/* 26_toon_shading.c - OpenGL-based cartoon (or "toon") shading
using Cg program from Chapter 7 of "The Cg Tutorial"
(Addison-Wesley, ISBN 0321194969). */
/* Requires the OpenGL Utility Toolkit (GLUT) and Cg runtime (version
1.5 or higher). */
#include <stdio.h> /* for printf and NULL */
#include <stdlib.h> /* for exit */
#include <string.h> /* for strlen */
#include <math.h> /* for sqrt, sin, and cos */
#include <assert.h> /* for assert */
#include <GL/glew.h>
#ifdef __APPLE__
#include <GLUT/glut.h>
#else
#include <GL/glut.h>
#endif
#ifdef _WIN32
#include <GL/wglew.h>
#else
#ifdef __APPLE__
#include <OpenGL/OpenGL.h>
#else
#include <GL/glxew.h>
#endif
#endif
#include <Cg/cg.h> /* Can't include this? Is Cg Toolkit installed! */
#include <Cg/cgGL.h>
static CGcontext myCgContext;
static CGprofile myCgVertexProfile,
myCgFragmentProfile;
static CGprogram myCgVertexProgram,
myCgFragmentProgram;
static CGparameter myCgVertexParam_modelViewProj,
myCgVertexParam_lightPosition,
myCgVertexParam_eyePosition,
myCgVertexParam_shininess,
myCgFragmentParam_Kd,
myCgFragmentParam_Ks;
static const char *myProgramName = "26_toon_shading",
*myVertexProgramFileName = "C9E3v_toonShading.cg",
/* Page 247 */ *myVertexProgramName = "C9E3v_toonShading",
*myFragmentProgramFileName = "C9E4f_toonShading.cg",
/* Page 248 */ *myFragmentProgramName = "C9E4f_toonShading";
static float myProjectionMatrix[16];
static float eyeHeight = 0.0f; /* Vertical height of light. */
static float eyeAngle = 0.53f; /* Angle in radians eye rotates around monkey. */
static float lightAngle = -0.4; /* Angle light rotates around scene. */
static float lightHeight = 1.0f; /* Vertical height of light. */
static float headSpin = 0.0f; /* Head spin in degrees. */
static float shininess = 8.9f;
static float Kd[4] = { 0.8f, 0.6f, 0.2f, 1.0f }; /* Diffuse color */
static float Ks[4] = { 0.3f, 0.3f, 4.0f, 0.0f }; /* Specular color */
/* Model data: MonkeyHead_vertices, MonkeyHead_normals, and MonkeyHead_triangles */
#include "MonkeyHead.h"
static void drawMonkeyHead(void)
{
static GLfloat *texcoords = NULL; /* Malloc'ed buffer, never freed. */
/* Generate a set of 2D texture coordinate from the scaled (x,y)
vertex positions. */
if (texcoords == NULL) {
const int numVertices = sizeof(MonkeyHead_vertices) /
(3*sizeof(MonkeyHead_vertices[0]));
const float scaleFactor = 1.5;
int i;
texcoords = (GLfloat*) malloc(2 * numVertices * sizeof(GLfloat));
if (texcoords == NULL) {
fprintf(stderr, "%s: malloc failed\n", myProgramName);
exit(1);
}
for (i=0; i<numVertices; i++) {
texcoords[i*2 + 0] = scaleFactor * MonkeyHead_vertices[i*3 + 0];
texcoords[i*2 + 1] = scaleFactor * MonkeyHead_vertices[i*3 + 1];
}
}
glEnableClientState(GL_VERTEX_ARRAY);
glEnableClientState(GL_NORMAL_ARRAY);
glEnableClientState(GL_TEXTURE_COORD_ARRAY);
glVertexPointer(3, GL_FLOAT, 3*sizeof(GLfloat), MonkeyHead_vertices);
glNormalPointer(GL_FLOAT, 3*sizeof(GLfloat), MonkeyHead_normals);
glTexCoordPointer(2, GL_FLOAT, 2*sizeof(GLfloat), texcoords);
glDrawElements(GL_TRIANGLES, 3*MonkeyHead_num_of_triangles,
GL_UNSIGNED_SHORT, MonkeyHead_triangles);
}
static void checkForCgError(const char *situation)
