Add SetBlendColor command

next.json

@@ -441,6 +441,15 @@
                     {"name": "reference", "type": "uint32_t"}
                 ]
             },
+            {
+                "name": "set blend color",
+                "args": [
+                    {"name": "r", "type": "float"},
+                    {"name": "g", "type": "float"},
+                    {"name": "b", "type": "float"},
+                    {"name": "a", "type": "float"}
+                ]
+            },
             {
                 "name": "set bind group",
                 "args": [
@@ -688,6 +697,9 @@
             {"value": 1, "name":"linear"}
         ]
     },
+    "float": {
+        "category": "native"
+    },
     "framebuffer": {
         "category": "object"
     },

src/backend/CommandBuffer.cpp

@@ -236,6 +236,12 @@ namespace backend {
                         cmd->~SetStencilReferenceCmd();
                     }
                     break;
+                case Command::SetBlendColor:
+                    {
+                        SetBlendColorCmd* cmd = commands->NextCommand<SetBlendColorCmd>();
+                        cmd->~SetBlendColorCmd();
+                    }
+                    break;
                 case Command::SetBindGroup:
                     {
                         SetBindGroupCmd* cmd = commands->NextCommand<SetBindGroupCmd>();
@@ -345,6 +351,10 @@ namespace backend {
                 commands->NextCommand<SetStencilReferenceCmd>();
                 break;
 
+            case Command::SetBlendColor:
+                commands->NextCommand<SetBlendColorCmd>();
+                break;
+
             case Command::SetBindGroup:
                 commands->NextCommand<SetBindGroupCmd>();
                 break;
@@ -570,6 +580,16 @@ namespace backend {
                     }
                     break;
 
+                case Command::SetBlendColor:
+                    {
+                        iterator.NextCommand<SetBlendColorCmd>();
+                        if (!state->HaveRenderPass()) {
+                            HandleError("Can't set blend color without an active render pass");
+                            return false;
+                        }
+                    }
+                    break;
+
                 case Command::SetBindGroup:
                     {
                         SetBindGroupCmd* cmd = iterator.NextCommand<SetBindGroupCmd>();
@@ -779,6 +799,15 @@ namespace backend {
         cmd->reference = reference;
     }
 
+    void CommandBufferBuilder::SetBlendColor(float r, float g, float b, float a) {
+        SetBlendColorCmd* cmd = allocator.Allocate<SetBlendColorCmd>(Command::SetBlendColor);
+        new(cmd) SetBlendColorCmd;
+        cmd->r = r;
+        cmd->g = g;
+        cmd->b = b;
+        cmd->a = a;
+    }
+
     void CommandBufferBuilder::SetBindGroup(uint32_t groupIndex, BindGroupBase* group) {
         if (groupIndex >= kMaxBindGroups) {
             HandleError("Setting bind group over the max");

src/backend/CommandBuffer.h

@@ -81,6 +81,7 @@ namespace backend {
             void SetComputePipeline(ComputePipelineBase* pipeline);
             void SetRenderPipeline(RenderPipelineBase* pipeline);
             void SetStencilReference(uint32_t reference);
+            void SetBlendColor(float r, float g, float b, float a);
             void SetBindGroup(uint32_t groupIndex, BindGroupBase* group);
             void SetIndexBuffer(BufferBase* buffer, uint32_t offset, nxt::IndexFormat format);
 

src/backend/Commands.h

@@ -44,6 +44,7 @@ namespace backend {
         SetRenderPipeline,
         SetPushConstants,
         SetStencilReference,
+        SetBlendColor,
         SetBindGroup,
         SetIndexBuffer,
         SetVertexBuffers,
@@ -139,6 +140,10 @@ namespace backend {
         uint32_t reference;
     };
 
+    struct SetBlendColorCmd {
+        float r, g, b, a;
+    };
+
     struct SetBindGroupCmd {
         uint32_t index;
         Ref<BindGroupBase> group;

src/backend/d3d12/CommandBufferD3D12.cpp

@@ -485,6 +485,14 @@ namespace d3d12 {
                     }
                     break;
 
+                case Command::SetBlendColor:
+                    {
+                        SetBlendColorCmd* cmd = commands.NextCommand<SetBlendColorCmd>();
+                        ASSERT(lastRenderPipeline);
+                        commandList->OMSetBlendFactor(static_cast<const FLOAT*>(&cmd->r));
+                    }
+                    break;
+
                 case Command::SetBindGroup:
                     {
                         SetBindGroupCmd* cmd = commands.NextCommand<SetBindGroupCmd>();

src/backend/metal/CommandBufferMTL.mm

@@ -402,6 +402,20 @@ namespace metal {
                     }
                     break;
 
+                case Command::SetBlendColor:
+                    {
+                        SetBlendColorCmd* cmd = commands.NextCommand<SetBlendColorCmd>();
+
+                        ASSERT(encoders.render);
+
+                        [encoders.render
+                            setBlendColorRed:cmd->r
+                            green:cmd->g
+                            blue:cmd->b
+                            alpha:cmd->a ];
+                    }
+                    break;
+
                 case Command::SetBindGroup:
                     {
                         SetBindGroupCmd* cmd = commands.NextCommand<SetBindGroupCmd>();

src/backend/opengl/CommandBufferGL.cpp

@@ -336,6 +336,12 @@ namespace opengl {
                     }
                     break;
 
+                case Command::SetBlendColor:
+                    {
+                        commands.NextCommand<SetBlendColorCmd>();
+                    }
+                    break;
+
                 case Command::SetBindGroup:
                     {
                         SetBindGroupCmd* cmd = commands.NextCommand<SetBindGroupCmd>();