我如何使OpenGL Specular Light工作？

问题描述 投票：2回答：1

如何在OpenGL中制作高光照明？我使用python并且我一直在努力学习它是如何工作的，我已经能够使纹理工作，深度，创建一个基本的游戏玩法，但现在我试图让镜面光照像手电筒一样工作，所以我将它的位置不断改变为玩家的位置以及玩家所在的方向，但它不起作用！

import pyglet, math
from pyglet.gl import *

tela = pyglet.window.Window(height=500, width=500, caption="Halloween")
glEnable(GL_DEPTH_TEST)
glEnable(GL_TEXTURE_2D)
glEnable(GL_LIGHTING)
glLightfv(GL_LIGHT0, GL_AMBIENT, (GLfloat*4)(0,0,0,1))
glLightfv(GL_LIGHT0, GL_DIFFUSE, (GLfloat*4)(0,0,0,1))
glEnable(GL_LIGHT0)
tela.set_mouse_visible(False)
pos = [0,0,0]
rotX = rotY = pre = 0
comando = {"a":0,"d":0,"w":0,"s":0}
Dparede = pyglet.image.load("inf/Parede_Branca.png").get_image_data().get_data('RGBA', 225*4)
parede = pyglet.resource.image("inf/Parede_Branca.png").get_texture()
Dchao = pyglet.image.load("inf/Madeira.png").get_image_data().get_data('RGBA', 225*4)
chao = pyglet.resource.image("inf/Madeira.png").get_texture()

@tela.event
def on_draw():
    global pos, comando, rotX, rotY, parede, chao, Dchao, Dparede
    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT)
    if comando["w"] == 1:
        pos[2] += math.cos(math.pi*rotX/180)
        pos[0] += math.sin(math.pi*rotX/180)
    if comando["s"] == 1:
        pos[2] -= math.cos(math.pi*rotX/180)
        pos[0] -= math.sin(math.pi*rotX/180)
    if comando["d"] == 1:
        pos[2] += math.sin(math.pi*rotX/180)
        pos[0] -= math.cos(math.pi*rotX/180)
    if comando["a"] == 1:
        pos[2] -= math.sin(math.pi*rotX/180)
        pos[0] += math.cos(math.pi*rotX/180)
    glMatrixMode(GL_PROJECTION)
    glLoadIdentity()
    gluPerspective(45, 1, 0.1, 1000)
    glMatrixMode(GL_MODELVIEW)
    glLoadIdentity()
    if pos[0] < -188:
        pos[0] = -188
    if pos[2] < -188:
        pos[2] = -188
    if pos[0] > 188:
        pos[0] = 188
    if pos[2] > 188:
        pos[2] = 188
    glLightfv(GL_LIGHT0, GL_SPECULAR, (GLfloat*4)(1,1,1,1))
    glLightfv(GL_LIGHT0, GL_POSITION, (GLfloat*4)(pos[0],pos[1]-1,pos[2],1))
    glLightfv(GL_LIGHT0, GL_SPOT_DIRECTION, (GLfloat*3)(pos[0]+1000*(math.sin(math.pi*rotX/180)),pos[1]+1000*(math.cos(math.pi*rotY/180)), pos[2]+1000*(math.cos(math.pi*rotX/180))))
    glLightfv(GL_LIGHT0, GL_SPOT_CUTOFF, (GLfloat*1)(45))

    gluLookAt(pos[0], pos[1], pos[2], pos[0]+math.sin(math.pi*rotX/180), pos[1]+math.cos(math.pi*rotY/180), pos[2]+math.cos(math.pi*rotX/180), 0, 10, 0)

    glBindTexture(GL_TEXTURE_2D, chao.id)
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_MIRRORED_REPEAT)
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_MIRRORED_REPEAT)
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR)
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR)
    glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, 225, 225, 0, GL_RGBA, GL_UNSIGNED_BYTE, Dchao)

    glMaterialfv(GL_FRONT_AND_BACK, GL_SPECULAR, (GLfloat*4)(1,1,1,1))
    glMaterialfv(GL_FRONT_AND_BACK, GL_SHININESS, (GLfloat*1)(100))
    glMaterialfv(GL_FRONT_AND_BACK, GL_EMISSION, (GLfloat*4)(0,0,0,1))

    # chão
    glBegin(GL_POLYGON)
    glTexCoord2f(0,0)
    glVertex3f(-200,-20,200)
    glTexCoord2f(0,10)
    glVertex3f(-200,-20,-200)
    glTexCoord2f(10,10)
    glVertex3f(200,-20,-200)
    glTexCoord2f(10,0)
    glVertex3f(200,-20,200)
    glEnd()

    glBindTexture(GL_TEXTURE_2D, parede.id)
    glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, 225, 225, 0, GL_RGBA, GL_UNSIGNED_BYTE, Dparede)

    # teto
    glBegin(GL_POLYGON)
    glTexCoord2f(0,0)
    glVertex3f(-200,20,200)
    glTexCoord2f(0,50)
    glVertex3f(-200,20,-200)
    glTexCoord2f(50,50)
    glVertex3f(200,20,-200)
    glTexCoord2f(50,0)
    glVertex3f(200,20,200)
    glEnd()