{
CGerror error;
const char *string = cgGetLastErrorString(&error);
if (error != CG_NO_ERROR) {
printf("%s: %s: %s\n",
myProgramName, situation, string);
if (error == CG_COMPILER_ERROR) {
printf("%s\n", cgGetLastListing(myCgContext));
}
exit(1);
}
}
/* Forward declared GLUT callbacks registered by main. */
static void reshape(int width, int height);
static void display(void);
static void keyboard(unsigned char c, int x, int y);
static void menu(int item);
static void mouse(int button, int state, int x, int y);
static void motion(int x, int y);
/* Other forward declared functions. */
static void requestSynchronizedSwapBuffers(void);
static float diffuseRamp(float x);
static float specularRamp(float x);
static float edgeRamp(float x);
static void loadRamp(GLuint texobj, int size, float (*func)(float x));
/* Use enum to assign unique symbolic OpenGL texture names. */
enum {
TO_BOGUS = 0,
TO_DIFFUSE_RAMP,
TO_SPECULAR_RAMP,
TO_EDGE_RAMP,
};
int main(int argc, char **argv)
{
int i;
glutInitWindowSize(400, 400);
glutInitDisplayMode(GLUT_RGB | GLUT_DOUBLE | GLUT_DEPTH);
glutInit(&argc, argv);
glutCreateWindow(myProgramName);
glutDisplayFunc(display);
glutKeyboardFunc(keyboard);
glutReshapeFunc(reshape);
glutMouseFunc(mouse);
glutMotionFunc(motion);
/* Initialize OpenGL entry points. */
if (glewInit()!=GLEW_OK || !GLEW_VERSION_1_1) {
fprintf(stderr, "%s: failed to initialize GLEW, OpenGL 1.1 required.\n", myProgramName);
exit(1);
}
requestSynchronizedSwapBuffers();
glClearColor(0.1, 0.1, 0.5, 0); /* Gray background. */
glEnable(GL_DEPTH_TEST); /* Hidden surface removal. */
myCgContext = cgCreateContext();
checkForCgError("creating context");
cgGLSetDebugMode(CG_FALSE);
/* The example uses two texture units so let the Cg runtime manage
binding our samplers. */
cgGLSetManageTextureParameters(myCgContext, CG_TRUE);
cgSetParameterSettingMode(myCgContext, CG_DEFERRED_PARAMETER_SETTING);
/* Compile and load the vertex program. */
myCgVertexProfile = cgGLGetLatestProfile(CG_GL_VERTEX);
cgGLSetOptimalOptions(myCgVertexProfile);
checkForCgError("selecting vertex profile");
myCgVertexProgram =
cgCreateProgramFromFile(
myCgContext, /* Cg runtime context */
CG_SOURCE, /* Program in human-readable form */
myVertexProgramFileName, /* Name of file containing program */
myCgVertexProfile, /* Profile: OpenGL ARB vertex program */
myVertexProgramName, /* Entry function name */
NULL); /* No extra compiler options */
checkForCgError("creating vertex program from file");
cgGLLoadProgram(myCgVertexProgram);
checkForCgError("loading vertex program");
#define GET_VERT_PARAM(name) \
myCgVertexParam_##name = \
cgGetNamedParameter(myCgVertexProgram, #name); \
checkForCgError("could not get " #name " parameter");
GET_VERT_PARAM(modelViewProj);
GET_VERT_PARAM(lightPosition);
GET_VERT_PARAM(eyePosition);
GET_VERT_PARAM(shininess);
cgSetParameter1f(myCgVertexParam_shininess, shininess);
myCgFragmentProfile = cgGLGetLatestProfile(CG_GL_FRAGMENT);
cgGLSetOptimalOptions(myCgFragmentProfile);
checkForCgError("selecting fragment profile");
/* Compile and load the fragment program. */
myCgFragmentProgram =
cgCreateProgramFromFile(
