mirror of
https://github.com/glfw/glfw.git
synced 2024-09-20 05:42:17 +00:00
406 lines
8.3 KiB
C
406 lines
8.3 KiB
C
/*****************************************************************************
|
|
* Wave Simulation in OpenGL
|
|
* (C) 2002 Jakob Thomsen
|
|
* http://home.in.tum.de/~thomsen
|
|
* Modified for GLFW by Sylvain Hellegouarch - sh@programmationworld.com
|
|
* Modified for variable frame rate by Marcus Geelnard
|
|
* 2003-Jan-31: Minor cleanups and speedups / MG
|
|
*****************************************************************************/
|
|
|
|
#include <stdio.h>
|
|
#include <stdlib.h>
|
|
#include <math.h>
|
|
#include <GL/glfw.h>
|
|
|
|
#ifndef M_PI
|
|
#define M_PI 3.1415926535897932384626433832795
|
|
#endif
|
|
|
|
/* Maximum delta T to allow for differential calculations */
|
|
#define MAX_DELTA_T 0.01
|
|
|
|
/* Animation speed (10.0 looks good) */
|
|
#define ANIMATION_SPEED 10.0
|
|
|
|
|
|
GLfloat alpha = 210.0f, beta = -70.0f;
|
|
GLfloat zoom = 2.0f;
|
|
|
|
int running = 1;
|
|
|
|
struct Vertex
|
|
{
|
|
GLfloat x,y,z;
|
|
GLfloat r,g,b;
|
|
};
|
|
|
|
#define GRIDW 50
|
|
#define GRIDH 50
|
|
#define VERTEXNUM (GRIDW*GRIDH)
|
|
|
|
#define QUADW (GRIDW-1)
|
|
#define QUADH (GRIDH-1)
|
|
#define QUADNUM (QUADW*QUADH)
|
|
|
|
GLuint quad[4*QUADNUM];
|
|
struct Vertex vertex[VERTEXNUM];
|
|
|
|
/* The grid will look like this:
|
|
*
|
|
* 3 4 5
|
|
* *---*---*
|
|
* | | |
|
|
* | 0 | 1 |
|
|
* | | |
|
|
* *---*---*
|
|
* 0 1 2
|
|
*/
|
|
|
|
void initVertices( void )
|
|
{
|
|
int x,y,p;
|
|
|
|
/* place the vertices in a grid */
|
|
for(y=0;y<GRIDH;y++)
|
|
for(x=0;x<GRIDW;x++)
|
|
{
|
|
p = y*GRIDW + x;
|
|
|
|
//vertex[p].x = (-GRIDW/2)+x+sin(2.0*M_PI*(double)y/(double)GRIDH);
|
|
//vertex[p].y = (-GRIDH/2)+y+cos(2.0*M_PI*(double)x/(double)GRIDW);
|
|
vertex[p].x = (GLfloat)(x-GRIDW/2)/(GLfloat)(GRIDW/2);
|
|
vertex[p].y = (GLfloat)(y-GRIDH/2)/(GLfloat)(GRIDH/2);
|
|
vertex[p].z = 0;//sin(d*M_PI);
|
|
//vertex[p].r = (GLfloat)x/(GLfloat)GRIDW;
|
|
//vertex[p].g = (GLfloat)y/(GLfloat)GRIDH;
|
|
//vertex[p].b = 1.0-((GLfloat)x/(GLfloat)GRIDW+(GLfloat)y/(GLfloat)GRIDH)/2.0;
|
|
if((x%4<2)^(y%4<2))
|
|
{
|
|
vertex[p].r = 0.0;
|
|
}
|
|
else
|
|
{
|
|
vertex[p].r=1.0;
|
|
}
|
|
|
|
vertex[p].g = (GLfloat)y/(GLfloat)GRIDH;
|
|
vertex[p].b = 1.f-((GLfloat)x/(GLfloat)GRIDW+(GLfloat)y/(GLfloat)GRIDH)/2.f;
|
|
}
|
|
|
|
for(y=0;y<QUADH;y++)
|
|
for(x=0;x<QUADW;x++)
|
|
{
|
|
p = 4*(y*QUADW + x);
|
|
|
|
/* first quad */
|
|
quad[p+0] = y *GRIDW+x; /* some point */
|
|
quad[p+1] = y *GRIDW+x+1; /* neighbor at the right side */
|
|
quad[p+2] = (y+1)*GRIDW+x+1; /* upper right neighbor */
|
|
quad[p+3] = (y+1)*GRIDW+x; /* upper neighbor */
|
|
}
|
|
}
|
|
|
|
double dt;
|
|
double p[GRIDW][GRIDH];
|
|
double vx[GRIDW][GRIDH], vy[GRIDW][GRIDH];
|
|
double ax[GRIDW][GRIDH], ay[GRIDW][GRIDH];
|
|
|
|
|
|
|
|
void initSurface( void )
|
|
{
|
|
int x, y;
|
|
double dx, dy, d;
|
|
|
|
for(y = 0; y<GRIDH; y++)
|
|
{
|
|
for(x = 0; x<GRIDW; x++)
|
|
{
|
|
