403 строки
8.2 KiB
C
403 строки
8.2 KiB
C
/*****************************************************************************
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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");
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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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