Stantard shader in Fade mode not working on iOS

Unity Engine
1

Hi,

I’m using the standard shader in Fade mode to fade some object’s alpha from 0 to 1 on a prefab with an animation. The scenario is :

  • Prefab is instantiated with standard shader in Opaque mode.
  • I start the animation.
  • When it’s started, I set the shader’s mode to Fade by doing this :
foreach (Material m in meshRenderer.materials) {
                        Material currentMaterial = m;
                        currentMaterial.SetFloat("_Mode", 2f);
                        currentMaterial.SetInt("_SrcBlend", (int)UnityEngine.Rendering.BlendMode.SrcAlpha);
                        currentMaterial.SetInt("_DstBlend", (int)UnityEngine.Rendering.BlendMode.OneMinusSrcAlpha);
                        currentMaterial.SetInt("_ZWrite", 0);
                        currentMaterial.DisableKeyword("_ALPHATEST_ON");
                        currentMaterial.EnableKeyword("_ALPHABLEND_ON");
                        currentMaterial.DisableKeyword("_ALPHAPREMULTIPLY_ON");
                        Color c = currentMaterial.color;
                        currentMaterial.color = new Color(c.r, c.g, c.b, 0f);
                    }
  • I start fading the objects alpha from 0 to 1.
  • When it’s done, I reset the shader’s mode to Opaque by doing this :
foreach (Material m in meshRenderer.materials) {
                        Material currentMaterial = m;
                        currentMaterial.SetFloat("_Mode", 0f);
                        currentMaterial.SetInt("_SrcBlend", (int)UnityEngine.Rendering.BlendMode.One);
                        currentMaterial.SetInt("_DstBlend", (int)UnityEngine.Rendering.BlendMode.Zero);
                        currentMaterial.SetInt("_ZWrite", 1);
                        currentMaterial.DisableKeyword("_ALPHATEST_ON");
                        currentMaterial.DisableKeyword("_ALPHABLEND_ON");
                        currentMaterial.DisableKeyword("_ALPHAPREMULTIPLY_ON");
                        Color c = currentMaterial.color;
                        currentMaterial.color = new Color(c.r, c.g, c.b, 1f);
                    }

It’s working well in the Editor but when I build it on iOS (I tried setting the Graphics API to Automatic, and I also tried to force it to Open GL ES 2.0, 3.0 and Metal), the fading doesn’t work at all.

Do you have an idea what the issue could be ?

Here’s my fading coroutine by the way :

private IEnumerator FadeObjectIn()
    {
        float time = 0.5f;
        MeshRenderer meshRenderer = GetComponent<MeshRenderer>();
        if (meshRenderer != null) {
            foreach (Material m in meshRenderer.materials) {
                Material currentMaterial = m;
                Color c = currentMaterial.color;
                float t = 0f;
                while (t <= 1f) {
                    c.a = Mathf.Lerp(0f, 1f, t);
                    t += Time.deltaTime/time;
                    currentMaterial.color = c;
                    yield return null;
                }
            }
            SetShaderMode(BlendMode.Opaque);
        }
    }
2

wow, first time to know you can handle shaderlab syntax in that way

I guess when built into iOS platform, the shader is changed or compiled for optimization.