int GzPutTriangle(GzRender *render, int numParts, GzToken *nameList,
GzPointer *valueList)
/* numParts - how many names and values */
{
/*
- pass in a triangle description with tokens and values corresponding to
GZ_NULL_TOKEN: do nothing - no values
GZ_POSITION: 3 vert positions
- Invoke the scan converter and return an error code
*/
if (NULL != nameList && NULL != render && NULL != valueList)
{
int nLowestY = 0;
for (int i = 0; i < numParts; i++)
{
if (nameList[i] == GZ_POSITION)
{
// get points
GzCoord* gzPoints = (GzCoord*)valueList[i];
// sort the vertices by Y using bubble sort technique
for (int i = 0; i <= 1; i++)
{
nLowestY = i;
for (int j = i + 1; j <= 2; j++)
{
if (gzPoints[nLowestY][Y] > gzPoints[j][Y])
{
nLowestY = j;
}
}
if (nLowestY != i)
{
SwapVertices(gzPoints, nLowestY, i);
}
}
if (gzPoints[0][Y] == gzPoints[1][Y])
{
if (gzPoints[0][X] > gzPoints[1][X])
{
SwapVertices(gzPoints, 0, 1);
}
}
else if (gzPoints[1][Y] == gzPoints[2][Y])
{
if (gzPoints[1][X] < gzPoints[2][X])
{
SwapVertices(gzPoints, 2, 1);
}
}
// Find two Edges of the triangle to compute the normal vector
GzCoord Triedge12;
Triedge12[X] = gzPoints[1][X] - gzPoints[0][X];
Triedge12[Y] = gzPoints[1][Y] - gzPoints[0][Y];
Triedge12[Z] = gzPoints[1][Z] - gzPoints[0][Z];
GzCoord Triedge23;
Triedge23[X] = gzPoints[2][X] - gzPoints[1][X];
Triedge23[Y] = gzPoints[2][Y] - gzPoints[1][Y];
Triedge23[Z] = gzPoints[2][Z] - gzPoints[1][Z];
// compute the normal vector by doing the cross product of two edges
float fOutvectorX = Triedge12[Y] * Triedge23[Z] - Triedge12[Z] * Triedge23[Y];
float fOutvectorY = Triedge12[Z] * Triedge23[X] - Triedge12[X] * Triedge23[Z];
float fOutvectorZ = Triedge12[X] * Triedge23[Y] - Triedge12[Y] * Triedge23[X];
//Ax + By + Cz + D = 0 ------- [1]
float D = -(fOutvectorX * gzPoints[0][X]) - (fOutvectorY * gzPoints[0][Y]) - (fOutvectorZ * gzPoints[0][Z]);
int nLeft = 0, nRight = 0;
GetBoundingBoxWidth(nLeft, nRight, gzPoints);
// get the T/B from the sorted Y vertices
int nTop = (int)floor(gzPoints[0][Y]);
int nBottom = (int)ceil(gzPoints[2][Y]);
float interpolatedZ = 0.0f;
// for each pixel(x,y) in the bounding box evaluate equation [1]
for (int x = nLeft; x < nRight; x++)
{
for (int y = nTop; y < nBottom; y++)
{
float Edge12 = 0.0f, Edge23 = 0.0f, Edge31 = 0.0f;
Edge12 = (gzPoints[1][Y] - gzPoints[0][Y])*((float)x - gzPoints[0][X]) - (gzPoints[1][X] - gzPoints[0][X])*((float)y - gzPoints[0][Y]);
Edge23 = (gzPoints[2][Y] - gzPoints[1][Y])*((float)x - gzPoints[1][X]) - (gzPoints[2][X] - gzPoints[1][X])*((float)y - gzPoints[1][Y]);
Edge31 = (gzPoints[0][Y] - gzPoints[2][Y])*((float)x - gzPoints[2][X]) - (gzPoints[0][X] - gzPoints[2][X])*((float)y - gzPoints[2][Y]);
if (((Edge12 > 0) && (Edge23 > 0) && (Edge31 > 0)) || ((Edge12 < 0) && (Edge23 < 0) && (Edge31 < 0))
|| (Edge12 == 0 || Edge23 == 0 || Edge31 == 0))
{
// Z - buffer to remove hidden surfaces
interpolatedZ = (- (fOutvectorX * x) - (fOutvectorY * y) - D) / fOutvectorZ;
GzDepth zCurrentValFb = 0;
GzIntensity red = 0;
GzIntensity green = 0;
GzIntensity blue = 0;
GzIntensity alpha = 0;
// get the current values from the frambuffer
GzGetDisplay(render->display, x, y, &red, &green, &blue, &alpha, &zCurrentValFb);
