func (b *VertexBuffer) SetVertices(src []byte, usage Usage) error {
gl.VertexArray(0).Bind()
b.bind()
// set size of buffer and invalidate it
gl.BufferData(gl.ARRAY_BUFFER, len(src), nil, usage.gl())
if len(src) > 0 {
// if unmap returns false, the buffer we wrote to is no longer valid and we
// need to try again. though, this is apparently uncommon in modern
// drivers. this means it is not feasible to compute/copy vertices directly
// into the mapped buffer. however, it would be nice to provide a
// failure-capable API to do this.
const maxretries = 5
retries := 0
for ; retries < maxretries; retries++ {
ptr := gl.MapBuffer(gl.ARRAY_BUFFER, gl.WRITE_ONLY)
slicehdr := reflect.SliceHeader{
Data: uintptr(ptr),
Len: len(src),
Cap: len(src),
}
dest := *(*[]byte)(unsafe.Pointer(&slicehdr))
copy(dest, src)
if gl.UnmapBuffer(gl.ARRAY_BUFFER) {
break
}
}
if retries == maxretries {
return errMapBufferFailed
}
}
b.count = len(src) / b.format.Stride()
return nil
}
func (renderer *renderer) unbind() {
gl.VertexArray(0).Bind()
if err := CheckGlError(); err != nil {
err.Description = "gl.VertexArray(0).Bind()"
panic(err)
}
}
func (b *IndexBuffer) setIndices(copyTo func(unsafe.Pointer), usage Usage, size int) error {
gl.VertexArray(0).Bind()
b.bind()
gl.BufferData(gl.ELEMENT_ARRAY_BUFFER, size, nil, usage.gl())
if size > 0 {
const maxretries = 5
retries := 0
for ; retries < maxretries; retries++ {
ptr := gl.MapBuffer(gl.ELEMENT_ARRAY_BUFFER, gl.WRITE_ONLY)
copyTo(ptr)
if gl.UnmapBuffer(gl.ELEMENT_ARRAY_BUFFER) {
break
}
}
if retries == maxretries {
return errMapBufferFailed
}
}
return nil
}
func (batch VaoBatch) Exit() {
gl.VertexArray(0).Bind()
// Cannot fail with argument 0.
}
func (this VAO) Bind() {
if lastVAO != this {
lastVAO = this
gl.VertexArray.Bind(gl.VertexArray(this))
}
}