Uniform buffer format building

--HG--
branch : opengl3

code/nel/src/3d/driver/opengl3/driver_opengl_uniform_buffer.h

@@ -38,6 +38,154 @@ extern const char *GLSLHeaderUniformBuffer;
 } // NLDRIVERGL3
 } // NL3D
 
+#include "nel/misc/string_mapper.h"
+
+namespace NL3D {
+
+// Uniform buffer format generation following glsl std140 rules
+class CUniformBufferFormat
+{
+public:
+	enum TType
+	{
+		Float, // float
+		FloatVec2, // CVector2D
+		FloatVec3,
+		FloatVec4, // CVector
+		SInt, // sint32
+		SIntVec2,
+		SIntVec3,
+		SIntVec4,
+		UInt, // uint32
+		UIntVec2,
+		UIntVec3,
+		UIntVec4,
+		Bool,
+		BoolVec2,
+		BoolVec3,
+		BoolVec4,
+		FloatMat2,
+		FloatMat3,
+		FloatMat4, // CMatrix
+		FloatMat2x3,
+		FloatMat2x4,
+		FloatMat3x2,
+		FloatMat3x4,
+		FloatMat4x2,
+		FloatMat4x3,
+	};
+
+	struct CEntry
+	{
+		NLMISC::TStringId Name;
+		TType Type;
+		sint Offset;
+		sint Count;
+
+		inline sint stride()
+		{
+			return Count == 1
+				? s_TypeSize[Type]
+				: ((s_TypeSize[Type] + 15) & ~0xF);
+		}
+		inline sint size()
+		{
+			return stride() * Count;
+		}
+	};
+
+	// Push a variable. Returns the byte offset in uniform buffer
+	sint push(const std::string &name, TType type, sint count = 1)
+	{
+		nlassert(count > 0);
+		sint baseAlign = count == 1 
+			? s_TypeAlignment[type] 
+			: ((s_TypeAlignment[type] + 15) & ~0xF);
+		sint baseOffset = m_Entries.size()
+			? m_Entries.back().Offset + m_Entries.back().stride()
+			: 0;
+		sint alignOffset = baseOffset;
+		alignOffset += (baseAlign - 1);
+		alignOffset &= ~(baseAlign - 1); // Note: alignment MUST BE power of 2 for this to work
+		m_Entries.resize(m_Entries.size() + 1);
+		CEntry &entry = m_Entries.back();
+		entry.Name = NLMISC::CStringMapper::map(name);
+		entry.Type = type;
+		entry.Offset = alignOffset;
+		entry.Count = count;
+		return baseOffset;
+	}
+
+	inline const CEntry *get() { return &m_Entries[0]; }
+	inline size_t size() { return m_Entries.size(); }
+	
+private:
+	static const sint s_TypeAlignment[];
+	static const sint s_TypeSize[];
+
+	typedef std::vector<CEntry> TEntries;
+	TEntries m_Entries;
+
+};
+
+const sint CUniformBufferFormat::s_TypeAlignment[] = {
+	4, // Float
+	8,
+	16,
+	16,
+	4, // SInt
+	8,
+	16,
+	16,
+	4, // UInt
+	8,
+	16,
+	16,
+	4, // Bool
+	8,
+	16,
+	16,
+	16, // FloatMat2
+	16,
+	16,
+	16, // FloatMat2x3
+	16,
+	16, // FloatMat3x2
+	16,
+	16, // FloatMat4x2
+	16,
+};
+
+const sint CUniformBufferFormat::s_TypeSize[] = {
+	4, // Float
+	8,
+	12,
+	16,
+	4, // SInt
+	8,
+	12,
+	16,
+	4, // UInt
+	8,
+	12,
+	16,
+	4, // Bool
+	8,
+	12,
+	16,
+	16 + 8, // FloatMat2
+	16 + 16 + 12, // FloatMat3
+	16 + 16 + 16 + 16, // FloatMat4
+	16 + 12, // FloatMat2x3
+	16 + 16, // FloatMat2x4
+	16 + 16 + 8, // FloatMat3x2
+	16 + 16 + 16, // FloatMat3x4
+	16 + 16 + 16 + 8, // FloatMat4x2
+	16 + 16 + 16 + 12, // FloatMat4x3
+};
+
+}
+
 #endif // NL_DRIVER_OPENGL_UNIFORM_BUFFER_H
 
 /* end of file */