我正在制作投球游戏。到目前为止，我已完成编码以创建一个球和一个锥体。
我现在要做的是当按下UP-KEY时，球应向锥体移动
我尝试做的是使用计时器功能并调用 glutPostRedisplay（），以便球的Y坐标递增（点击UP-KEY后）显示/移动。但问题是，当我这样做时，锥和球开始远离屏幕移动（因为glTranslate（）或glRotate（）方法在显示功能内）
当按下UP-KEY时，请建议让我的代码将球移向该锥体。
#include <GL/glut.h>
#include <stdlib.h>
#include <Math.h> // Needed for sin, cos
#define PI 3.14159265f
int windowWidth = 640; // Windowed mode's width
int windowHeight = 480; // Windowed mode's height
int windowPosX = 50; // Windowed mode's top-left corner x
int windowPosY = 50; // Windowed mode's top-left corner y
GLfloat ballRadius = 0.1f; // Radius of the bouncing ball
GLfloat ballX = 0.0f; // Ball's center (x, y) position
GLfloat ballY = 0.0f;
GLfloat ballXMax, ballXMin, ballYMax, ballYMin; // Ball's center (x, y) bounds
GLfloat xSpeed = 0.02f; // Ball's speed in x and y directions
GLfloat ySpeed = 0.007f;
int refreshMillis = 30; // Refresh period in milliseconds
// Projection clipping area
GLdouble clipAreaXLeft, clipAreaXRight, clipAreaYBottom, clipAreaYTop;
bool fullScreenMode = true; // Full-screen or windowed mode?
bool paused = false; // Movement paused or resumed
bool moveUp = false, moveDown = false;
GLfloat xSpeedSaved, ySpeedSaved; // To support resume
/* Called back when the timer expired */
void Timer(int value) {
glutPostRedisplay(); // Post a paint request to activate display()
glutTimerFunc(refreshMillis, Timer, 0); // subsequent timer call at milliseconds
}
/* Callback handler for normal-key event */
void keyboard(unsigned char key, int x, int y) {
switch (key) {
case 27: // ESC key
exit(0);
break;
}
}
/* Callback handler for special-key event */
void specialKeys(int key, int x, int y) {
switch (key) {
case GLUT_KEY_F1: // F1: Toggle between full-screen and windowed mode
fullScreenMode = !fullScreenMode; // Toggle state
if (fullScreenMode) { // Full-screen mode
windowPosX = glutGet(GLUT_WINDOW_X); // Save parameters for restoring later
windowPosY = glutGet(GLUT_WINDOW_Y);
windowWidth = glutGet(GLUT_WINDOW_WIDTH);
windowHeight = glutGet(GLUT_WINDOW_HEIGHT);
glutFullScreen(); // Switch into full screen
} else { // Windowed mode
glutReshapeWindow(windowWidth, windowHeight); // Switch into windowed mode
glutPositionWindow(windowPosX, windowPosX); // Position top-left corner
}
break;
case GLUT_KEY_RIGHT: // Right: increase x speed
xSpeed *= 1.05f;
break;
case GLUT_KEY_LEFT: // Left: decrease x speed
xSpeed *= 0.95f;
break;
case GLUT_KEY_HOME: // Up: increase y speed
ySpeed *= 1.05f;
break;
case GLUT_KEY_END: // Down: decrease y speed
ySpeed *= 0.95f;
break;
case GLUT_KEY_DOWN:
moveUp = false;
moveDown = true;
break;
case GLUT_KEY_UP:
ballY += ySpeed;
/*moveDown = false;
moveUp = true;*/
break;
case GLUT_KEY_PAGE_UP: // Page-Up: increase ball's radius
ballRadius *= 1.05f;
ballXMin = clipAreaXLeft + ballRadius;
ballXMax = clipAreaXRight - ballRadius;
ballYMin = clipAreaYBottom + ballRadius;
ballYMax = clipAreaYTop - ballRadius;
break;
case GLUT_KEY_PAGE_DOWN: // Page-Down: decrease ball's radius
ballRadius *= 0.95f;
ballXMin = clipAreaXLeft + ballRadius;
ballXMax = clipAreaXRight - ballRadius;
ballYMin = clipAreaYBottom + ballRadius;
ballYMax = clipAreaYTop - ballRadius;
break;
}
}
static void resize(int width, int height) {
GLfloat aspect = (GLfloat) width / (GLfloat) height;
glMatrixMode(GL_PROJECTION);
glLoadIdentity();
glFrustum(-aspect, aspect, -1.0, 1.0, 2.0, 100.0);
if (height == 0)
height = 1; // To prevent divide by 0
// Set the viewport to cover the new window
glViewport(0, 0, width, height);
if (width >= height) {
clipAreaXLeft = -1.0 * aspect;
clipAreaXRight = 1.0 * aspect;
clipAreaYBottom = -1.0;
clipAreaYTop = 1.0;
} else {
clipAreaXLeft = -1.0;
clipAreaXRight = 1.0;
clipAreaYBottom = -1.0 / aspect;
clipAreaYTop = 1.0 / aspect;
}
}
static void display(void) {
