Original Post
Hi all, I have just started using vbos(vertex buffer objects) and I am getting seg fault in glDrawArrays.I am using glsl for shaders . Can any tell me where did i go wrong.... here is the code
#include "timestamp.h"
#define GL_GLEXT_PROTOTYPES
#include <cstdlib>
#include <GL/glut.h>
#include <stdio.h>
#include <malloc.h>
#include <stdlib.h>
#include <fcntl.h>
#include <unistd.h>
#include <iostream>
#include <cmath>
#include <sys/time.h>
#include <string>
using namespace std;
using std::string;
GLint loc1,loc2,loc3,loc4;
GLhandleARB vertexShader, fragmentShader, geometryShader, shader;
GLdouble transformt[16] = {1.0, 0.0, 0.0, 0.0, 0.0, 1.0, 0.0, 0.0, 0.0, 0.0, 1.0, 0.0, 0.847826, -0.0869565, -18.1358, 1.0};
float initpoint[3];
float line=0.0;
float angler = 0.0;
float anglerx= 0.0;
float mx=0,my=0,mz=0;
//Subdivision Parameter
int kdiv = 4;
int numpatches;
float **gx,**gy,**gz;
GLuint Vboid;
GLfloat* vertices;
int vCount=0;
void VboInitialize()
{
vCount=kdiv*kdiv*6;
vertices=new float[vCount*3];
int index=0;
float dx=1.0/kdiv;
float dy=1.0/kdiv;
for(int i=0;i<kdiv;i++)
for(int j=0;j<kdiv;j++)
{
vertices[index]=j*dx;index++;
vertices[index]=i*dy;index++;
vertices[index]=1.0;index++;
vertices[index]=(j+1)*dx;index++;
vertices[index]=i*dy;index++;
vertices[index]=1.0;index++;
vertices[index]=j*dx;index++;
vertices[index]=(i+1)*dy;index++;
vertices[index]=1.0;index++;
vertices[index]=(j+1)*dx;index++;
vertices[index]=i*dy;index++;
vertices[index]=1.0;index++;
vertices[index]=(j+1)*dx;index++;
vertices[index]=(i+1)*dy;index++;
vertices[index]=1.0;index++;
vertices[index]=j*dx;index++;
vertices[index]=(i+1)*dy;index++;
vertices[index]=1.0;index++;
}
glGenBuffersARB(1,&Vboid);
glBindBufferARB(GL_ARRAY_BUFFER_ARB,Vboid);
glBufferDataARB(GL_ARRAY_BUFFER_ARB,vCount*3*sizeof float),vertices,GL_STATIC_DRAW_ARB);
//delete [] vertices;
}
//global field of view
char *textFileRead(char *fn) {
FILE *fp;
char *content = NULL;
int f,count;
f = open(fn, O_RDONLY);
count = lseek(f, 0, SEEK_END);
close(f);
if (fn != NULL) {
fp = fopen(fn,"rt");
if (fp != NULL) {
if (count > 0) {
content = (char *)malloc(sizeof(char) * (count+1));
count = fread(content,sizeof(char),count,fp);
content[count] = '\0';
}
fclose(fp);
}
}
return content;
}
void printInfoLog(GLhandleARB obj, char * shadername){
int infologLength = 0;
int charsWritten = 0;
char *infoLog;
glGetObjectParameterivARB(obj, GL_OBJECT_INFO_LOG_LENGTH_ARB,
&infologLength);
if (infologLength > 0)
{
infoLog = (char *)malloc(infologLength);
glGetInfoLogARB(obj, infologLength, &charsWritten, infoLog);
printf("%s\n",shadername);
printf("%s\n",infoLog);
free(infoLog);
}
}
//Initializing the shaders
void initShaders() {
char *vs,*fs,*gs;
vertexShader = glCreateShaderObjectARB(GL_VERTEX_SHADER_ARB);
fragmentShader = glCreateShaderObjectARB(GL_FRAGMENT_SHADER_ARB);
geometryShader = glCreateShaderObjectARB(GL_GEOMETRY_SHADER_EXT);
vs = textFileRead("vertexshader.glsl");
