GLApp.swift

// Modules should be imported
import Foundation
import Cglew
import Cglfw
import OpenGL.GL3


// Shader source code
fileprivate var vShaderCode = """
#version 330 core\n
layout (location = 0) in vec3 vertex;\n
void main() {\n
    gl_Position = vec4(vertex, 1.0);\n
}\0
"""

fileprivate var fShaderCode = """
#version 330 core\n
out lowp vec4 FragColor;\n
void main() {\n
    FragColor = vec4(1.0, 0.1, 0.0, 1.0);\n
}\0
"""

public class GLApp {
    // Setup vertices data
    private var VBO: UInt32 = 0
    private var VAO: UInt32 = 0
    private var shader: Shader!
    func setup() {
      var vertices: [Float] = [
          -0.5, -0.5, 0.0, // left
          0.5, -0.5, 0.0, // right
          0.0,  0.5, 0.0  // top
      ]

      shader = Shader(vShaderCode: vShaderCode, fShaderCode: fShaderCode)
      shader.compileShader()

      glGenVertexArrays(1, &VAO)
      glBindVertexArray(VAO)

      glGenBuffers(1, &VBO)
      glBindBuffer(GLenum(GL_ARRAY_BUFFER), VBO)
      glBufferData(GLenum(GL_ARRAY_BUFFER), vertices.count * MemoryLayout<Float>.size, &vertices, GLenum(GL_STATIC_DRAW))
      glEnableVertexAttribArray(0)

      glVertexAttribPointer(0, 3, GLenum(GL_FLOAT), GLboolean(GL_FALSE), GLsizei(3 * MemoryLayout<Float>.size), nil)
      glBindVertexArray(0)
      glBindBuffer(GLenum(GL_ARRAY_BUFFER), 0)
    }
}