void DrawGLScene() // Main Drawing Routine
{
GLmatrix16f Minv, Inv;
GLvector4f lp;
// Clear Color Buffer, Depth Buffer, Stencil Buffer
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT | GL_STENCIL_BUFFER_BIT);
glColor4f(0.7f, 0.4f, 0.0f, 1.0f);
glLoadIdentity();
glPushMatrix(); {
glTranslatef(0.0f, 0.0f, -20.0f); // Zoom Into Screen 20 Units
glLightfv(GL_LIGHT1, GL_POSITION, LightPos); // Position Light1
glTranslatef(SpherePos[0], SpherePos[1], SpherePos[2]); // Position The Sphere
gluSphere(q, 1.5f, 32, 16); // Draw A Sphere
} glPopMatrix();
glPushMatrix(); {
glTranslatef(0.0f, 0.0f, -20.0f); // Zoom Into The Screen 20 Units
DrawGLRoom(); // Draw The Room
glTranslatef(ObjPos[0], ObjPos[1], ObjPos[2]); // Position The Object
glRotatef(xrot, 1.0f, 0.0f, 0.0f); // Spin It On The X Axis By xrot
glRotatef(yrot, 0.0f, 1.0f, 0.0f); // Spin It On The Y Axis By yrot
DrawGLObject(obj); // Procedure For Drawing The Loaded Object
// 获得光源的位置(返回值是在视觉坐标系下的)
glGetLightfv(GL_LIGHT1, GL_POSITION, lp);
glGetFloatv(GL_MODELVIEW_MATRIX, Minv);
m3dInvertMatrix44(Inv, Minv);
// 把光源位置从视觉坐标系下变换到当前的场景坐标系(obj)下.
VMatMult(Inv, lp);
// 开始渲染阴影
CastShadow(&obj, lp);
// 用一个小黄球标记出光源的位置
glPushMatrix(); {
glColor4f(0.7f, 0.4f, 0.0f, 1.0f); // Set Color To Purplish Blue
glDisable(GL_LIGHTING); // Disable Lighting
glDepthMask(GL_FALSE); // Disable Depth Mask
glTranslatef(lp[0], lp[1], lp[2]);
gluSphere(q, 0.2f, 16, 8);
glEnable(GL_LIGHTING); // Enable Lighting
glDepthMask(GL_TRUE); // Enable Depth Mask
} glPopMatrix();
} glPopMatrix();
xrot += xspeed;
yrot += yspeed;
glFlush();
glutSwapBuffers();
}
bool doMesh2TexelUnits(void) {
GLfloat c[4]={0.0f,0.0f,0.0f,1.0f}; // holds current vertex
GLfloat n[4]={0.0f,0.0f,0.0f,1.0f}; // normalized normal of current surface
GLfloat s[4]={0.0f,0.0f,0.0f,1.0f}; // s-texture coordinate direction, normalized
GLfloat t[4]={0.0f,0.0f,0.0f,1.0f}; // t-texture coordinate direction, normalized
GLfloat l[4]; // holds our lightposition to be transformed into object space
GLfloat Minv[16]; // holds the inverted modelview matrix to do so.
int i;
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT); // Clear The Screen And The Depth Buffer
// Build Inverse Modelview Matrix First. This Substitutes One Push/Pop With One glLoadIdentity();
// Simply Build It By Doing All Transformations Negated And In Reverse Order.