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
glColor3d(0, 0, 1);
glPushMatrix();
glTranslated(-1.0, 0.5, -10);
glRotated(70, -1.0, 0.0, 0.0);
glutSolidCone(1, 2, 70, 50);
glPopMatrix();
glTranslatef(ballX, ballY, -6.0f); // Translate to (xPos, yPos)
// Use triangular segments to form a circle
glBegin(GL_TRIANGLE_FAN);
glColor3f(0.0f, 0.0f, 1.0f); // Blue
glVertex2f(0.0f, 0.0f); // Center of circle
int numSegments = 100;
GLfloat angle;
for (int i = 0; i <= numSegments; i++) { // Last vertex same as first vertex
angle = i * 2.0f * PI / numSegments; // 360 deg for all segments
glVertex2f(cos(angle) * ballRadius, sin(angle) * ballRadius);
}
glEnd();
if (moveUp)
ballY += ySpeed;
if (moveDown)
ballY -= ySpeed;
// Check if the ball exceeds the edges
if (ballX > ballXMax) {
ballX = ballXMax;
xSpeed = -xSpeed;
} else if (ballX < ballXMin) {
ballX = ballXMin;
xSpeed = -xSpeed;
}
if (ballY > ballYMax) {
ballY = ballYMax;
ySpeed = -ySpeed;
} else if (ballY < ballYMin) {
ballY = ballYMin;
ySpeed = -ySpeed;
}
glutSwapBuffers();
}
/*
const GLfloat light_ambient[] = { 0.0f, 0.0f, 0.0f, 1.0f };
const GLfloat light_diffuse[] = { 1.0f, 1.0f, 1.0f, 1.0f };
const GLfloat light_specular[] = { 1.0f, 1.0f, 1.0f, 1.0f };
const GLfloat light_position[] = { 2.0f, 5.0f, 5.0f, 0.0f };
const GLfloat mat_ambient[] = { 0.7f, 0.7f, 0.7f, 1.0f };
const GLfloat mat_diffuse[] = { 0.8f, 0.8f, 0.8f, 1.0f };
const GLfloat mat_specular[] = { 1.0f, 1.0f, 1.0f, 1.0f };
const GLfloat high_shininess[] = { 100.0f };
*/
/* Program entry point */
int main(int argc, char *argv[]) {
glutInit(&argc, argv);
glutInitWindowSize(windowWidth, windowHeight); // Initial window width and height
glutInitWindowPosition(windowPosX, windowPosY); // Initial window top-left corner (x, y)
glutInitDisplayMode(GLUT_RGB | GLUT_DOUBLE | GLUT_DEPTH);
glutCreateWindow("Balling game");
glutReshapeFunc(resize);
glutDisplayFunc(display);
glClearColor(1, 1, 1, 1);
glutSpecialFunc(specialKeys); // Register callback handler for special-key event
glutKeyboardFunc(keyboard); // Register callback handler for special-key event
glutFullScreen(); // Put into full screen
/*glEnable(GL_CULL_FACE);
glCullFace(GL_BACK);
glEnable(GL_DEPTH_TEST);
glDepthFunc(GL_LESS);
glEnable(GL_LIGHT0);
glEnable(GL_NORMALIZE);
glEnable(GL_COLOR_MATERIAL);
glEnable(GL_LIGHTING);
glLightfv(GL_LIGHT0, GL_AMBIENT, light_ambient);
glLightfv(GL_LIGHT0, GL_DIFFUSE, light_diffuse);
glLightfv(GL_LIGHT0, GL_SPECULAR, light_specular);
glLightfv(GL_LIGHT0, GL_POSITION, light_position);
glMaterialfv(GL_FRONT, GL_AMBIENT, mat_ambient);
glMaterialfv(GL_FRONT, GL_DIFFUSE, mat_diffuse);
glMaterialfv(GL_FRONT, GL_SPECULAR, mat_specular);
glMaterialfv(GL_FRONT, GL_SHININESS, high_shininess);*/
glutMainLoop();
return EXIT_SUCCESS;
}
答案 0 :(得分：0)
@Immueggpain 这是在按下UP_KEY时向上移动球（2d）的代码。
#include <GL/glut.h> // GLUT, include glu.h and gl.h
#include <Math.h> // Needed for sin, cos
#define PI 3.14159265f
// Global variables
char title[] = "Full-Screen & Windowed Mode"; // Windowed mode's title
int windowWidth = 640; // Windowed mode's width
int windowHeight = 480; // Windowed mode's height
int windowPosX = 50; // Windowed mode's top-left corner x
int windowPosY = 50; // Windowed mode's top-left corner y
GLfloat ballRadius = 0.1f; // Radius of the bouncing ball
GLfloat ballX = 0.0f; // Ball's center (x, y) position
GLfloat ballY = 0.0f;
GLfloat ballXMax, ballXMin, ballYMax, ballYMin; // Ball's center (x, y) bounds
GLfloat xSpeed = 0.02f; // Ball's speed in x and y directions
GLfloat ySpeed = 0.007f;
int refreshMillis = 30; // Refresh period in milliseconds
// Projection clipping area
GLdouble clipAreaXLeft, clipAreaXRight, clipAreaYBottom, clipAreaYTop;
bool fullScreenMode = true; // Full-screen or windowed mode?
