/
vertexbuffer.go
66 lines (56 loc) · 1.66 KB
/
vertexbuffer.go
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package render
import (
"github.com/go-gl/gl/v4.1-core/gl"
)
// VertexBuffer represents a vertexbuffer.
type VertexBuffer struct {
id uint32
}
// AllocateBuffer allocates the size of the underlying buffer.
func (v *VertexBuffer) AllocateBuffer(numBytes int) {
if v.id == 0 {
gl.GenBuffers(1, &v.id)
}
gl.BindBuffer(gl.ARRAY_BUFFER, v.id)
gl.BufferData(gl.ARRAY_BUFFER, numBytes, gl.Ptr(nil), gl.STATIC_DRAW)
}
// BufferFloat32 buffers a float32 slice.
func (v *VertexBuffer) BufferFloat32(data []float32) {
if v.id == 0 {
gl.GenBuffers(1, &v.id)
}
gl.BindBuffer(gl.ARRAY_BUFFER, v.id)
gl.BufferData(gl.ARRAY_BUFFER, len(data)*4, gl.Ptr(data), gl.STATIC_DRAW)
}
// BufferSubFloat32 buffers a float32 slice into a portion of the underlying
// buffer.
func (v *VertexBuffer) BufferSubFloat32(data []float32, offset int) {
if v.id == 0 {
gl.GenBuffers(1, &v.id)
}
gl.BindBuffer(gl.ARRAY_BUFFER, v.id)
gl.BufferSubData(gl.ARRAY_BUFFER, offset, len(data)*4, gl.Ptr(data))
}
// Bind binds the vertexbuffer.
func (v *VertexBuffer) Bind() {
gl.BindBuffer(gl.ARRAY_BUFFER, v.id)
}
// Unbind unbinds the vertexbuffer.
func (v *VertexBuffer) Unbind() {
gl.BindBuffer(gl.ARRAY_BUFFER, 0)
}
// Draw renders the vertexbuffer.
func (v *VertexBuffer) Draw(mode uint32, first int32, count int32) {
gl.DrawArrays(mode, first, count)
}
// DrawInstanced renders multiple instances of the vertexbuffer.
func (v *VertexBuffer) DrawInstanced(mode uint32, first int32, count int32, primcount int32) {
gl.DrawArraysInstanced(mode, first, count, primcount)
}
// Destroy deallocates the vertexbuffer.
func (v *VertexBuffer) Destroy() {
if v.id != 0 {
gl.DeleteBuffers(1, &v.id)
v.id = 0
}
}