glLoadIdentity();
glRotatef(-yrot,0.0f,1.0f,0.0f);
glRotatef(-xrot,1.0f,0.0f,0.0f);
glTranslatef(0.0f,0.0f,-z);
glGetFloatv(GL_MODELVIEW_MATRIX,Minv);
glLoadIdentity();
glTranslatef(0.0f,0.0f,z);
glRotatef(xrot,1.0f,0.0f,0.0f);
glRotatef(yrot,0.0f,1.0f,0.0f);
// Transform The Lightposition Into Object Coordinates:
l[0]=LightPosition[0];
l[1]=LightPosition[1];
l[2]=LightPosition[2];
l[3]=1.0f; // Homogenous Coordinate
VMatMult(Minv,l);
/* PASS#1: Texel-Unit 0: Use Texture "Bump"
No Blend
No Lighting
No Offset Texture-Coordinates
Texture-Operation "Replace"
Texel-Unit 1: Use Texture "Invbump"
No Lighting
Offset Texture Coordinates
Texture-Operation "Replace"
*/
// TEXTURE-UNIT #0
glActiveTextureARB(GL_TEXTURE0_ARB);
glEnable(GL_TEXTURE_2D);
glBindTexture(GL_TEXTURE_2D, bump[filter]);
glTexEnvf(GL_TEXTURE_ENV, (GLenum)GL_TEXTURE_ENV_MODE, GL_COMBINE_EXT);
glTexEnvf(GL_TEXTURE_ENV, (GLenum)GL_COMBINE_RGB_EXT, GL_REPLACE);
// TEXTURE-UNIT #1:
glActiveTextureARB(GL_TEXTURE1_ARB);
glEnable(GL_TEXTURE_2D);
glBindTexture(GL_TEXTURE_2D, invbump[filter]);
glTexEnvf (GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_COMBINE_EXT);
glTexEnvf (GL_TEXTURE_ENV, (GLenum)GL_COMBINE_RGB_EXT, GL_ADD);
// General Switches:
glDisable(GL_BLEND);
glDisable(GL_LIGHTING);
glBegin(GL_QUADS);
// Front Face
n[0]=0.0f; n[1]=0.0f; n[2]=1.0f;
s[0]=1.0f; s[1]=0.0f; s[2]=0.0f;
t[0]=0.0f; t[1]=1.0f; t[2]=0.0f;
for (i=0; i<4; i++) {
c[0]=data[5*i+2];
c[1]=data[5*i+3];
c[2]=data[5*i+4];
SetUpBumps(n,c,l,s,t);
glMultiTexCoord2fARB(GL_TEXTURE0_ARB,data[5*i] , data[5*i+1]);
glMultiTexCoord2fARB(GL_TEXTURE1_ARB,data[5*i]+c[0], data[5*i+1]+c[1]);
glVertex3f(data[5*i+2], data[5*i+3], data[5*i+4]);
}
// Back Face
n[0]=0.0f; n[1]=0.0f; n[2]=-1.0f;
s[0]=-1.0f; s[1]=0.0f; s[2]=0.0f;
t[0]=0.0f; t[1]=1.0f; t[2]=0.0f;
for (i=4; i<8; i++) {
c[0]=data[5*i+2];
c[1]=data[5*i+3];
c[2]=data[5*i+4];
SetUpBumps(n,c,l,s,t);
glMultiTexCoord2fARB(GL_TEXTURE0_ARB,data[5*i] , data[5*i+1]);
glMultiTexCoord2fARB(GL_TEXTURE1_ARB,data[5*i]+c[0], data[5*i+1]+c[1]);
glVertex3f(data[5*i+2], data[5*i+3], data[5*i+4]);
}
// Top Face
n[0]=0.0f; n[1]=1.0f; n[2]=0.0f;
s[0]=1.0f; s[1]=0.0f; s[2]=0.0f;
t[0]=0.0f; t[1]=0.0f; t[2]=-1.0f;
for (i=8; i<12; i++) {
c[0]=data[5*i+2];
c[1]=data[5*i+3];
c[2]=data[5*i+4];
SetUpBumps(n,c,l,s,t);
glMultiTexCoord2fARB(GL_TEXTURE0_ARB,data[5*i] , data[5*i+1] );
glMultiTexCoord2fARB(GL_TEXTURE1_ARB,data[5*i]+c[0], data[5*i+1]+c[1]);
glVertex3f(data[5*i+2], data[5*i+3], data[5*i+4]);
}
// Bottom Face
n[0]=0.0f; n[1]=-1.0f; n[2]=0.0f;
s[0]=-1.0f; s[1]=0.0f; s[2]=0.0f;
