl, nWidth, nHeight)
LOCAL pt AS POINTAPI
LOCAL t AS DOUBLE
GetCursorPos pt
t = TIMER
glClear %GL_COLOR_BUFFER_BIT
' // Select and setup the modelview matrix
glMatrixMode %GL_MODELVIEW
glLoadIdentity
gluLookAt 0.0!, 1.0!, 0.0!, _ ' Eye-position
0.0!, 20.0!, 0.0!, _ ' View-point
0.0!, 0.0!, 1.0! ' Up-vector
' // Draw a rotating colorful triangle
glTranslatef 0.0!, 14.0!, 0.0!
glRotatef 0.3! * pt.x + t * 100.0!, 0.0!, 0.0!, 1.0!
glBegin %GL_TRIANGLES
glColor3f 1.0!, 0.0!, 0.0!
glVertex3f -5.0!, 0.0!, -4.0!
glColor3f 0.0!, 1.0!, 0.0!
glVertex3f 5.0!, 0.0!, -4.0!
glColor3f 0.0!, 0.0!, 1.0!
glVertex3f 0.0!, 0.0!, 6.0!
glEnd
' // Required: Force execution of GL commands in finite time
glFlush
' // Required: Force repainting of the control
InvalidateRect hCtl, BYVAL %NULL, %TRUE
END METHOD
' ====================================================================================
' ====================================================================================
' Processes keystrokes
' Parameters:
' * hwnd = Window hande
' * vKeyCode = Virtual key code
' * bKeyDown = %TRUE if key is pressed; %FALSE if it is released
' ====================================================================================
METHOD ProcessKeystrokes (BYVAL hwnd AS DWORD, BYVAL vKeyCode AS LONG, BYVAL bKeyDown AS LONG)
SELECT CASE AS LONG vKeyCode
CASE %VK_ESCAPE
' // Quit if Esc key pressed
SendMessage hwnd, %WM_CLOSE, 0, 0
END SELECT
END METHOD
' ====================================================================================
END INTERFACE
END CLASS
' =======================================================================================
' ========================================================================================
' Main
' ========================================================================================
FUNCTION WinMain (BYVAL hInstance AS DWORD, BYVAL hPrevInstance AS DWORD, BYVAL lpszCmdLine AS WSTRINGZ PTR, BYVAL nCmdShow AS LONG) AS LONG
' // Create an instance of the CWindow class
LOCAL pWindow AS IWindow
pWindow = CLASS "CWindow"
IF ISNOTHING(pWindow) THEN EXIT FUNCTION
' // Create the main window
LOCAL hwnd AS DWORD
hwnd = pWindow.CreateWindow(%NULL, "CWindow with a OpenGL Graphic Control", 0, 0, 600, 400, 0, 0, CODEPTR(WindowProc))
' // Center the window
pWindow.CenterWindow
' // Create an instance of the OpenGL lesson class
pGL = CLASS "CSpinningTrianle"
IF ISNOTHING(pGL) THEN EXIT FUNCTION
' // Add an OpenGL aware graphic control
LOCAL hCtl AS DWORD
hCtl = pWindow.AddGlCtx(hwnd, %IDC_GLCTX, "", 0, 0, pWindow.ClientWidth, pWindow.ClientHeight)
GlCtx_SetResizable hCtl, %TRUE ' // Make the control resizable
' // Show the window
ShowWindow hwnd, nCmdShow
UpdateWindow hwnd
' // Process Windows messages
LOCAL bDone AS LONG
LOCAL vKeyCode AS LONG
LOCAL bKeyDown AS LONG
LOCAL msg AS tagMSG
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
' // Calculate and display the number of frames per second
LOCAL t AS DOUBLE
LOCAL t0 AS DOUBLE
LOCAL fps AS DOUBLE
LOCAL nFrames AS LONG
LOCAL szCaption AS WSTRINGZ * 256
t = INT(TIMER)
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
' // Draw the scene
pGL.DrawScene(hCtl)
' // Process the keystrokes
IF vKeyCode THEN
pGL.ProcessKeystrokes(hwnd, vKeyCode, bKeyDown)
vKeyCode = 0
END IF
LOOP
FUNCTION = msg.wParam
END FUNCTION
' ========================================================================================
' ========================================================================================
' Main callback function.
' ========================================================================================
FUNCTION WindowProc (BYVAL hwnd AS DWORD, BYVAL uMsg AS DWORD, BYVAL wParam AS DWORD, BYVAL lParam AS LONG) AS LONG
SELECT CASE uMsg
CASE %WM_SYSCOMMAND
' // Close the window
IF (wParam AND &HFFF0) = %SC_CLOSE THEN
SendMessage hwnd, %WM_CLOSE, 0, 0
EXIT FUNCTION
END IF
CASE %WM_SIZE
' // If the window isn't minimized, resize it
LOCAL hCtl AS DWORD
hCtl = GetDlgItem(hwnd, %IDC_GLCTX)
IF wParam <> %SIZE_MINIMIZED THEN
' // Resize the control
MoveWindow hCtl, 0, 0, AfxGetWindowClientWidth(hwnd), AfxGetWindowClientHeight(hwnd), %TRUE
' // Resize and render the OpenGL scene
pGL.SetupScene ' // Setup the scene
pGL.ResizeScene(hCtl) ' // Resize the scene
pGL.DrawScene(hCtl) ' // Draw the scene
END IF
CASE %WM_DESTROY
' // End the application
PostQuitMessage 0
EXIT FUNCTION
END SELECT
' // Pass unprocessed messages to Windows
FUNCTION = DefWindowProc(hwnd, uMsg, wParam, lParam)
END FUNCTION
' ========================================================================================
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