我从未理解过如何在OpenGL中使用动画。我正在研究他的项目试图让它运作但从未让滑雪者移动。试图弄清楚如何解决这个问题。
#include "../shared/gltools.h" // OpenGL toolkit
#define PI 3.14159265
float a = -5;//maybe
float b = 29;
float c = 27;
float d = 28.25;
float e = 28.5;
bool lookUp;
bool setback;
bool lookDown;
bool lookLeft;
bool lookRight;
bool walkForward;
bool walkBackward;
bool strafeLeft;
bool strafeRight;
float xTranslation;
float yTranslation;
float zTranslation;
float yRotationAngle;
float zRotationAngle;
float xRotationAngle;
int mouseLastx;
int mouseLasty;
float sunRotationAngle=0;
float sunRadius = 150.0;
float day=0;
float dusk=1;
// Light values and coordinates
GLfloat lightPos[] = { 0.0f, 30.0f, 0.0f, 1.0f };
GLfloat lightPos2[] = { 0.0f, 0.0f, 40.0f, 1.0f };
GLfloat specular[] = { 1.0f, 1.0f, 1.0f, 1.0f};
GLfloat specular2[] = { 0.0f, 1.0f, 0.0f, 1.0f};
GLfloat diffuse[] = { 1.0f, 1.0f, 1.0f, 1.0f};
GLfloat diffuse2[] = { 0.0f, 0.3f, 0.0f, 1.0f};
GLloat specref[] = { 1.0f, 1.0f, 1.0f, 1.0f };
GLfloat ambientLight[] = { 0.5f, 0.5f, 0.5f, 1.0f};
GLfloat spotDir[] = { 0.0f, 0.0f, -1.0f };
void mouseMovement(int x, int y)
{
int mouseDiffx=x-mouseLastx;
int mouseDiffy=y-mouseLasty;
mouseLastx=x;
mouseLasty=y; //set lasty to the current y position
xRotationAngle += (GLfloat) mouseDiffy;
yRotationAngle += (GLfloat) mouseDiffx;
if (xRotationAngle>=90)
xRotationAngle=90;
if (xRotationAngle<=-90)
xRotationAngle=-90;
//cout << "x:" << x << "y:" << y << endl;
}
void drawcabin()
{
glColor3ub(0, 0, 0);
glBegin(GL_TRIANGLES);
//glTranslatef(0,-5,0); // move view left
//glNormal3f(-3,0.7,-1.7);
//glutSolidCube(5.0f);
glNormal3d(0,0.7,0.7);
glVertex3d(0,6,0);
glVertex3d(-3,3.5,-2);
glVertex3d(2,3.5,-2);
glNormal3d(2,-1,1);
glVertex3d(0,6,0);
glVertex3d(-3,3.5,-2);
glVertex3d(2,3.5,-2);
glTranslatef(0,-5,0); // move view left
glNormal3d(-3,0.7,-1.7);
glEnd();
glColor3ub(185, 0, 0);
glutSolidCube(5.0f);
}
void drawskislope()
{
glColor3ub(0, 0, 0);
glBegin(GL_QUADS);
glTranslatef(0,-5,90); // move view left
glColor3ub(185, 122, 87);
glNormal3d(0,5,1);
glVertex3d(10,0,5);
glVertex3d(10,.5,5);
glVertex3d(15,.5,5);
glVertex3d(15,0,5);//small square
glColor3ub(201, 192, 187);
glVertex3d(11.5,.5,5);
glVertex3d(13.5,.5,5);
glVertex3d(13.5,-10,5);
glVertex3d(11.5,-10,5);
//slope start
glTranslatef(0,-5,0); // move view left
// glNormal3d(-3,0.7,-1.7);
glEnd();
}
void drawskier()
{
float a = -5;//maybe
float b = 29;
float c = 27;
float d = 28.25;
float e = 28.5;
glBegin(GL_QUADS);
glTranslatef(0,-5,0); // move view
glColor3ub(185, 122, 87);
glNormal3d(0,5,1);
//Do While loop
// do
// {
// to move skier do a loop and update a in the translate
glTranslatef(0,a,0); // move view
glVertex3d(c,0,5);//10
glVertex3d(c,.1,5);//10
glVertex3d(b,.1,5);//15
glVertex3d(b,0,5);//skis on skier
glNormal3d(0,5,1);
glVertex3d(d,0,5);
glVertex3d(d,1.35,5);
glVertex3d(e,1.35,5);
glVertex3d(e,0,5);//body on skier
glutSwapBuffers;
// }while(b>15); //try to animate
glEnd();
glFlush();
b=b-1;
c=c-1;
d=d-1;
e=e-1;
glutPostRedisplay();
glTranslatef(30,3,0); // move view left
glColor3ub(168, 220, 109);
glutSolidSphere(.5,7,8); //sphere-head
glPushMatrix();
glTranslatef(3.5,-100,2);
glutSolidSphere(25,15,15); //sphere
glPopMatrix();
}
void updatescene()
{
}
///////////////////////////////////////////////////////////
// Called to draw scene
void RenderScene(void)
{
GLUquadricObj *pObj; // Quadric Object
pObj = gluNewQuadric();
gluQuadricNormals(pObj, GLU_SMOOTH);
