技术文章 > NEHE OpenGL源代码(20)

NEHE OpenGL源代码(20)

2018-10-17 23:47

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//---------------------------------------------------------------------------
#include <vcl.h>
#include <windows.h> // Header file for windows
#include <math.h> // Header file for windows math library
#include <stdio.h> // Header file for standard Input/Output
#include <gl\gl.h> // Header file for the OpenGL32 library
#include <gl\glu.h> // Header file for the GLu32 library
#include <gl\glaux.h> // Header file for the GLaux library
#pragma hdrstop
//---------------------------------------------------------------------------
#pragma argsused
HGLRC hRC = NULL; // Permanent rendering context
HDC hDC = NULL; // Private GDI device context
HWND hWnd = NULL; // Holds our window handle
HINSTANCE hInstance = NULL; // Holds the instance of the application
bool keys[256]; // Array used for the keyboard routine
bool active = true; // Window active flag set to TRUE by default
bool fullscreen = true; // Fullscreen flag set to fullscreen mode by default
bool masking = true; // Masking On/Off
bool mp; // M pressed?
bool sp; // Space pressed?
bool scene; // Which scene to draw
GLuint texture[5]; // Storage for our five textures
GLuint loop; // Generic loop variable
GLfloat roll; // Rolling texture
AUX_RGBImageRec *LoadBMP(char *Filename) // Loads a bitmap image
{
FILE *File = NULL; // File handle
if (!Filename) // Make sure a filename was given
{
return NULL; // If not return NULL
}
File = fopen(Filename,“r“); // Check to see if the file exists
if (File) // Does the file exist?
{
fclose(File); // Close the handle
return auxDIBImageLoad(Filename); // Load the bitmap and return a pointer
}
return NULL; // If load failed return NULL
}
int LoadGLTextures() // Load bitmaps and convert to textures
{
int Status = false; // Status indicator
AUX_RGBImageRec *TextureImage[5]; // Create storage space for the textures
memset(TextureImage,0,sizeof(void *)*5); // Set the pointer to NULL
if ((TextureImage[0] = LoadBMP(“Data/logo.bmp“)) && // Logo texture
(TextureImage[1]=LoadBMP(“Data/mask1.bmp“)) && // First mask
(TextureImage[2]=LoadBMP(“Data/image1.bmp“)) && // First image
(TextureImage[3]=LoadBMP(“Data/mask2.bmp“)) && // Second mask
(TextureImage[4]=LoadBMP(“Data/image2.bmp“))) // Second image
{
Status = true; // Set the status to TRUE
glGenTextures(5, &texture[0]); // Create five textures
for (loop = 0; loop < 5; loop++) // Loop through all 5 textures
{
glBindTexture(GL_TEXTURE_2D, texture[loop]);
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, TextureImage[loop]->sizeX, TextureImage[loop]->sizeY, 0, GL_RGB, GL_UNSIGNED_BYTE, TextureImage[loop]->data);
}
}
for (loop = 0; loop < 5; loop++) // Loop through all 5 textures
{
if (TextureImage[loop]) // If texture exists
{
if (TextureImage[loop]->data) // If texture image exists
{
free(TextureImage[loop]->data); // Free the texture image memory
}
free(TextureImage[loop]); // Free the image structure
}
}
return Status; // Return the status
}
LRESULT CALLBACK WndProc(HWND, UINT, WPARAM, LPARAM); // Declaration for WndProc
GLvoid ReSizeGLScene(GLsizei width, GLsizei height) // Resize and initialize the GL window
