在这段代码中，我试图根据可以移动的灯光的位置适当地为表面着色。因此，当您移动灯光时，曲面会更新。另外，我希望有两个不同颜色的灯光都在同一表面上着色。不幸的是，表面颜色仍然是静态的。
我想要的东西：
1）在移动灯光时使表面更新，并使用将同时使用两种颜色的矢量（我不是100％做到这一点）。
2）不管阴影/灯光如何，使灯光和法线保持静态颜色。
#include <math.h>
#include <stdio.h>
#include <stdlib.h>
#include <iostream>
#ifdef MAC
#include <GLUT/glut.h>
#else
#include <GL/glut.h>
#endif
//Camera variables
int xangle = -270;
int yangle = 0;
//Control Modes (Rotate mode by default)
int mode = 0;
int lightmode = 0;
//Player Position (Y offset so it would not be straddling the grid)
float cubeX = 0;
float cubeY = 0.5;
float cubeZ = 0;
//Vertex arrays for surface
float surfaceX [12][12];
float surfaceY [12][12];
float surfaceZ [12][12];
//Surface Normal arrays
float Nx[11][11];
float Ny[11][11];
float Nz[11][11];
//Color arrays
float R[11][11];
float G[11][11];
float B[11][11];
//Material properties
float Ka = 0.2;
float Kd = 0.4;
float Ks = 0.4;
float Kp = 0.5;
//Light position and color variables
float Light1x = 0;
float Light1y = 5;
float Light1z = 0;
float Light1r = 1;
float Light1g = 0;
float Light1b = 0;
float Light2x = -5;
float Light2y = 5;
float Light2z = -5;
float Light2r = 0;
float Light2g = 1;
float Light2b = 0;
//Random number generator
float RandomNumber(float Min, float Max)
{
return ((float(rand()) / float(RAND_MAX)) * (Max - Min)) + Min;
}
//---------------------------------------
// Initialize material properties
//---------------------------------------
void init_material(float Ka, float Kd, float Ks, float Kp,
float Mr, float Mg, float Mb)
{
// Material variables
float ambient[] = { Ka * Mr, Ka * Mg, Ka * Mb, 1.0 };
float diffuse[] = { Kd * Mr, Kd * Mg, Kd * Mb, 1.0 };
float specular[] = { Ks * Mr, Ks * Mg, Ks * Mb, 1.0 };
// Initialize material
glMaterialfv(GL_FRONT_AND_BACK, GL_AMBIENT, ambient);
glMaterialfv(GL_FRONT_AND_BACK, GL_DIFFUSE, diffuse);
glMaterialfv(GL_FRONT_AND_BACK, GL_SPECULAR, specular);
glMaterialf(GL_FRONT_AND_BACK, GL_SHININESS, Kp);
}
//---------------------------------------
// Initialize light source
//---------------------------------------
void init_light(int light_source, float Lx, float Ly, float Lz,
float Lr, float Lg, float Lb)
{
// Light variables
float light_position[] = { Lx, Ly, Lz, 0.0 };
float light_color[] = { Lr, Lg, Lb, 1.0 };
// Initialize light source
glEnable(GL_LIGHTING);
glEnable(light_source);
glLightfv(light_source, GL_POSITION, light_position);
glLightfv(light_source, GL_AMBIENT, light_color);
glLightfv(light_source, GL_DIFFUSE, light_color);
glLightfv(light_source, GL_SPECULAR, light_color);
glLightf(light_source, GL_CONSTANT_ATTENUATION, 1.0);
glLightf(light_source, GL_LINEAR_ATTENUATION, 0.0);
glLightf(light_source, GL_QUADRATIC_ATTENUATION, 0.0);
glLightModeli(GL_LIGHT_MODEL_LOCAL_VIEWER, GL_FALSE);
glLightModeli(GL_LIGHT_MODEL_TWO_SIDE, GL_TRUE);
}
//---------------------------------------
// Initialize surface
//---------------------------------------
