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

import (
	"flag"
	"fmt"
	"os"
)

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

func main() {
	scale := flag.Float64("scale", 1.0, "`scale of output image")
	filename := flag.String("filename", "beginning.exr", "output filename")
	intensity := flag.Float64("intensity", 5.0, "fill_light intensity")
	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", 0.0, "green colour channel")
	blue := flag.Float64("blue", 0.0, "blue colour channel")

	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
	}

	r := within(*red)
	g := within(*green)
	b := within(*blue)

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

	width := int(640.0 * s)
	height := int(480.0 * s)

	d := fmt.Printf

	d("##RenderMan\n")
	d("##Machine Generated By %q\n", "beginning.go")
	d("##Cmd go run beginning.go -scale %.3f -intensity %.2f -maxsamples %d -minsamples %d -red %.3f -green %.3f -blue %.3f -filename %q\n",
			*scale,*intensity,*maxsamples,*minsamples,*red,*green,*blue,*filename)
	d("##Scene beginning.rib\n")
	d("version 3.04\n")
	d("Display %q %q %q\n", *filename, "openexr", "rgba")
	d("Format %d %d 1\n", width, height)
	d("Projection %q %q [60]\n", "perspective", "float fov")
	d("Hider %q %q [%d] %q [%d] %q [%d]\n", "raytrace", "int maxsamples", *maxsamples, "int minsamples", *minsamples, "int incremental", 100)
	d("Integrator %q %q\n", "PxrPathTracer", "example")
	d("WorldBegin\n")
	d("\tTranslate 0 0 10\n")
	d("\tAttributeBegin\n")
	d("\t\tTranslate 0 10 -5\n")
	d("\t\tScale 3 3 3\n")
	d("\t\tLight %q %q %q [%.2f]\n", "PxrSphereLight", "fill_light", "float intensity", *intensity)
	d("\tAttributeEnd\n")
	d("\tAttributeBegin\n")
	d("\t\tTranslate 0 0 -10\n")
	d("\t\tRotate 180 0 1 0\n")
	d("\t\tScale 2 2 2\n")
	d("\t\tLight %q %q\n", "PxrSphereLight", "key_light")
	d("\tAttributeEnd\n")
	d("\tAttributeBegin\n")
	d("\t\tBxdf %q %q %q [%.2f %.2f %.2f]\n", "PxrDiffuse", "surface", "color diffuseColor", r, g, b)
	d("\t\tScale 2 4 2\n")
	d("\t\tSphere 1 -1 1 360\n")
	d("\tAttributeEnd\n")
	d("WorldEnd\n")
}