{
if (height == 0) // Prevent A Divide By Zero By
{
height = 1; // Making height equal One
}
glViewport(0, 0, width, height); // Reset the current viewport
glMatrixMode(GL_PROJECTION); // Select the projection matrix
glLoadIdentity(); // Reset the projection matrix
// Calculate the aspect ratio of the window
gluPerspective(45.0f,(GLfloat)width/(GLfloat)height,0.1f,100.0f);
glMatrixMode(GL_MODELVIEW); // Select the modelview matrix
glLoadIdentity(); // Reset the modelview matrix
}
int InitGL(GLvoid) // All setup for OpenGL goes here
{
if (!LoadGLTextures()) // Jump to texture loading routine
{
return false; // If texture didn“t load return FALSE
}
glClearColor(0.0f, 0.0f, 0.0f, 0.0f); // Clear the background color to black
glClearDepth(1.0); // Enables clearing of the depth buffer
glEnable(GL_DEPTH_TEST); // Enable depth testing
glShadeModel(GL_SMOOTH); // Enables smooth color shading
glEnable(GL_TEXTURE_2D); // Enable 2D texture mapping
return TRUE; // Initialization went OK
}
int DrawGLScene(GLvoid) // Here“s where we do all the drawing
{
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT); // clear screen and depth buffer
glLoadIdentity(); // Reset the current modelview matrix
glTranslatef(0.0f,0.0f,-2.0f); // Move into the screen 5 units
glBindTexture(GL_TEXTURE_2D, texture[0]); // Select our logo texture
glBegin(GL_QUADS); // Start drawing a textured quad
glTexCoord2f(0.0f, -roll+0.0f); glVertex3f(-1.1f, -1.1f, 0.0f); // Bottom left
glTexCoord2f(3.0f, -roll+0.0f); glVertex3f( 1.1f, -1.1f, 0.0f); // Bottom right
glTexCoord2f(3.0f, -roll+3.0f); glVertex3f( 1.1f, 1.1f, 0.0f); // Top right
glTexCoord2f(0.0f, -roll+3.0f); glVertex3f(-1.1f, 1.1f, 0.0f); // Top left
glEnd(); // Done drawing the quad
glEnable(GL_BLEND); // Enable blending
glDisable(GL_DEPTH_TEST); // Disable depth testing
if (masking) // Is masking enabled?
{
glBlendFunc(GL_DST_COLOR,GL_ZERO); // Blend screen color with zero (Black)
}
if (scene) // Are we drawing the second scene?
{
glTranslatef(0.0f,0.0f,-1.0f); // Translate into the screen one unit
glRotatef(roll*360,0.0f,0.0f,1.0f); // Rotate on the Z axis 360 degrees.
if (masking) // Is masking on?
{
glBindTexture(GL_TEXTURE_2D, texture[3]); // Select the second mask texture
glBegin(GL_QUADS); // Start drawing a textured quad
glTexCoord2f(0.0f, 0.0f); glVertex3f(-1.1f, -1.1f, 0.0f); // Bottom left
glTexCoord2f(1.0f, 0.0f); glVertex3f( 1.1f, -1.1f, 0.0f); // Bottom right
glTexCoord2f(1.0f, 1.0f); glVertex3f( 1.1f, 1.1f, 0.0f); // Top right
glTexCoord2f(0.0f, 1.0f); glVertex3f(-1.1f, 1.1f, 0.0f); // Top left
glEnd(); // Done drawing the quad
}
glBlendFunc(GL_ONE, GL_ONE); // Copy image 2 color to the screen
glBindTexture(GL_TEXTURE_2D, texture[4]); // Select the second image texture
glBegin(GL_QUADS); // Start drawing a textured quad
glTexCoord2f(0.0f, 0.0f); glVertex3f(-1.1f, -1.1f, 0.0f); // Bottom left
glTexCoord2f(1.0f, 0.0f); glVertex3f( 1.1f, -1.1f, 0.0f); // Bottom right
glTexCoord2f(1.0f, 1.0f); glVertex3f( 1.1f, 1.1f, 0.0f); // Top right
glTexCoord2f(0.0f, 1.0f); glVertex3f(-1.1f, 1.1f, 0.0f); // Top left
glEnd(); // Done drawing the quad
}
else // Otherwise
{
if (masking) // Is masking on?
