[Feat] (Tessellation): implement glPatchParameterfv and bake the default levels into both pass-through control stages

MobileGL/MG_State/GLState/Core.cpp

@@ -812,6 +812,22 @@ namespace MobileGL::MG_State {
             m_renderState.SetPatchVertices(vertices);
         }
 
+        void GLContext::SetPatchDefaultOuterLevel(const FloatVec4& levels) {
+            m_renderState.SetPatchDefaultOuterLevel(levels);
+        }
+
+        const FloatVec4& GLContext::GetPatchDefaultOuterLevel() const {
+            return m_renderState.GetPatchDefaultOuterLevel();
+        }
+
+        void GLContext::SetPatchDefaultInnerLevel(const FloatVec2& levels) {
+            m_renderState.SetPatchDefaultInnerLevel(levels);
+        }
+
+        const FloatVec2& GLContext::GetPatchDefaultInnerLevel() const {
+            return m_renderState.GetPatchDefaultInnerLevel();
+        }
+
         Uint GLContext::GetPatchVertices() const {
             return m_renderState.GetPatchVertices();
         }

MobileGL/MG_State/GLState/Core.h

@@ -213,6 +213,10 @@ namespace MobileGL {
                 Float GetPointSize() const;
                 void SetPatchVertices(Uint vertices);
                 Uint GetPatchVertices() const;
+                void SetPatchDefaultOuterLevel(const FloatVec4& levels);
+                const FloatVec4& GetPatchDefaultOuterLevel() const;
+                void SetPatchDefaultInnerLevel(const FloatVec2& levels);
+                const FloatVec2& GetPatchDefaultInnerLevel() const;
                 void SetPolygonOffset(Float factor, Float units);
                 Float GetPolygonOffsetFactor() const;
                 Float GetPolygonOffsetUnits() const;

MobileGL/MG_State/GLState/RenderState/RenderState.cpp

@@ -217,6 +217,31 @@ namespace MobileGL {
                 return m_parameters.PatchVertices;
             }
 
+            // BumpVersions(), not just ++m_version, for the same reason SetPatchVertices does it:
+            // these levels are compiled INTO the synthesized pass-through tessellation control
+            // stage on both backends, so changing one makes an already-built program stale.
+            void RenderState::SetPatchDefaultOuterLevel(const FloatVec4& levels) {
+                if (m_parameters.PatchDefaultOuterLevel == levels) return;
+
+                m_parameters.PatchDefaultOuterLevel = levels;
+                BumpVersions();
+            }
+
+            const FloatVec4& RenderState::GetPatchDefaultOuterLevel() const {
+                return m_parameters.PatchDefaultOuterLevel;
+            }
+
+            void RenderState::SetPatchDefaultInnerLevel(const FloatVec2& levels) {
+                if (m_parameters.PatchDefaultInnerLevel == levels) return;
+
+                m_parameters.PatchDefaultInnerLevel = levels;
+                BumpVersions();
+            }
+
+            const FloatVec2& RenderState::GetPatchDefaultInnerLevel() const {
+                return m_parameters.PatchDefaultInnerLevel;
+            }
+
             void RenderState::SetPolygonOffset(Float factor, Float units) {
                 if (m_parameters.PolygonOffsetFactor == factor && m_parameters.PolygonOffsetUnits == units) return;
 

MobileGL/MG_State/GLState/RenderState/RenderState.h

@@ -240,6 +240,13 @@ namespace MobileGL {
         Float PointSize = 1.0f;
         // GL_PATCH_VERTICES: how many vertices one tessellation patch consumes.
         Uint PatchVertices = 3;
+        // GL_PATCH_DEFAULT_OUTER_LEVEL / GL_PATCH_DEFAULT_INNER_LEVEL (glPatchParameterfv). The
+        // tessellation levels used when a program has an evaluation stage and NO control stage -
+        // GL's fixed-function pass-through (4.6 core 11.2.2). Both backends have to synthesize
+        // that stage, and they bake these numbers into it, so a change here makes an already-built
+        // one stale exactly as PATCH_VERTICES does. Default 1.0, per table 23.44.
+        FloatVec4 PatchDefaultOuterLevel = FloatVec4(1.0f, 1.0f, 1.0f, 1.0f);
+        FloatVec2 PatchDefaultInnerLevel = FloatVec2(1.0f, 1.0f);
         Float PolygonOffsetFactor = 0.0f;
         Float PolygonOffsetUnits = 0.0f;
 
@@ -374,6 +381,10 @@ namespace MobileGL {
                 Float GetPointSize() const;
                 void SetPatchVertices(Uint vertices);
                 Uint GetPatchVertices() const;
+                void SetPatchDefaultOuterLevel(const FloatVec4& levels);
+                const FloatVec4& GetPatchDefaultOuterLevel() const;
+                void SetPatchDefaultInnerLevel(const FloatVec2& levels);
+                const FloatVec2& GetPatchDefaultInnerLevel() const;
                 void SetPolygonOffset(Float factor, Float units);
                 Float GetPolygonOffsetFactor() const;
                 Float GetPolygonOffsetUnits() const;