func draw(width, height int) {
gl.Viewport(0, 0, width, height)
gl.Clear(gl.COLOR_BUFFER_BIT)
gl.BindBuffer(gl.ARRAY_BUFFER, verticesArrayBuffer)
gl.VertexAttribPointer(attrPos, 4, gl.FLOAT, false, 6*4, 0)
// bind texture - FIX size of vertex
gl.VertexAttribPointer(attrTexIn, 2, gl.FLOAT, false, 6*4, 4*4)
gl.ActiveTexture(gl.TEXTURE0)
gl.BindTexture(gl.TEXTURE_2D, textureBuffer)
gl.Uniform1i(unifTexture, 0)
gl.DrawArrays(gl.TRIANGLE_FAN, 0, 4)
gl.Flush()
gl.Finish()
}
func initShaders() {
program := Program(FragmentShader(fsh), VertexShader(vsh))
gl.UseProgram(program)
attrPos = uint(gl.GetAttribLocation(program, "pos"))
attrTexIn = uint(gl.GetAttribLocation(program, "texIn"))
unifTexture = gl.GetUniformLocation(program, "texture")
gl.EnableVertexAttribArray(attrPos)
gl.EnableVertexAttribArray(attrTexIn)
// Upload vertices data
gl.GenBuffers(1, gl.Void(&verticesArrayBuffer))
gl.BindBuffer(gl.ARRAY_BUFFER, verticesArrayBuffer)
gl.BufferData(gl.ARRAY_BUFFER, len(vertices)*4, gl.Void(&vertices[0]), gl.STATIC_DRAW)
// Upload texture data
imageBuffer, width, height := loadImage()
gl.GenTextures(1, gl.Void(&textureBuffer))
gl.BindTexture(gl.TEXTURE_2D, textureBuffer)
gl.TexParameteri(gl.TEXTURE_2D, gl.TEXTURE_MIN_FILTER, gl.NEAREST)
gl.TexImage2D(gl.TEXTURE_2D, 0, gl.RGBA, width, height, 0, gl.RGBA, gl.UNSIGNED_BYTE, gl.Void(&imageBuffer[0]))
gl.ClearColor(0.0, 0.0, 0.0, 1.0)
}