func Cylinder(r, h gl.Float, slices int, hollow, solid bool) {
res := 2 * math.Pi / float64(slices)
mode := gl.LINE_LOOP
if solid {
mode = gl.QUADS
}
gl.Begin(gl.Enum(mode))
for a := 0.0; a < 2*math.Pi; a += res {
gl.Normal3f(gl.Float(math.Cos(a)), gl.Float(math.Sin(a)), 0)
gl.Vertex3f(r*gl.Float(math.Cos(a)), r*gl.Float(math.Sin(a)), 0)
gl.Vertex3f(r*gl.Float(math.Cos(a)), r*gl.Float(math.Sin(a)), h)
a += res
gl.Vertex3f(r*gl.Float(math.Cos(a)), r*gl.Float(math.Sin(a)), h)
gl.Vertex3f(r*gl.Float(math.Cos(a)), r*gl.Float(math.Sin(a)), 0)
}
gl.End()
if !hollow {
// X Y plane
if h < 0 {
gl.Normal3f(0, 0, 1)
} else {
gl.Normal3f(0, 0, -1)
}
Circle(r, slices, solid)
// Top (or bottom)
if h < 0 {
gl.Normal3f(0, 0, -1)
} else {
gl.Normal3f(0, 0, 1)
}
gl.Translatef(0, 0, h)
Circle(r, slices, solid)
}
}
func Triangle(one, two, three Point, solid bool) {
mode := gl.LINE_LOOP
if solid {
mode = gl.TRIANGLES
}
gl.Begin(gl.Enum(mode))
gl.Vertex3f(one.X, one.Y, one.Z)
gl.Vertex3f(two.X, two.Y, two.Z)
gl.Vertex3f(three.X, three.Y, three.Z)
gl.End()
}
func compileShader(shaderType ShaderType, scripts []*gl.Char) (gl.Uint, error) {
shaderID := gl.CreateShader(gl.Enum(shaderType))
gl.ShaderSource(shaderID, gl.Sizei(len(scripts)), &scripts[0], nil)
gl.CompileShader(shaderID)
if err := checkShaderCompiled(shaderID, shaderType); err != nil {
return 0, err
}
return shaderID, checkForErrors()
}
func Rectangle(one, two Point, solid bool) {
mode := gl.LINE_LOOP
if solid {
mode = gl.QUADS
}
gl.Begin(gl.Enum(mode)) // Clockwise from top right
gl.Vertex3f(one.X, one.Y, one.Z) // Q1
gl.Vertex3f(one.X, two.Y, one.Z) // Q4
gl.Vertex3f(two.X, two.Y, two.Z) // Q3
gl.Vertex3f(two.X, one.Y, two.Z) // Q2
gl.End()
}
func Ellipse(rX, rY gl.Float, slices int, solid bool) {
mode := gl.LINE_LOOP
if solid {
mode = gl.POLYGON
}
res := 2 * math.Pi / float64(slices)
gl.Begin(gl.Enum(mode))
gl.Vertex2f(0, 0)
for a := 0.0; a < 2*math.Pi; a += res {
gl.Vertex2f(rX*gl.Float(math.Cos(a)), rY*gl.Float(math.Sin(a)))
}
gl.End()
}
func Box(x, y, z float32, solid bool) {
mode := gl.LINE_LOOP
if solid {
mode = gl.QUADS
}
X := gl.Float(x) / 2
Y := gl.Float(y) / 2
Z := gl.Float(z) / 2
gl.Begin(gl.Enum(mode))
gl.Normal3f(0, 0, 1) // Positive Z Face
gl.Vertex3f(-X, -Y, Z)
gl.Vertex3f(X, -Y, Z)
gl.Vertex3f(X, Y, Z)
gl.Vertex3f(-X, Y, Z)
gl.Normal3f(0, 0, -1) // Negative Z Face
gl.Vertex3f(-X, -Y, -Z)
gl.Vertex3f(-X, Y, -Z)
gl.Vertex3f(X, Y, -Z)
gl.Vertex3f(X, -Y, -Z)
gl.Normal3f(0, 1, 0) // Positive Y Face
gl.Vertex3f(-X, Y, -Z)
gl.Vertex3f(-X, Y, Z)
gl.Vertex3f(X, Y, Z)
gl.Vertex3f(X, Y, -Z)
gl.Normal3f(0, -1, 0) // Negative Y Face
gl.Vertex3f(-X, -Y, -Z)
gl.Vertex3f(X, -Y, -Z)
gl.Vertex3f(X, -Y, Z)
gl.Vertex3f(-X, -Y, Z)
gl.Normal3f(1, 0, 0) // Positive X Face
gl.Vertex3f(X, -Y, -Z)
gl.Vertex3f(X, Y, -Z)
gl.Vertex3f(X, Y, Z)
gl.Vertex3f(X, -Y, Z)
gl.Normal3f(-1, 0, 0) // Negative X Face
gl.Vertex3f(-X, -Y, -Z)
gl.Vertex3f(-X, -Y, Z)
gl.Vertex3f(-X, Y, Z)
gl.Vertex3f(-X, Y, -Z)
gl.End()
}
// NewShape creates a new Shape object based on the verticies and shape type.
func NewShape(shapeType ShapeType, verticies []float64) (*Shape, error) {
verticies32 := make([]float32, len(verticies))
for i, val := range verticies {
verticies32[i] = float32(val)
}
shape := &Shape{mode: gl.Enum(shapeType), size: len(verticies), vertexBuffer: 0, verticies: verticies32,
scaleX: 1, scaleY: 1}
gl.GenBuffers(1, &shape.vertexBuffer)
gl.BindBuffer(gl.ARRAY_BUFFER, gl.Uint(shape.vertexBuffer))
gl.BufferData(gl.ARRAY_BUFFER, gl.Sizeiptr(shape.size*4), gl.Pointer(&shape.verticies[0]), gl.DYNAMIC_DRAW)
gl.BindBuffer(gl.ARRAY_BUFFER, 0)
return shape, checkForErrors()
}
