[WGL/P] Fixed linePointDistance so we can account for points behind the objects

1 files changed, 11 insertions, 4 deletions

diff --git a/Year 2/Computer Graphics with WebGL/Project/shaders.js b/Year 2/Computer Graphics with WebGL/Project/shaders.js
index 1657f5b..302ed50 100644
--- a/Year 2/Computer Graphics with WebGL/Project/shaders.js
+++ b/Year 2/Computer Graphics with WebGL/Project/shaders.js
@@ -59,11 +59,16 @@ var fShader = `
 	uniform vec3 uAmbientColor;

 	uniform vec3 uDiffuseColor;

 	

-	uniform vec3 uLightDir;	

+	uniform vec3 uLightDir;

 

 	// Thanks https://en.wikipedia.org/wiki/Distance_from_a_point_to_a_line#Vector_formulation

 	float linePointDistance(vec3 linePoint, vec3 lineDir, vec3 point) {

-		return length((point - linePoint) - dot(point - linePoint, lineDir) * lineDir);

+		vec3 projectionDir = dot(point - linePoint, lineDir) * lineDir; // aka projectionVector - linePoint

+		float dist = length((point - linePoint) - projectionDir); // aka length of perpendicular vector

+		// if pointing in opposite directions, meaning if the cloest point is behind us

+		if (dot(projectionDir, lineDir) < 0.0)

+			return -dist;

+		return dist;

 	}

 

 	// Thanks https://en.wikipedia.org/wiki/Line%E2%80%93sphere_intersection#Calculation_using_vectors_in_3D

@@ -134,7 +139,8 @@ var fShader = `
 		// Does the ray pass through any blackholes

 		int bhStatus = 2;

 		for (int i = 0; i < 5; i++) {

-			if (linePointDistance(ray, step, uBH[i].xyz) < uBH[i].a * 3.0) {

+			float dist = linePointDistance(ray, step, uBH[i].xyz);

+			if (dist >= 0.0 && dist < uBH[i].a * 3.0) {

 				bhStatus = rayMarchInBH(uBH[i], ray, step);

 			}

 		}

@@ -145,7 +151,8 @@ var fShader = `
 

 		// Does the ray hit a star

 		for (int i = 0; i < 5; i++) {

-			if (linePointDistance(ray, step, uStars[i].xyz) < uStars[i].a) {

+			float dist = linePointDistance(ray, step, uStars[i].xyz);

+			if (dist >= 0.0 && dist < uStars[i].a) {

 				return calculateColor(bhStatus == 2, uStars[i], ray, step);

 			}

 		}