func makeDot(v mgl32.Vec2, a float32, i int, clr mgl32.Vec4) mesh.Mesh {
m := mesh.Mesh{
Nmbr: mesh.Number(i),
Dpth: 0.5,
Vrts: []mgl32.Vec2{
{-dotx, 0}, // 0
{0, -doty}, // 1
{dotx, 0}, // 2
{0, doty}, // 3
},
Clrs: []mgl32.Vec4{
clr,
},
Trngls: []mesh.Triangle{
{
Vnd: mesh.Nd{0, 1, 2},
Flvr: mesh.CONVEX,
},
{
Vnd: mesh.Nd{2, 3, 0},
Flvr: mesh.CONVEX,
},
},
}
m.Transform(mgl32.HomogRotate2D(a)) // rotate by a
m.Transform(mgl32.Translate2D(v.Elem())) // translate by v
return m
}
func (self *pane) setTransform() {
// generate transform matrix to convert to (zoomed & panned) pixel space
m := mgl32.Translate2D(-1.0, -1.0) // move origin to corner
zm := mgl32.Scale2D(
self.zoom[0]*2.0/float32(self.width),
self.zoom[1]*2.0/float32(self.height))
pm := mgl32.Translate2D(self.pan[0], self.pan[1])
m = m.Mul3(zm)
self.transform = m.Mul3(pm)
// generate untransform from pixel space to unzoomed & unpanned mesh space
upm := mgl32.Translate2D(-self.pan[0], -self.pan[1])
uzm := mgl32.Scale2D(1.0/self.zoom[0], 1.0/self.zoom[1])
self.untransform = upm.Mul3(uzm)
t := []float32{}
for _, s := range self.transform {
t = append(t, float32(s))
}
self.gl.UniformMatrix3fv(self.uTransform, false, t)
}