void init_surface()
{
//Initialize X, select column
for (int i = 0; i < 12; i++)
{
//Select row
//Surface is +1 so the far right normal will be generated correctly
for (int j = 0; j < 12; j++)
{
//-5 to compensate for negative coordinate values
surfaceX[i][j] = i-5;
//Generate random surface height
surfaceY[i][j] = RandomNumber(5, 7) - 5;
//surfaceY[i][j] = 0;
surfaceZ[i][j] = j-5;
}
}
}
void define_normals()
{
//Define surface normals
for (int i = 0; i < 11; i++)
{
for (int j = 0; j < 11; j++)
{
//Get two tangent vectors
float Ix = surfaceX[i+1][j] - surfaceX[i][j];
float Iy = surfaceY[i+1][j] - surfaceY[i][j];
float Iz = surfaceZ[i+1][j] - surfaceZ[i][j];
float Jx = surfaceX[i][j+1] - surfaceX[i][j];
float Jy = surfaceY[i][j+1] - surfaceY[i][j];
float Jz = surfaceZ[i][j+1] - surfaceZ[i][j];
//Do cross product, inverted for upward normals
Nx[i][j] = - Iy * Jz + Iz * Jy;
Ny[i][j] = - Iz * Jx + Ix * Jz;
Nz[i][j] = - Ix * Jy + Iy * Jx;
//Original vectors
//Nx[i][j] = Iy * Jz - Iz * Jy;
//Ny[i][j] = Iz * Jx - Ix * Jz;
//Nz[i][j] = Ix * Jy - Iy * Jx;
float length = sqrt(
Nx[i][j] * Nx[i][j] +
Ny[i][j] * Ny[i][j] +
Nz[i][j] * Nz[i][j]);
if (length > 0)
{
Nx[i][j] /= length;
Ny[j][j] /= length;
Nz[i][j] /= length;
}
}
}
}
void calc_color()
{
for (int i = 0; i < 10; i++)
{
for (int j = 0; j < 10; j++)
{
//Calculate light vector
//Light position, hardcoded for now 0,1,1
float Lx = Light1x - surfaceX[i][j];
float Ly = Light1y - surfaceY[i][j];
float Lz = Light1z - surfaceZ[i][j];
//std::cout << "Lx: " << Lx << std::endl;
//std::cout << "Ly: " << Ly << std::endl;
//std::cout << "Lz: " << Lz << std::endl;
//Grab surface normals
//These are Nx,Ny,Nz due to compiler issues
float Na = Nx[i][j];
float Nb = Ny[i][j];
float Nc = Nz[i][j];
//std::cout << "Na: " << Na << std::endl;
//std::cout << "Nb: " << Nb << std::endl;
//std::cout << "Nc: " << Nc << std::endl;
//Do cross product
float Color = (Na * Lx) + (Nb * Ly) + (Nc * Lz);
//std::cout << "Color: " << Color << std::endl;
R[i][j] = Color;
G[i][j] = Color;
B[i][j] = Color;
}
}
}
//---------------------------------------
// Init function for OpenGL
//---------------------------------------
void init()
{
glClearColor(0.0, 0.0, 0.0, 1.0);
glMatrixMode(GL_PROJECTION);
glLoadIdentity();
//Viewing Window Modified
glOrtho(-7.0, 7.0, -7.0, 7.0, -7.0, 7.0);
glMatrixMode(GL_MODELVIEW);
glLoadIdentity();
//Rotates camera
//glRotatef(30.0, 1.0, 1.0, 1.0);
glEnable(GL_DEPTH_TEST);
//Project 3 code
init_surface();
define_normals();
//Shading code
glShadeModel(GL_SMOOTH);
glEnable(GL_NORMALIZE);
//X,Y,Z - R,G,B
init_light(GL_LIGHT1, Light1x, Light1y, Light1z, Light1r, Light1g, Light1b);
//init_light(GL_LIGHT2, Light2x, Light2y, Light2z, Light2r, Light2g, Light2b);
//init_light(GL_LIGHT2, 0, 1, 0, 0.5, 0.5, 0.5);
}
void keyboard(unsigned char key, int x, int y)
{
///TODO: allow user to change color of light
//Controls
//Toggle Mode
