[Fix] (GL): accept GL_SRC_ALPHA_SATURATE as a source and destination blend factor

MobileGL/MG_Pipe/MGPipeValueTypes.h

@@ -50,6 +50,9 @@ namespace MobileGL {
         OneMinusSrc1Color,
         Src1Alpha,
         OneMinusSrc1Alpha,
+        // GL_SRC_ALPHA_SATURATE: (f, f, f, 1) with f = min(As, 1 - Ad). Legal as a source and a
+        // destination factor in desktop GL. Appended so the values above keep their encoding.
+        SrcAlphaSaturate,
         BlendFactorCount,
         Unknown = -1
     };

MobileGL/MG_Test/State/RenderStateTest.cpp

@@ -104,6 +104,23 @@ TEST_F(RenderStateTest, IndexedBlendTogglesStillWork) {
     EXPECT_EQ(MG_Impl::GLImpl::GetError(), GL_NO_ERROR);
 }
 
+TEST_F(RenderStateTest, SrcAlphaSaturateIsAcceptedAsSourceAndDestinationFactor) {
+    // Desktop GL takes GL_SRC_ALPHA_SATURATE for all four factors (KHR-GL30.api.coverage).
+    MG_Impl::GLImpl::BlendFuncSeparate(GL_SRC_ALPHA_SATURATE, GL_SRC_ALPHA_SATURATE, GL_SRC_ALPHA_SATURATE,
+                                       GL_SRC_ALPHA_SATURATE);
+    EXPECT_EQ(MG_Impl::GLImpl::GetError(), GL_NO_ERROR);
+    for (const GLenum pname : {GL_BLEND_SRC_RGB, GL_BLEND_DST_RGB, GL_BLEND_SRC_ALPHA, GL_BLEND_DST_ALPHA}) {
+        GLint value = 0;
+        MG_Impl::GLImpl::GetIntegerv(pname, &value);
+        EXPECT_EQ(value, GL_SRC_ALPHA_SATURATE) << "pname " << pname;
+    }
+
+    MG_Impl::GLImpl::BlendFunci(1, GL_SRC_ALPHA_SATURATE, GL_SRC_ALPHA_SATURATE);
+    EXPECT_EQ(MG_Impl::GLImpl::GetError(), GL_NO_ERROR);
+    MG_Impl::GLImpl::BlendFunc(GL_ONE, GL_ZERO);
+    EXPECT_EQ(MG_Impl::GLImpl::GetError(), GL_NO_ERROR);
+}
+
 // ---------------------------------------------------------------------------------------------
 // ARB_viewport_array: indexed viewport / scissor / depth-range state
 // ---------------------------------------------------------------------------------------------

MobileGL/MG_Util/Converters/GLToMG/RenderStateEnumConverter.cpp

@@ -48,6 +48,8 @@ namespace MobileGL {
                 return BlendFactor::Src1Alpha;
             case GL_ONE_MINUS_SRC1_ALPHA:
                 return BlendFactor::OneMinusSrc1Alpha;
+            case GL_SRC_ALPHA_SATURATE:
+                return BlendFactor::SrcAlphaSaturate;
             default:
                 return BlendFactor::Unknown;
             }

MobileGL/MG_Util/Converters/MGToGL/RenderStateEnumConverter.cpp

@@ -49,6 +49,8 @@ namespace MobileGL {
                 return GL_SRC1_ALPHA;
             case BlendFactor::OneMinusSrc1Alpha:
                 return GL_ONE_MINUS_SRC1_ALPHA;
+            case BlendFactor::SrcAlphaSaturate:
+                return GL_SRC_ALPHA_SATURATE;
             default:
                 return GL_UNKNOWN_MGL;
             }

MobileGL/MG_Util/Converters/MGToStr/RenderStateEnumConverter.cpp

@@ -48,6 +48,8 @@ namespace MobileGL {
                 return "Src1Alpha";
             case BlendFactor::OneMinusSrc1Alpha:
                 return "OneMinusSrc1Alpha";
+            case BlendFactor::SrcAlphaSaturate:
+                return "SrcAlphaSaturate";
             default:
                 return "Unknown";
             }

MobileGL/MG_Util/Converters/MGToVk/RenderStateEnumConverter.cpp

@@ -200,6 +200,8 @@ namespace MobileGL {
                 return VK_BLEND_FACTOR_SRC1_ALPHA;
             case BlendFactor::OneMinusSrc1Alpha:
                 return VK_BLEND_FACTOR_ONE_MINUS_SRC1_ALPHA;
+            case BlendFactor::SrcAlphaSaturate:
+                return VK_BLEND_FACTOR_SRC_ALPHA_SATURATE;
             default:
                 return VK_BLEND_FACTOR_ONE;
             }