有人知道如何创建类似于苹果示例中的水材质吗？
"scene.scn" 中有一个名为 "geotherm_01" 的对象，该对象具有材质 "_1_terrasses_orange_water" 和 "_1_terrasses_eau"，可以创建出缓慢动画看起来逼真的水。
我尝试在我的测试项目中重复相同的材质，但无法得到相同的结果。
1个回答
11
使用在Xcode SceneKit场景编辑器中显示的着色器修改器来实现这种水效果。最重要的材质属性是法线贴图，它将用于影响光照以模拟完全平坦几何体上的波纹。
更具体地说，.surface 入口点的修饰符是
float waterSpeed = u_time * -0.1;vec2 uvs = _surface.normalTexcoord;uvs.x *= 2;vec3 tn = texture2D(u_normalTexture, vec2(uvs.x, uvs.y + waterSpeed)).xyz;tn = tn * 2 - 1;vec3 tn2 = texture2D(u_normalTexture, vec2(uvs.x + 0.35 , uvs.y + 0.35 + (waterSpeed * 1.3))).xyz;tn2 = tn2 * 2 - 1;vec3 rn = (tn + tn2) * 0.5;mat3 ts = mat3(_surface.tangent, _surface.bitangent, _surface.geometryNormal);_surface.normal = normalize(ts * rn);
这是代码的注释版本：
// Elapsed time in seconds
float waterSpeed = u_time * -0.1;
// Texture coordinates that will be used to sample the normal map
vec2 uvs = _surface.normalTexcoord;
uvs.x *= 2;
// Sample the normal map
vec3 tn = texture2D(u_normalTexture, vec2(uvs.x, uvs.y + waterSpeed)).xyz;
// The texture stores values in the [0, 1] range
// Express the coordinates of the normal vector in the [-1, +1] range
tn = tn * 2 - 1;
// Sample the normal map again, using the `waterSpeed` offset this time
// in order to produce the animation effect
vec3 tn2 = texture2D(u_normalTexture, vec2(uvs.x + 0.35 , uvs.y + 0.35 + (waterSpeed * 1.3))).xyz;
tn2 = tn2 * 2 - 1;
// Combine the two normals (static and animated) to produce a richer (more complex and less uniform) effect
vec3 rn = (tn + tn2) * 0.5;
// Normals in the normal map are expressed in tangent space
// Convert them to object space and override the surface normal to simulate wavelets
mat3 ts = mat3(_surface.tangent, _surface.bitangent, _surface.geometryNormal);
_surface.normal = normalize(ts * rn);
- mnuages
1
1谢谢你，mnuages。 - Manifestor
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