C++ TIMER::GetTime方法代码示例

//Perform per-frame updates
void UpdateFrame()
{
	//set currentTime and timePassed
	static double lastTime=timer.GetTime();
	double currentTime=timer.GetTime();
	double timePassed=currentTime-lastTime;
	lastTime=currentTime;

	//Update window
	WINDOW::Instance()->Update();

	//Update the lights
	for(int i=0; i<numLights; ++i)
	{
		lights[i].position+=lights[i].velocity*float(timePassed)/1000;

		//bounce off the borders
		if(lights[i].position.x>1.0f && lights[i].velocity.x>0.0f)
			lights[i].velocity.x=-lights[i].velocity.x;
		if(lights[i].position.x<-1.0f && lights[i].velocity.x<0.0f)
			lights[i].velocity.x=-lights[i].velocity.x;

		if(lights[i].position.z>1.0f && lights[i].velocity.z>0.0f)
			lights[i].velocity.z=-lights[i].velocity.z;
		if(lights[i].position.z<-1.0f && lights[i].velocity.z<0.0f)
			lights[i].velocity.z=-lights[i].velocity.z;
	}
	
	//Toggle vertex program/fixed function
	if(WINDOW::Instance()->IsKeyPressed('1') && GLEE_NV_vertex_program)
	{
		useVP1=true;
		useVP2=false;
		useFixedFunction=false;
	}
	
	if(WINDOW::Instance()->IsKeyPressed('2') && GLEE_NV_vertex_program2)
	{
		useVP1=false;
		useVP2=true;
		useFixedFunction=false;
	}

	if(WINDOW::Instance()->IsKeyPressed('3'))
	{
		useVP1=false;
		useVP2=false;
		useFixedFunction=true;
	}

	//Render frame
	RenderFrame(currentTime, timePassed);
}

//draw a frame
void RenderFrame()
{
	//Clear buffers
	glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
	glLoadIdentity();										//reset modelview matrix


	glEnable(GL_LIGHTING);
	glTranslatef(0.0f, 0.0f, -30.0f);
	glRotatef((float)timer.GetTime()/30, 1.0f, 0.0f, 1.0f);
	cubeGrid.DrawSurface(threshold);
	glDisable(GL_LIGHTING);

	
	fpsCounter.Update();											//update frames per second counter
	glColor4f(0.0f, 0.0f, 1.0f, 1.0f);
	window.StartTextMode();
	window.Print(0, 28, "FPS: %.2f", fpsCounter.GetFps());			//print the fps
	glColor4f(1.0f, 1.0f, 0.0f, 1.0f);
	window.Print(0, 48, "Grid Size: %d", gridSize);
	window.Print(0, 68, "%d triangles drawn", cubeGrid.numFacesDrawn);
	window.EndTextMode();
	glColor4f(1.0f, 1.0f, 1.0f, 1.0f);

	if(window.isKeyPressed(VK_F1))
	{
		window.SaveScreenshot();
		window.SetKeyReleased(VK_F1);
	}

	window.SwapBuffers();									//swap buffers

	//check for any opengl errors
	window.CheckGLError();

	//quit if necessary
	if(window.isKeyPressed(VK_ESCAPE))
		PostQuitMessage(0);
}

//Called to draw scene
void Display(void)
{
	//angle of spheres in scene. Calculate from time
	float angle=timer.GetTime()/10;	



	//First pass - from light's point of view
	glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
	
	glMatrixMode(GL_PROJECTION);
	glLoadMatrixf(lightProjectionMatrix);

	glMatrixMode(GL_MODELVIEW);
	glLoadMatrixf(lightViewMatrix);

	//Use viewport the same size as the shadow map
	glViewport(0, 0, shadowMapSize, shadowMapSize);

	//Draw back faces into the shadow map
	glCullFace(GL_FRONT);

	//Disable color writes, and use flat shading for speed
	glShadeModel(GL_FLAT);
	glColorMask(0, 0, 0, 0);
	
	//Draw the scene
	DrawScene(angle);

	//Read the depth buffer into the shadow map texture
	glBindTexture(GL_TEXTURE_2D, shadowMapTexture);
	glCopyTexSubImage2D(GL_TEXTURE_2D, 0, 0, 0, 0, 0, shadowMapSize, shadowMapSize);

	//restore states
	glCullFace(GL_BACK);
	glShadeModel(GL_SMOOTH);
	glColorMask(1, 1, 1, 1);
	

	

	//2nd pass - Draw from camera's point of view
	glClear(GL_DEPTH_BUFFER_BIT);

	glMatrixMode(GL_PROJECTION);
	glLoadMatrixf(cameraProjectionMatrix);
	
	glMatrixMode(GL_MODELVIEW);
	glLoadMatrixf(cameraViewMatrix);

	glViewport(0, 0, windowWidth, windowHeight);

	//Use dim light to represent shadowed areas
	glLightfv(GL_LIGHT1, GL_POSITION, VECTOR4D(lightPosition));
	glLightfv(GL_LIGHT1, GL_AMBIENT, white*0.2f);
	glLightfv(GL_LIGHT1, GL_DIFFUSE, white*0.2f);
	glLightfv(GL_LIGHT1, GL_SPECULAR, black);
	glEnable(GL_LIGHT1);
	glEnable(GL_LIGHTING);

	DrawScene(angle);
	


	//3rd pass
	//Draw with bright light
	glLightfv(GL_LIGHT1, GL_DIFFUSE, white);
	glLightfv(GL_LIGHT1, GL_SPECULAR, white);

	//Calculate texture matrix for projection
	//This matrix takes us from eye space to the light's clip space
	//It is postmultiplied by the inverse of the current view matrix when specifying texgen
	static MATRIX4X4 biasMatrix(0.5f, 0.0f, 0.0f, 0.0f,
								0.0f, 0.5f, 0.0f, 0.0f,
								0.0f, 0.0f, 0.5f, 0.0f,
								0.5f, 0.5f, 0.5f, 1.0f);	//bias from [-1, 1] to [0, 1]
	MATRIX4X4 textureMatrix=biasMatrix*lightProjectionMatrix*lightViewMatrix;
	//MATRIX4X4 textureMatrix=lightProjectionMatrix*lightViewMatrix;
	//Set up texture coordinate generation.
	glTexGeni(GL_S, GL_TEXTURE_GEN_MODE, GL_EYE_LINEAR);
	glTexGenfv(GL_S, GL_EYE_PLANE, textureMatrix.GetRow(0));
	glEnable(GL_TEXTURE_GEN_S);

	glTexGeni(GL_T, GL_TEXTURE_GEN_MODE, GL_EYE_LINEAR);
	glTexGenfv(GL_T, GL_EYE_PLANE, textureMatrix.GetRow(1));
	glEnable(GL_TEXTURE_GEN_T);

	glTexGeni(GL_R, GL_TEXTURE_GEN_MODE, GL_EYE_LINEAR);
	glTexGenfv(GL_R, GL_EYE_PLANE, textureMatrix.GetRow(2));
	glEnable(GL_TEXTURE_GEN_R);

	glTexGeni(GL_Q, GL_TEXTURE_GEN_MODE, GL_EYE_LINEAR);
	glTexGenfv(GL_Q, GL_EYE_PLANE, textureMatrix.GetRow(3));
	glEnable(GL_TEXTURE_GEN_Q);

	//Bind & enable shadow map texture
	glBindTexture(GL_TEXTURE_2D, shadowMapTexture);
	glEnable(GL_TEXTURE_2D);

//.........这里部分代码省略.........