t[0]=0.0f; t[1]=0.0f; t[2]=-1.0f;
for (i=12; i<16; i++) {
c[0]=data[5*i+2];
c[1]=data[5*i+3];
c[2]=data[5*i+4];
SetUpBumps(n,c,l,s,t);
glMultiTexCoord2fARB(GL_TEXTURE0_ARB,data[5*i] , data[5*i+1] );
glMultiTexCoord2fARB(GL_TEXTURE1_ARB,data[5*i]+c[0], data[5*i+1]+c[1]);
glVertex3f(data[5*i+2], data[5*i+3], data[5*i+4]);
}
// Right Face
n[0]=1.0f; n[1]=0.0f; n[2]=0.0f;
s[0]=0.0f; s[1]=0.0f; s[2]=-1.0f;
t[0]=0.0f; t[1]=1.0f; t[2]=0.0f;
for (i=16; i<20; i++) {
c[0]=data[5*i+2];
c[1]=data[5*i+3];
c[2]=data[5*i+4];
SetUpBumps(n,c,l,s,t);
glMultiTexCoord2fARB(GL_TEXTURE0_ARB,data[5*i] , data[5*i+1] );
glMultiTexCoord2fARB(GL_TEXTURE1_ARB,data[5*i]+c[0], data[5*i+1]+c[1]);
glVertex3f(data[5*i+2], data[5*i+3], data[5*i+4]);
}
// Left Face
n[0]=-1.0f; n[1]=0.0f; n[2]=0.0f;
s[0]=0.0f; s[1]=0.0f; s[2]=1.0f;
t[0]=0.0f; t[1]=1.0f; t[2]=0.0f;
for (i=20; i<24; i++) {
c[0]=data[5*i+2];
c[1]=data[5*i+3];
c[2]=data[5*i+4];
SetUpBumps(n,c,l,s,t);
glMultiTexCoord2fARB(GL_TEXTURE0_ARB,data[5*i] , data[5*i+1] );
glMultiTexCoord2fARB(GL_TEXTURE1_ARB,data[5*i]+c[0], data[5*i+1]+c[1]);
glVertex3f(data[5*i+2], data[5*i+3], data[5*i+4]);
}
glEnd();
/* PASS#2 Use Texture "Base"
Blend GL_DST_COLOR To GL_SRC_COLOR (Multiplies By 2)
Lighting Enabled
No Offset Texture-Coordinates
*/
glActiveTextureARB(GL_TEXTURE1_ARB);
glDisable(GL_TEXTURE_2D);
glActiveTextureARB(GL_TEXTURE0_ARB);
if (!emboss) {
glTexEnvf (GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_MODULATE);
glBindTexture(GL_TEXTURE_2D,texture[filter]);
glBlendFunc(GL_DST_COLOR,GL_SRC_COLOR);
glEnable(GL_BLEND);
glEnable(GL_LIGHTING);
doCube();
}
xrot+=xspeed;
yrot+=yspeed;
if (xrot>360.0f) xrot-=360.0f;
if (xrot<0.0f) xrot+=360.0f;
if (yrot>360.0f) yrot-=360.0f;
if (yrot<0.0f) yrot+=360.0f;
/* LAST PASS: Do The Logos! */
doLogo();
return true; // Keep Going
}
bool doMesh1TexelUnits(void) {
GLfloat c[4]={0.0f,0.0f,0.0f,1.0f}; // Holds Current Vertex
GLfloat n[4]={0.0f,0.0f,0.0f,1.0f}; // Normalized Normal Of Current Surface
GLfloat s[4]={0.0f,0.0f,0.0f,1.0f}; // s-Texture Coordinate Direction, Normalized
GLfloat t[4]={0.0f,0.0f,0.0f,1.0f}; // t-Texture Coordinate Direction, Normalized
GLfloat l[4]; // Holds Our Lightposition To Be Transformed Into Object Space
GLfloat Minv[16]; // Holds The Inverted Modelview Matrix To Do So.
int i;
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT); // Clear The Screen And The Depth Buffer
// Build Inverse Modelview Matrix First. This Substitutes One Push/Pop With One glLoadIdentity();
// Simply Build It By Doing All Transformations Negated And In Reverse Order.
