void CMirror::drawMirrorImage(void (*drawScene)(), const CLighting& lighting)
{
glClear(GL_STENCIL_BUFFER_BIT);
if (showMirror)
{
// Don't update color or depth.
glDisable(GL_DEPTH_TEST);
glColorMask(GL_FALSE, GL_FALSE, GL_FALSE, GL_FALSE);
// Draw 1 into the stencil buffer.
glEnable(GL_STENCIL_TEST);
glStencilOp(GL_REPLACE, GL_REPLACE, GL_REPLACE);
glStencilFunc(GL_ALWAYS, 1, 0xffffffff);
// Now render mirror; mirror pixels just get their stencil set to 1.
glEnable(GL_CULL_FACE);
drawMirror(MIRROR_FRONT);
glDisable(GL_CULL_FACE);
// Re-enable update of color and depth.
glColorMask(GL_TRUE, GL_TRUE, GL_TRUE, GL_TRUE);
glEnable(GL_DEPTH_TEST);
// Now, only render where stencil is set to 1.
glStencilFunc(GL_EQUAL, 1, 0xffffffff); // draw if ==1
glStencilOp(GL_KEEP, GL_KEEP, GL_KEEP);
glPushMatrix();
applyReflectionMatrix();
lighting.init(); // mirror light sources
drawScene(); // render the reflected scene
glPopMatrix();
glDisable(GL_STENCIL_TEST);
lighting.init(); // back to the original light sources
// Back face culling will get used to only draw either the front side or the
// back side of the mirror. This let's us get a mirror with two distinct
// appearances. The front surface is reflective and kind of grayish.
// The back surface is not reflective and blue.
// Draw "back" of mirror in blue.
glColor4f(0.1f, 0.1f, 0.5f, 1.0f);
glEnable(GL_CULL_FACE);
glCullFace(GL_FRONT);
drawMirror(MIRROR_BACK);
glCullFace(GL_BACK);
glDisable(GL_CULL_FACE);
// Draw the mirror with stencil value 3.
glEnable(GL_STENCIL_TEST);
glStencilFunc(GL_ALWAYS, 3, 0xffffffff);
glStencilOp(GL_KEEP, GL_KEEP, GL_REPLACE);
// Draw reflective side of mirror. Use blending to blend in reflection.
glEnable(GL_BLEND);
glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
glColor4f(0.9, 0.9, 0.9, 0.3);
glCullFace(GL_BACK);
drawMirror(MIRROR_FRONT);
glDisable(GL_BLEND);
drawMirror(MIRROR_BOUNDARY);
}
}
void drawScene()
{
int i;
ground.draw();
for(i=0;i<numTrees;i++) trees[i].draw();
glShadeModel(GL_SMOOTH);
lighting.enable();
for(i=0;i<numFlowers;i++) flowers[i].draw();
monument.draw();
ball1.draw();
ball2.draw();
lighting.disable();
}
void init(void)
{
// select clearing color (for glClear)
glClearColor (1.0, 1.0, 1.0, 0.0); // RGB-value for white
// initialize view (simple perspective projection)
glMatrixMode(GL_PROJECTION);
glLoadIdentity();
gluPerspective(6.0, (GLfloat) windowWidth/(GLfloat) windowHeight, 5.0, 55.0);
gluLookAt(0,0,45, -0.8,0.2,0, 0,1,0);
trackball.tbInit(GLUT_LEFT_BUTTON);
lighting.init();
// Initialise balls
ball1.setPosition(CVec3df(-2,0,-1));
ball1.setVelocity(CVec3df(25,0,0));
ball2.setPosition(CVec3df(2,0.20,-1));
ball2.setVelocity(CVec3df(-33,30,0));
ball1.setMass(2.25);
ball2.setMass(1);
// Distribute trees randomly over the front half of the ground plane such
// that the minimum distance between any two trees is at least minDistanceTrees
GLfloat x,z,xx,zz; // (x,z) positions of trees
bool validPosition;
int i;
for(i=0;i<numTrees;i++)
{
do {
validPosition=true;
x=(GLfloat) randomDouble(-1.95,1.95);
z=(GLfloat) randomDouble(0,1.95);
for(int j=0;j<i;j++)
{ // position is valid if the distance between the trunks of each tree is at least minDistanceTrees
trees[j].getPosition(xx,zz);
if (sqrt((xx-x)*(xx-x)+(zz-z)*(zz-z))<minDistanceTrees) { validPosition=false; break;}
}
} while (validPosition==false);
trees[i].setPosition(x,z);
}
// Distribute flowers randomly over the back half of the ground plane such
// that the minimum distance between any two flowers is at least minDistanceFlowers
// x,z,xx,zz; // (x,z) positions of trees
for(i=0;i<numFlowers;i++)
{
do {
validPosition=true;
x=(GLfloat) randomDouble(-1.95,1.95);
z=(GLfloat) randomDouble(-1.8,-1.1);
for(int j=0;j<i;j++)
{ // position is valid if the distance between the stems of each tree is at least minDistanceFlowers
flowers[j].getPosition(xx,zz);
if (sqrt((xx-x)*(xx-x)+(zz-z)*(zz-z))<minDistanceFlowers) { validPosition=false; break;}
}
} while (validPosition==false);
flowers[i].setPosition(x,z);
}
// initialise three texture names
glPixelStorei(GL_UNPACK_ALIGNMENT, 1);
glGenTextures(3, texName);
ground.setTexture(texName[0]);
monument.setTexture(texName[1]);
trees[0].setTexture(texName[2]);
}
