#include "surface.hpp"
#include "polygon.hpp"
#include "main.hpp"

/*******************************************************************************
** SurfaceCreate
*******************************************************************************/
void
SurfaceCreate(Surface* surface, Vector poly[], int n, int colour, float angle, float z)
{   
   Vector up = {0.0f, 1.0f, 0.0f};
   Matrix   reverse;
   Vector   lo, hi;
   Vector* tmp = (Vector*) malloc(n * sizeof(Vector));

   ThrowIf(!tmp, "Could not allocate temporary surface memory");
   
   memset(surface, 0, sizeof(Surface));
   
   surface->colour = colour;

   TrianglePlane(poly, surface->plane);  
   /*
   ** Calculate surface matrix.
   */
   MatrixView  (surface->matrix, surface->plane, up, angle);
   VectorNegate(surface->matrix[0], surface->matrix[0]);
   VectorNegate(surface->matrix[1], surface->matrix[1]);   
   /*
   ** Transform polygon into surface space and calculate surface extents.
   */      
   PolygonTransform(tmp, poly, n, surface->matrix);
   PolygonExtent(lo, hi, tmp, n);
   /*
   ** Snap polygon extents to lightmap grid.
   */      
   surface->lo[0] = (float)floor(lo[0] / 16.0f) * 16.0f;
   surface->lo[1] = (float)floor(lo[1] / 16.0f) * 16.0f;
   surface->lo[2] = lo[2];
   surface->hi[0] = (float)ceil (hi[0] / 16.0f) * 16.0f;
   surface->hi[1] = (float)ceil (hi[1] / 16.0f) * 16.0f;                
   surface->hi[2] = hi[2];
   /*
   ** Calculate surfaces width & height.
   */
   surface->width  = (int)surface->hi[0] - (int)surface->lo[0];
   surface->height = (int)surface->hi[1] - (int)surface->lo[1];

   ThrowIf(surface->width  <= 0, "Zero width surface");
   ThrowIf(surface->height <= 0, "Zero height surface");     
   /*
   ** Calculate surfaces PMN vectors.
   */           
   VectorCreate(surface->PMN[0], surface->lo[0], surface->lo[1], surface->lo[2] + z);
   VectorCreate(surface->PMN[1], surface->hi[0] - surface->lo[0], 0.0f, 0.0f);
   VectorCreate(surface->PMN[2], 0.0f, surface->hi[1] - surface->lo[1], 0.0f);
   /*
   ** Transform PMN vectors back into world space.
   */   
   MatrixTranspose(reverse, surface->matrix);

   TriangleTransform(surface->PMN, surface->PMN, reverse);

   free(tmp);   
}