feat/fix: misc shader changes (fix normals, lighting, uv)

src/app/niko/scene-components/grass.tsx

@@ -224,6 +224,7 @@ export default function Grass({
 			shader.vertexShader = `
             uniform float uTime;
             varying vec2 vGrassUv;
+            varying vec3 vWorldPos;
             
             float hash(vec2 p) {
                 return fract(sin(dot(p, vec2(127.1, 311.7))) * 43758.5453);
@@ -233,12 +234,10 @@ export default function Grass({
                 vec2 i = floor(p);
                 vec2 f = fract(p);
                 f = f * f * (3.0 - 2.0 * f);
-				
                 float a = hash(i);
                 float b = hash(i + vec2(1.0, 0.0));
                 float c = hash(i + vec2(0.0, 1.0));
                 float d = hash(i + vec2(1.0, 1.0));
-				
                 return mix(mix(a, b, f.x), mix(c, d, f.x), f.y);
             }
             
@@ -246,23 +245,21 @@ export default function Grass({
                 float value = 0.0;
                 float amplitude = 0.5;
                 float frequency = 1.0;
-				
                 for(int i = 0; i < 4; i++) {
                     value += amplitude * noise(p * frequency);
                     frequency *= 2.0;
                     amplitude *= 0.5;
                 }
-				
                 return value;
             }
             
             ${shader.vertexShader}
         `;
+
 			shader.vertexShader = shader.vertexShader.replace(
 				'#include <begin_vertex>',
 				`
             #include <begin_vertex>
-			vGrassUv = uv;
             ${grassVert}
             `
 			);
@@ -270,8 +267,10 @@ export default function Grass({
 			shader.fragmentShader = `
             uniform float uTime;
             varying vec2 vGrassUv;
+            varying vec3 vWorldPos;
             ${shader.fragmentShader}
         `;
+
 			shader.fragmentShader = shader.fragmentShader.replace(
 				'#include <color_fragment>',
 				`

src/app/niko/scene-components/shaders/grass.frag

@@ -1,13 +1,17 @@
-float ao = smoothstep(0.0, 0.7, vGrassUv.y);
-ao = mix(0.05, 1.0, ao);
-
-vec3 rootColor = diffuseColor.rgb * 0.4;
-vec3 tipColor = diffuseColor.rgb * 1.5;
+float ao = smoothstep(0.0, 0.8, vGrassUv.y);
+ao = mix(0.15, 1.0, ao);
 
+vec3 rootColor = diffuseColor.rgb * 0.35;
+vec3 tipColor = diffuseColor.rgb * 1.3;
 vec3 grassColor = mix(rootColor, tipColor, vGrassUv.y);
-grassColor *= ao;
 
-float translucency = pow(vGrassUv.y, 2.0) * 0.5;
-grassColor += diffuseColor.rgb * translucency;
+vec3 viewDir = normalize(cameraPosition - vWorldPos);
+vec3 lightDir = normalize(vec3(15.0, 25.0, 15.0)); 
 
-diffuseColor.rgb = grassColor;
+float backLighting = max(0.0, dot(viewDir, -lightDir));
+backLighting = pow(backLighting, 3.0) * smoothstep(0.2, 1.0, vGrassUv.y);
+
+vec3 sssColor = vec3(0.4, 0.8, 0.3) * diffuseColor.rgb; 
+grassColor += sssColor * backLighting * 1.5;
+
+diffuseColor.rgb = grassColor * ao;

src/app/niko/scene-components/shaders/grass.vert

@@ -1,3 +1,5 @@
+vGrassUv = uv;
+
 vec4 worldPos = modelMatrix * instanceMatrix * vec4(0.0, 0.0, 0.0, 1.0);
 float gx = worldPos.x;
 float gz = worldPos.z;
@@ -8,7 +10,6 @@ float windSpeed = 1.5;
 float windTime = uTime * windSpeed;
 vec2 windSamplePos = (worldPos.xz * 0.05) - (mainWindDir * windTime * 0.2);
 
-
 float windBase = fbm(windSamplePos * 0.8) * 0.4 + 0.2;
 float gustNoise = fbm(windSamplePos * 0.4);
 float gust = pow(gustNoise, 3.0) * 1.8;
@@ -36,3 +37,6 @@ float swayAmount = (totalWind + spring) * uv.y * uv.y;
 transformed.x += swayAmount * windDir.x;
 transformed.z += swayAmount * windDir.y;
 transformed.y -= abs(swayAmount) * 0.2;
+
+objectNormal = vec3(0.0, 1.0, 0.0); 
+vWorldPos = (modelMatrix * instanceMatrix * vec4(transformed, 1.0)).xyz;