void ChangeSize(int w, int h)
{
GLint i;
windowWidth = shadowWidth = w;
windowHeight = shadowHeight = h;
if (!npotTexturesAvailable)
{
// Find the largest power of two that will fit in window.
// Try each width until we get one that's too big
i = 0;
while ((1 << i) <= shadowWidth)
i++;
shadowWidth = (1 << (i-1));
// Now for height
i = 0;
while ((1 << i) <= shadowHeight)
i++;
shadowHeight = (1 << (i-1));
}
if (shadowWidth > maxTexSize)
{
shadowWidth = maxTexSize;
}
if (shadowHeight > maxTexSize)
{
shadowHeight = maxTexSize;
}
RegenerateShadowMap();
}
void SpecialKeys(int key, int x, int y)
{
switch (key)
{
case GLUT_KEY_LEFT:
if (controlCamera)
cameraPos[0] -= 5.0f;
else
lightPos[0] -= 5.0f;
break;
case GLUT_KEY_RIGHT:
if (controlCamera)
cameraPos[0] += 5.0f;
else
lightPos[0] += 5.0f;
break;
case GLUT_KEY_UP:
if (controlCamera)
cameraPos[2] -= 5.0f;
else
lightPos[2] -= 5.0f;
break;
case GLUT_KEY_DOWN:
if (controlCamera)
cameraPos[2] += 5.0f;
else
lightPos[2] += 5.0f;
break;
default:
break;
}
// We don't need to regenerate the shadow map
// if only the camera angle changes
if (!controlCamera)
RegenerateShadowMap();
// Refresh the Window
glutPostRedisplay();
}
// This function does any needed initialization on the rendering
// context.
void SetupRC()
{
fprintf(stdout, "Shadow Mapping Demo\n\n");
// Make sure required functionality is available!
if (!GLEE_VERSION_1_4 && !GLEE_ARB_shadow)
{
fprintf(stderr, "Neither OpenGL 1.4 nor GL_ARB_shadow"
" extension is available!\n");
Sleep(2000);
exit(0);
}
// Check for optional extensions
if (GLEE_ARB_shadow_ambient)
{
ambientShadowAvailable = GL_TRUE;
}
else
{
fprintf(stderr, "GL_ARB_shadow_ambient extension not available!\n");
fprintf(stderr, "Extra ambient rendering pass will be required.\n\n");
Sleep(2000);
}
if (GLEE_VERSION_2_0 || GLEE_ARB_texture_non_power_of_two)
{
npotTexturesAvailable = GL_TRUE;
}
else
{
fprintf(stderr, "Neither OpenGL 2.0 nor GL_ARB_texture_non_power_of_two extension\n");
fprintf(stderr, "is available! Shadow map will be lower resolution (lower quality).\n\n");
Sleep(2000);
}
glGetIntegerv(GL_MAX_TEXTURE_SIZE, &maxTexSize);
fprintf(stdout, "Controls:\n");
fprintf(stdout, "\tRight-click for menu\n\n");
fprintf(stdout, "\tx/X\t\tMove +/- in x direction\n");
fprintf(stdout, "\ty/Y\t\tMove +/- in y direction\n");
fprintf(stdout, "\tz/Z\t\tMove +/- in z direction\n\n");
fprintf(stdout, "\tf/F\t\tChange polygon offset factor +/-\n\n");
fprintf(stdout, "\tq\t\tExit demo\n\n");
// Black background
glClearColor(0.0f, 0.0f, 0.0f, 1.0f );
// Hidden surface removal
glEnable(GL_DEPTH_TEST);
glDepthFunc(GL_LEQUAL);
glPolygonOffset(factor, 0.0f);
// Set up some lighting state that never changes
glShadeModel(GL_SMOOTH);
glEnable(GL_LIGHTING);
glEnable(GL_COLOR_MATERIAL);
glEnable(GL_NORMALIZE);
glEnable(GL_LIGHT0);
// Set up some texture state that never changes
glGenTextures(1, &shadowTextureID);
glBindTexture(GL_TEXTURE_2D, shadowTextureID);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
glTexParameteri(GL_TEXTURE_2D, GL_DEPTH_TEXTURE_MODE, GL_INTENSITY);
if (ambientShadowAvailable)
glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_COMPARE_FAIL_VALUE_ARB,
0.5f);
glTexGeni(GL_S, GL_TEXTURE_GEN_MODE, GL_EYE_LINEAR);