{
glBindTexture(GL_TEXTURE_2D, texture[1]); // Select the first mask texture
glBegin(GL_QUADS); // Start drawing a textured quad
glTexCoord2f(roll+0.0f, 0.0f); glVertex3f(-1.1f, -1.1f, 0.0f); // Bottom left
glTexCoord2f(roll+4.0f, 0.0f); glVertex3f( 1.1f, -1.1f, 0.0f); // Bottom right
glTexCoord2f(roll+4.0f, 4.0f); glVertex3f( 1.1f, 1.1f, 0.0f); // Top right
glTexCoord2f(roll+0.0f, 4.0f); glVertex3f(-1.1f, 1.1f, 0.0f); // Top left
glEnd(); // Done drawing the quad
}
glBlendFunc(GL_ONE, GL_ONE); // Copy image 1 color to the screen
glBindTexture(GL_TEXTURE_2D, texture[2]); // Select the first image texture
glBegin(GL_QUADS); // Start drawing a textured quad
glTexCoord2f(roll+0.0f, 0.0f); glVertex3f(-1.1f, -1.1f, 0.0f); // Bottom left
glTexCoord2f(roll+4.0f, 0.0f); glVertex3f( 1.1f, -1.1f, 0.0f); // Bottom right
glTexCoord2f(roll+4.0f, 4.0f); glVertex3f( 1.1f, 1.1f, 0.0f); // Top right
glTexCoord2f(roll+0.0f, 4.0f); glVertex3f(-1.1f, 1.1f, 0.0f); // Top left
glEnd(); // Done drawing the quad
}
glEnable(GL_DEPTH_TEST); // Enable depth testing
glDisable(GL_BLEND); // Disable blending
roll += 0.002f; // Increase our texture roll variable
if (roll > 1.0f) // Is roll greater than one
{
roll -= 1.0f; // Subtract 1 from roll
}
return true; // Everything went OK
}
GLvoid KillGLWindow(GLvoid) // Properly kill the window
{
if (fullscreen) // Are we in fullscreen mode?
{
ChangeDisplaySettings(NULL,0); // If so switch back to the desktop
ShowCursor(true); // Show mouse pointer
}
if (hRC) // Do we have a rendering context?
{
if (!wglMakeCurrent(NULL,NULL)) // Are we able to release the DC and RC contexts?
{
MessageBox(NULL,“Release of DC and RC failed.“,“SHUTDOWN ERROR“,MB_OK | MB_ICONINFORMATION);
}
if (!wglDeleteContext(hRC)) // Are we able to delete the RC?
{
MessageBox(NULL,“Release rendering context failed.“,“SHUTDOWN ERROR“,MB_OK | MB_ICONINFORMATION);
}
hRC = NULL; // Set RC to NULL
}
if (hDC && !ReleaseDC(hWnd,hDC)) // Are we able to release the DC
{
MessageBox(NULL,“Release device context failed.“,“SHUTDOWN ERROR“,MB_OK | MB_ICONINFORMATION);
hDC = NULL; // Set DC to NULL
}
if (hWnd && !DestroyWindow(hWnd)) // Are we able to destroy the window?
