boids/mesh.go at master · adinfinit/boids · GitHub

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
// +build ignore

package main

import (
	"github.com/adinfinit/g"
	"github.com/go-gl/gl/v3.3-core/gl"
)

type Program struct {
	ID uint32

	VertexPositionLoc uint32

	ModelPositionLoc  uint32
	ModelDirectionLoc uint32
}

type Mesh struct {
	Program uint32

	VAO uint32
	VBO uint32
	IBO uint32

	Vertices []Vertex
	Indicies []uint16
}

type Vertex struct {
	Position g.Vec3
}

func (mesh *Mesh) Upload() error {
	// setup instance data
	gl.GenVertexArrays(1, &mesh.VAO)
	gl.BindVertexArray(mesh.VAO)

	gl.GenBuffers(1, &mesh.VBO)
	gl.BindBuffer(gl.ARRAY_BUFFER, mesh.VBO)
	gl.BufferData(gl.ARRAY_BUFFER, len(mesh.Vertices)*4, gl.Ptr(mesh.Vertices), gl.STATIC_DRAW)

	meshPositionAttrib := uint32(gl.GetAttribLocation(program, gl.Str("VertexPosition\x00")))
	gl.EnableVertexAttribArray(meshPositionAttrib)
	gl.VertexAttribPointer(meshPositionAttrib, 3, gl.FLOAT, false, 5*4, gl.PtrOffset(0))

	gl.GenBuffers(1, &mesh.IBO)
	gl.BindBuffer(gl.ELEMENT_ARRAY_BUFFER, mesh.IBO)
	gl.BufferData(gl.ELEMENT_ARRAY_BUFFER, 2*len(mesh.Indicies), gl.Ptr(mesh.Indicies), gl.STATIC_DRAW)
}