myCgContext, /* Cg runtime context */
CG_SOURCE, /* Program in human-readable form */
myFragmentProgramFileName, /* Name of file containing program */
myCgFragmentProfile, /* Profile: OpenGL ARB vertex program */
myFragmentProgramName, /* Entry function name */
NULL); /* No extra compiler options */
checkForCgError("creating fragment program from file");
cgGLLoadProgram(myCgFragmentProgram);
checkForCgError("loading fragment program");
#define GET_FRAG_PARAM(name) \
myCgFragmentParam_##name = \
cgGetNamedParameter(myCgFragmentProgram, #name); \
checkForCgError("could not get " #name " parameter");
GET_FRAG_PARAM(Kd);
GET_FRAG_PARAM(Ks);
cgSetParameter4fv(myCgFragmentParam_Kd, Kd);
cgSetParameter4fv(myCgFragmentParam_Ks, Ks);
for (i=0; i<3; i++) {
static GLuint texobj[3] = { TO_DIFFUSE_RAMP, TO_SPECULAR_RAMP, TO_EDGE_RAMP };
static const char *name[3] = { "diffuseRamp", "specularRamp", "edgeRamp" };
static float (*func[3])(float x) = { diffuseRamp, specularRamp, edgeRamp };
CGparameter sampler;
sampler = cgGetNamedParameter(myCgFragmentProgram, name[i]);
checkForCgError("getting sampler ramp parameter");
loadRamp(texobj[i], 256, func[i]);
cgGLSetTextureParameter(sampler, texobj[i]);
checkForCgError("setting sampler ramp texture");
}
/* Create GLUT menu. */
glutCreateMenu(menu);
glutAddMenuEntry("[ ] Animate", ' ');
glutAddMenuEntry("[+] Increase shininess", ' ');
glutAddMenuEntry("[-] Decrease shininess", ' ');
glutAddMenuEntry("[w] Toggle wireframe", 'w');
glutAttachMenu(GLUT_RIGHT_BUTTON);
glutMainLoop();
return 0;
}
/* Callback function for loadRamp */
float diffuseRamp(float x)
{
if (x > 0.5) {
return x*x*(3-2*x);
} else {
return 0.5f;
}
}
/* Callback function for loadRamp */
float specularRamp(float x)
{
if (x > 0.2f) {
return x;
} else {
return 0.0f;
}
}
/* Callback function for loadRamp */
float edgeRamp(float x)
{
if (x < 0.2f) {
return 1.0f;
} else {
return 0.85f;
}
}
/* Create a 1D texture ramp by evaluating func over the range [0,1]. */
void loadRamp(GLuint texobj, int size, float (*func)(float x))
{
int bytesForRamp = size*sizeof(float);
float *ramp = malloc(bytesForRamp);
float *slot = ramp;
float dx = 1.0 / size;
float x;
int i;
if (NULL == ramp) {
fprintf(stderr, "%s: memory allocation failed\n", myProgramName);
exit(1);
}
for (i=0, x=0.0, slot=ramp; i<size; i++, x += dx, slot++) {
float v = func(x);
*slot = v;
}
#ifndef GL_CLAMP_TO_EDGE
#define GL_CLAMP_TO_EDGE 0x812F /* Added by OpenGL 1.2 */
#endif
glBindTexture(GL_TEXTURE_1D, texobj);
glTexImage1D(GL_TEXTURE_1D, 0, GL_INTENSITY16, size, 0, GL_LUMINANCE, GL_FLOAT, ramp);
glTexParameteri(GL_TEXTURE_1D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
glTexParameteri(GL_TEXTURE_1D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
glTexParameteri(GL_TEXTURE_1D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
}
/* Forward declared routine used by reshape callback. */
static void buildPerspectiveMatrix(double fieldOfView,
double aspectRatio,
double zMin, double zMax,
float m[16]);
static void reshape(int width, int height)
{
double aspectRatio = (float) width / (float) height;
double fieldOfView = 40.0; /* Degrees */
