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402 lines
8.2 KiB
402 lines
8.2 KiB
/***************************************************************************** |
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* Wave Simulation in OpenGL |
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* (C) 2002 Jakob Thomsen |
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* http://home.in.tum.de/~thomsen |
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* Modified for GLFW by Sylvain Hellegouarch - sh@programmationworld.com |
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* Modified for variable frame rate by Marcus Geelnard |
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* 2003-Jan-31: Minor cleanups and speedups / MG |
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*****************************************************************************/ |
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#include <stdio.h> |
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#include <stdlib.h> |
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#include <math.h> |
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#include <GL/glfw3.h> |
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#ifndef M_PI |
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#define M_PI 3.1415926535897932384626433832795 |
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#endif |
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/* Maximum delta T to allow for differential calculations */ |
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#define MAX_DELTA_T 0.01 |
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/* Animation speed (10.0 looks good) */ |
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#define ANIMATION_SPEED 10.0 |
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GLfloat alpha = 210.0f, beta = -70.0f; |
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GLfloat zoom = 2.0f; |
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int running = 1; |
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struct Vertex |
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{ |
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GLfloat x,y,z; |
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GLfloat r,g,b; |
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}; |
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#define GRIDW 50 |
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#define GRIDH 50 |
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#define VERTEXNUM (GRIDW*GRIDH) |
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#define QUADW (GRIDW-1) |
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#define QUADH (GRIDH-1) |
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#define QUADNUM (QUADW*QUADH) |
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GLuint quad[4*QUADNUM]; |
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struct Vertex vertex[VERTEXNUM]; |
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/* The grid will look like this: |
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* |
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* 3 4 5 |
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* *---*---* |
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* | | | |
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* | 0 | 1 | |
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* | | | |
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* *---*---* |
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* 0 1 2 |
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*/ |
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void initVertices( void ) |
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{ |
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int x,y,p; |
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/* place the vertices in a grid */ |
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for(y=0;y<GRIDH;y++) |
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for(x=0;x<GRIDW;x++) |
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{ |
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p = y*GRIDW + x; |
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//vertex[p].x = (-GRIDW/2)+x+sin(2.0*M_PI*(double)y/(double)GRIDH); |
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//vertex[p].y = (-GRIDH/2)+y+cos(2.0*M_PI*(double)x/(double)GRIDW); |
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vertex[p].x = (GLfloat)(x-GRIDW/2)/(GLfloat)(GRIDW/2); |
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vertex[p].y = (GLfloat)(y-GRIDH/2)/(GLfloat)(GRIDH/2); |
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vertex[p].z = 0;//sin(d*M_PI); |
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//vertex[p].r = (GLfloat)x/(GLfloat)GRIDW; |
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//vertex[p].g = (GLfloat)y/(GLfloat)GRIDH; |
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//vertex[p].b = 1.0-((GLfloat)x/(GLfloat)GRIDW+(GLfloat)y/(GLfloat)GRIDH)/2.0; |
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if((x%4<2)^(y%4<2)) |
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{ |
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vertex[p].r = 0.0; |
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} |
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else |
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{ |
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vertex[p].r=1.0; |
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} |
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vertex[p].g = (GLfloat)y/(GLfloat)GRIDH; |
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vertex[p].b = 1.f-((GLfloat)x/(GLfloat)GRIDW+(GLfloat)y/(GLfloat)GRIDH)/2.f; |
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} |
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for(y=0;y<QUADH;y++) |
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for(x=0;x<QUADW;x++) |
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{ |
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p = 4*(y*QUADW + x); |
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/* first quad */ |
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quad[p+0] = y *GRIDW+x; /* some point */ |
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quad[p+1] = y *GRIDW+x+1; /* neighbor at the right side */ |
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quad[p+2] = (y+1)*GRIDW+x+1; /* upper right neighbor */ |
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quad[p+3] = (y+1)*GRIDW+x; /* upper neighbor */ |
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} |
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} |
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double dt; |
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double p[GRIDW][GRIDH]; |
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double vx[GRIDW][GRIDH], vy[GRIDW][GRIDH]; |
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double ax[GRIDW][GRIDH], ay[GRIDW][GRIDH]; |
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void initSurface( void ) |
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{ |
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int x, y; |
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double dx, dy, d; |
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for(y = 0; y<GRIDH; y++) |
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{ |
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for(x = 0; x<GRIDW; x++) |
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{ |
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dx = (double)(x-GRIDW/2); |
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dy = (double)(y-GRIDH/2); |
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d = sqrt( dx*dx + dy*dy ); |
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if(d < 0.1 * (double)(GRIDW/2)) |
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{ |
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d = d * 10.0; |
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p[x][y] = -cos(d * (M_PI / (double)(GRIDW * 4))) * 100.0; |
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} |
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else |
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{ |
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p[x][y] = 0.0; |
