draw.c

allows the user to select files containing objects and draw them using one of the available project

#include <assert.h>

#include "draw.h"


/* Local variables */
static MATRIX_4x4 te;
static MATRIX_4x4 projection;

/*
 * Sets the window and the viewport.
 */
void DrawSetTransformation (const RECT *pWindow, const RECT *pViewport)
{
  MATRIX_4x4 scale, translateInWnd, translateInView, temp;

  assert (pWindow != NULL && pViewport != NULL);
  
  /* Build the transformation matrixes */
  MatrixTranslation (-pWindow->left, -pWindow->bottom, 0, translateInWnd);
  MatrixScale ((pViewport->right - pViewport->left)/(pWindow->right - pWindow->left),
               ((pViewport->top - pViewport->bottom))/(pWindow->top - pWindow->bottom),
               0,
               scale);

  MatrixTranslation (pViewport->left, pViewport->bottom, 0, translateInView);

  /* Perform the multiplications */
  MatrixMultiply (translateInView, scale, temp);
  MatrixMultiply (temp, translateInWnd, te);
}

/*
 * Sets the projection type
 */
void DrawSetProjection (const MATRIX_4x4 proj)
{
  memcpy (projection, proj, sizeof (MATRIX_4x4));
}

/*
 * Draws the object using the current projection
 */
void DrawObject (HDC hDC, const POBJECT_3D pObject)
{
  int x1, y1, x2, y2, i, j;
 
  PPOINT_3D pPoint;
  MATRIX_4x4 matrix;
  POBJECT_3D pTempObj;
  
  assert (pObject != NULL);

  MatrixMultiply (te, projection, matrix);
  pTempObj = ObjectMultiply (pObject, matrix);
  
  for (i = 0; i < pTempObj->cCols; i++)
    for (j = 0; j < pTempObj->cRows; j++) {
      pPoint = &pTempObj->ppPoints [i][j];
      x1 = (int) pPoint->x;
      y1 = (int) pPoint->y;


      if (i + 1 < pTempObj->cCols) {
        pPoint = &pTempObj->ppPoints [i + 1][j];
        x2 = (int) pPoint->x;
        y2 = (int) pPoint->y;
        MoveToEx (hDC, x1, y1, NULL);
        LineTo (hDC, x2, y2);
      }

      if (j - 1 >= 0) {
        pPoint = &pTempObj->ppPoints [i][j - 1];
        x2 = (int) pPoint->x;
        y2 = (int) pPoint->y;
        MoveToEx (hDC, x1, y1, NULL);
        LineTo (hDC, x2, y2);
      }

    }

  ObjectFree (pTempObj);
}