{
MessageBox(NULL,“Could not release hWnd.“,“SHUTDOWN ERROR“,MB_OK | MB_ICONINFORMATION);
hWnd = NULL; // Set hWnd to NULL
}
if (!UnregisterClass(“OpenGL“,hInstance)) // Are we able to unregister class
{
MessageBox(NULL,“Could not unregister class.“,“SHUTDOWN ERROR“,MB_OK | MB_ICONINFORMATION);
hInstance = NULL; // Set hInstance to NULL
}
}
/* This Code Creates Our OpenGL Window. Parameters Are:
* title - Title To Appear At The Top Of The Window
* width - Width Of The GL Window Or Fullscreen Mode
* height - Height Of The GL Window Or Fullscreen Mode
* bits - Number Of Bits To Use For Color (8/16/24/32)
* fullscreenflag - Use Fullscreen Mode (TRUE) Or Windowed Mode (FALSE)*/

BOOL CreateGLWindow(char* title, int width, int height, int bits, bool fullscreenflag)
{
GLuint PixelFormat; // Holds the results after searching for a match
WNDCLASS wc; // Windows class structure
DWORD dwExStyle; // Window extended style
DWORD dwStyle; // Window style
RECT WindowRect; // Grabs rctangle upper left / lower right values
WindowRect.left = (long)0; // Set left value to 0
WindowRect.right = (long)width; // Set right value to requested width
WindowRect.top = (long)0; // Set top value to 0
WindowRect.bottom = (long)height; // Set bottom value to requested height
fullscreen = fullscreenflag; // Set the global fullscreen flag
hInstance = GetModuleHandle(NULL); // Grab an instance for our window
wc.style = CS_HREDRAW | CS_VREDRAW | CS_OWNDC; // Redraw on size, and own DC for window
wc.lpfnWndProc = (WNDPROC) WndProc; // WndProc handles messages
wc.cbClsExtra = 0; // No extra window data
wc.cbWndExtra = 0; // No extra window data
wc.hInstance = hInstance; // Set the Instance
wc.hIcon = LoadIcon(NULL, IDI_WINLOGO); // Load the default icon
wc.hCursor = LoadCursor(NULL, IDC_ARROW); // Load the arrow pointer
wc.hbrBackground = NULL; // No background required for GL
wc.lpszMenuName = NULL; // We don“t want a menu
wc.lpszClassName = “OpenGL“; // Set the class name
if (!RegisterClass(&wc)) // Attempt to register the window class
{
MessageBox(NULL,“Failed To Register The Window Class.“,“ERROR“,MB_OK|MB_ICONEXCLAMATION);
return false; // Return FALSE
}

if (fullscreen) // Attempt fullscreen mode?
{
DEVMODE dmScreenSettings; // Device mode
memset(&dmScreenSettings,0,sizeof(dmScreenSettings)); // Makes sure memory“s cleared
dmScreenSettings.dmSize = sizeof(dmScreenSettings); // Size of the devmode structure
dmScreenSettings.dmPelsWidth = width; // Selected screen width
dmScreenSettings.dmPelsHeight = height; // Selected screen height
dmScreenSettings.dmBitsPerPel = bits; // Selected bits per pixel
dmScreenSettings.dmFields=DM_BITSPERPEL|DM_PELSWIDTH|DM_PELSHEIGHT;
// Try to set selected mode and get results. NOTE: CDS_FULLSCREEN gets rid of start bar.
if (ChangeDisplaySettings(&dmScreenSettings,CDS_FULLSCREEN)!=DISP_CHANGE_SUCCESSFUL)
{
// If the mode fails, offer two options. Quit or use windowed mode.
if (MessageBox(NULL,“The requested fullscreen mode is not supported by\nyour video card. Use windowed mode instead?“,“NeHe GL“,MB_YESNO|MB_ICONEXCLAMATION)==IDYES)
{
fullscreen = false; // Windowed mode selected. Fullscreen = FALSE
}
else
{
// Pop up a message box letting user know the program is closing.
MessageBox(NULL,“Program will now close.“,“ERROR“,MB_OK|MB_ICONSTOP);
return false; // Return FALSE
}
}
}
if (fullscreen) // Are We Still In Fullscreen Mode?