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} |
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vx[x][y] = 0.0; |
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vy[x][y] = 0.0; |
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} |
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} |
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} |
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/* Draw view */ |
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void draw_screen( void ) |
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{ |
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/* Clear the color and depth buffers. */ |
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glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT); |
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/* We don't want to modify the projection matrix. */ |
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glMatrixMode(GL_MODELVIEW); |
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glLoadIdentity(); |
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/* Move back. */ |
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glTranslatef(0.0, 0.0, -zoom); |
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/* Rotate the view */ |
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glRotatef(beta, 1.0, 0.0, 0.0); |
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glRotatef(alpha, 0.0, 0.0, 1.0); |
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//glDrawArrays(GL_POINTS,0,VERTEXNUM); /* Points only */ |
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glDrawElements(GL_QUADS, 4*QUADNUM, GL_UNSIGNED_INT, quad); |
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//glDrawElements(GL_LINES, QUADNUM, GL_UNSIGNED_INT, quad); |
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glfwSwapBuffers(); |
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} |
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/* Initialize OpenGL */ |
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void setup_opengl( void ) |
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{ |
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/* Our shading model--Gouraud (smooth). */ |
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glShadeModel(GL_SMOOTH); |
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/* Culling. */ |
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//glCullFace(GL_BACK); |
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//glFrontFace(GL_CCW); |
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//glEnable(GL_CULL_FACE); |
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/* Switch on the z-buffer. */ |
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glEnable(GL_DEPTH_TEST); |
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glEnableClientState(GL_VERTEX_ARRAY); |
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glEnableClientState(GL_COLOR_ARRAY); |
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glVertexPointer(3/*3 components per vertex (x,y,z)*/, GL_FLOAT, sizeof(struct Vertex), vertex); |
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glColorPointer(3/*3 components per vertex (r,g,b)*/, GL_FLOAT, sizeof(struct Vertex), &vertex[0].r); //Pointer to the first color |
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glPointSize(2.0); |
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/* Background color is black. */ |
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glClearColor(0, 0, 0, 0); |
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} |
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/* Modify the height of each vertex according to the pressure. */ |
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void adjustGrid( void ) |
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{ |
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int pos; |
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int x, y; |
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for(y = 0; y<GRIDH; y++) |
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{ |
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for(x = 0; x<GRIDW; x++) |
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{ |
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pos = y*GRIDW + x; |
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vertex[pos].z = (float) (p[x][y]*(1.0/50.0)); |
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} |
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} |
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} |
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/* Calculate wave propagation */ |
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void calc( void ) |
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{ |
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int x, y, x2, y2; |
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double time_step = dt * ANIMATION_SPEED; |
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/* compute accelerations */ |
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for(x = 0; x < GRIDW; x++) |
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{ |
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x2 = (x + 1) % GRIDW; |
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for(y = 0; y < GRIDH; y++) |
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{ |
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ax[x][y] = p[x][y] - p[x2][y]; |
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} |
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} |
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for(y = 0; y < GRIDH;y++) |
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{ |
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y2 = (y + 1) % GRIDH; |
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for(x = 0; x < GRIDW; x++) |
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{ |
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ay[x][y] = p[x][y] - p[x][y2]; |
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} |
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} |
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/* compute speeds */ |
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for(x = 0; x < GRIDW; x++) |
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{ |
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for(y = 0; y < GRIDH; y++) |
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{ |
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vx[x][y] = vx[x][y] + ax[x][y] * time_step; |
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vy[x][y] = vy[x][y] + ay[x][y] * time_step; |
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} |
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} |
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/* compute pressure */ |
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for(x = 1; x < GRIDW; x++) |
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{ |
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x2 = x - 1; |
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for(y = 1; y < GRIDH; y++) |
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{ |
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y2 = y - 1; |
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p[x][y] = p[x][y] + (vx[x2][y] - vx[x][y] + vy[x][y2] - vy[x][y]) * time_step; |
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} |
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} |
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} |
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/* Handle key strokes */ |
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void handle_key_down(GLFWwindow window, int key, int action) |
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{ |
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if( action != GLFW_PRESS ) |
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{ |
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return; |
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} |
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switch(key) { |
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case GLFW_KEY_ESC: |
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running = 0; |
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break; |
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case GLFW_KEY_SPACE: |
