Ok, each vert has a color, i need to draw the polygon. It needs to be shaded, (i think i''m using gouraud?) but anyway...this source almost works...but for some reason it doesn''t..
The main bugs:
- Completely horisonial lines (in that curcumstance, there is a divide by 0)
- color phase outs aren''t working properly (there can be more of a color, but not less) (the color deltas won''t become negitive)
- drawing stops after the y value reaches LocalVerts[NumVerts].y
any help would be greatly appreciated. Thank you.
Here''s the source:
int CPolygon::DrawSolid(UINT* Buffer,int Pitch)
{
//re-order the localverts
//so that LocalVerts[0] is the topmost vert
//first, find out which vert is the topmost and
//which is the lowest
int index = 0;
int TopVert = 0;
for(index=0; index <= NumVerts; index++)
{
if(Verts[TopVert].y > Verts[index].y)
{
//the new top vert is LocalVerts[index]
TopVert = index;
}
}
//ok, now adjust the verts so that TopVert is the top vert
//create a buffer that will hold the verts for this methon only
//to keep from messing up the global verts.
VERTEX2D* LocalVerts = new VERTEX2D[NumVerts];
//copy ''em in!
for(index = 0; index <= (NumVerts - TopVert - 1); index++)
{
//set all the ones after the TopVert
LocalVerts[index] = Verts[TopVert+index];
}
//set all the ones before the TopVert
for( ; index < NumVerts; index++)
{
LocalVerts[index] = Verts[abs(NumVerts - index - TopVert)];
}
//find the lowest vert
int LowVert = 0;
for(index = 0; index <= NumVerts; index++);
{
if(LocalVerts[LowVert].y < LocalVerts[index].y)
{
LowVert = index;
}
}
//verts are now in the correct order.
//ok, so now LocalVerts[0] is the topmost vert.
//draw this sucker
int Height = abs((int)((LocalVerts[0].y - LocalVerts[LowVert].y) +0.5 )) ;
//both are origionating at LocalVerts[0]
//Left is aiming for LocalVerts[NumVerts-1]
//right is aiming for LocalVerts[1]
//set the verts to which we are aiming.
int AimToLeft = NumVerts-1;
int AimToRight = 1;
int CurrentVertLeft = 0;
int CurrentVertRight = 0;
//all legnths are verticle
double LeftLength = fabs(LocalVerts[CurrentVertLeft].y - LocalVerts[AimToLeft].y);
double RightLength = fabs(LocalVerts[CurrentVertRight].y - LocalVerts[AimToRight].y);
//the left deltas
double dLeftAlpha = (((LocalVerts[AimToLeft].Color - LocalVerts[CurrentVertLeft].Color) >> 24) & 0xFF) / LeftLength;
double dLeftRed = (((LocalVerts[AimToLeft].Color - LocalVerts[CurrentVertLeft].Color) >> 16) & 0xFF) / LeftLength;
double dLeftGreen = (((LocalVerts[AimToLeft].Color - LocalVerts[CurrentVertLeft].Color) >> 8) & 0xFF) / LeftLength;
double dLeftBlue = ((LocalVerts[AimToLeft].Color - LocalVerts[CurrentVertLeft].Color) & 0xFF) / LeftLength;
double dRightAlpha = (((LocalVerts[AimToRight].Color - LocalVerts[CurrentVertRight].Color) >> 24) & 0xFF) / RightLength;
double dRightRed = (((LocalVerts[AimToRight].Color - LocalVerts[CurrentVertRight].Color) >> 16) & 0xFF) / RightLength;
double dRightGreen = (((LocalVerts[AimToRight].Color - LocalVerts[CurrentVertRight].Color) >> 8) & 0xFF) / RightLength;
double dRightBlue = ((LocalVerts[AimToRight].Color - LocalVerts[CurrentVertRight].Color) & 0xFF) / RightLength;
//start ''em on the topmost vert
double RightAlphaCurr = ((LocalVerts[CurrentVertRight].Color & (255 << 24)) >> 24 );
double RightRedCurr = ((LocalVerts[CurrentVertRight].Color & (255 << 16)) >> 16 );
double RightGreenCurr =((LocalVerts[CurrentVertRight].Color & (255 << 8)) >> 8 );
double RightBlueCurr =(LocalVerts[CurrentVertRight].Color & (255));
double LeftAlphaCurr = ((LocalVerts[CurrentVertLeft].Color & (255 << 24)) >> 24 );
double LeftRedCurr = ((LocalVerts[CurrentVertLeft].Color & (255 << 16)) >> 16 );
double LeftGreenCurr = ((LocalVerts[CurrentVertLeft].Color & (255 << 8)) >> 8 );
double LeftBlueCurr =(LocalVerts[CurrentVertLeft].Color & (255));
//ok, now start the loop
double RightXCurr = (LocalVerts[CurrentVertRight].x + xPos);
double LeftXCurr = (LocalVerts[CurrentVertLeft].x + xPos);
double DeltaXYLeft = fabs(((LocalVerts[CurrentVertLeft].x - LocalVerts[AimToLeft].x)/(LocalVerts[CurrentVertLeft].y - LocalVerts[AimToLeft].y)));
double DeltaXYRight = fabs(((LocalVerts[CurrentVertRight].x - LocalVerts[AimToRight].x)/(LocalVerts[CurrentVertRight].y - LocalVerts[AimToRight].y)));
int y = (int)LocalVerts[0].y;
for(; y <= Height; y++)
{
DrawShadedLine((int)LeftXCurr,y+yPos,_RGB32BIT((int)LeftAlphaCurr,(int)LeftRedCurr,(int)LeftGreenCurr,(int)LeftBlueCurr),
(int)RightXCurr,y+yPos,_RGB32BIT((int)RightAlphaCurr,(int)RightRedCurr,(int)RightGreenCurr,(int)RightBlueCurr),
Buffer,Pitch);
if(LeftXCurr >= (LocalVerts[AimToLeft].x + xPos ))
{
//We hit the left vert.
