bflibrary: Add gpoly_point struct to draw_gpoly()

Another step in making draw_gpoly() easier to understand.

Author: mefistotelis

bflibrary/include/poly_gp.h

@@ -28,6 +28,15 @@ extern "C" {
 
 #pragma pack(1)
 
+struct gpoly_point {
+    int Y;
+    int X;
+    int X_prc;
+    int S;
+    int U;
+    int V;
+};
+
 struct gpoly_factors {
     int S[4];
 };
@@ -40,33 +49,14 @@ struct gpoly_state {
     int ratioCA_X2Y;
     int ratioBA_X2Y;
     int ratioCB_X2Y;
+    int var_134;
+    struct gpoly_point ptA;
+    struct gpoly_point ptB;
+    struct gpoly_point ptC;
     struct gpoly_factors incC;
     struct gpoly_factors incD;
-    int ptA_Y;
-    int ptA_X;
-    int ptA_X_prc;
-    int ptA_S;
-    int ptA_U;
-    int ptA_V;
-    int ptB_Y;
-    int ptB_X;
-    int ptB_X_prc;
-    int ptB_S;
-    int ptB_U;
-    int ptB_V;
-    int ptC_Y;
-    int ptC_X;
-    int ptC_X_prc;
-    int ptC_S;
-    int ptC_U;
-    int ptC_V;
-    int var_134;
     struct gpoly_factors incA;
     struct gpoly_factors incB;
-    int var_0BC;
-    int var_0B8;
-    int var_0B4;
-    int var_0A8;
     struct gpoly_blends bldA;
     struct gpoly_blends bldB;
 };