{
dwExStyle = WS_EX_APPWINDOW; // Window extended style
dwStyle = WS_POPUP; // Windows style
ShowCursor(false); // Hide mouse pointer
}
else
{
dwExStyle=WS_EX_APPWINDOW | WS_EX_WINDOWEDGE; // Window extended style
dwStyle=WS_OVERLAPPEDWINDOW; // Windows style
}
AdjustWindowRectEx(&WindowRect, dwStyle, FALSE, dwExStyle); // Adjust window to true requested size
// Create the window
if (!(hWnd = CreateWindowEx(dwExStyle, // Extended Style For The Window
“OpenGL“, // Class name
title, // Window title
dwStyle | // Defined window style
WS_CLIPSIBLINGS | // Required window style
WS_CLIPCHILDREN, // Required window style
0, 0, // Window position
WindowRect.right-WindowRect.left, // Calculate window width
WindowRect.bottom-WindowRect.top, // Calculate window height
NULL, // No parent window
NULL, // No menu
hInstance, // Instance
NULL))) // Dont pass anything to WM_CREATE
{
KillGLWindow(); // Reset the display
MessageBox(NULL,“Window Creation Error.“,“ERROR“,MB_OK|MB_ICONEXCLAMATION);
return false; // Return FALSE
}
static PIXELFORMATDESCRIPTOR pfd = // pfd tells windows how we want things to be
{
sizeof(PIXELFORMATDESCRIPTOR), // Size of this pixel format descriptor
1, // Version number
PFD_DRAW_TO_WINDOW | // Format must support window
PFD_SUPPORT_OPENGL | // Format must support OpenGL
PFD_DOUBLEBUFFER, // Must support double buffering
PFD_TYPE_RGBA, // Request an RGBA format
bits, // Select our color depth
0, 0, 0, 0, 0, 0, // Color bits ignored
0, // No alpha buffer
0, // Shift bit ignored
0, // No accumulation buffer
0, 0, 0, 0, // Accumulation bits ignored
16, // 16Bit Z-Buffer (Depth buffer)
0, // No stencil buffer
0, // No auxiliary buffer
PFD_MAIN_PLANE, // Main drawing layer
0, // Reserved
0, 0, 0 // Layer masks ignored
};

if (!(hDC=GetDC(hWnd))) // Did we get a device context?
{
KillGLWindow(); // Reset the display
MessageBox(NULL,“Can“t create a GL device context.“,“ERROR“,MB_OK|MB_ICONEXCLAMATION);
return false; // Return FALSE
}
if (!(PixelFormat=ChoosePixelFormat(hDC,&pfd))) // Did windows find a matching pixel format?
{
KillGLWindow(); // Reset the display
MessageBox(NULL,“Can“t find a suitable pixelformat.“,“ERROR“,MB_OK|MB_ICONEXCLAMATION);
return false; // Return FALSE
}
if(!SetPixelFormat(hDC,PixelFormat,&pfd)) // Are we able to set the pixel format?
{
KillGLWindow(); // Reset the display
MessageBox(NULL,“Can“t set the pixelformat.“,“ERROR“,MB_OK|MB_ICONEXCLAMATION);
return false; // Return FALSE
}
if (!(hRC=wglCreateContext(hDC))) // Are we able to get a rendering context?
{
KillGLWindow(); // Reset the display
MessageBox(NULL,“Can“t create a GL rendering context.“,“ERROR“,MB_OK|MB_ICONEXCLAMATION);
return false; // Return FALSE
}
if(!wglMakeCurrent(hDC,hRC)) // Try to activate the rendering context
{
KillGLWindow(); // Reset the display
MessageBox(NULL,“Can“t activate the GL rendering context.“,“ERROR“,MB_OK|MB_ICONEXCLAMATION);
return false; // Return FALSE
}
ShowWindow(hWnd,SW_SHOW); // Show the window
SetForegroundWindow(hWnd); // Slightly higher priority
SetFocus(hWnd); // Sets keyboard focus to the window
ReSizeGLScene(width, height); // Set up our perspective GL screen
if (!InitGL()) // Initialize our newly created GL window
{
KillGLWindow(); // Reset the display
MessageBox(NULL,“Initialization failed.“,“ERROR“,MB_OK|MB_ICONEXCLAMATION);
return false; // Return FALSE
}
return true; // Success
}
LRESULT CALLBACK WndProc(HWND hWnd, // Handle for this window
UINT uMsg, // Message for this window
WPARAM wParam, // Additional message information
LPARAM lParam) // Additional message information
{
switch (uMsg) // Check for windows messages
{
case WM_ACTIVATE: // Watch for window activate message
{
if (!HIWORD(wParam)) // Check minimization state
{
active = true; // Program is active
}
else
{
active = false; // Program is no longer active
}
return 0; // Return to the message loop
}
case WM_SYSCOMMAND: // Intercept system commands
{
switch (wParam) // Check system calls
{
case SC_SCREENSAVE: // Screensaver trying to start?