bool paused = false; // Movement paused or resumed
bool moveUp = false, moveDown = false;
GLfloat xSpeedSaved, ySpeedSaved; // To support resume
/* Initialize OpenGL Graphics */
void initGL() {
glClearColor(0.0, 0.0, 0.0, 1.0); // Set background (clear) color to black
}
/* Callback handler for window re-paint event */
void display() {
glClear(GL_COLOR_BUFFER_BIT); // Clear the color buffer
glMatrixMode(GL_MODELVIEW); // To operate on the model-view matrix
glLoadIdentity(); // Reset model-view matrix
glColor3d(0, 0, 1);
glPushMatrix();
glTranslated(-1.0, 0.5, -10);
glRotated(70, -1.0, 0.0, 0.0);
glutSolidCone(1, 2, 70, 50);
glPopMatrix();
glTranslatef(ballX, ballY, 0.0f); // Translate to (xPos, yPos)
// Use triangular segments to form a circle
glBegin(GL_TRIANGLE_FAN);
glColor3f(0.0f, 0.0f, 1.0f); // Blue
glVertex2f(0.0f, 0.0f); // Center of circle
int numSegments = 100;
GLfloat angle;
for (int i = 0; i <= numSegments; i++) { // Last vertex same as first vertex
angle = i * 2.0f * PI / numSegments; // 360 deg for all segments
glVertex2f(cos(angle) * ballRadius, sin(angle) * ballRadius);
}
glEnd();
glutSwapBuffers(); // Swap front and back buffers (of double buffered mode)
// Animation Control - compute the location for the next refresh
//ballX += xSpeed;
if (moveUp)
ballY += ySpeed;
if (moveDown)
ballY -= ySpeed;
// Check if the ball exceeds the edges
if (ballX > ballXMax) {
ballX = ballXMax;
xSpeed = -xSpeed;
} else if (ballX < ballXMin) {
ballX = ballXMin;
xSpeed = -xSpeed;
}
if (ballY > ballYMax) {
ballY = ballYMax;
ySpeed = -ySpeed;
} else if (ballY < ballYMin) {
ballY = ballYMin;
ySpeed = -ySpeed;
}
}
/* Call back when the windows is re-sized */
void reshape(GLsizei width, GLsizei height) {
// Compute aspect ratio of the new window
if (height == 0)
height = 1; // To prevent divide by 0
GLfloat aspect = (GLfloat) width / (GLfloat) height;
// Set the viewport to cover the new window
glViewport(0, 0, width, height);
// Set the aspect ratio of the clipping area to match the viewport
glMatrixMode(GL_PROJECTION); // To operate on the Projection matrix
glLoadIdentity(); // Reset the projection matrix
if (width >= height) {
clipAreaXLeft = -1.0 * aspect;
clipAreaXRight = 1.0 * aspect;
clipAreaYBottom = -1.0;
clipAreaYTop = 1.0;
} else {
clipAreaXLeft = -1.0;
clipAreaXRight = 1.0;
clipAreaYBottom = -1.0 / aspect;
clipAreaYTop = 1.0 / aspect;
}
gluOrtho2D(clipAreaXLeft, clipAreaXRight, clipAreaYBottom, clipAreaYTop);
ballXMin = clipAreaXLeft + ballRadius;
ballXMax = clipAreaXRight - ballRadius;
ballYMin = clipAreaYBottom + ballRadius;
ballYMax = clipAreaYTop - ballRadius;
}
/* Called back when the timer expired */
void Timer(int value) {
glutPostRedisplay(); // Post a paint request to activate display()
glutTimerFunc(refreshMillis, Timer, 0); // subsequent timer call at milliseconds
}
/* Callback handler for normal-key event */
void keyboard(unsigned char key, int x, int y) {
switch (key) {
case 27: // ESC key
exit(0);
break;
}
}
/* Callback handler for special-key event */
void specialKeys(int key, int x, int y) {
switch (key) {
