/
mesh_buffer.go
139 lines (111 loc) · 2.65 KB
/
mesh_buffer.go
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package glutils
import "github.com/pzsz/gl"
const (
BUF_NORMAL = 1
BUF_COLOUR = 2
BUF_TEX_COORD0 = 4
BUF_ATTR0 = 8
RENDER_POLYGONS = 1
RENDER_STRIPE = 2
MAX_ATTR = 2
)
type MeshBufferAttribute struct {
Name string
Size int
}
type MeshBuffer struct {
vertexArray []uint8
indiceArray []uint8
VertexBuffer gl.Buffer
IndiceBuffer gl.Buffer
Buffers int
RenderOp int
VertexCount int
IndiceCount int
Attributes []MeshBufferAttribute
}
func NewMeshBuffer(indiceCount, vertexCount, renderOp, buffers int, attr ...MeshBufferAttribute) *MeshBuffer {
ret := &MeshBuffer{
Buffers: buffers,
RenderOp: renderOp,
VertexCount: vertexCount,
IndiceCount: indiceCount,
Attributes: attr}
return ret
}
func (self *MeshBuffer) AllocArrays() {
vs := self.CalcVertexSize()
self.vertexArray = make([]uint8, 0, vs*self.VertexCount)
self.indiceArray = make([]uint8, 0, 2*self.IndiceCount)
}
func (self *MeshBuffer) GetArrays() (vertexArray, indiceArray []uint8) {
vertexArray, indiceArray = self.vertexArray, self.indiceArray
return
}
func (self *MeshBuffer) AllocBuffers() {
if self.VertexBuffer == 0 {
self.VertexBuffer = gl.GenBuffer()
}
if self.IndiceBuffer == 0 {
self.IndiceBuffer = gl.GenBuffer()
}
}
func (self *MeshBuffer) HaveVBO() bool {
return self.VertexBuffer != 0
}
func (self *MeshBuffer) Destroy() {
if self.VertexBuffer != 0 {
self.VertexBuffer.Delete()
}
if self.IndiceBuffer != 0 {
self.IndiceBuffer.Delete()
}
self.vertexArray = nil
self.indiceArray = nil
}
func (self *MeshBuffer) CopyArraysToVBO() {
self.AllocBuffers()
vs := self.CalcVertexSize()
self.VertexBuffer.Bind(gl.ARRAY_BUFFER)
gl.BufferData(gl.ARRAY_BUFFER, vs*self.VertexCount,
self.vertexArray, gl.STATIC_DRAW)
gl.BufferUnbind(gl.ARRAY_BUFFER)
self.IndiceBuffer.Bind(gl.ELEMENT_ARRAY_BUFFER)
gl.BufferData(gl.ELEMENT_ARRAY_BUFFER, 2*self.IndiceCount,
self.indiceArray, gl.STATIC_DRAW)
gl.BufferUnbind(gl.ELEMENT_ARRAY_BUFFER)
}
func (self *MeshBuffer) CalcVertexSize() int {
return self.CalcVertexOffset(0)
}
func (self *MeshBuffer) SetAttribute(i int, attr MeshBufferAttribute) {
self.Attributes[i] = attr
}
func (self *MeshBuffer) CalcVertexOffset(element int) int {
ret := 3 * 4 // POS
if element == BUF_NORMAL {
return ret
}
if (self.Buffers & BUF_NORMAL) != 0 {
ret += 3 * 4
}
if element == BUF_COLOUR {
return ret
}
if (self.Buffers & BUF_COLOUR) != 0 {
ret += 4
}
if element == BUF_TEX_COORD0 {
return ret
}
if (self.Buffers & BUF_TEX_COORD0) != 0 {
ret += 2 * 4
}
if element == BUF_ATTR0 {
return ret
}
if (self.Buffers & BUF_ATTR0) != 0 {
ret += 4 * self.Attributes[0].Size
}
return ret
}