112 lines
3 KiB
Go
112 lines
3 KiB
Go
package main
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// RIGHT : x
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// FORWARD : Y
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// UP : Z
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import (
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"math"
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rl "github.com/gen2brain/raylib-go/raylib"
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)
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const MAX_DIST = 1000.0
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const MAX_STEP = 1000
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const EPS = 0.01
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const WIDTH = 250
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const HEIGHT = 250
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const PI = math.Pi
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var lightPos Vector3 = Vector3{0, -200, 600}
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var sphere Sphere = Sphere{Vector3{0, 100, 5}, 10, RED_MAT}
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var plane Plane = Plane{Vector3{0, 0, 1}, 0, WHITE_GREY_GRID_MAT}
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var scene SmoothUnionSDF = SmoothUnionSDF{sphere, plane, 3.5}
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// var scene UnionSDF = UnionSDF{sphere, plane}
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var cameraPos Vector3 = Vector3{0, -10, 30}
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// radius, theta, phi
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var screenSpherical Vector3 = Vector3{10, PI/2 + 0.2, PI / 2}
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var screenPhysicalSize float64 = 5
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func phongShading(point Vector3, normal Vector3, mat Material) Vector3 {
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lightVec := (lightPos.Sub(point)).Normalized()
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reflectLight := Reflect(lightVec.Scale(-1), normal)
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eyeVec := (cameraPos.Sub(point)).Normalized()
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ambiant := mat.ambiantColor.GetColor(point).Scale(0.1)
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diffusePower := mat.diffuseFac * max(0, normal.Dot(lightVec))
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diffuse := mat.diffuseColor.GetColor(point).Scale(diffusePower)
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specularPower := mat.specularFac * math.Pow(max(0, -reflectLight.Dot(eyeVec)), mat.specularExp)
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specular := mat.specularColor.GetColor(point).Scale(specularPower)
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return ambiant.Add(diffuse).Add(specular)
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}
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func rayMarch(origin Vector3, direction Vector3) (bool, Vector3) {
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p := origin
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for range MAX_STEP {
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dist, mat := scene.Distance(p)
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// fmt.Println(dist)
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if dist < EPS {
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// fmt.Println("hit")
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normal := Gradient(scene, p, EPS).Normalized()
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return true, phongShading(p, normal, mat)
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}
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if dist > MAX_DIST {
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break
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}
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// fmt.Println("Before")
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// fmt.Println(p, dist)
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p = p.Add(direction.Scale(dist))
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// fmt.Println("After")
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// fmt.Println(p, DistanceOnly(scene, p))
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}
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return false, GREY
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}
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func genImage() *rl.Image {
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screenCartesian, _, theta_vec, phi_vec := screenSpherical.SphericalToCartesian()
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screenCenter := cameraPos.Add(screenCartesian)
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// fmt.Println(theta_vec, phi_vec)
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image := rl.GenImageColor(WIDTH, HEIGHT, rl.Black)
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for pixel_x := range WIDTH {
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for pixel_y := range HEIGHT {
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sx := screenPhysicalSize * (float64(pixel_x)/WIDTH - 0.5)
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sy := screenPhysicalSize * (float64(pixel_y)/WIDTH - 0.5)
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origin := screenCenter.Add(phi_vec.Scale(-sx)).Add(theta_vec.Scale(sy))
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direction := (origin.Sub(cameraPos)).Normalized()
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// fmt.Println(origin, direction)
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hit, color_vec := rayMarch(origin, direction)
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var fr, fg, fb float64
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if hit {
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fr, fg, fb = color_vec.Unpack()
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} else {
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fr, fg, fb = 0, 0, 0
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}
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fr, fg, fb = Clamp(fr, 0, 255), Clamp(fg, 0, 255), Clamp(fb, 0, 255)
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r, g, b := uint8(fr), uint8(fg), uint8(fb)
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rl.ImageDrawPixel(image, int32(pixel_x), int32(pixel_y), rl.Color{R: r, G: g, B: b, A: 255})
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}
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}
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return image
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}
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func main() {
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rl.InitWindow(WIDTH, HEIGHT, "raymarching")
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texture := rl.LoadTextureFromImage(genImage())
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for !rl.WindowShouldClose() {
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rl.BeginDrawing()
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rl.ClearBackground(rl.Black)
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rl.DrawTexture(texture, 0, 0, rl.White)
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rl.EndDrawing()
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}
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}
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