case SC_MONITORPOWER: // Monitor trying to enter powersave?
return 0; // Prevent from happening
}
break; // Exit
}
case WM_CLOSE: // Did we receive a close message?
{
PostQuitMessage(0); // Send a quit message
return 0; // Jump back
}
case WM_KEYDOWN: // Is a key being held down?
{
keys[wParam] = true; // If so, mark it as TRUE
return 0; // Jump back
}
case WM_KEYUP: // Has a key been released?
{
keys[wParam] = false; // If so, mark it as FALSE
return 0; // Jump back
}
case WM_SIZE: // Resize the OpenGL window
{
ReSizeGLScene(LOWORD(lParam),HIWORD(lParam)); // LoWord = Width, HiWord = Height
return 0; // Jump back
}
}
// Pass all unhandled messages to DefWindowProc
return DefWindowProc(hWnd,uMsg,wParam,lParam);
}
WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, LPSTR lpCmdLine, int nCmdShow)
{
MSG msg; // Windows message structure
bool done = false; // Bool variable to exit loop
// Ask the user which screen mode they prefer
if (MessageBox(NULL,“Would you like to run in fullscreen mode?“, “Start FullScreen?“,MB_YESNO|MB_ICONQUESTION)==IDNO)
{
fullscreen = false; // Windowed mode
}
// Create our OpenGL window
if (!CreateGLWindow(“NeHe“s Masking Tutorial“,640,480,16,fullscreen))
{
return 0; // Quit if window was not created
}
while(!done) // Loop that runs while done = FALSE
{
if (PeekMessage(&msg,NULL,0,0,PM_REMOVE)) // Is there a message waiting?
{
if (msg.message == WM_QUIT) // Have we received a quit message?
{
done = true; // If so done = TRUE
}
else // If not, deal with window messages
{
TranslateMessage(&msg); // Translate the message
DispatchMessage(&msg); // Dispatch the message
}
}
else // If there are no messages
{
// Draw the scene. Watch for ESC key and quit messages from DrawGLScene()
if ((active && !DrawGLScene()) || keys[VK_ESCAPE]) // Active? Was there a quit received?
{
done = true; // ESC or DrawGLScene signalled a quit
}
else // Not time to quit, update screen
{
SwapBuffers(hDC); // Swap buffers (double buffering)
if (keys[“ “] && !sp) // Is space being pressed?
{
sp = true; // Tell program spacebar is being held
scene = !scene; // Toggle from one scene to the other
}
if (!keys[“ “]) // Has spacebar been released?
{
sp=FALSE; // Tell program spacebar has been released
}
if (keys[“M“] && !mp) // Is M being pressed?
{
mp = true; // Tell program M is being held
masking = !masking; // Toggle masking mode OFF/ON
}
if (!keys[“M“]) // Has M been released?
{
mp = false; // Tell program that M has been released
}
if (keys[VK_F1]) // Is F1 being pressed?
{
keys[VK_F1] = false; // If so make key FALSE
KillGLWindow(); // Kill our current window
fullscreen = !fullscreen; // Toggle fullscreen / windowed mode
// Recreate our OpenGL window
if (!CreateGLWindow(“NeHe“s Masking Tutorial“,640,480,16,fullscreen))
{
return 0; // Quit if window was not created
}
}
}
}
}
// Shutdown
KillGLWindow(); // Kill the window
return (msg.wParam); // Exit the program
}
//---------------------------------------------------------------------------