glTexGeni(GL_T, GL_TEXTURE_GEN_MODE, GL_EYE_LINEAR);
glTexGeni(GL_R, GL_TEXTURE_GEN_MODE, GL_EYE_LINEAR);
glTexGeni(GL_Q, GL_TEXTURE_GEN_MODE, GL_EYE_LINEAR);
RegenerateShadowMap();
}
void KeyPressFunc(unsigned char key, int x, int y)
{
switch (key)
{
case 'f':
factor++;
glPolygonOffset(factor, 0.0f);
RegenerateShadowMap();
break;
case 'F':
factor--;
glPolygonOffset(factor, 0.0f);
RegenerateShadowMap();
break;
case 'x':
if (controlCamera)
cameraPos[0] += 5.0f;
else
lightPos[0] += 5.0f;
break;
case 'X':
if (controlCamera)
cameraPos[0] -= 5.0f;
else
lightPos[0] -= 5.0f;
break;
case 'y':
if (controlCamera)
cameraPos[1] += 5.0f;
else
lightPos[1] += 5.0f;
break;
case 'Y':
if (controlCamera)
cameraPos[1] -= 5.0f;
else
lightPos[1] -= 5.0f;
break;
case 'z':
if (controlCamera)
cameraPos[2] += 5.0f;
else
lightPos[2] += 5.0f;
break;
case 'Z':
if (controlCamera)
cameraPos[2] -= 5.0f;
else
lightPos[2] -= 5.0f;
break;
case 'q':
case 'Q':
case 27 : /* ESC */
exit(0);
}
// We don't need to regenerate the shadow map
// if only the camera angle changes
if (!controlCamera)
RegenerateShadowMap();
// Refresh the Window
glutPostRedisplay();
}
void myDisplay()
{
RegenerateShadowMap();
glMatrixMode(GL_PROJECTION);
glLoadIdentity();
gluPerspective(45.0, (double)gWinWidth/(double)gWinHeight, 0.1, 1000.0);
glMatrixMode(GL_MODELVIEW);
glLoadIdentity();
caculateCameraView(gViewMode);
camera.view();
glViewport(0, 0, gWinWidth, gWinHeight);
glPushMatrix();
glTranslatef(lightPosition[0], lightPosition[1], lightPosition[2]);
glColor3ub(255, 255, 40);
gluSphere(gluNewQuadric(), 1.0, 60, 60);
glPopMatrix();
//------------------------------------------------------------------
// Track light position
glLightfv(GL_LIGHT0, GL_POSITION, lightPosition);
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
// Because there is no support for an "ambient"
// shadow compare fail value, we'll have to
// draw an ambient pass first...
glLightfv(GL_LIGHT0, GL_AMBIENT, lowAmbient);
glLightfv(GL_LIGHT0, GL_DIFFUSE, lowDiffuse);
// Draw objects in the scene
draw();
glLightfv(GL_LIGHT0, GL_AMBIENT, ambientLight);
glLightfv(GL_LIGHT0, GL_DIFFUSE, diffuseLight);
// Set up shadow comparison
glEnable(GL_TEXTURE_2D);
glTexEnvi(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_MODULATE);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_COMPARE_MODE, GL_COMPARE_R_TO_TEXTURE);
// Enable alpha test so that shadowed fragments are discarded
glAlphaFunc(GL_GREATER, 0.9f);
glEnable(GL_ALPHA_TEST);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
//glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
//glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
// Set up the eye plane for projecting the shadow map on the scene
glEnable(GL_TEXTURE_GEN_S);
glEnable(GL_TEXTURE_GEN_T);
glEnable(GL_TEXTURE_GEN_R);
glEnable(GL_TEXTURE_GEN_Q);
glTexGenfv(GL_S, GL_EYE_PLANE, sPlane);
glTexGenfv(GL_T, GL_EYE_PLANE, tPlane);
glTexGenfv(GL_R, GL_EYE_PLANE, rPlane);
glTexGenfv(GL_Q, GL_EYE_PLANE, qPlane);
// Draw objects in the scene
draw();
glDisable(GL_ALPHA_TEST);
glDisable(GL_TEXTURE_2D);
glDisable(GL_TEXTURE_GEN_S);
glDisable(GL_TEXTURE_GEN_T);
glDisable(GL_TEXTURE_GEN_R);
glDisable(GL_TEXTURE_GEN_Q);
// Flush drawing commands
glutSwapBuffers();
}