case GLUT_KEY_F1: // F1: Toggle between full-screen and windowed mode
fullScreenMode = !fullScreenMode; // Toggle state
if (fullScreenMode) { // Full-screen mode
windowPosX = glutGet(GLUT_WINDOW_X); // Save parameters for restoring later
windowPosY = glutGet(GLUT_WINDOW_Y);
windowWidth = glutGet(GLUT_WINDOW_WIDTH);
windowHeight = glutGet(GLUT_WINDOW_HEIGHT);
glutFullScreen(); // Switch into full screen
} else { // Windowed mode
glutReshapeWindow(windowWidth, windowHeight); // Switch into windowed mode
glutPositionWindow(windowPosX, windowPosX); // Position top-left corner
}
break;
case GLUT_KEY_RIGHT: // Right: increase x speed
xSpeed *= 1.05f;
break;
case GLUT_KEY_LEFT: // Left: decrease x speed
xSpeed *= 0.95f;
break;
case GLUT_KEY_HOME: // Up: increase y speed
ySpeed *= 1.05f;
break;
case GLUT_KEY_END: // Down: decrease y speed
ySpeed *= 0.95f;
break;
case GLUT_KEY_DOWN:
moveUp = false;
moveDown = true;
break;
case GLUT_KEY_UP:
moveDown = false;
moveUp = true;
break;
case GLUT_KEY_PAGE_UP: // Page-Up: increase ball's radius
ballRadius *= 1.05f;
ballXMin = clipAreaXLeft + ballRadius;
ballXMax = clipAreaXRight - ballRadius;
ballYMin = clipAreaYBottom + ballRadius;
ballYMax = clipAreaYTop - ballRadius;
break;
case GLUT_KEY_PAGE_DOWN: // Page-Down: decrease ball's radius
ballRadius *= 0.95f;
ballXMin = clipAreaXLeft + ballRadius;
ballXMax = clipAreaXRight - ballRadius;
ballYMin = clipAreaYBottom + ballRadius;
ballYMax = clipAreaYTop - ballRadius;
break;
}
}
/* Callback handler for mouse event */
void mouse(int button, int state, int x, int y) {
if (button == GLUT_LEFT_BUTTON && state == GLUT_DOWN) { // Pause/resume
paused = !paused; // Toggle state
if (paused) {
xSpeedSaved = xSpeed; // Save parameters for restore later
ySpeedSaved = ySpeed;
xSpeed = 0; // Stop movement
ySpeed = 0;
} else {
xSpeed = xSpeedSaved; // Restore parameters
ySpeed = ySpeedSaved;
}
}
}
/* Main function: GLUT runs as a console application starting at main() */
int main(int argc, char** argv) {
glutInit(&argc, argv); // Initialize GLUT
glutInitDisplayMode(GLUT_DOUBLE); // Enable double buffered mode
glutInitWindowSize(windowWidth, windowHeight); // Initial window width and height
glutInitWindowPosition(windowPosX, windowPosY); // Initial window top-left corner (x, y)
glutCreateWindow(title); // Create window with given title
glutDisplayFunc(display); // Register callback handler for window re-paint
glutReshapeFunc(reshape); // Register callback handler for window re-shape
glutTimerFunc(0, Timer, 0); // First timer call immediately
glutSpecialFunc(specialKeys); // Register callback handler for special-key event
glutKeyboardFunc(keyboard); // Register callback handler for special-key event
glutFullScreen(); // Put into full screen
glutMouseFunc(mouse); // Register callback handler for mouse event
initGL(); // Our own OpenGL initialization
glutMainLoop(); // Enter event-processing loop
return 0;
}
这是绘制圆锥的小代码（在3d中）。
glColor3d(0, 0, 1);
glPushMatrix();
glTranslated(-1.0, 0.5, -10);
glRotated(70, -1.0, 0.0, 0.0);
glutSolidCone(1, 2, 70, 50);
glPopMatrix();
但是当我将此代码放在显示方法中时，它不显示圆锥。
也许与 glFrustum（） 有关，但我不知道怎么办？
有什么建议吗？