/* renderman/fromscratch/quadratics_params.go
 * mae 012018
 */
package main

import (
	"flag"
	"fmt"
	"os"
	"strings"
	"reflect"

	"gitlab.com/mae.earth/renderman/fromscratch/library/format"
)

const Version string = "renderman/fromscratch/quadratics_params program 1"

func main() {
	scale := flag.Float64("scale", 1.0, "`scale of output image")
	maxsamples := flag.Int("maxsamples", 512, "maxsamples for raytrace hider")
	minsamples := flag.Int("minsamples", 16, "minsamples for raytrace hider")
	red := flag.Float64("red", 1.0, "red colour channel")
	green := flag.Float64("green", 0.6, "green colour channel")
	blue := flag.Float64("blue", 0.0, "blue colour channel")
	constant := flag.Bool("constant",false,"render with constant surfaces")

	help := flag.Bool("help",false,"print the help")

	flag.Parse()

	if *help {
		fmt.Printf("%s\n\nhelp -\n",Version)
		flag.PrintDefaults()
		os.Exit(0)
	}		

	within := func(d float64) float64 {
		if d < 0.000000 {
			return 0.0
		}
		if d > 1.000000 {
			return 1.0
		}
		return d
	}

	color := [3]float64{within(*red),within(*green),within(*blue)}
		

	s := *scale
	if s < 0.1 {
		s = 0.1
	}
	if s > 5.0 {
		s = 5.0
	}

	width := int(800.0 * s)
	height := int(400.0 * s)

	/* process the parameterlist using reflection */
	p := func(params ...interface{}) string {
		if len(params) == 0 {
			return ""
		}
		
		out := make([]string,len(params))

		for i,param := range params {
			
			if param == nil {
				out = append(out,"<nil>")
				continue
			}

			switch reflect.TypeOf(param).String() {
				case "string":
					str,_ := param.(string)
					out[i] = fmt.Sprintf("%q",str)
				break
				case "float64":
					f,_ := param.(float64)
					/* make use of the RIB's floating point notation to compact output values */
					out[i] = fmt.Sprintf("[%s]",format.Float64(f))
				break
				case "int":
					d,_ := param.(int)
					out[i] = fmt.Sprintf("[%d]",d)
				break
				case "[3]float64":
					fs,_ := param.([3]float64)
					out[i] = fmt.Sprintf("[%s]",format.Float64(fs)) 
				break
				default:

					out[i] = fmt.Sprintf("<unknown type %s>",reflect.TypeOf(param))
				break
			}
		}

		return strings.Join(out," ")
	}

	/* strip the first word and use as the label */
	label := func(str string) string {
		parts := strings.Split(str," ")
		return strings.ToLower(parts[0])
	}

	exr := func(str string) string {
		return label(str) + ".exr"
	}


	d := fmt.Printf

	d("##RenderMan\n")
	d("##Machine Generated By %q\n", "quadratics_params.go")
	d("##Version %q\n",Version)
	d("##Scene quadrics_params.rib\n")
	d("version 3.04\n")
	d("Format %d %d 1\n", width, height)
	d("Display %q %q %q\n",exr("sphere_params"),"openexr","rgba")
	d("Projection %q %s\n", "perspective", p("float fov",60.0))
	d("Hider %q %s\n","raytrace",p("int maxsamples",*maxsamples,"int minsamples",*minsamples,"int incremental",100))
	d("Integrator %q %q\n", "PxrPathTracer", "example")
	d("PixelFilter %q 4 4\n","gaussian")
	
	if ! *constant {
		d("ArchiveBegin %q\n","lighting")
		d("\tAttributeBegin\n")
		d("\t\tAttribute %q %s\n","identifier",p("name","fill_light"))
		d("\t\tTranslate 0 15 0\n")
		d("\t\tScale 3 3 3\n")
		d("\t\tLight %q %q %s\n","PxrSphereLight","fill_light",p("float intensity",8.0,"float temperature",7500.0))
		d("\tAttributeEnd\n")
		d("\tAttributeBegin\n")
		d("\t\tAttribute %q %s\n","identifier",p("name","key_light"))
		d("\t\tTranslate 0 0 -5\n")
		d("\t\tScale 3 3 3\n")
		d("\t\tLight %q %q %s\n","PxrSphereLight","key_light",p("float intensity",8.0,"float temperature",3000.0))
		d("\tAttributeEnd\n")
		d("ArchiveEnd\n")
	}
	
	/* ri.h : RiSphere(float radius, float zmin,float zmax, float tmax, ...); */
	radius := 1.0
	zmin := -1.0
	zmax := 1.0
	tmax := 360.0

	dzmax := 1.0 / (14.0 + 1)
	dtmax := 360.0 / 56.0

	array := func(r ...float64) string {
		return format.Floatv(r)
	}

	d("WorldBegin\n")
	d("\t\tTranslate 0 4 20\n")

	if ! *constant {
		d("\t\tReadArchive %q\n","lighting")
	}
	for y := -12.0; y < 8.0; y += 4.0 {	
		
		for x := -20.0; x < 20.0; x += 3.0 {

			if y > -8.0 {

				tmax -= dtmax			
				zmin = -1.0
				zmax = 1.0
			} else {
				zmin += dzmax
				zmax -= dzmax
			}

			d("\t\tAttributeBegin\n")
			d("\t\t\tAttribute %q %s\n","identifier",p("name","sphere"))
			d("\t\t\tTranslate %s\n",array(x,y,0.0))
			if *constant {
				d("\t\t\tBxdf %q %q %s\n","PxrDiffuse","surface",p("color diffuseColor",color))
			} else {	
				d("\t\t\tBxdf %q %q %s\n","PxrConstant","surface",p("color emitColor",color))
			}
			d("\t\t\tSphere %s\n",array(radius,zmin,zmax,tmax))
			d("\t\tAttributeEnd\n")
		}
	}

	d("WorldEnd\n")


}