OpenGL 虚拟漫游

#include <stdio.h> #include <stdlib.h> #include <math.h> #include <time.h> #include <GL/glut.h> #include "texture.h" #define PI 3.14159 struct particle { float t; // 粒子的寿命 float v; // 粒子的运动速度 float d; // 粒子的运动方向 float x, y, z; // 粒子的位置坐标 float xd, zd; // X 和 Z 方向上的增量 char type; // 粒子的状态（移动或淡化） float a; // 粒子淡化的 alpha 值 struct particle *next, *prev; }; struct point { float x, y, z; }; int WindW, WindH; unsigned *teximage; // 粒子的纹理 GLuint texture[2]; // 纹理ID float a=0; struct particle *fn[3]; /* Fountains */ char temp[128]="FPS: 0.000000"; // 以下是用于计算帧率的变量 int frame_counter=0; time_t curtime; clock_t last_time; float cur_time; float total_frames; struct point upv, cam; // 摄像机的位置和向上的方向矢量 // 初始化函数 void Init() { fn[0] = NULL; fn[1] = NULL; fn[2] = NULL; upv.x = -5; upv.y = 5; upv.z = -5; cam.x = 200; cam.y = 200; cam.z = 200; glGenTextures(3, texture); glClearColor(0, 0, 0, 0); glBlendFunc(GL_SRC_ALPHA, GL_ONE); glEnable(GL_BLEND); glEnable(GL_TEXTURE_2D); } // 在屏幕上绘制字符串 void draw_string(void *font, const char* string) { while(*string) glutStrokeCharacter(font, *string++); } static float gettime(void) { clock_t time_new, time_raz; time_new=clock(); time_raz=time_new-last_time; last_time=time_new; return(time_raz/(float)CLOCKS_PER_SEC); } // 装入纹理 void LoadTexture(char *fn, int t_num) { int texwid, texht; int texcomps; teximage = read_texture(fn, &texwid, &texht, &texcomps); if (!teximage) { printf("Sorry, can't read texture file..."); exit(0); } glBindTexture(GL_TEXTURE_2D, texture[t_num]); glPixelStorei(GL_UNPACK_ALIGNMENT, 1); glTexImage2D(GL_TEXTURE_2D, 0, GL_LUMINANCE, texwid, texht, 0, GL_RGBA, GL_UNSIGNED_BYTE, teximage); glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST); glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST); if ((t_num == 0) || (t_num == 2)) glTexEnvf(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_MODULATE); /* Special for particles */ if (t_num == 1) { // 设置地面的重复纹理参数 glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT); glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT); } free(teximage); } void Reshape(int width, int height) { glViewport(0, 0, width, height); glMatrixMode(GL_PROJECTION); glLoadIdentity(); glFrustum(-0.5, 0.5, -0.5, 0.5, 1, 1000); glMatrixMode(GL_MODELVIEW); WindW = width; WindH = height; } //添加新的粒子 void AddParticles() { struct particle *tempp; int i, j; for (j=0; j<3; j++) for (i=0; i<2; i++) { tempp = (struct particle *)malloc(sizeof(struct particle)); if (fn[j]) fn[j]->prev = tempp; tempp->next = fn[j]; fn[j] = tempp; tempp->t = -9.9; tempp->v = (float)(rand() % 200000)/100000+1; // 速度 tempp->d = (float)(rand() % 400)/100-2; // 方向角度 // 开始运动的坐标 tempp->x = 0; tempp->y = 0; tempp->z = 0; tempp->xd = cos((tempp->d*3.14159)/180)*tempp->v/4; tempp->zd = sin((tempp->d*3.14159)/180)*tempp->v; tempp->type = 0; // 粒子的状态是运动的 tempp->a = 1; // 粒子的Alpha初始值是1 } } // 移动粒子 void MoveParticles() { struct particle *tempp; int j; for (j=0; j<3; j++) { tempp = fn[j]; // 选择喷泉 while (tempp) { if (tempp->type == 0) // 如果粒子是运动的 { tempp->x += tempp->xd; tempp->z += tempp->zd; tempp->y = -(9.8*(tempp->t*tempp->t/4))/2+122.5; // 计算高度 tempp->t += 0.1; // 寿命递增 if (tempp->y < 0) tempp->type = 1; // 如果粒子落到地上，则粒子淡化 } else // 粒子落到地上 { tempp->y = -(9.8*(tempp->t*tempp->t/4))/2+122.5; tempp->a -= 0.1; // 粒子淡化 } tempp = tempp->next; //进行下一个粒子的计算 } } } // 删除粒子 void DeleteParticles() { struct particle *tempp, *temp1; int j; for (j=0; j<3; j++) { tempp = fn[j]; while (tempp) { if ((tempp->type == 1) && (tempp->a <= 0)) // 粒子死亡 { // 删除粒子 temp1 = tempp->prev; tempp->prev->next = tempp->next; if (tempp->next) tempp->next->prev = temp1; free(tempp); tempp = temp1; } tempp = tempp->next; } } } //求矢量差积 C = A x B void vect_mult(struct point *A, struct point *B, struct point *C) { /* Vector multiply */ C->x = A->y*B->z - A->z*B->y; C->y = A->z*B->x - A->x*B->z; C->z = A->x*B->y - A->y*B->x; } // 矢量单位化 void normalize(struct point *V) { float d; // 矢量长度 d = sqrt(V->x*V->x + V->y*V->y + V->z*V->z); // 单位化 V->x /= d; V->y /= d; V->z /= d; } void DrawFountain() { int j; struct particle *tempp; struct point vectd, vectl; float alpha, ttx, ttz; glBindTexture(GL_TEXTURE_2D, texture[0]); AddParticles(); MoveParticles(); DeleteParticles(); glPushMatrix(); for (j=0; j<3; j++) { glBegin(GL_QUADS); tempp = fn[j]; while (tempp) { // 旋转喷泉 alpha = ((j*120+a)*PI)/180; ttx = tempp->x*cos(alpha)-tempp->z*sin(alpha); ttz = tempp->x*sin(alpha)+tempp->z*cos(alpha); // 计算方向矢量A vectd.x = ttx - cam.x; vectd.y = tempp->y - cam.y; vectd.z = ttz - cam.z; vect_mult(&vectd, &upv, &vectl); normalize(&vectl); vectl.x *= 5; vectl.y *= 5; vectl.z *= 5; glColor4f(0.5, 0.5, 1, tempp->a); // 绘制粒子及纹理映射 glTexCoord2f(0, 0); glVertex3f((ttx-vectl.x), (tempp->y-upv.y), (ttz-vectl.z)); glTexCoord2f(1, 0); glVertex3f((ttx+vectl.x), (tempp->y-upv.y), (ttz+vectl.z)); glTexCoord2f(1, 1); glVertex3f((ttx+vectl.x), (tempp->y+upv.y), (ttz+vectl.z)); glTexCoord2f(0, 1); glVertex3f((ttx-vectl.x), (tempp->y+upv.y), (ttz-vectl.z)); tempp = tempp->next; // 下一个粒子 } glEnd(); } glPopMatrix(); } // 场景绘制函数 void Draw(void) { glClear(GL_COLOR_BUFFER_BIT); glLoadIdentity(); glBindTexture(GL_TEXTURE_2D, texture[1]); a += 0.2; gluLookAt(cam.x, cam.y, cam.z, 0, 0, 0, upv.x, upv.y, upv.z); // 绘制地面 glColor3f(0.9, 0.9, 1); glPushMatrix(); glRotatef(a, 0, -1, 0); glBegin(GL_QUADS); glTexCoord2f(0, 0); glVertex3f(-100, 0, -100); glTexCoord2f(2, 0); glVertex3f(-100, 0, 100); glTexCoord2f(2, 2); glVertex3f(100, 0, 100); glTexCoord2f(0, 2); glVertex3f(100, 0, -100); glEnd(); glPopMatrix(); // 绘制喷泉 DrawFountain(); glBindTexture(GL_TEXTURE_2D, texture[2]); glColor4f(1, 1, 0, 0.8); glPushMatrix(); glRotatef(a, 0, -1, 0); glBegin(GL_QUADS); glTexCoord2f(0, 0); glVertex3f(-100, 0, -100); glTexCoord2f(1, 0); glVertex3f(-100, 0, 100); glTexCoord2f(1, 1); glVertex3f(100, 0, 100); glTexCoord2f(0, 1); glVertex3f(100, 0, -100); glEnd(); glPopMatrix(); // 计算帧率 frame_counter++; if((frame_counter % 40) == 0) { frame_counter = 0; cur_time=gettime(); sprintf(temp, "FPS: %f", 40.0/cur_time); } // 绘制显示帧率的字符串 glColor3f(1, 1, 1); glDisable(GL_TEXTURE_2D); glLoadIdentity(); glTranslatef(-4.9, 4.5, -10); glScalef(0.003, 0.003, 0.004); draw_string(GLUT_STROKE_ROMAN, temp); glEnable(GL_TEXTURE_2D); glFlush(); glutSwapBuffers(); } static void Key(unsigned char key, int x, int y) { switch (key) { case 27: exit(0); break; } } void timf(int value) { glutPostRedisplay(); glutTimerFunc(16, timf, 0); } int