glBindVertexArray.c

#include <iostream>
using namespace std;
#include "vgl.h"
#include "LoadShaders.h"

enum VAO_IDs { Triangles, NumVAOs };
enum Buffer_IDs { ArrayBuffer, NumBuffers };
enum Attrib_IDs { vPosition = 0 };

GLuint VAOs[NumVAOs];
GLuint Buffers[NumBuffers];
const GLuint NumVertices = 6;

void init(void){
	glGenVertexArrays(NumVAOs, VAOs);
	glBindVertexArray(VAOs[Triangles]);

	GLfloat vertices[NumVertices][2] = {
		{ -0.90, -0.90 }, // Triangle 1
		{ 0.85, -0.90 },
		{ -0.90, 0.85 },
		{ 0.90, -0.85 }, // Triangle 2
		{ 0.90, 0.90 },
		{ -0.85, 0.90 }
	};

	glGenBuffers(NumBuffers, Buffers);
	glBindBuffer(GL_ARRAY_BUFFER, Buffers[ArrayBuffer]);
	glBufferData(GL_ARRAY_BUFFER, sizeof(vertices),
	vertices, GL_STATIC_DRAW);

	ShaderInfo shaders[] = {
		{ GL_VERTEX_SHADER, "triangles.vert" },
		{ GL_FRAGMENT_SHADER, "triangles.frag" },
		{ GL_NONE, NULL }
	};

	GLuint program = LoadShaders(shaders);
	glUseProgram(program);
	
	glVertexAttribPointer(vPosition, 2, GL_FLOAT, GL_FALSE, 0, BUFFER_OFFSET(0));
	glEnableVertexAttribArray(vPosition);
}


void display(void){
	glClear(GL_COLOR_BUFFER_BIT);
	glBindVertexArray(VAOs[Triangles]);
	glDrawArrays(GL_TRIANGLES, 0, NumVertices);
	glFlush();
}