glLoadIdentity();
glRotatef(-yrot,0.0f,1.0f,0.0f);
glRotatef(-xrot,1.0f,0.0f,0.0f);
glTranslatef(0.0f,0.0f,-z);
glGetFloatv(GL_MODELVIEW_MATRIX,Minv);
glLoadIdentity();
glTranslatef(0.0f,0.0f,z);
glRotatef(xrot,1.0f,0.0f,0.0f);
glRotatef(yrot,0.0f,1.0f,0.0f);
// Transform The Lightposition Into Object Coordinates:
l[0]=LightPosition[0];
l[1]=LightPosition[1];
l[2]=LightPosition[2];
l[3]=1.0f; // Homogenous Coordinate
VMatMult(Minv,l);
/* PASS#1: Use Texture "Bump"
No Blend
No Lighting
No Offset Texture-Coordinates */
glBindTexture(GL_TEXTURE_2D, bump[filter]);
glDisable(GL_BLEND);
glDisable(GL_LIGHTING);
doCube();
/* PASS#2: Use Texture "Invbump"
Blend GL_ONE To GL_ONE
No Lighting
Offset Texture Coordinates
*/
glBindTexture(GL_TEXTURE_2D,invbump[filter]);
glBlendFunc(GL_ONE,GL_ONE);
glDepthFunc(GL_LEQUAL);
glEnable(GL_BLEND);
glBegin(GL_QUADS);
// Front Face
n[0]=0.0f; n[1]=0.0f; n[2]=1.0f;
s[0]=1.0f; s[1]=0.0f; s[2]=0.0f;
t[0]=0.0f; t[1]=1.0f; t[2]=0.0f;
for (i=0; i<4; i++) {
c[0]=data[5*i+2];
c[1]=data[5*i+3];
c[2]=data[5*i+4];
SetUpBumps(n,c,l,s,t);
glTexCoord2f(data[5*i]+c[0], data[5*i+1]+c[1]);
glVertex3f(data[5*i+2], data[5*i+3], data[5*i+4]);
}
// Back Face
n[0]=0.0f; n[1]=0.0f; n[2]=-1.0f;
s[0]=-1.0f; s[1]=0.0f; s[2]=0.0f;
t[0]=0.0f; t[1]=1.0f; t[2]=0.0f;
for (i=4; i<8; i++) {
c[0]=data[5*i+2];
c[1]=data[5*i+3];
c[2]=data[5*i+4];
SetUpBumps(n,c,l,s,t);
glTexCoord2f(data[5*i]+c[0], data[5*i+1]+c[1]);
glVertex3f(data[5*i+2], data[5*i+3], data[5*i+4]);
}
// Top Face
n[0]=0.0f; n[1]=1.0f; n[2]=0.0f;
s[0]=1.0f; s[1]=0.0f; s[2]=0.0f;
t[0]=0.0f; t[1]=0.0f; t[2]=-1.0f;
for (i=8; i<12; i++) {
c[0]=data[5*i+2];
c[1]=data[5*i+3];
c[2]=data[5*i+4];
SetUpBumps(n,c,l,s,t);
glTexCoord2f(data[5*i]+c[0], data[5*i+1]+c[1]);
glVertex3f(data[5*i+2], data[5*i+3], data[5*i+4]);
}
// Bottom Face
n[0]=0.0f; n[1]=-1.0f; n[2]=0.0f;
s[0]=-1.0f; s[1]=0.0f; s[2]=0.0f;
t[0]=0.0f; t[1]=0.0f; t[2]=-1.0f;
for (i=12; i<16; i++) {
c[0]=data[5*i+2];
c[1]=data[5*i+3];
c[2]=data[5*i+4];
SetUpBumps(n,c,l,s,t);
glTexCoord2f(data[5*i]+c[0], data[5*i+1]+c[1]);
glVertex3f(data[5*i+2], data[5*i+3], data[5*i+4]);
}
// Right Face
n[0]=1.0f; n[1]=0.0f; n[2]=0.0f;
s[0]=0.0f; s[1]=0.0f; s[2]=-1.0f;
t[0]=0.0f; t[1]=1.0f; t[2]=0.0f;
for (i=16; i<20; i++) {
c[0]=data[5*i+2];
c[1]=data[5*i+3];
c[2]=data[5*i+4];
SetUpBumps(n,c,l,s,t);
glTexCoord2f(data[5*i]+c[0], data[5*i+1]+c[1]);
glVertex3f(data[5*i+2], data[5*i+3], data[5*i+4]);
}
// Left Face
n[0]=-1.0f; n[1]=0.0f; n[2]=0.0f;
s[0]=0.0f; s[1]=0.0f; s[2]=1.0f;
t[0]=0.0f; t[1]=1.0f; t[2]=0.0f;
for (i=20; i<24; i++) {
c[0]=data[5*i+2];
c[1]=data[5*i+3];
c[2]=data[5*i+4];
SetUpBumps(n,c,l,s,t);
glTexCoord2f(data[5*i]+c[0], data[5*i+1]+c[1]);
glVertex3f(data[5*i+2], data[5*i+3], data[5*i+4]);
}
glEnd();
/* PASS#3: Use Texture "Base"
Blend GL_DST_COLOR To GL_SRC_COLOR (Multiplies By 2)
Lighting Enabled
No Offset Texture-Coordinates
*/
if (!emboss) {
glTexEnvf (GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_MODULATE);
glBindTexture(GL_TEXTURE_2D,texture[filter]);
glBlendFunc(GL_DST_COLOR,GL_SRC_COLOR);
glEnable(GL_LIGHTING);
doCube();
}
xrot+=xspeed;
yrot+=yspeed;
if (xrot>360.0f) xrot-=360.0f;