GLfloat horizontalMovement=1;
GLfloat verticalMovement=0;
horizontalMovement=cos(xRotationAngle*PI/180);
verticalMovement=-sin(xRotationAngle*PI/180);
// Reset Model view matrix stack
glMatrixMode(GL_MODELVIEW);
glLoadIdentity();
horizontalMovement=cos(xRotationAngle*PI/180);
verticalMovement=-sin(xRotationAngle*PI/180);
if (lookDown)
{
xRotationAngle+=1;
if (xRotationAngle>=90)
xRotationAngle=90;
}
if (lookUp)
{
xRotationAngle-=1;
if (xRotationAngle<=-90)
xRotationAngle=-90;
}
if (lookRight)
{
yRotationAngle+=1;
if (yRotationAngle>=360)
yRotationAngle=0;
}
if (lookLeft)
{
yRotationAngle-=1;
if (yRotationAngle<=-360)
yRotationAngle=0;
}
if (walkForward)
{
zTranslation+=cos(yRotationAngle*PI/180)*horizontalMovement;
xTranslation-=sin(yRotationAngle*PI/180)*horizontalMovement;
yTranslation-=verticalMovement;
}
if (walkBackward)
{
zTranslation-=cos(yRotationAngle*PI/180)*horizontalMovement;
xTranslation+=sin(yRotationAngle*PI/180)*horizontalMovement;
yTranslation+=verticalMovement;
}
if (strafeRight)
{
zTranslation+=cos((yRotationAngle+90)*PI/180);
xTranslation-=sin((yRotationAngle+90)*PI/180);
}
if (strafeLeft)
{
zTranslation-=cos((yRotationAngle+90)*PI/180);
xTranslation+=sin((yRotationAngle+90)*PI/180);
}
if (setback)
{
zTranslation=0;
xTranslation=0;
yTranslation=0;
}
// Reset Model view matrix stack
glMatrixMode(GL_MODELVIEW);
glLoadIdentity();
glRotatef(xRotationAngle,1,0,0);
glRotatef(zRotationAngle,0,0,1);
glRotatef(yRotationAngle,0,1,0);
glTranslatef(xTranslation,yTranslation,zTranslation);
//glRotatef(-15,1,0,0);
//glRotatef(90,0,1,0);
glTranslatef(0,-0.50,-10);
glPolygonMode(GL_FRONT_AND_BACK,GL_FILL);
sunRotationAngle++;
// Clear the window with current clearing color
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
glColor3d(0,0,0);
glLineWidth(2);
//snow
glColor3ub(255, 255, 255);
glBegin(GL_QUADS);
glNormal3f(0,1,0);
for (int i=-100;i<=200;i+=10) //x
for (int j=-100;j<=200;j+=10)//z
{
float y1=(-j)*.25;
float y2=(-j+10)*.25;
glVertex3d(i+10,y2,-100);
glVertex3d(i,y2,-100);
glVertex3d(i,y1,-100);
glVertex3d(i+10,y1,-100);
}
glEnd();
glPushMatrix();
glTranslatef(-10,14,-50);
drawcabin();
drawskislope();
drawskier();
glPopMatrix();
// Flush drawing commands
glutSwapBuffers();
glutPostRedisplay();
//GLfloat horizontalMovement=1;
// GLfloat verticalMovement=0;
}
void TimerFunction(int value)
{
// Redraw the scene with new coordinates
glutPostRedisplay();
updatescene();
glutTimerFunc(16,TimerFunction, 1);
}
///////////////////////////////////////////////////////////
// Setup the rendering context
void SetupRC(void)
{
lookUp=false;
lookDown=false;
lookLeft=false;
lookRight=false;
walkForward=false;
walkBackward=false;
strafeLeft=false;
strafeRight=false;
yRotationAngle=0;
xRotationAngle=0;
zRotationAngle=0;
xTranslation=0;
yTranslation=0;
zTranslation=0;
// White background
glClearColor(0.5f,0.95f, 1.0f, 1.0f );
// Set drawing color to green
glColor3f(0.0f, 1.0f, 0.0f);
// Set color shading model to flat
glShadeModel(GL_SMOOTH);
// Clock wise wound polygons are front facing, this is reversed
// because we are using triangle fans
glFrontFace(GL_CCW);
glEnable (GL_DEPTH_TEST);
}
void ChangeSize(int w, int h)
{
//GLfloat nRange = 100.0f;
// Prevent a divide by zero
if(h == 0)
h = 1;
// Set Viewport to window dimensions
glViewport(0, 0, w, h);
// Reset projection matrix stack
glMatrixMode(GL_PROJECTION);
glLoadIdentity();
