[PICA] Implement drawArrays, get our first triangle data

include/PICA/gpu.hpp

@@ -10,6 +10,8 @@ class GPU {
 	ShaderUnit shaderUnit;
 	std::array<u32, regNum> regs; // GPU internal registers
 
+	void drawArrays();
+
 public:
 	GPU(Memory& mem) : mem(mem) {}
 	void clearBuffer(u32 startAddress, u32 endAddress, u32 value, u32 control);

include/PICA/regs.hpp

@@ -2,6 +2,12 @@
 
 namespace PICAInternalRegs {
 	enum : u32 {
+		// Draw command regs
+		VertexCountReg = 0x228,
+		VertexOffsetReg = 0x22A,
+		SignalDrawArrays = 0x22E,
+
+		// Vertex shader registers
 		VertexShaderTransferEnd = 0x2BF,
 		VertexShaderTransferIndex = 0x2CB,
 		VertexShaderData0 = 0x2CC,