/* Build projection matrix once. */
buildPerspectiveMatrix(fieldOfView, aspectRatio,
1.0, 50.0, /* Znear and Zfar */
myProjectionMatrix);
glMatrixMode(GL_PROJECTION);
glLoadIdentity();
gluPerspective(fieldOfView, aspectRatio,
1.0, 50.0); /* Znear and Zfar */
glMatrixMode(GL_MODELVIEW);
glViewport(0, 0, width, height);
}
static const double myPi = 3.14159265358979323846;
static void buildPerspectiveMatrix(double fieldOfView,
double aspectRatio,
double zNear, double zFar,
float m[16])
{
double sine, cotangent, deltaZ;
double radians = fieldOfView / 2.0 * myPi / 180.0;
deltaZ = zFar - zNear;
sine = sin(radians);
/* Should be non-zero to avoid division by zero. */
assert(deltaZ);
assert(sine);
assert(aspectRatio);
cotangent = cos(radians) / sine;
m[0*4+0] = cotangent / aspectRatio;
m[0*4+1] = 0.0;
m[0*4+2] = 0.0;
m[0*4+3] = 0.0;
m[1*4+0] = 0.0;
m[1*4+1] = cotangent;
m[1*4+2] = 0.0;
m[1*4+3] = 0.0;
m[2*4+0] = 0.0;
m[2*4+1] = 0.0;
m[2*4+2] = -(zFar + zNear) / deltaZ;
m[2*4+3] = -2 * zNear * zFar / deltaZ;
m[3*4+0] = 0.0;
m[3*4+1] = 0.0;
m[3*4+2] = -1;
m[3*4+3] = 0;
}
/* Build a row-major (C-style) 4x4 matrix transform based on the
parameters for gluLookAt. */
static void buildLookAtMatrix(double eyex, double eyey, double eyez,
double centerx, double centery, double centerz,
double upx, double upy, double upz,
float m[16])
{
double x[3], y[3], z[3], mag;
/* Difference eye and center vectors to make Z vector. */
z[0] = eyex - centerx;
z[1] = eyey - centery;
z[2] = eyez - centerz;
/* Normalize Z. */
mag = sqrt(z[0]*z[0] + z[1]*z[1] + z[2]*z[2]);
if (mag) {
z[0] /= mag;
z[1] /= mag;
z[2] /= mag;
}
/* Up vector makes Y vector. */
y[0] = upx;
y[1] = upy;
y[2] = upz;
/* X vector = Y cross Z. */
x[0] = y[1]*z[2] - y[2]*z[1];
x[1] = -y[0]*z[2] + y[2]*z[0];
x[2] = y[0]*z[1] - y[1]*z[0];
/* Recompute Y = Z cross X. */
y[0] = z[1]*x[2] - z[2]*x[1];
y[1] = -z[0]*x[2] + z[2]*x[0];
y[2] = z[0]*x[1] - z[1]*x[0];
/* Normalize X. */
mag = sqrt(x[0]*x[0] + x[1]*x[1] + x[2]*x[2]);
if (mag) {
x[0] /= mag;
x[1] /= mag;
x[2] /= mag;
}
/* Normalize Y. */
mag = sqrt(y[0]*y[0] + y[1]*y[1] + y[2]*y[2]);
if (mag) {
y[0] /= mag;
y[1] /= mag;
y[2] /= mag;
}
/* Build resulting view matrix. */
m[0*4+0] = x[0]; m[0*4+1] = x[1];
m[0*4+2] = x[2]; m[0*4+3] = -x[0]*eyex + -x[1]*eyey + -x[2]*eyez;
m[1*4+0] = y[0]; m[1*4+1] = y[1];
m[1*4+2] = y[2]; m[1*4+3] = -y[0]*eyex + -y[1]*eyey + -y[2]*eyez;
m[2*4+0] = z[0]; m[2*4+1] = z[1];
m[2*4+2] = z[2]; m[2*4+3] = -z[0]*eyex + -z[1]*eyey + -z[2]*eyez;
m[3*4+0] = 0.0; m[3*4+1] = 0.0; m[3*4+2] = 0.0; m[3*4+3] = 1.0;
}
static void makeRotateMatrix(float angle,
float ax, float ay, float az,
float m[16])
{
float radians, sine, cosine, ab, bc, ca, tx, ty, tz;
float axis[3];
float mag;
axis[0] = ax;
axis[1] = ay;
axis[2] = az;
mag = sqrt(axis[0]*axis[0] + axis[1]*axis[1] + axis[2]*axis[2]);
if (mag) {
axis[0] /= mag;
axis[1] /= mag;
axis[2] /= mag;
}
radians = angle * myPi / 180.0;
sine = sin(radians);
cosine = cos(radians);
ab = axis[0] * axis[1] * (1 - cosine);
bc = axis[1] * axis[2] * (1 - cosine);
ca = axis[2] * axis[0] * (1 - cosine);
tx = axis[0] * axis[0];
ty = axis[1] * axis[1];
tz = axis[2] * axis[2];