fs = textFileRead("fragmentshader.glsl");
gs = textFileRead("subdivisiongs.glsl");
const char * ff = fs;
const char * vv = vs;
const char * gg = gs;
glShaderSourceARB(vertexShader, 1, &vv,NULL);
glShaderSourceARB(fragmentShader, 1, &ff,NULL);
glShaderSourceARB(geometryShader, 1, ≫,NULL);
free(vs);free(fs);free(gs);
glCompileShaderARB(vertexShader);
printInfoLog( vertexShader,"vertexshader.glsl" );
glCompileShaderARB(fragmentShader);
printInfoLog( fragmentShader, "fragmentshader.glsl" );
glCompileShaderARB(geometryShader);
printInfoLog( geometryShader, "subdivisionshader.glsl" );
shader = glCreateProgramObjectARB();
glAttachObjectARB( shader, vertexShader);
glAttachObjectARB( shader, fragmentShader);
glAttachObjectARB( shader, geometryShader);
//Input type primitive and Output type primitive Last line is essential to specify the maximum number of output vertices
glProgramParameteriEXT( shader, GL_GEOMETRY_INPUT_TYPE_EXT , GL_TRIANGLES );
glProgramParameteriEXT( shader, GL_GEOMETRY_OUTPUT_TYPE_EXT , GL_TRIANGLE_STRIP );
printf("%s\n",gluErrorString(glGetError()));
glProgramParameteriEXT( shader, GL_GEOMETRY_VERTICES_OUT_EXT, 1024);
printf("%s\n",gluErrorString(glGetError()));
glLinkProgramARB( shader );
printf("%s\n",gluErrorString(glGetError()));
glUseProgramObjectARB( shader );
printf("%s\n",gluErrorString(glGetError()));
loc1 = glGetUniformLocation(shader,"gx1");
loc2 = glGetUniformLocation(shader,"gy1");
loc3 = glGetUniformLocation(shader,"gz1");
}
// Displaying the Patch
void displaypatch(int m)
{
glPushMatrix();
//glMultMatrixd(transformt);
//glTranslatef(0.847826, -0.0869565, -18.1358);
glTranslatef(0, 0, -18.1358);
glTranslatef(mx,my,mz);
glRotatef(angler,0,1,0);
glRotatef(anglerx,1,0,0);
glDepthFunc(GL_LESS);
glEnable(GL_DEPTH_TEST);
glEnable(GL_COLOR_MATERIAL);
glColor3f(1.0,0.875,0.575);
glUniformMatrix4fv(loc1,1,0,gx[m]);
glUniformMatrix4fv(loc2,1,0,gy[m]);
glUniformMatrix4fv(loc3,1,0,gz[m]);
glEnableClientState(GL_VERTEX_ARRAY);
glBindBufferARB(GL_ARRAY_BUFFER_ARB,Vboid);
glVertexPointer(3,GL_FLOAT,0,0 );
glDrawArrays(GL_TRIANGLES,0,vCount);
glDisableClientState(GL_VERTEX_ARRAY);
glBindBufferARB(GL_ARRAY_BUFFER_ARB,0);
glPopMatrix();
}
//Initializing OpenGL Variables
void setupGL( )
{
glMatrixMode(GL_PROJECTION);
glLoadIdentity();
//glFrustum(-3.38394, 3.38394, -3.38394,3.38394, 13.67, 30.5098);
gluPerspective(45.0f,(2*3.38394) /(2*3.38394) , 13.67, 30.5078);
glMatrixMode(GL_MODELVIEW);
glLoadIdentity();
GLfloat light0_position[] = {0 ,0, 30.0, 0 };
glLightfv(GL_LIGHT0, GL_POSITION, light0_position);
GLfloat mat_diffuse[4] = { 1, 1, 1, 1 };
GLfloat mat_specular[4] = { 0.88, 0.88, 0.88, 0.88 };
GLfloat mat_shininess[] = { 100 };
GLfloat global_ambient[] = { 0.2, 0.2, 0.5, 1.0 };
GLfloat light0_ambient[] = { 0.2, 0.2, 0.2, 0.2 };
GLfloat light0_diffuse[] = { 0.85, 0.85, 0.85, 1.0 };
GLfloat light1_diffuse[] = { -0.01, -0.01, -0.03, -0.03 };
