float ao = smoothstep(0.0, 0.4, vGrassUv.y);
ao = mix(0.2, 1.0, ao); // Roots are 20% brightness

vec3 rootColor = diffuseColor.rgb * 0.4;
vec3 tipColor = diffuseColor.rgb * 1.3 + vec3(0.1, 0.1, 0.0);

vec3 grassColor = mix(rootColor, tipColor, vGrassUv.y);
grassColor *= ao;

float translucency = pow(vGrassUv.y, 2.0) * 0.5;
grassColor += vec3(0.1, 0.2, 0.0) * translucency;

diffuseColor.rgb = grassColor;
