From 67c153f589b80f2024056b648e9e0ac37044c6c4 Mon Sep 17 00:00:00 2001
From: halx99 <halx99@live.com>
Date: Fri, 14 Feb 2020 21:40:33 +0800
Subject: [PATCH] Make multi-meta-textures support works on Metal.

---
 .../backend/metal/CommandBufferMTL.mm         | 38 ++++++++++---------
 cocos/renderer/backend/metal/TextureMTL.h     |  2 +-
 .../backend/opengl/CommandBufferGL.cpp        |  3 +-
 3 files changed, 22 insertions(+), 21 deletions(-)

diff --git a/cocos/renderer/backend/metal/CommandBufferMTL.mm b/cocos/renderer/backend/metal/CommandBufferMTL.mm
index e43760b8b4..775edcbecc 100644
--- a/cocos/renderer/backend/metal/CommandBufferMTL.mm
+++ b/cocos/renderer/backend/metal/CommandBufferMTL.mm
@@ -178,12 +178,12 @@ namespace
         return mtlDescritpor;
     }
     
-    id<MTLTexture> getMTLTexture(TextureBackend* texture)
+    id<MTLTexture> getMTLTexture(TextureBackend* texture, int index = 0)
     {
         switch (texture->getTextureType())
         {
             case TextureType::TEXTURE_2D:
-                return static_cast<TextureMTL*>(texture)->getMTLTexture();
+                return static_cast<TextureMTL*>(texture)->getMTLTexture(index);
             case TextureType::TEXTURE_CUBE:
                 return static_cast<TextureCubeMTL*>(texture)->getMTLTexture();
             default:
@@ -422,27 +422,29 @@ void CommandBufferMTL::doSetTextures(bool isVertex) const
 
     for(const auto& iter : bindTextureInfos)
     {
-        //FIXME: should support texture array.
-        int i = 0;
         auto location = iter.first;
         const auto& textures = iter.second.textures;
+        const auto& slot = iter.second.slot;
         
-        if (isVertex)
+        int i = 0;
+        for (const auto& texture: textures)
         {
-            [_mtlRenderEncoder setVertexTexture:getMTLTexture(textures[i])
-                                    atIndex:location];
-            [_mtlRenderEncoder setVertexSamplerState:getMTLSamplerState(textures[i])
-                                         atIndex:location];
+            int metaIdx = slot[i++];
+            if (isVertex)
+            {
+                [_mtlRenderEncoder setVertexTexture:getMTLTexture(texture, metaIdx)
+                                        atIndex:location];
+                [_mtlRenderEncoder setVertexSamplerState:getMTLSamplerState(texture)
+                                             atIndex:location];
+            }
+            else
+            {
+                [_mtlRenderEncoder setFragmentTexture:getMTLTexture(texture, metaIdx)
+                                          atIndex:location];
+                [_mtlRenderEncoder setFragmentSamplerState:getMTLSamplerState(texture)
+                                               atIndex:location];
+            }
         }
-        else
-        {
-            [_mtlRenderEncoder setFragmentTexture:getMTLTexture(textures[i])
-                                      atIndex:location];
-            [_mtlRenderEncoder setFragmentSamplerState:getMTLSamplerState(textures[i])
-                                           atIndex:location];
-        }
-        
-        ++i;
     }
 }
 
diff --git a/cocos/renderer/backend/metal/TextureMTL.h b/cocos/renderer/backend/metal/TextureMTL.h
index cd91a5d5db..0aa030ffad 100644
--- a/cocos/renderer/backend/metal/TextureMTL.h
+++ b/cocos/renderer/backend/metal/TextureMTL.h
@@ -124,7 +124,7 @@ public:
      * Get MTLTexture object.
      * @return A MTLTexture object.
      */
-    inline id<MTLTexture> getMTLTexture() const { return _mtlTextures[0]; }
+    inline id<MTLTexture> getMTLTexture(int index = 0) const { return _mtlTextures[index]; }
     
     /**
      * Get MTLSamplerState object
diff --git a/cocos/renderer/backend/opengl/CommandBufferGL.cpp b/cocos/renderer/backend/opengl/CommandBufferGL.cpp
index e7ecfe05f9..02d94578f0 100644
--- a/cocos/renderer/backend/opengl/CommandBufferGL.cpp
+++ b/cocos/renderer/backend/opengl/CommandBufferGL.cpp
@@ -487,8 +487,7 @@ void CommandBufferGL::setUniforms(ProgramGL* program) const
             int i = 0;
             for (const auto& texture: textures)
             {
-                applyTexture(texture, slot[i]);
-                ++i;
+                applyTexture(texture, slot[i++]);
             }
             
             auto arrayCount = slot.size();