Move everything into one directory, update links
This commit is contained in:
James Gregory
parent
b946ff9e70
commit
4eef8b2919
680 changed files with 1638 additions and 1638 deletions
195
54-04.html
Normal file
195
54-04.html
Normal file
|
|
@ -0,0 +1,195 @@
|
|||
<HTML>
|
||||
<HEAD>
|
||||
<META name=vsisbn content="1576101746">
|
||||
<META name=vstitle content="Michael Abrash's Graphics Programming Black Book, Special Edition">
|
||||
<META name=vsauthor content="Michael Abrash">
|
||||
<META name=vspublisher content="The Coriolis Group">
|
||||
<META name=vspubdate content="07/01/97">
|
||||
<META name=vscategory content="Web and Software Development: Game Development,Web and Software Development: Graphics and Multimedia Development">
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
<TITLE>Michael Abrash's Graphics Programming Black Book Special Edition: 3-D Shading</TITLE>
|
||||
|
||||
<!-- HEADER -->
|
||||
<!-- Empty Reference Subhead -->
|
||||
|
||||
<!--ISBN=1576101746//-->
|
||||
<!--TITLE=Michael Abrash's Graphics Programming Black Book Special Edition//-->
|
||||
<!--AUTHOR=Michael Abrash//-->
|
||||
<!--PUBLISHER=The Coriolis Group, Inc.//-->
|
||||
<!--CHAPTER=54//-->
|
||||
<!--PAGES=1025-1027//-->
|
||||
<!--UNASSIGNED1//-->
|
||||
<!--UNASSIGNED2//--></HEAD><BODY LINK=#0000FF ALINK=#000099 VLINK=#0000FF BGCOLOR=#FFFFFF>
|
||||
|
||||
<CENTER>
|
||||
<TABLE BORDER>
|
||||
<TR>
|
||||
<TD><A HREF="54-03.html">Previous</A></TD>
|
||||
<TD><A HREF="index.html">Table of Contents</A></TD>
|
||||
<TD><A HREF="54-05.html">Next</A></TD>
|
||||
</TR>
|
||||
</TABLE>
|
||||
</CENTER>
|
||||
<P><BR></P>
|
||||
<P><B>LISTING 54.2 DRAWPOBJ.C</B></P>
|
||||
<!-- CODE //-->
|
||||
<PRE>
|
||||
/* Draws all visible faces in the specified polygon-based object. The object
|
||||
must have previously been transformed and projected, so that all vertex
|
||||
arrays are filled in. Ambient and diffuse shading are supported. */
|
||||
#include "polygon.h"
|
||||
|
||||
void DrawPObject(PObject * ObjectToXform)
|
||||
{
|
||||
int i, j, NumFaces = ObjectToXform->NumFaces, NumVertices;
|
||||
int * VertNumsPtr, Spot;
|
||||
Face * FacePtr = ObjectToXform->FaceList;
|
||||
Point * ScreenPoints = ObjectToXform->ScreenVertexList;
|
||||
PointListHeader Polygon;
|
||||
Fixedpoint Diffusion;
|
||||
ModelColor ColorTemp;
|
||||
ModelIntensity IntensityTemp;
|
||||
Point3 UnitNormal, *NormalStartpoint, *NormalEndpoint;
|
||||
long v1, v2, w1, w2;
|
||||
Point Vertices[MAX-POLY-LENGTH];
|
||||
|
||||
/* Draw each visible face (polygon) of the object in turn */
|
||||
for (i=0; i<NumFaces; i++, FacePtr++) {
|
||||
/* Remember where we can find the start and end of the polygon's
|
||||
unit normal in view space, and skip over the unit normal endpoint
|
||||
entry. The end and start points of the unit normal to the polygon
|
||||
must be the first and second entries in the polgyon's vertex list.
|
||||
Note that the second point is also an active polygon vertex */
|
||||
VertNumsPtr = FacePtr->VertNums;
|
||||
NormalEndpoint = &ObjectToXform->XformedVertexList[*VertNumsPtr++];
|
||||
NormalStartpoint = &ObjectToXform->XformedVertexList[*VertNumsPtr];
|
||||
/* Copy over the face's vertices from the vertex list */
|
||||
NumVertices = FacePtr->NumVerts;
|
||||
for (j=0; j<NumVertices; j++)
|
||||
Vertices[j] = ScreenPoints[*VertNumsPtr++];
|
||||
/* Draw only if outside face showing (if the normal to the polygon
|
||||
in screen coordinates points toward the viewer; that is, has a
|
||||
positive Z component) */
|
||||
v1 = Vertices[1].X - Vertices[0].X;
|
||||
w1 = Vertices[NumVertices-1].X - Vertices[0].X;
|
||||
v2 = Vertices[1].Y - Vertices[0].Y;
|
||||
w2 = Vertices[NumVertices-1].Y - Vertices[0].Y;
|
||||
if ((v1*w2 - v2*w1) > 0) {
|
||||
/* It is facing the screen, so draw */
|
||||
/* Appropriately adjust the extent of the rectangle used to
|
||||
erase this object later */
|
||||
for (j=0; j<NumVertices; j++) {
|
||||
if (Vertices[j].X >
|
||||
ObjectToXform->EraseRect[NonDisplayedPage].Right)
