func NewSprite(vertices []float32, program *gg.Program, texture *gg.Texture) (*Sprite, error) {
buf := new(bytes.Buffer)
if err := binary.Write(buf, binary.LittleEndian, vertices); err != nil {
return nil, err
}
pvbo := gg.CreateBuffer()
gg.BindBuffer(gg.ARRAY_BUFFER, pvbo)
gg.BufferData(gg.ARRAY_BUFFER, buf.Bytes(), gg.STATIC_DRAW)
texVertices := []float32{
0, 0,
0, 1,
1, 1,
1, 0,
}
buf.Reset()
if err := binary.Write(buf, binary.LittleEndian, texVertices); err != nil {
return nil, err
}
tvbo := gg.CreateBuffer()
gg.BindBuffer(gg.ARRAY_BUFFER, tvbo)
gg.BufferData(gg.ARRAY_BUFFER, buf.Bytes(), gg.STATIC_DRAW)
return &Sprite{
pvbo: pvbo,
tvbo: tvbo,
program: program,
tex: texture,
}, nil
}
func (s *Sprite) Draw() {
gg.UseProgram(s.program)
vattrib, err := gg.GetAttribLocation(s.program, "vertex_position")
if err != nil {
log.Fatal(err)
}
gg.EnableVertexAttribArray(vattrib)
gg.BindBuffer(gg.ARRAY_BUFFER, s.pvbo)
gg.VertexAttribPointer(vattrib, 3, gg.FLOAT, false, 0, 0)
tattrib, err := gg.GetAttribLocation(s.program, "vertex_texture")
if err != nil {
log.Fatal(err)
}
gg.EnableVertexAttribArray(tattrib)
gg.BindBuffer(gg.ARRAY_BUFFER, s.tvbo)
gg.VertexAttribPointer(tattrib, 2, gg.FLOAT, false, 0, 0)
gg.ActiveTexture(gg.TEXTURE0)
gg.BindTexture(gg.TEXTURE_2D, s.tex)
texUniform, err := gg.GetUniformLocation(s.program, "tex_loc")
if err != nil {
log.Fatal(err)
}
gg.Uniform1i(texUniform, 0)
gg.DrawArrays(gg.TRIANGLE_FAN, 0, 4)
}
func NewTriangle(vertices []float32, program *gg.Program) (*Triangle, error) {
buf := new(bytes.Buffer)
if err := binary.Write(buf, binary.LittleEndian, vertices); err != nil {
return nil, err
}
vbo := gg.CreateBuffer()
gg.BindBuffer(gg.ARRAY_BUFFER, vbo)
gg.BufferData(gg.ARRAY_BUFFER, buf.Bytes(), gg.STATIC_DRAW)
return &Triangle{
vbo: vbo,
program: program,
}, nil
}
func NewSprite(width, height float32, program *gg.Program, texture *gg.Texture) *Sprite {
s := &Sprite{
scale: 1,
width: width,
height: height,
tex: texture,
program: program,
}
pvertices := []float32{
0, 0, 0,
0, s.height, 0,
s.width, s.height, 0,
s.width, 0, 0,
}
buf := new(bytes.Buffer)
if err := binary.Write(buf, binary.LittleEndian, pvertices); err != nil {
panic(err)
}
s.pbuf = gg.CreateBuffer()
gg.BindBuffer(gg.ARRAY_BUFFER, s.pbuf)
gg.BufferData(gg.ARRAY_BUFFER, buf.Bytes(), gg.STATIC_DRAW)
tvertices := []float32{
0, 0,
0, 1,
1, 1,
1, 0,
}
buf.Reset()
if err := binary.Write(buf, binary.LittleEndian, tvertices); err != nil {
panic(err)
}
s.tbuf = gg.CreateBuffer()
gg.BindBuffer(gg.ARRAY_BUFFER, s.tbuf)
gg.BufferData(gg.ARRAY_BUFFER, buf.Bytes(), gg.STATIC_DRAW)
return s
}
func (s *Sprite) Draw() error {
gg.UseProgram(s.program)
model := s.transform()
modelUniform, err := gg.GetUniformLocation(s.program, "model")
if err != nil {
return err
}
gg.UniformMatrix4fv(modelUniform, model[:])
gg.ActiveTexture(gg.TEXTURE0)
gg.BindTexture(gg.TEXTURE_2D, s.tex)
textureUniform, err := gg.GetUniformLocation(s.program, "tex_loc")
if err != nil {
return err
}
gg.Uniform1i(textureUniform, 0)
vattrib, err := gg.GetAttribLocation(s.program, "vertex_position")
if err != nil {
return err
}
gg.EnableVertexAttribArray(vattrib)
gg.BindBuffer(gg.ARRAY_BUFFER, s.pbuf)
gg.VertexAttribPointer(vattrib, 3, gg.FLOAT, false, 0, 0)
tattrib, err := gg.GetAttribLocation(s.program, "vertex_texture")
if err != nil {
return err
}
gg.EnableVertexAttribArray(tattrib)
gg.BindBuffer(gg.ARRAY_BUFFER, s.tbuf)
gg.VertexAttribPointer(tattrib, 2, gg.FLOAT, false, 0, 0)
gg.DrawArrays(gg.TRIANGLE_FAN, 0, 4)
return nil
}
func (t *Triangle) Draw() {
gg.UseProgram(t.program)
colorUniform, err := gg.GetUniformLocation(t.program, "color")
if err != nil {
log.Fatal(err)
}
gg.Uniform4f(colorUniform, 1.0, 0.0, 1.0, 1.0)
vattrib, err := gg.GetAttribLocation(t.program, "vertex_position")
if err != nil {
log.Fatal(err)
}
gg.EnableVertexAttribArray(vattrib)
gg.BindBuffer(gg.ARRAY_BUFFER, t.vbo)
gg.VertexAttribPointer(vattrib, 3, gg.FLOAT, false, 0, 0)
gg.DrawArrays(gg.TRIANGLE_FAN, 0, 3)
}