glDrawArray (how do you code it?)

OpenGL OpenGL: Basic Coding
1

In short, I have a 3Dmax file I exported and wanted to simply display it. I had to remove textures… all stuff that might make it complicated.

So far I’ve done this… (its not working)


#include <glut.h>
#include "my_modeldata.h"



GLfloat gfPosX = 0.0;//they control animation
GLfloat gfDeltaX = .0001;//determins the rate of change

void Draw()
{
	glClear(GL_COLOR_BUFFER_BIT);
	
	glEnableClientState(GL_VERTEX_ARRAY);
	glDrawArrays(GL_TRIANGLE_STRIP,0,4);
	glVertexPointer(3,GL_FLOAT,0,vertArray);
	//"vertArray" is my exported object
	//from 3Dmax
		
	glutPostRedisplay();
	glutSwapBuffers();//double buffering
}

void Init()
{	glClearColor(0.0,0.0,0.0,0.0);//background
	glMatrixMode(GL_PROJECTION);//??do research on it
	glLoadIdentity();
	glOrtho(0.0, 1.0,0.0,1.0,-1.0,1.0);
	
	glEnableClientState(GL_NORMAL_ARRAY);
}

int main()
{
	glutInitDisplayMode(GLUT_DOUBLE | GLUT_RGB | GLUT_DEPTH);
	glutInitWindowSize(250, 250); 
	glutInitWindowPosition(250, 250);
	glutCreateWindow("ANIMATION AND LIGHTING");
	Init();
	glutDisplayFunc(Draw);
	glutMainLoop();
	return 0;
}



#define TRIANGLECOUNT 1024
#define VERTEXCOUNT 3072


//this is my header file with my 3d max object.



float vertArray[] = {

0.7,0,1.2,.............
2

using a debugger, I found out that the error occurs on “glDrawArrays(GL_TRIANGLE_STRIP,0,4);” (in the draw function)

3

You enable normal array but dont set glNormalPointer.

4

You have the order of your glDrawArrays and your glVertexPointer the wrong way around. The correct order should be EnableClientState, set *Pointer, then Draw.

5

thanks it got rid of that error but, my screen is just blank now

6

In “glDrawArray” what should be the first and last count, I’ve looked I’m kinda confused and the definition is currently confusing at the moment