dx = (double)(x-GRIDW/2);
|
|
dy = (double)(y-GRIDH/2);
|
|
d = sqrt( dx*dx + dy*dy );
|
|
if(d < 0.1 * (double)(GRIDW/2))
|
|
{
|
|
d = d * 10.0;
|
|
p[x][y] = -cos(d * (M_PI / (double)(GRIDW * 4))) * 100.0;
|
|
}
|
|
else
|
|
{
|
|
p[x][y] = 0.0;
|
|
}
|
|
vx[x][y] = 0.0;
|
|
vy[x][y] = 0.0;
|
|
}
|
|
}
|
|
}
|
|
|
|
|
|
/* Draw view */
|
|
void draw_screen( void )
|
|
{
|
|
/* Clear the color and depth buffers. */
|
|
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
|
|
|
|
/* We don't want to modify the projection matrix. */
|
|
glMatrixMode(GL_MODELVIEW);
|
|
glLoadIdentity();
|
|
|
|
/* Move back. */
|
|
glTranslatef(0.0, 0.0, -zoom);
|
|
/* Rotate the view */
|
|
glRotatef(beta, 1.0, 0.0, 0.0);
|
|
glRotatef(alpha, 0.0, 0.0, 1.0);
|
|
|
|
//glDrawArrays(GL_POINTS,0,VERTEXNUM); /* Points only */
|
|
glDrawElements(GL_QUADS, 4*QUADNUM, GL_UNSIGNED_INT, quad);
|
|
//glDrawElements(GL_LINES, QUADNUM, GL_UNSIGNED_INT, quad);
|
|
|
|
glfwSwapBuffers();
|
|
}
|
|
|
|
|
|
/* Initialize OpenGL */
|
|
void setup_opengl( void )
|
|
{
|
|
/* Our shading model--Gouraud (smooth). */
|
|
glShadeModel(GL_SMOOTH);
|
|
|
|
/* Culling. */
|
|
//glCullFace(GL_BACK);
|
|
//glFrontFace(GL_CCW);
|
|
//glEnable(GL_CULL_FACE);
|
|
|
|
/* Switch on the z-buffer. */
|
|
glEnable(GL_DEPTH_TEST);
|
|
|
|
glEnableClientState(GL_VERTEX_ARRAY);
|
|
glEnableClientState(GL_COLOR_ARRAY);
|
|
glVertexPointer(3/*3 components per vertex (x,y,z)*/, GL_FLOAT, sizeof(struct Vertex), vertex);
|
|
glColorPointer(3/*3 components per vertex (r,g,b)*/, GL_FLOAT, sizeof(struct Vertex), &vertex[0].r); //Pointer to the first color
|
|
glPointSize(2.0);
|
|
|
|
/* Background color is black. */
|
|
glClearColor(0, 0, 0, 0);
|
|
}
|
|
|
|
|
|
/* Modify the height of each vertex according to the pressure. */
|
|
void adjustGrid( void )
|
|
{
|
|
int pos;
|
|
int x, y;
|
|
|
|
for(y = 0; y<GRIDH; y++)
|
|
{
|
|
for(x = 0; x<GRIDW; x++)
|
|
{
|
|
pos = y*GRIDW + x;
|
|
vertex[pos].z = (float) (p[x][y]*(1.0/50.0));
|
|
}
|
|
}
|
|
}
|
|
|
|
|
|
/* Calculate wave propagation */
|
|
void calc( void )
|
|
{
|
|
int x, y, x2, y2;
|
|
double time_step = dt * ANIMATION_SPEED;
|
|
|
|
/* compute accelerations */
|
|
for(x = 0; x < GRIDW; x++)
|
|
{
|
|
x2 = (x + 1) % GRIDW;
|
|
for(y = 0; y < GRIDH; y++)
|
|
{
|
|
ax[x][y] = p[x][y] - p[x2][y];
|
|
}
|
|
}
|
|
|
|
for(y = 0; y < GRIDH;y++)
|
|
{
|
|
y2 = (y + 1) % GRIDH;
|
|
for(x = 0; x < GRIDW; x++)
|
|
{
|
|
ay[x][y] = p[x][y] - p[x][y2];
|
|
}
|
|
}
|
|
|
|
/* compute speeds */
|
|
for(x = 0; x < GRIDW; x++)
|
|
{
|
|
for(y = 0; y < GRIDH; y++)
|
|
{
|
|
vx[x][y] = vx[x][y] + ax[x][y] * time_step;
|
|
vy[x][y] = vy[x][y] + ay[x][y] * time_step;
|
|
}
|
|
}
|
|
|
|
/* compute pressure */
|
|
for(x = 1; x < GRIDW; x++)
|
|
{
|
|
x2 = x - 1;
|
|
for(y = 1; y < GRIDH; y++)
|
|
{
|
|
y2 = y - 1;
|
|
p[x][y] = p[x][y] + (vx[x2][y] - vx[x][y] + vy[x][y2] - vy[x][y]) * time_step;
|
|
}
|
|
}
|
|
}
|
|
|
|
|
|
/* Handle key strokes */
|
|
void handle_key_down(GLFWwindow window, int key, int action)
|