if (xrot<0.0f) xrot+=360.0f;
if (yrot>360.0f) yrot-=360.0f;
if (yrot<0.0f) yrot+=360.0f;
/* LAST PASS: Do The Logos! */
doLogo();
return true; // Keep Going
}
void SceneTutorial27::Draw()
{
Scene::Draw();
float Minv[16];
float wlp[4];
float lp[4];
// Clear Color Buffer, Depth Buffer, Stencil Buffer
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT | GL_STENCIL_BUFFER_BIT);
glLoadIdentity(); // Reset Modelview Matrix
glTranslatef(0.0f, 0.0f, -20.0f); // Zoom Into Screen 20 Units
glLightfv(GL_LIGHT1, GL_POSITION, LightPos); // Position Light1
glTranslatef(SpherePos[0], SpherePos[1], SpherePos[2]); // Position The Sphere
gluSphere(q, 1.5f, 32, 16); // Draw A Sphere
// calculate light's position relative to local coordinate system
// dunno if this is the best way to do it, but it actually works
// if u find another aproach, let me know ;)
// we build the inversed matrix by doing all the actions in reverse order
// and with reverse parameters (notice -xrot, -yrot, -ObjPos[], etc.)
glLoadIdentity(); // Reset Matrix
glRotatef(-yrot, 0.0f, 1.0f, 0.0f); // Rotate By -yrot On Y Axis
glRotatef(-xrot, 1.0f, 0.0f, 0.0f); // Rotate By -xrot On X Axis
glGetFloatv(GL_MODELVIEW_MATRIX,Minv); // Retrieve ModelView Matrix (Stores In Minv)
lp[0] = LightPos[0]; // Store Light Position X In lp[0]
lp[1] = LightPos[1]; // Store Light Position Y In lp[1]
lp[2] = LightPos[2]; // Store Light Position Z In lp[2]
lp[3] = LightPos[3]; // Store Light Direction In lp[3]
VMatMult(Minv, lp); // We Store Rotated Light Vector In 'lp' Array
glTranslatef(-ObjPos[0], -ObjPos[1], -ObjPos[2]); // Move Negative On All Axis Based On ObjPos[] Values (X, Y, Z)
glGetFloatv(GL_MODELVIEW_MATRIX,Minv); // Retrieve ModelView Matrix From Minv
wlp[0] = 0.0f; // World Local Coord X To 0
wlp[1] = 0.0f; // World Local Coord Y To 0
wlp[2] = 0.0f; // World Local Coord Z To 0
wlp[3] = 1.0f;
VMatMult(Minv, wlp); // We Store The Position Of The World Origin Relative To The
// Local Coord. System In 'wlp' Array
lp[0] += wlp[0]; // Adding These Two Gives Us The
lp[1] += wlp[1]; // Position Of The Light Relative To
lp[2] += wlp[2]; // The Local Coordinate System
glColor4f(0.7f, 0.4f, 0.0f, 1.0f); // Set Color To An Orange
glLoadIdentity(); // Reset Modelview Matrix
glTranslatef(0.0f, 0.0f, -20.0f); // Zoom Into The Screen 20 Units
DrawGLRoom(); // Draw The Room
glTranslatef(ObjPos[0], ObjPos[1], ObjPos[2]); // Position The Object
glRotatef(xrot, 1.0f, 0.0f, 0.0f); // Spin It On The X Axis By xrot
glRotatef(yrot, 0.0f, 1.0f, 0.0f); // Spin It On The Y Axis By yrot
DrawShadowedObject(obj); // Procedure For Drawing The Loaded Object
castShadow(obj, lp ); // Procedure For Casting The Shadow Based On The Silhouette
glColor4f(0.7f, 0.4f, 0.0f, 1.0f); // Set Color To Purplish Blue
glDisable(GL_LIGHTING); // Disable Lighting
glDepthMask(GL_FALSE); // Disable Depth Mask
glTranslatef(lp[0], lp[1], lp[2]); // Translate To Light's Position
// Notice We're Still In Local Coordinate System
gluSphere(q, 0.2f, 16, 8); // Draw A Little Yellow Sphere (Represents Light)
glEnable(GL_LIGHTING); // Enable Lighting
glDepthMask(GL_TRUE); // Enable Depth Mask
glutSwapBuffers();
}