Tutorial 10.Vertex Animation

Banyak obyek sebetulnya bukan benda rigid. Sebagai contoh adalah bendera atau selembar kertas. Program 14 memberi ilustrasi tentang bagaimana membuat suatu bendera berkibar. Program 14 melakukan ilusi berkibar dengan merubah posisi relatif suatu vertex terhadap koordinat bendanya. Cara yang lebih canggih mencakup proses pemodelan dinamika benderanya.

TUGAS: Terangkan bagaimana cara bekerjanya animasi bendera tersebut.

// Vertex Animation// Program ini menampilkan animasi pada tiap vertex// Image Loadernya menggunakan library tambahan yaitu SOIL (Simple OpenGL Image Library)#include <math.h> // Math Library Header File#include <stdio.h>#include <stdlib.h>#include <string.h>#include <stdarg.h>#include <GL/glut.h>#include <SOIL/SOIL.h>

float points[45][45][3]; // The Array for the points on the grid of our "Wave"int wiggle_count = 0; // Counter used to control how fast flag waves

GLfloat xRot; // X rotationGLfloat yRot; // y rotationGLfloat zRot; // z rotationGLfloat hold; // Temporarily holds a floating value

GLuint texture; // Storage for one texture

void init(void);GLuint LoadGLTextures(const char* filename);void myTimeOut(int id);void myKeyboard(unsigned char key, int x, int y);void resize(int width, int height);

void renderScene(void);

int main(int argc, char* argv[]){ glutInit(&argc, argv); glutInitDisplayMode(GLUT_DOUBLE | GLUT_DEPTH); glutInitWindowSize(500, 500); glutInitWindowPosition(0, 0); glutCreateWindow("Vertex Animation");

glutDisplayFunc(renderScene); glutKeyboardFunc(myKeyboard); glutReshapeFunc(resize); glutTimerFunc(100, myTimeOut, 0); init();

glutMainLoop();

return 0;}

GLuint LoadGLTextures(const char* filename) // Load Bitmaps And Convert To Textures{ GLuint tex_2d; /* load an image file directly as a new OpenGL texture */ tex_2d = SOIL_load_OGL_texture(filename, SOIL_LOAD_AUTO, SOIL_CREATE_NEW_ID, SOIL_FLAG_MIPMAPS | SOIL_FLAG_INVERT_Y | SOIL_FLAG_NTSC_SAFE_RGB | SOIL_FLAG_COMPRESS_TO_DXT);

/* check for an error during the load process */ if(tex_2d == 0) { printf( "SOIL loading error: '%s'\n", SOIL_last_result() ); }

glBindTexture(GL_TEXTURE_2D, tex_2d);

// Typical Texture Generation Using Data From The Bitmap glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_MIN_FILTER,GL_LINEAR); glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_MAG_FILTER,GL_LINEAR);

return tex_2d; // Return

Success}

void init(void){ texture = LoadGLTextures("Pirateflag.png"); // Load the texture image glEnable(GL_TEXTURE_2D); // Enable Texture Mapping glShadeModel(GL_SMOOTH); // Enable Smooth Shading glClearColor(1.0f, 0.0f, 0.0f, 0.5f); // Red Background (Dangerous!!!!) glClearDepth(1.0f); // Depth Buffer Setup glEnable(GL_DEPTH_TEST); // Enables Depth Testing glDepthFunc(GL_LEQUAL); // Type of depth testing to do glHint(GL_PERSPECTIVE_CORRECTION_HINT, GL_NICEST); // Really nice perspective calculation glPolygonMode(GL_BACK, GL_FILL); // Back face is solid glPolygonMode(GL_FRONT, GL_LINE); // Front face is made of line

for(int x = 0; x < 45; ++x) { for(int y = 0; y < 45; ++y) { points[x][y][0] = (float)((x/5.0f) - 4.5f); points[x][y][1] = (float)((y/5.0f) - 4.5f); points[x][y][2] = (float)(sin((((x / 5.0f) * 40.0f) / 360.0f) * M_PI * 2.0f));

} }}

void myKeyboard(unsigned char key, int x, int y) // Keyboard event{ switch(key) { case 27: // Exit if 'Esc' key is pressed exit(0); break;

}}

void myTimeOut(int id){ glutPostRedisplay(); // Request redisplay glutTimerFunc(100, myTimeOut, 0); // request next timer event}

void renderScene(void) // Here where we do all the drawing{ int x, y; float float_x, float_y, float_xb, float_yb; glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT); // Clear the screen and depth buffer glLoadIdentity(); // Reset the view

glTranslatef(0.0f, 0.0f, -12.0f); glRotatef(xRot, 1.0f, 0.0f, 0.0f); glRotatef(yRot, 0.0f, 1.0f, 0.0f); glRotatef(zRot, 0.0f, 0.0f, 1.0f);

// glBindTexture(GL_TEXTURE_2D, texture); glBegin(GL_QUADS); for(x = 0; x < 44; ++x) { for(y = 0; y < 44; ++y) { float_x = float(x)/44.0f; float_y = float(y)/44.0f; float_xb = float(x+1)/44.0f; float_yb = float(y+1)/ 44.0f;

glTexCoord2f(float_x, float_y); glVertex3f(points[x][y][0], points[x][y][1], points[x][y][2]);

glTexCoord2f(float_x, float_yb); glVertex3f(points[x][y+1][0], points[x][y+1][1], points[x][y+1][2]);

glTexCoord2f(float_xb, float_yb); glVertex3f(points[x+1][y+1][0], points[x+1][y+1][1],

points[x+1][y+1][2]);

glTexCoord2f(float_xb, float_y); glVertex3f(points[x+1][y][0], points[x+1][y][1], points[x+1][y][2]);

} } glEnd();

if(wiggle_count == 1) { for(y = 0; y < 45; ++y) { hold = points[0][y][2]; for(x = 0; x < 44; ++x) { points[x][y][2] = points[x+1][y][2]; }

points[44][y][2] = hold; } wiggle_count = 0; }

wiggle_count++;

xRot = 0.3f; yRot = 0.2f; zRot = 0.4f;

glFlush(); glutSwapBuffers();

}

// Resize and initialize windowvoid resize(int width, int height){ glViewport(0, 0, width, height); // Reset current viewport glMatrixMode(GL_PROJECTION); // Select projection Matrix glLoadIdentity(); // Reset projection Matrix gluPerspective(45.0, (GLdouble)width / (GLdouble)height, 1.0, 300.0); // Calculate aspect ratio of the window

glMatrixMode(GL_MODELVIEW); // Select modelview matrix glLoadIdentity(); // Reset modelview matrix}