m[0] = tx + cosine * (1 - tx);
m[1] = ab + axis[2] * sine;
m[2] = ca - axis[1] * sine;
m[3] = 0.0f;
m[4] = ab - axis[2] * sine;
m[5] = ty + cosine * (1 - ty);
m[6] = bc + axis[0] * sine;
m[7] = 0.0f;
m[8] = ca + axis[1] * sine;
m[9] = bc - axis[0] * sine;
m[10] = tz + cosine * (1 - tz);
m[11] = 0;
m[12] = 0;
m[13] = 0;
m[14] = 0;
m[15] = 1;
}
static void makeTranslateMatrix(float x, float y, float z, float m[16])
{
m[0] = 1; m[1] = 0; m[2] = 0; m[3] = x;
m[4] = 0; m[5] = 1; m[6] = 0; m[7] = y;
m[8] = 0; m[9] = 0; m[10] = 1; m[11] = z;
m[12] = 0; m[13] = 0; m[14] = 0; m[15] = 1;
}
/* Simple 4x4 matrix by 4x4 matrix multiply. */
static void multMatrix(float dst[16],
const float src1[16], const float src2[16])
{
float tmp[16];
int i, j;
for (i=0; i<4; i++) {
for (j=0; j<4; j++) {
tmp[i*4+j] = src1[i*4+0] * src2[0*4+j] +
src1[i*4+1] * src2[1*4+j] +
src1[i*4+2] * src2[2*4+j] +
src1[i*4+3] * src2[3*4+j];
}
}
/* Copy result to dst (so dst can also be src1 or src2). */
for (i=0; i<16; i++)
dst[i] = tmp[i];
}
void
loadMVP(const float modelView[16])
{
float transpose[16];
int i, j;
for (i=0; i<4; i++) {
for (j=0; j<4; j++) {
transpose[i*4+j] = modelView[j*4+i];
}
}
glLoadMatrixf(transpose);
}
static void display(void)
{
/* World-space positions for light and eye. */
const float eyePosition[4] = { 8*sin(eyeAngle),
eyeHeight,
8*cos(eyeAngle), 1 };
const float lightPosition[4] = { 2.5*sin(lightAngle),
lightHeight,
2.5*cos(lightAngle), 1 };
float translateMatrix[16], rotateMatrix[16],
modelMatrix[16], viewMatrix[16],
modelViewMatrix[16], modelViewProjMatrix[16];
buildLookAtMatrix(eyePosition[0], eyePosition[1], eyePosition[2],
0, 0, 0,
0, 1, 0,
viewMatrix);
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
cgGLEnableProfile(myCgVertexProfile);
checkForCgError("enabling vertex profile");
cgGLEnableProfile(myCgFragmentProfile);
checkForCgError("enabling fragment profile");
cgGLBindProgram(myCgVertexProgram);
checkForCgError("binding vertex program");
cgGLBindProgram(myCgFragmentProgram);
checkForCgError("binding fragment program");
/* modelView = rotateMatrix * translateMatrix */
makeRotateMatrix(headSpin, 0, 1, 0, rotateMatrix);
makeTranslateMatrix(0, 0, 0, translateMatrix);
multMatrix(modelMatrix, translateMatrix, rotateMatrix);
/* Set world-space eye position. */
cgSetParameter3fv(myCgVertexParam_eyePosition, eyePosition);
cgSetParameter3fv(myCgVertexParam_lightPosition, lightPosition);
/* modelViewMatrix = viewMatrix * modelMatrix */
multMatrix(modelViewMatrix, viewMatrix, modelMatrix);
/* modelViewProj = projectionMatrix * modelViewMatrix */
multMatrix(modelViewProjMatrix, myProjectionMatrix, modelViewMatrix);
/* Set matrix parameter with row-major matrix. */
cgSetMatrixParameterfr(myCgVertexParam_modelViewProj, modelViewProjMatrix);
cgUpdateProgramParameters(myCgVertexProgram);
drawMonkeyHead();
cgGLDisableProfile(myCgVertexProfile);
checkForCgError("disabling vertex profile");
cgGLDisableProfile(myCgFragmentProfile);
checkForCgError("disabling fragment profile");
glPushMatrix();
/* glLoadMatrixf expects a column-major matrix but Cg matrices are
row-major (matching C/C++ arrays) so used loadMVP to transpose