//reclaculate the deltas, and positions for
//the left side
CurrentVertLeft = AimToLeft;
AimToLeft--;
LeftLength = fabs(LocalVerts[CurrentVertLeft].y - LocalVerts[AimToLeft].y);
LeftXCurr = (LocalVerts[CurrentVertLeft].x + xPos);
dLeftAlpha = (((LocalVerts[AimToLeft].Color - LocalVerts[CurrentVertLeft].Color) >> 24) & 0xFF) / LeftLength;
dLeftRed = (((LocalVerts[AimToLeft].Color - LocalVerts[CurrentVertLeft].Color) >> 16) & 0xFF) / LeftLength;
dLeftGreen = (((LocalVerts[AimToLeft].Color - LocalVerts[CurrentVertLeft].Color) >> 8) & 0xFF) / LeftLength;
dLeftBlue = ((LocalVerts[AimToLeft].Color - LocalVerts[CurrentVertLeft].Color) & 0xFF) / LeftLength;
LeftAlphaCurr = ((LocalVerts[CurrentVertLeft].Color & (255 << 24)) >> 24 );
LeftRedCurr = ((LocalVerts[CurrentVertLeft].Color & (255 << 16)) >> 16 );
LeftGreenCurr = ((LocalVerts[CurrentVertLeft].Color & (255 << 8)) >> 8 );
LeftBlueCurr =(LocalVerts[CurrentVertLeft].Color & (255));
DeltaXYLeft = fabs(((LocalVerts[CurrentVertLeft].x - LocalVerts[AimToLeft].x)/(LocalVerts[CurrentVertLeft].y - LocalVerts[AimToLeft].y)));
}
if(RightXCurr >= (LocalVerts[AimToRight].x + xPos))
{
//We hit the right vert.
//recalculate the deltas and positions for
//the right side
CurrentVertRight = AimToRight;
AimToLeft++;
RightXCurr = (LocalVerts[CurrentVertRight].x + xPos);
RightLength = fabs(LocalVerts[CurrentVertRight].y - LocalVerts[AimToRight].y);
dRightAlpha = (((LocalVerts[AimToRight].Color - LocalVerts[CurrentVertRight].Color) >> 24) & 0xFF) / RightLength;
dRightRed = (((LocalVerts[AimToRight].Color - LocalVerts[CurrentVertRight].Color) >> 16) & 0xFF) / RightLength;
dRightGreen = (((LocalVerts[AimToRight].Color - LocalVerts[CurrentVertRight].Color) >> 8) & 0xFF) / RightLength;
dRightBlue = ((LocalVerts[AimToRight].Color - LocalVerts[CurrentVertRight].Color) & 0xFF) / RightLength;
RightAlphaCurr = ((LocalVerts[CurrentVertRight].Color & (255 << 24)) >> 24 );
RightRedCurr = ((LocalVerts[CurrentVertRight].Color & (255 << 16)) >> 16 );
RightGreenCurr =((LocalVerts[CurrentVertRight].Color & (255 << 8)) >> 8 );
RightBlueCurr =(LocalVerts[CurrentVertRight].Color & (255));
DeltaXYRight = fabs(((LocalVerts[CurrentVertRight].x - LocalVerts[AimToRight].x)/(LocalVerts[CurrentVertRight].y - LocalVerts[AimToRight].y)));
}
RightXCurr += DeltaXYRight;
LeftXCurr += DeltaXYLeft;
LeftAlphaCurr += dLeftAlpha;
LeftRedCurr += dLeftRed;
LeftGreenCurr += dLeftGreen;
LeftBlueCurr += dLeftBlue;
RightAlphaCurr += dRightAlpha;
RightRedCurr += dRightRed;
RightGreenCurr += dRightGreen;
RightBlueCurr += dRightBlue;
}
//delete the local verts
delete [] LocalVerts;
return 1;
}