GLfloat light0_specular[] = { 0.85, 0.85, 0.85, 0.85 };
GLfloat light_position[] = {0,0,0,1};
glMaterialfv(GL_FRONT_AND_BACK, GL_AMBIENT_AND_DIFFUSE, mat_diffuse);
glMaterialfv(GL_FRONT_AND_BACK, GL_SPECULAR, mat_specular);
glMaterialfv(GL_FRONT_AND_BACK, GL_SHININESS, mat_shininess);
glLightfv(GL_LIGHT0, GL_AMBIENT, light0_ambient);
glLightfv(GL_LIGHT0, GL_DIFFUSE, light0_diffuse);
glLightfv(GL_LIGHT0, GL_SPECULAR, light0_specular);
glLightfv(GL_LIGHT1, GL_DIFFUSE, light1_diffuse);
glLightfv(GL_LIGHT1, GL_SPECULAR, light0_specular);
glLightfv(GL_LIGHT2, GL_SPECULAR, light0_specular);
glLightfv(GL_LIGHT3, GL_SPECULAR, light0_specular);
glEnable(GL_LIGHTING);
glEnable(GL_LIGHT0);
glEnable(GL_LIGHT1);
glEnable(GL_LIGHT2);
glEnable(GL_LIGHT3);
glEnable(GL_NORMALIZE);
glEnable(GL_DEPTH_TEST);
glEnable(GL_COLOR_MATERIAL);
}
// Display Function
void display()
{
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
glUseProgramObjectARB( shader );
if(line==1.0)glPolygonMode(GL_FRONT_AND_BACK,GL_LINE);
else glPolygonMode(GL_FRONT_AND_BACK,GL_FILL);
glFinish();
timestamp t1=timenow();
for(int i=0;i<numpatches;i++)
{
//if(i==31)
displaypatch(i);
}
glFinish();
float time=timenow()-t1;
printf("render speed %f\n" , 1/time);
glutSwapBuffers();
}
// Keyboard Function
void keyboardfunc(unsigned char key, int x, int y)
{
switch (key) {
case 'a': mx+=0.1;
break;
case 'd': mx-=0.1;
break;
case 'w': mz+=0.1;
break;
case 's': mz-=0.1;
break;
case 'r': my-=0.1;
break;
case 'f': my+=0.1;
break;
case 'z':
kdiv++;
break;
case 'x':
kdiv--;
break;
case 'l':
if(line==0)line+=1.0;
else line=0;
break;
case 27:
exit(0);
}
glutPostRedisplay();
}
void speckey(int c,int x,int y){
if(c==GLUT_KEY_LEFT){
angler+=10.0;
}
if(c==GLUT_KEY_UP){
anglerx+=10.0;
}
if(c==GLUT_KEY_RIGHT){
angler-=10.0;
}
if(c==GLUT_KEY_DOWN){
anglerx-=10.0;
}
glutPostRedisplay();
}
void usage(const char *myname)
{
fprintf(stderr, "Usage: %s geometryvectorfile\n", myname);
exit(1);
}
int main(int argc, char *argv[])
{
initpoint[0] = -0.847826;
initpoint[1] = 0.0869565;
initpoint[2] = 1.04435;
if( argc < 2 )
usage(argv[0]);
const char * gfilename = argv[1];
FILE * gf = fopen(gfilename,"r");
fscanf(gf,"%d",&numpatches);
//Allocating memory to geometry vectors
gx = new float* [numpatches];
gy = new float* [numpatches];
gz = new float* [numpatches];
for(int i=0;i<numpatches;i++)
{
gx = new float[16];
gy = new float[16];
gz = new float[16];
}
//Reading Geometry Vectors
for(int i=0;i<numpatches;i++)
{
for(int j=0;j<16;j++)
fscanf(gf,"%f",&gx[j]);
for(int j=0;j<16;j++)
fscanf(gf,"%f",&gy[j]);
for(int j=0;j<16;j++)
fscanf(gf,"%f",&gz[j]);
}
VboInitialize();
glutInitWindowSize(512, 512);
glutInitDisplayMode(GLUT_DOUBLE | GLUT_RGBA | GLUT_DEPTH);
glutInit(&argc, argv);
if (argc < 2)
usage(argv[0]);
glutCreateWindow("Subdivision Shader");
glutDisplayFunc(display);
glutIdleFunc(display);
glutKeyboardFunc(keyboardfunc);
glutSpecialFunc(speckey);
setupGL();
initShaders();
glutMainLoop();
}