if (key == 'q')
{
if(mode == 0)
{
mode = 1;
std::cout << "Switched to Light mode (" << mode << ")" << std::endl;
}
else if(mode == 1)
{
mode = 0;
std::cout << "Switched to Rotate mode (" << mode << ")" << std::endl;
}
}
//Toggle light control
else if (key == 'e')
{
if(lightmode == 0)
{
lightmode = 1;
std::cout << "Switched to controlling light 2 (" << lightmode << ")" << std::endl;
}
else if(lightmode == 1)
{
lightmode = 0;
std::cout << "Switched to controlling light 1 (" << lightmode << ")" << std::endl;
}
}
////Rotate Camera (mode 0)
//Up & Down
else if (key == 's' && mode == 0)
xangle += 5;
else if (key == 'w' && mode == 0)
xangle -= 5;
//Left & Right
else if (key == 'a' && mode == 0)
yangle -= 5;
else if (key == 'd' && mode == 0)
yangle += 5;
////Move Light (mode 1)
//Forward & Back
else if (key == 'w' && mode == 1)
{
if (lightmode == 0)
{
Light1z = Light1z - 1;
//init_surface();
//define_normals();
calc_color();
glutPostRedisplay();
}
else if (lightmode == 1)
Light2z = Light2z - 1;
//init_surface();
}
else if (key == 's' && mode == 1)
{
if (lightmode == 0)
Light1z = Light1z + 1;
else if (lightmode == 1)
Light2z = Light2z + 1;
}
//Strafe
else if (key == 'd' && mode == 1)
{
if (lightmode == 0)
Light1x = Light1x + 1;
else if (lightmode == 1)
Light2x = Light2x + 1;
}
else if (key == 'a' && mode == 1)
{
if (lightmode == 0)
Light1x = Light1x - 1;
else if (lightmode == 1)
Light2x = Light2x - 1;
}
//Up & Down (Cube offset by +0.5 in Y)
else if (key == 'z' && mode == 1)
{
if (lightmode == 0)
Light1y = Light1y + 1;
else if (lightmode == 1)
Light2y = Light2y + 1;
}
else if (key == 'x' && mode == 1)
{
if (lightmode == 0)
Light1y = Light1y - 1;
else if (lightmode == 1)
Light2y = Light2y - 1;
}
//Redraw objects
glutPostRedisplay();
}
//---------------------------------------
// Display callback for OpenGL
//---------------------------------------
void display()
{
// Clear the screen
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
//Rotation Code
glMatrixMode(GL_MODELVIEW);
glLoadIdentity();
glRotatef(xangle, 1.0, 0.0, 0.0);
glRotatef(yangle, 0.0, 1.0, 0.0);
//Light Code
init_material(Ka, Kd, Ks, 100 * Kp, 0.8, 0.6, 0.4);
//Color Code
calc_color();
//Draw the squares, select column
for (int i = 0; i <= 9; i++)
{
//Select row
for (int j = 0; j <= 9; j++)
{
glBegin(GL_POLYGON);
//Surface starts at top left
//Counter clockwise
glColor3f(R[i][j], G[i][j], B[i][j]);
glNormal3f(Nx[i][j], Ny[i][j], Nz[i][j]);
glVertex3f(surfaceX[i][j], surfaceY[i][j], surfaceZ[i][j]);
glColor3f(R[i][j+1], G[i][j+1], B[i][j+1]);
glNormal3f(Nx[i][j+1], Ny[i][j+1], Nz[i][j+1]);
glVertex3f(surfaceX[i][j+1], surfaceY[i][j+1], surfaceZ[i][j+1]);
glColor3f(R[i+1][j+1], G[i+1][j+1], B[i+1][j+1]);
glNormal3f(Nx[i+1][j+1], Ny[i+1][j+1], Nz[i+1][j+1]);
glVertex3f(surfaceX[i+1][j+1], surfaceY[i+1][j+1], surfaceZ[i+1][j+1]);
glColor3f(R[i+1][j], G[i+1][j], B[i+1][j]);
