lesson42.cpp

关于OpenGL的实例教程源代码

		{
			mx=int(rand()%(width/2))*2;									// Pick A New Random X Position
			my=int(rand()%(height/2))*2;								// Pick A New Random Y Position
		}
		while (tex_data[((mx+(width*my))*3)]==0);						// Keep Picking A Random Position Until We Find
	}																	// One That Has Already Been Tagged (Safe Starting Point)

	dir=int(rand()%4);													// Pick A Random Direction

	if ((dir==0) && (mx<=(width-4)))									// If The Direction Is 0 (Right) And We Are Not At The Far Right
	{
		if (tex_data[(((mx+2)+(width*my))*3)]==0)						// And If The Room To The Right Has Not Already Been Visited
		{
			UpdateTex(mx+1,my);											// Update The Texture To Show Path Cut Out Between Rooms
			mx+=2;														// Move To The Right (Room To The Right)
		}
	}

	if ((dir==1) && (my<=(height-4)))									// If The Direction Is 1 (Down) And We Are Not At The Bottom
	{
		if (tex_data[((mx+(width*(my+2)))*3)]==0)						// And If The Room Below Has Not Already Been Visited
		{
			UpdateTex(mx,my+1);											// Update The Texture To Show Path Cut Out Between Rooms
			my+=2;														// Move Down (Room Below)
		}
	}

	if ((dir==2) && (mx>=2))											// If The Direction Is 2 (Left) And We Are Not At The Far Left
	{
		if (tex_data[(((mx-2)+(width*my))*3)]==0)						// And If The Room To The Left Has Not Already Been Visited
		{
			UpdateTex(mx-1,my);											// Update The Texture To Show Path Cut Out Between Rooms
			mx-=2;														// Move To The Left (Room To The Left)
		}
	}

	if ((dir==3) && (my>=2))											// If The Direction Is 3 (Up) And We Are Not At The Top
	{
		if (tex_data[((mx+(width*(my-2)))*3)]==0)						// And If The Room Above Has Not Already Been Visited
		{
			UpdateTex(mx,my-1);											// Update The Texture To Show Path Cut Out Between Rooms
			my-=2;														// Move Up (Room Above)
		}
	}

	UpdateTex(mx,my);													// Update Current Room
}

void Draw (void)														// Our Drawing Routine
{
	RECT	rect;														// Holds Coordinates Of A Rectangle

	GetClientRect(g_window->hWnd, &rect);								// Get Window Dimensions
	int window_width=rect.right-rect.left;								// Calculate The Width (Right Side-Left Side)
	int window_height=rect.bottom-rect.top;								// Calculate The Height (Bottom-Top)

	// Update Our Texture... This Is The Key To The Programs Speed... Much Faster Than Rebuilding The Texture Each Time
	glTexSubImage2D(GL_TEXTURE_2D, 0, 0, 0, width, height, GL_RGB, GL_UNSIGNED_BYTE, tex_data);

	glClear (GL_COLOR_BUFFER_BIT);										// Clear Screen

	for (int loop=0; loop<4; loop++)									// Loop To Draw Our 4 Views
	{
		glColor3ub(r[loop],g[loop],b[loop]);							// Assign Color To Current View

		if (loop==0)													// If We Are Drawing The First Scene
		{
			// Set The Viewport To The Top Left.  It Will Take Up Half The Screen Width And Height
			glViewport (0, window_height/2, window_width/2, window_height/2);
			glMatrixMode (GL_PROJECTION);								// Select The Projection Matrix
			glLoadIdentity ();											// Reset The Projection Matrix
			// Set Up Ortho Mode To Fit 1/4 The Screen (Size Of A Viewport)
			gluOrtho2D(0, window_width/2, window_height/2, 0);
		}

		if (loop==1)													// If We Are Drawing The Second Scene
		{
			// Set The Viewport To The Top Right.  It Will Take Up Half The Screen Width And Height
			glViewport (window_width/2, window_height/2, window_width/2, window_height/2);
			glMatrixMode (GL_PROJECTION);								// Select The Projection Matrix
			glLoadIdentity ();											// Reset The Projection Matrix
			// Set Up Perspective Mode To Fit 1/4 The Screen (Size Of A Viewport)
			gluPerspective( 45.0, (GLfloat)(width)/(GLfloat)(height), 0.1f, 500.0 ); 
		}

		if (loop==2)													// If We Are Drawing The Third Scene
		{
			// Set The Viewport To The Bottom Right.  It Will Take Up Half The Screen Width And Height
			glViewport (window_width/2, 0, window_width/2, window_height/2);
			glMatrixMode (GL_PROJECTION);								// Select The Projection Matrix
			glLoadIdentity ();											// Reset The Projection Matrix
			// Set Up Perspective Mode To Fit 1/4 The Screen (Size Of A Viewport)
			gluPerspective( 45.0, (GLfloat)(width)/(GLfloat)(height), 0.1f, 500.0 ); 
		}