|
{
|
|
if( action != GLFW_PRESS )
|
|
{
|
|
return;
|
|
}
|
|
|
|
switch(key) {
|
|
case GLFW_KEY_ESC:
|
|
running = 0;
|
|
break;
|
|
case GLFW_KEY_SPACE:
|
|
initSurface();
|
|
break;
|
|
case GLFW_KEY_LEFT:
|
|
alpha+=5;
|
|
break;
|
|
case GLFW_KEY_RIGHT:
|
|
alpha-=5;
|
|
break;
|
|
case GLFW_KEY_UP:
|
|
beta-=5;
|
|
break;
|
|
case GLFW_KEY_DOWN:
|
|
beta+=5;
|
|
break;
|
|
case GLFW_KEY_PAGEUP:
|
|
if(zoom>1) zoom-=1;
|
|
break;
|
|
case GLFW_KEY_PAGEDOWN:
|
|
zoom+=1;
|
|
break;
|
|
default:
|
|
break;
|
|
}
|
|
}
|
|
|
|
|
|
/* Callback function for window resize events */
|
|
void handle_resize( GLFWwindow window, int width, int height )
|
|
{
|
|
float ratio = 1.0f;
|
|
|
|
if( height > 0 )
|
|
{
|
|
ratio = (float) width / (float) height;
|
|
}
|
|
|
|
/* Setup viewport (Place where the stuff will appear in the main window). */
|
|
glViewport(0, 0, width, height);
|
|
|
|
/*
|
|
* Change to the projection matrix and set
|
|
* our viewing volume.
|
|
*/
|
|
glMatrixMode(GL_PROJECTION);
|
|
glLoadIdentity();
|
|
gluPerspective(60.0, ratio, 1.0, 1024.0);
|
|
}
|
|
|
|
|
|
/* Program entry point */
|
|
int main(int argc, char* argv[])
|
|
{
|
|
/* Dimensions of our window. */
|
|
int width, height;
|
|
/* Style of our window. */
|
|
int mode;
|
|
/* Frame time */
|
|
double t, t_old, dt_total;
|
|
GLFWwindow window;
|
|
|
|
/* Initialize GLFW */
|
|
if(glfwInit() == GL_FALSE)
|
|
{
|
|
fprintf(stderr, "GLFW initialization failed\n");
|
|
exit(-1);
|
|
}
|
|
|
|
/* Desired window properties */
|
|
width = 640;
|
|
height = 480;
|
|
mode = GLFW_WINDOW;
|
|
|
|
glfwOpenWindowHint(GLFW_DEPTH_BITS, 16);
|
|
|
|
/* Open window */
|
|
window = glfwOpenWindow(width,height,mode);
|
|
if (!window)
|
|
{
|
|
fprintf(stderr, "Could not open window\n");
|
|
glfwTerminate();
|
|
exit(-1);
|
|
}
|
|
|
|
/* Set title */
|
|
glfwSetWindowTitle( window, "Wave Simulation" );
|
|
|
|
glfwSwapInterval( 1 );
|
|
|
|
/* Keyboard handler */
|
|
glfwSetKeyCallback( window, handle_key_down );
|
|
glfwEnable( window, GLFW_KEY_REPEAT );
|
|
|
|
/* Window resize handler */
|
|
glfwSetWindowSizeCallback( window, handle_resize );
|
|
|
|
/* Initialize OpenGL */
|
|
setup_opengl();
|
|
|
|
/* Initialize simulation */
|
|
initVertices();
|
|
initSurface();
|
|
adjustGrid();
|
|
|
|
/* Initialize timer */
|
|
t_old = glfwGetTime() - 0.01;
|
|
|
|
/* Main loop */
|
|
while(running)
|
|
{
|
|
/* Timing */
|
|
t = glfwGetTime();
|
|
dt_total = t - t_old;
|
|
t_old = t;
|
|
|
|
/* Safety - iterate if dt_total is too large */
|
|
while( dt_total > 0.0f )
|
|
{
|
|
/* Select iteration time step */
|
|
dt = dt_total > MAX_DELTA_T ? MAX_DELTA_T : dt_total;
|
|
dt_total -= dt;
|
|
|
|
/* Calculate wave propagation */
|
|
calc();
|
|
}
|
|
|
|
/* Compute height of each vertex */
|
|
adjustGrid();
|
|
|
|
/* Draw wave grid to OpenGL display */
|
|
draw_screen();
|
|
|
|
glfwPollEvents();
|
|
|
|
/* Still running? */
|
|
running = running && glfwIsWindow( window );
|
|
}
|
|
|
|
glfwTerminate();
|
|
|
|
return 0;
|
|
}
|