the Cg version. */
loadMVP(modelViewMatrix);
glTranslatef(lightPosition[0], lightPosition[1], lightPosition[2]);
glColor3f(1,1,0); /* yellow */
glutSolidSphere(0.05, 10, 10); /* sphere to represent light position */
glColor3f(1,1,1); /* reset back to white */
glPopMatrix();
glutSwapBuffers();
}
/* Spin the monkey's head when animating. */
static void idle(void)
{
headSpin -= 0.5;
if (headSpin < -360) {
headSpin += 360;
}
glutPostRedisplay();
}
static void keyboard(unsigned char c, int x, int y)
{
static int animating = 0;
static int wireframe = 0;
switch (c) {
case ' ':
animating = !animating; /* Toggle */
if (animating) {
glutIdleFunc(idle);
} else {
glutIdleFunc(NULL);
}
break;
case '+':
shininess *= 1.05;
printf("shininess = %f\n", shininess);
cgSetParameter1f(myCgVertexParam_shininess, shininess);
glutPostRedisplay();
break;
case '-':
shininess /= 1.05;
printf("shininess = %f\n", shininess);
cgSetParameter1f(myCgVertexParam_shininess, shininess);
glutPostRedisplay();
break;
case 'w':
wireframe = !wireframe; /* Toggle */
if (wireframe) {
glPolygonMode(GL_FRONT_AND_BACK, GL_LINE);
} else {
glPolygonMode(GL_FRONT_AND_BACK, GL_FILL);
}
glutPostRedisplay();
break;
case 27: /* Esc key */
/* Demonstrate proper deallocation of Cg runtime data structures.
Not strictly necessary if we are simply going to exit. */
cgDestroyProgram(myCgVertexProgram);
cgDestroyContext(myCgContext);
exit(0);
break;
}
}
static void menu(int item)
{
/* Pass menu item character code to keyboard callback. */
keyboard((unsigned char)item, 0, 0);
}
/* Use a motion and mouse GLUT callback to allow the viewer and light to
rotate around the monkey head and move the viewer up and down. */
static int beginx, beginy;
static int moving = 0;
static int movingLight = 0;
static int xLightBegin, yLightBegin;
void
motion(int x, int y)
{
const float heightBound = 8;
if (moving) {
eyeAngle += 0.005*(beginx - x);
eyeHeight += 0.01*(y - beginy);
if (eyeHeight > heightBound) {
eyeHeight = heightBound;
}
if (eyeHeight < -heightBound) {
eyeHeight = -heightBound;
}
beginx = x;
beginy = y;
glutPostRedisplay();
}
if (movingLight) {
lightAngle += 0.005*(x - xLightBegin);
lightHeight += 0.03*(yLightBegin - y);
xLightBegin = x;
yLightBegin = y;
glutPostRedisplay();
}
}
void
mouse(int button, int state, int x, int y)
{
const int spinButton = GLUT_LEFT_BUTTON,
lightButton = GLUT_MIDDLE_BUTTON;
if (button == spinButton && state == GLUT_DOWN) {
moving = 1;
beginx = x;
beginy = y;
}
if (button == spinButton && state == GLUT_UP) {
moving = 0;
}
if (button == lightButton && state == GLUT_DOWN) {
movingLight = 1;
xLightBegin = x;
yLightBegin = y;
}
if (button == lightButton && state == GLUT_UP) {
movingLight = 0;
}
}
/* Platform-specific code to request synchronized buffer swaps. */
static void requestSynchronizedSwapBuffers(void)
{
#if defined(__APPLE__)
#ifdef CGL_VERSION_1_2
const GLint sync = 1;
#else
const long sync = 1;
#endif
CGLSetParameter(CGLGetCurrentContext(), kCGLCPSwapInterval, &sync);
#elif defined(_WIN32)
if (wglSwapIntervalEXT) {
wglSwapIntervalEXT(1);
}
#else
if (glXSwapIntervalSGI) {
glXSwapIntervalSGI(1);
}
#endif
}