// Establish clipping volume (left, right, bottom, top, near, far)
GLfloat fAspect;
fAspect = (GLfloat)w / (GLfloat)h;
//glOrtho(-10,10,-10,10,0,1000);
gluPerspective(45,fAspect,0.1,1000);
// Reset Model view matrix stack
glMatrixMode(GL_MODELVIEW);
glLoadIdentity();
}
// Respond to arrow keys by moving the camera frame of reference
void SpecialKeys(int key, int x, int y)
{
if(key == GLUT_KEY_UP)
lookUp=true;
if(key == GLUT_KEY_DOWN)
lookDown=true;
if(key == GLUT_KEY_LEFT)
lookLeft=true;
if(key == GLUT_KEY_RIGHT)
lookRight=true;
// Refresh the Window
glutPostRedisplay();
}
void SpecialKeysUp(int key, int x, int y)
{
if(key == GLUT_KEY_UP)
lookUp=false;
if(key == GLUT_KEY_DOWN)
lookDown=false;
if(key == GLUT_KEY_LEFT)
lookLeft=false;
if(key == GLUT_KEY_RIGHT)
lookRight=false;
// Refresh the Window
glutPostRedisplay();
}
void keyboardFunc(unsigned char key, int x, int y)
{
switch(key)
{
case 'w':
walkForward=true;
break;
case 's':
walkBackward=true;
break;
case 'a':
strafeLeft=true;
break;
case 'd':
strafeRight=true;
break;
case 'r':
setback=true;
break;
default:
break;
}
}
void keyboardUpFunc(unsigned char key, int x, int y)
{
switch(key)
{
case 'w':
walkForward=false;
break;
case 's':
walkBackward=false;
break;
case 'a':
strafeLeft=false;
break;
case 'd':
strafeRight=false;
break;
default:
break;
}
}
///////////////////////////////////////////////////////////
// Main program entry point
int main(int argc, char* argv[])
{
glutInit(&argc, argv);
glutInitDisplayMode(GLUT_DOUBLE | GLUT_RGB | GLUT_DEPTH);
glutInitWindowSize(500,500);
glutCreateWindow("Assignment 2");
glutReshapeFunc(ChangeSize);
glutDisplayFunc(RenderScene);
glutSpecialFunc(SpecialKeys);
glutSpecialUpFunc(SpecialKeysUp);
glutKeyboardUpFunc(keyboardUpFunc);
glutKeyboardFunc(keyboardFunc);
glutPassiveMotionFunc(mouseMovement);
SetupRC();
glutMainLoop();
return 0;
}
答案 0 :(得分：1)
我的一般方法是使用glutTimerFunc()回调每16毫秒左右发布一次重新显示事件（约60 FPS）。
然后在glutDisplayFunc()回调中，您可以获取新的GLUT_ELAPSED_TIME来计算最后一帧的增量时间（dt）。
掌握dt，您可以更新任意数量的变量，例如角度或平移偏移。您需要使用dt而不是固定增量值来将动画速度与帧速率分离。
然后回到glutDisplayFunc()回调中，使用更新的状态变量绘制一个新帧。
这是一个使用上述方法以每秒约30度旋转方块的示例：
#include <GL/glut.h>
float angle = 0;
void update( const double dt )
{
// in degrees per second
const float SPEED = 30.0f;
// update angle
angle += ( SPEED * dt );
}
void display()
{
// GLUT_ELAPSED_TIME is in milliseconds
static int prvMs = glutGet( GLUT_ELAPSED_TIME );
const int curMs = glutGet( GLUT_ELAPSED_TIME );
// dt is in seconds
const double dt = ( curMs - prvMs ) / 1000.0;
prvMs = curMs;
// update world state
update( dt );
glClear( GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT );
// reset projection/modelview matrices each frame;
// this makes sure we have a known-good matrix
// stack each time through display()
glMatrixMode( GL_PROJECTION );
glLoadIdentity();
glOrtho( -2, 2, -2, 2, -1, 1 );
glMatrixMode( GL_MODELVIEW );
glLoadIdentity();
// draw rotated square
glRotatef( angle, 0, 0, 1 );
glBegin( GL_QUADS );
glColor3ub( 255, 0, 0 );
glVertex2i( -1, -1 );
glVertex2i( 1, -1 );
glVertex2i( 1, 1 );
glVertex2i( -1, 1 );
glEnd();
glutSwapBuffers();
}
void timer( int value )
{
glutPostRedisplay();
glutTimerFunc( 16, timer, 0 );
}
int main( int argc, char **argv )
{
glutInit( &argc, argv );
glutInitDisplayMode( GLUT_RGBA | GLUT_DEPTH | GLUT_DOUBLE );
glutInitWindowSize( 600, 600 );
glutCreateWindow( "GLUT" );
glutDisplayFunc( display );
glutTimerFunc( 0, timer, 0 );
glutMainLoop();
return 0;
}