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initSurface(); |
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break; |
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case GLFW_KEY_LEFT: |
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alpha+=5; |
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break; |
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case GLFW_KEY_RIGHT: |
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alpha-=5; |
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break; |
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case GLFW_KEY_UP: |
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beta-=5; |
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break; |
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case GLFW_KEY_DOWN: |
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beta+=5; |
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break; |
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case GLFW_KEY_PAGEUP: |
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if(zoom>1) zoom-=1; |
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break; |
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case GLFW_KEY_PAGEDOWN: |
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zoom+=1; |
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break; |
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default: |
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break; |
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} |
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} |
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/* Callback function for window resize events */ |
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void handle_resize( GLFWwindow window, int width, int height ) |
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{ |
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float ratio = 1.0f; |
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if( height > 0 ) |
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{ |
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ratio = (float) width / (float) height; |
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} |
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/* Setup viewport (Place where the stuff will appear in the main window). */ |
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glViewport(0, 0, width, height); |
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/* |
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* Change to the projection matrix and set |
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* our viewing volume. |
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*/ |
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glMatrixMode(GL_PROJECTION); |
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glLoadIdentity(); |
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gluPerspective(60.0, ratio, 1.0, 1024.0); |
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} |
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/* Program entry point */ |
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int main(int argc, char* argv[]) |
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{ |
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/* Dimensions of our window. */ |
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int width, height; |
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/* Style of our window. */ |
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int mode; |
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/* Frame time */ |
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double t, t_old, dt_total; |
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GLFWwindow window; |
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/* Initialize GLFW */ |
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if(glfwInit() == GL_FALSE) |
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{ |
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fprintf(stderr, "GLFW initialization failed\n"); |
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exit(-1); |
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} |
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/* Desired window properties */ |
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width = 640; |
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height = 480; |
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mode = GLFW_WINDOWED; |
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glfwOpenWindowHint(GLFW_DEPTH_BITS, 16); |
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/* Open window */ |
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window = glfwOpenWindow(width, height, mode, "Wave Simulation", NULL); |
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if (!window) |
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{ |
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fprintf(stderr, "Could not open window\n"); |
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glfwTerminate(); |
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exit(-1); |
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} |
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glfwSwapInterval( 1 ); |
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/* Keyboard handler */ |
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glfwSetKeyCallback( window, handle_key_down ); |
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glfwEnable( window, GLFW_KEY_REPEAT ); |
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/* Window resize handler */ |
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glfwSetWindowSizeCallback( window, handle_resize ); |
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/* Initialize OpenGL */ |
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setup_opengl(); |
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/* Initialize simulation */ |
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initVertices(); |
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initSurface(); |
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adjustGrid(); |
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/* Initialize timer */ |
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t_old = glfwGetTime() - 0.01; |
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/* Main loop */ |
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while(running) |
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{ |
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/* Timing */ |
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t = glfwGetTime(); |
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dt_total = t - t_old; |
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t_old = t; |
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/* Safety - iterate if dt_total is too large */ |
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while( dt_total > 0.0f ) |
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{ |
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/* Select iteration time step */ |
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dt = dt_total > MAX_DELTA_T ? MAX_DELTA_T : dt_total; |
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dt_total -= dt; |
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/* Calculate wave propagation */ |
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calc(); |
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} |
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/* Compute height of each vertex */ |
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adjustGrid(); |
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/* Draw wave grid to OpenGL display */ |
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draw_screen(); |
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glfwPollEvents(); |
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/* Still running? */ |
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running = running && glfwIsWindow( window ); |
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} |
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glfwTerminate(); |
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return 0; |
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}
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