// LayoutGeometry builds a vertex array object holding vertex attribute locations and
// buffer pointers for the given geometry.
func LayoutGeometry(s *Shader, geom *Geometry) *GeometryLayout {
vertices := geom.VertexBuffer
if s.vertexFormat != vertices.Format() {
panic("moo")
}
vao := gl.GenVertexArray()
vao.Bind()
var attrib gl.AttribLocation
vertices.bind()
var i VertexFormat
offset := 0
stride := s.vertexFormat.Stride()
for i = 1; i <= MaxVertexFormat; i <<= 1 {
if s.vertexFormat&i == 0 {
continue
}
name, ok := s.vertexAttrs[i]
if !ok {
// TODO: return error or something?
break
}
attrib = s.prog.GetAttribLocation(name)
if attrib >= 0 {
attrib.AttribPointer(i.attribElems(), i.attribType(), i.attribNormalized(), stride, uintptr(offset))
attrib.EnableArray()
}
offset += i.AttribBytes()
}
geom.IndexBuffer.bind()
layout := &GeometryLayout{
vao: vao,
idxbuf: &geom.IndexBuffer,
shader: s,
}
return layout
}
// renderBuffered uses VBO's. This is the preferred mode for systems
// where shader support is not present or deemed necessary.
func (mb *MeshBuffer) renderBuffered(mode gl.GLenum, m Mesh, program gl.Program) {
is, ic := m[mbIndexKey][0], m[mbIndexKey][1]
program.Use()
var attribLocation gl.AttribLocation
for _, value := range mb.attr {
if value.name == "index" {
continue
}
value.bind()
if value.Invalid() {
value.buffer()
}
attribLocation = program.GetAttribLocation(value.name)
attribLocation.EnableArray()
attribLocation.AttribPointer(value.size, value.typ, false, 0, uintptr(0))
value.unbind()
}
ia := mb.find(mbIndexKey)
ia.bind()
if ia.Invalid() {
ia.buffer()
}
gl.DrawElements(mode, ic, ia.typ, uintptr(is*ia.stride))
ia.unbind()
for _, value := range mb.attr {
if value.name == "index" {
continue
}
attribLocation := program.GetAttribLocation(value.name)
attribLocation.DisableArray()
}
}