// Compare between computed Zpix versus framebuffer Z value. If lesser write new pixel color, else dont do anything
if (interpolatedZ < zCurrentValFb)
{
zCurrentValFb = interpolatedZ;
red = (GzIntensity)ctoi((float)render->flatcolor[Red]);
green = (GzIntensity)ctoi((float)render->flatcolor[Green]);
blue = (GzIntensity)ctoi((float)render->flatcolor[Blue]);
//Writing new pixel value to the framebuffer
GzPutDisplay(render->display, x, y, red, green, blue, alpha, zCurrentValFb);
}
}
}
}
}
if (nameList[i] == GZ_NULL_TOKEN)
{
//Do nothing
continue;
}
}
return GZ_SUCCESS;
}
else
{
return GZ_FAILURE;
}
}
void mx_LevelGenerator::AddRoomCube( const Room* room )
{
for( int z= room->coord_min[2] - 1; z < room->coord_max[2]; z++ )
for( int y= room->coord_min[1] - 1; y < room->coord_max[1]; y++ )
for( int x= room->coord_min[0] - 1; x < room->coord_max[0]; x++ )
{
Element* element= ElementMap( x, y, z );
Element* el_x= ElementMap( x + 1, y, z );
Element* el_y= ElementMap( x, y + 1, z );
Element* el_z= ElementMap( x, y, z + 1 );
bool is_element= element == NULL;
bool is_el_x= el_x == NULL;
bool is_el_y= el_y == NULL;
bool is_el_z= el_z == NULL;
if( (is_element ^ is_el_x) && (element == room || el_x == room ) )
{
ReserveTrianglesAndVertices( 2, 4 );
mx_LevelVertex* v= out_level_data_.vertices + out_level_data_.vertex_count;
v[0].xyz[0]= float(x+1);
v[0].xyz[1]= float(y);
v[0].xyz[2]= float(z);
v[1].xyz[0]= float(x+1);
v[1].xyz[1]= float(y+1);
v[1].xyz[2]= float(z);
v[2].xyz[0]= float(x+1);
v[2].xyz[1]= float(y+1);
v[2].xyz[2]= float(z+1);
v[3].xyz[0]= float(x+1);
v[3].xyz[1]= float(y);
v[3].xyz[2]= float(z+1);
if( is_element ) SwapVertices( v[1].xyz, v[3].xyz );
GenQuadIndexation( out_level_data_.triangles + out_level_data_.triangle_count, out_level_data_.vertex_count );
out_level_data_.vertex_count+= 4;
out_level_data_.triangle_count+= 2;
}
if( (is_element ^ is_el_y) && (element == room || el_y == room ) )
{
ReserveTrianglesAndVertices( 2, 4 );
mx_LevelVertex* v= out_level_data_.vertices + out_level_data_.vertex_count;
v[0].xyz[0]= float(x);
v[0].xyz[1]= float(y+1);
v[0].xyz[2]= float(z);
v[1].xyz[0]= float(x);
v[1].xyz[1]= float(y+1);
v[1].xyz[2]= float(z+1);
v[2].xyz[0]= float(x+1);
v[2].xyz[1]= float(y+1);
v[2].xyz[2]= float(z+1);
v[3].xyz[0]= float(x+1);
v[3].xyz[1]= float(y+1);
v[3].xyz[2]= float(z);
if( is_element ) SwapVertices( v[1].xyz, v[3].xyz );
GenQuadIndexation( out_level_data_.triangles + out_level_data_.triangle_count, out_level_data_.vertex_count );
out_level_data_.vertex_count+= 4;
out_level_data_.triangle_count+= 2;
}
if( (is_element ^ is_el_z) && (element == room || el_z == room ) )
{
ReserveTrianglesAndVertices( 2, 4 );
mx_LevelVertex* v= out_level_data_.vertices + out_level_data_.vertex_count;
v[0].xyz[0]= float(x);
v[0].xyz[1]= float(y);
v[0].xyz[2]= float(z+1);
v[1].xyz[0]= float(x+1);
v[1].xyz[1]= float(y);
v[1].xyz[2]= float(z+1);
v[2].xyz[0]= float(x+1);
v[2].xyz[1]= float(y+1);
v[2].xyz[2]= float(z+1);
v[3].xyz[0]= float(x);
v[3].xyz[1]= float(y+1);
v[3].xyz[2]= float(z+1);
if( is_element ) SwapVertices( v[1].xyz, v[3].xyz );
GenQuadIndexation( out_level_data_.triangles + out_level_data_.triangle_count, out_level_data_.vertex_count );
out_level_data_.vertex_count+= 4;
out_level_data_.triangle_count+= 2;
}
} // or xyz
}