		if (loop==3)													// If We Are Drawing The Fourth Scene
		{
			// Set The Viewport To The Bottom Left.  It Will Take Up Half The Screen Width And Height
			glViewport (0, 0, window_width/2, window_height/2);
			glMatrixMode (GL_PROJECTION);								// Select The Projection Matrix
			glLoadIdentity ();											// Reset The Projection Matrix
			// Set Up Perspective Mode To Fit 1/4 The Screen (Size Of A Viewport)
			gluPerspective( 45.0, (GLfloat)(width)/(GLfloat)(height), 0.1f, 500.0 ); 
		}

		glMatrixMode (GL_MODELVIEW);									// Select The Modelview Matrix
		glLoadIdentity ();												// Reset The Modelview Matrix

		glClear (GL_DEPTH_BUFFER_BIT);									// Clear Depth Buffer

		if (loop==0)													// Are We Drawing The First Image?  (Original Texture... Ortho)
		{
			glBegin(GL_QUADS);											// Begin Drawing A Single Quad
				// We Fill The Entire 1/4 Section With A Single Textured Quad.
				glTexCoord2f(1.0f, 0.0f); glVertex2i(window_width/2, 0              );
				glTexCoord2f(0.0f, 0.0f); glVertex2i(0,              0              );
				glTexCoord2f(0.0f, 1.0f); glVertex2i(0,              window_height/2);
				glTexCoord2f(1.0f, 1.0f); glVertex2i(window_width/2, window_height/2);
			glEnd();													// Done Drawing The Textured Quad
		}

		if (loop==1)													// Are We Drawing The Second Image?  (3D Texture Mapped Sphere... Perspective)
		{
			glTranslatef(0.0f,0.0f,-14.0f);								// Move 14 Units Into The Screen

			glRotatef(xrot,1.0f,0.0f,0.0f);								// Rotate By xrot On The X-Axis
			glRotatef(yrot,0.0f,1.0f,0.0f);								// Rotate By yrot On The Y-Axis
			glRotatef(zrot,0.0f,0.0f,1.0f);								// Rotate By zrot On The Z-Axis

			glEnable(GL_LIGHTING);										// Enable Lighting
			gluSphere(quadric,4.0f,32,32);								// Draw A Sphere
			glDisable(GL_LIGHTING);										// Disable Lighting
		}
		
		if (loop==2)													// Are We Drawing The Third Image?  (Texture At An Angle... Perspective)
		{
			glTranslatef(0.0f,0.0f,-2.0f);								// Move 2 Units Into The Screen
			glRotatef(-45.0f,1.0f,0.0f,0.0f);							// Tilt The Quad Below Back 45 Degrees.
			glRotatef(zrot/1.5f,0.0f,0.0f,1.0f);						// Rotate By zrot/1.5 On The Z-Axis

			glBegin(GL_QUADS);											// Begin Drawing A Single Quad
				glTexCoord2f(1.0f, 1.0f); glVertex3f( 1.0f,  1.0f, 0.0f);
				glTexCoord2f(0.0f, 1.0f); glVertex3f(-1.0f,  1.0f, 0.0f);
				glTexCoord2f(0.0f, 0.0f); glVertex3f(-1.0f, -1.0f, 0.0f);
				glTexCoord2f(1.0f, 0.0f); glVertex3f( 1.0f, -1.0f, 0.0f);
			glEnd();													// Done Drawing The Textured Quad
		}

		if (loop==3)													// Are We Drawing The Fourth Image?  (3D Texture Mapped Cylinder... Perspective)
		{
			glTranslatef(0.0f,0.0f,-7.0f);								// Move 7 Units Into The Screen
			glRotatef(-xrot/2,1.0f,0.0f,0.0f);							// Rotate By -xrot/2 On The X-Axis
			glRotatef(-yrot/2,0.0f,1.0f,0.0f);							// Rotate By -yrot/2 On The Y-Axis
			glRotatef(-zrot/2,0.0f,0.0f,1.0f);							// Rotate By -zrot/2 On The Z-Axis

			glEnable(GL_LIGHTING);										// Enable Lighting
			glTranslatef(0.0f,0.0f,-2.0f);								// Translate -2 On The Z-Axis (To Rotate Cylinder Around The Center, Not An End)
			gluCylinder(quadric,1.5f,1.5f,4.0f,32,16);					// Draw A Cylinder
			glDisable(GL_LIGHTING);										// Disable Lighting
		}
	}

	glFlush ();															// Flush The GL Rendering Pipeline
}