|
||||
if (Vertices[j].X < SCREEN-WIDTH)
|
||||
ObjectToXform->EraseRect[NonDisplayedPage].Right =
|
||||
Vertices[j].X;
|
||||
else ObjectToXform->EraseRect[NonDisplayedPage].Right =
|
||||
SCREEN-WIDTH;
|
||||
if (Vertices[j].Y >
|
||||
ObjectToXform->EraseRect[NonDisplayedPage].Bottom)
|
||||
if (Vertices[j].Y < SCREEN-HEIGHT)
|
||||
ObjectToXform->EraseRect[NonDisplayedPage].Bottom =
|
||||
Vertices[j].Y;
|
||||
else ObjectToXform->EraseRect[NonDisplayedPage].Bottom=
|
||||
SCREEN-HEIGHT;
|
||||
if (Vertices[j].X <
|
||||
ObjectToXform->EraseRect[NonDisplayedPage].Left)
|
||||
if (Vertices[j].X > 0)
|
||||
ObjectToXform->EraseRect[NonDisplayedPage].Left =
|
||||
Vertices[j].X;
|
||||
else ObjectToXform->EraseRect[NonDisplayedPage].Left=0;
|
||||
if (Vertices[j].Y <
|
||||
ObjectToXform->EraseRect[NonDisplayedPage].Top)
|
||||
if (Vertices[j].Y > 0)
|
||||
ObjectToXform->EraseRect[NonDisplayedPage].Top =
|
||||
Vertices[j].Y;
|
||||
else ObjectToXform->EraseRect[NonDisplayedPage].Top=0;
|
||||
}
|
||||
/* See if there's any shading */
|
||||
if (FacePtr->ShadingType == 0) {
|
||||
/* No shading in effect, so just draw */
|
||||
DRAW-POLYGON(Vertices, NumVertices, FacePtr->ColorIndex, 0, 0);
|
||||
} else {
|
||||
/* Handle shading */
|
||||
/* Do ambient shading, if enabled */
|
||||
if (AmbientOn && (FacePtr->ShadingType & AMBIENT-SHADING)) {
|
||||
/* Use the ambient shading component */
|
||||
IntensityTemp = AmbientIntensity;
|
||||
} else {
|
||||
SET-INTENSITY(IntensityTemp, 0, 0, 0);
|
||||
}
|
||||
/* Do diffuse shading, if enabled */
|
||||
if (FacePtr->ShadingType & DIFFUSE-SHADING) {
|
||||
/* Calculate the unit normal for this polygon, for use in dot
|
||||
products */
|
||||
UnitNormal.X = NormalEndpoint->X - NormalStartpoint->X;
|
||||
UnitNormal.Y = NormalEndpoint->Y - NormalStartpoint->Y;
|
||||
UnitNormal.Z = NormalEndpoint->Z - NormalStartpoint->Z;
|
||||
/* Calculate the diffuse shading component for each active
|
||||
spotlight */
|
||||
for (Spot=0; Spot<MAX-SPOTS; Spot++) {
|
||||
if (SpotOn[Spot] != 0) {
|
||||
/* Spot is on, so sum, for each color component, the
|
||||
intensity, accounting for the angle of the light rays
|
||||
relative to the orientation of the polygon */
|
||||
/* Calculate cosine of angle between the light and the
|
||||
polygon normal; skip if spot is shining from behind
|
||||
the polygon */
|
||||
if ((Diffusion = DOT-PRODUCT(SpotDirectionView[Spot],
|
||||
UnitNormal)) > 0) {
|
||||
IntensityTemp.Red +=
|
||||
FixedMul(SpotIntensity[Spot].Red, Diffusion);
|
||||
IntensityTemp.Green +=
|
||||
FixedMul(SpotIntensity[Spot].Green, Diffusion);
|
||||
IntensityTemp.Blue +=
|
||||
FixedMul(SpotIntensity[Spot].Blue, Diffusion);
|
||||
}
|
||||
}
|
||||
}
|
||||
}
|
||||
/* Convert the drawing color to the desired fraction of the
|
||||
brightest possible color */
|
||||
IntensityAdjustColor(&ColorTemp, &FacePtr->FullColor,
|
||||
&IntensityTemp);
|
||||
/* Draw with the cumulative shading, converting from the general
|
||||
color representation to the best-match color index */
|
||||
DRAW-POLYGON(Vertices, NumVertices,
|
||||
ModelColorToColorIndex(&ColorTemp), 0, 0);
|
||||
}
|
||||
}
|
||||
}
|
||||
}
|
||||
</PRE>
|
||||
<!-- END CODE //-->
|
||||
<P><BR></P>
|
||||
<CENTER>
|
||||
<TABLE BORDER>
|
||||
<TR>
|
||||
<TD><A HREF="54-03.html">Previous</A></TD>
|
||||
<TD><A HREF="index.html">Table of Contents</A></TD>
|
||||
<TD><A HREF="54-05.html">Next</A></TD>
|
||||
</TR>
|
||||
</TABLE>
|
||||
</CENTER>
|
||||
|
||||
<hr width="90%" size="1" noshade>
|
||||
<div align="center">
|
||||
<font face="Verdana,sans-serif" size="1">Graphics Programming Black Book © 2001 Michael Abrash</font>
|
||||
</div>
|
||||
<!-- all of the reference materials (books) have the footer and subfoot reveresed -->
|
||||
<!-- reference_subfoot = footer -->
|
||||
<!-- reference_footer = subfoot -->
|
||||
|
||||
<!-- BEGIN SUB FOOTER -->
|
||||
</BODY>
|
||||
</HTML>
|
||||
|
||||
<!-- END FOOTER -->
|
||||
|
||||
|
||||
Loading…
Reference in a new issue