glNormal3f(Nx[i+1][j], Ny[i+1][j], Nz[i+1][j]);
glVertex3f(surfaceX[i+1][j], surfaceY[i+1][j], surfaceZ[i+1][j]);
glEnd();
}
}
//Draw the normals
for (int i = 0; i <= 10; i++)
{
for (int j = 0; j <= 10; j++)
{
glBegin(GL_LINES);
//glColor3f(0.0, 1.0, 1.0);
float length = 1;
glVertex3f(surfaceX[i][j], surfaceY[i][j], surfaceZ[i][j]);
glVertex3f(surfaceX[i][j]+length*Nx[i][j],
surfaceY[i][j]+length*Ny[i][j],
surfaceZ[i][j]+length*Nz[i][j]);
glEnd();
}
}
//Marking location of lights
glPointSize(10);
glBegin(GL_POINTS);
glColor3f(Light1r, Light1g, Light1b);
glVertex3f(Light1x, Light1y, Light1z);
glEnd();
glPointSize(10);
glBegin(GL_POINTS);
glColor3f(Light2r, Light2g, Light2b);
glVertex3f(Light2x, Light2y, Light2z);
glEnd();
//+Z = Moving TOWARD camera in opengl
//Origin point for reference
glPointSize(10);
glColor3f(1.0, 1.0, 0.0);
glBegin(GL_POINTS);
glVertex3f(0, 0, 0);
glEnd();
//Assign Color of Lines
float R = 1;
float G = 1;
float B = 1;
glBegin(GL_LINES);
glColor3f(R, G, B);
////Drawing the grid
//Vertical lines
for (int i = 0; i < 11; i++)
{
int b = -5 + i;
glVertex3f(b, 0, -5);
glVertex3f(b, 0, 5);
}
//Horizontal lines
for (int i = 0; i < 11; i++)
{
int b = -5 + i;
glVertex3f(-5,0,b);
glVertex3f(5,0,b);
}
glEnd();
glFlush();
}
//---------------------------------------
// Main program
//---------------------------------------
int main(int argc, char *argv[])
{
srand(time(NULL));
//Print Instructions
std::cout << "Project 3 Controls: " << std::endl;
std::cout << "q switches control mode" << std::endl;
std::cout << "w,a,s,d for camera rotation" << std::endl;
//Required
glutInit(&argc, argv);
//Window will default to a different size without
glutInitWindowSize(500, 500);
//Window will default to a different position without
glutInitWindowPosition(250, 250);
//
glutInitDisplayMode(GLUT_RGB | GLUT_SINGLE | GLUT_DEPTH);
//Required
glutCreateWindow("Project 3");
//Required, calls display function
glutDisplayFunc(display);
glutKeyboardFunc(keyboard);
//Required
init();
glutMainLoop();
return 0;
}
答案 0 :(得分：1)
1）在移动灯光时更新表面
在移动光源时，您错过了更新光源的位置。在功能display的开始处设置灯光位置。
请注意，当灯光位置由glLightfv(GL_LIGHT0, GL_POSITION, pos)设置时，
pos乘以当前模型视图矩阵。
因此，必须在glLoadIdentity“清除”模型视图矩阵之后设置灯光：
void display()
{
// Clear the screen
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
//Rotation Code
glMatrixMode(GL_MODELVIEW);
glLoadIdentity();
// init light
init_light(GL_LIGHT1, Light1x, Light1y, Light1z, Light1r, Light1g, Light1b);
init_light(GL_LIGHT2, Light2x, Light2y, Light2z, Light2r, Light2g, Light2b);
glRotatef(xangle, 1.0, 0.0, 0.0);
glRotatef(yangle, 0.0, 1.0, 0.0);
// [...]
}
2）不管阴影/灯光如何，使灯光和法线保持静态颜色。
在绘制表面之前启用照明，但是在绘制线和点之前禁用照明：
void display()
{
// [...]
// switch on lighting
glEnable(GL_LIGHTING);
//Draw the squares, select column
for (int i = 0; i <= 9; i++)
{
// [...]
}
// switch off lighting
glDisable(GL_LIGHTING);
//Draw the normals
for (int i = 0; i <= 10; i++)
{
// [...]
}
// [...]
}