    # parede
    glBegin(GL_POLYGON)
    glTexCoord2f(0,0)
    glVertex3f(-200,20,200)
    glTexCoord2f(0,50)
    glVertex3f(-200,20,-200)
    glTexCoord2f(10,50)
    glVertex3f(-200,-20,-200)
    glTexCoord2f(10,0)
    glVertex3f(-200,-20,200)
    glEnd()

    # parede
    glBegin(GL_POLYGON)
    glTexCoord2f(0,0)
    glVertex3f(-200,-20,-200)
    glTexCoord2f(0,50)
    glVertex3f(200,-20,-200)
    glTexCoord2f(10,50)
    glVertex3f(200,20,-200)
    glTexCoord2f(10,0)
    glVertex3f(-200,20,-200)
    glEnd()

    # parede
    glBegin(GL_POLYGON)
    glTexCoord2f(0,0)
    glVertex3f(200,-20,-200)
    glTexCoord2f(0,50)
    glVertex3f(200,-20,200)
    glTexCoord2f(10,50)
    glVertex3f(200,20,200)
    glTexCoord2f(10,0)
    glVertex3f(200,20,-200)
    glEnd()

    # parede
    glBegin(GL_POLYGON)
    glTexCoord2f(0,0)
    glVertex3f(-200,-20,200)
    glTexCoord2f(0,50)
    glVertex3f(200,-20,200)
    glTexCoord2f(10,50)
    glVertex3f(200,20,200)
    glTexCoord2f(10,0)
    glVertex3f(-200,20,200)
    glEnd()

@tela.event
def on_key_press(k,m):
    global comando
    if k == pyglet.window.key.A:
        comando["a"] = 1
    if k == pyglet.window.key.D:
        comando["d"] = 1
    if k == pyglet.window.key.W:
        comando["w"] = 1
    if k == pyglet.window.key.S:
        comando["s"] = 1
    if k == pyglet.window.key.Q:
        tela.close()

@tela.event
def on_key_release(k,m):
    global comando
    if k == pyglet.window.key.A:
        comando["a"] = 0
    if k == pyglet.window.key.D:
        comando["d"] = 0
    if k == pyglet.window.key.W:
        comando["w"] = 0
    if k == pyglet.window.key.S:
        comando["s"] = 0

@tela.event
def on_mouse_motion(x, y, dx, dy):
    global rotX, rotY, pre
    if pre == 0:
        rotX-=dx/2
        if rotY >= 0:
            rotY = -1
        if rotY <= -180:
            rotY = -179
        rotY+=dy
        if x > 400 or x < 100 or y > 400 or y < 100:
            tela.set_mouse_position(250,250)
            pre = 1
    else:
        pre = 0

def SRO(dt):
    on_draw()

pyglet.clock.schedule_interval(SRO, 1/120)

pyglet.app.run()

我已经尝试改变glMaterial，或改变照明中的不同东西，但没有正常工作，我只是希望照明像手电筒一样工作，请用代码给出答案

python python-3.x opengl glsl pyglet
1个回答
4
投票

由于固定功能灯模型的gouraud shading，你想要做的是不可能的。另见OpenGL Lighting on texture plane is not working，这是一个关于类似问题的问题。您可以将曲面（墙和地板）细分为较小的切片，因为仅针对顶点坐标计算光并在曲面上进行插值。表面中间的镜面高光不会出现。

我知道这不会让你满意。但请注意，由glBegin/glEnd序列绘制，固定函数矩阵堆栈和固定函数，每个顶点光模型，几十年来已被弃用。见Fixed Function Pipeline和Legacy OpenGL。阅读Vertex Specification和Shader，了解最先进的渲染方式。

如果你想“看到”任何东西，你就必须跳过聚光灯，因为它不能用于你的几何体：

glLightfv(GL_LIGHT0, GL_SPOT_CUTOFF, (GLfloat*1)(45))

但激活环境光漫射光：

glEnable(GL_LIGHTING)
glLightfv(GL_LIGHT0, GL_AMBIENT, (GLfloat*4)(1,1,1,1))
glLightfv(GL_LIGHT0, GL_DIFFUSE, (GLfloat*4)(1,1,1,1))
glEnable(GL_LIGHT0)

为了计算光，需要表面的法向矢量。

激活轻型号GL_LIGHT_MODEL_TWO_SIDE方：

glLightModeli(GL_LIGHT_MODEL_TWO_SIDE, GL_TRUE)

通过glNormal3f设置法线向量：

# chão
glBegin(GL_POLYGON)
glNormal3f(0, -1, 0)
glTexCoord2f(0,0)
glVertex3f(-200,-20,200)
glTexCoord2f(0,10)
glVertex3f(-200,-20,-200)
glTexCoord2f(10,10)
glVertex3f(200,-20,-200)
glTexCoord2f(10,0)
glVertex3f(200,-20,200)
glEnd()

glBindTexture(GL_TEXTURE_2D, parede.id)
glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, 128, 128, 0, GL_RGBA, GL_UNSIGNED_BYTE, Dparede)

# teto
glBegin(GL_POLYGON)
glNormal3f(0, -1, 0)
glTexCoord2f(0,0)
glVertex3f(-200,20,200)
glTexCoord2f(0,50)
glVertex3f(-200,20,-200)
glTexCoord2f(50,50)
glVertex3f(200,20,-200)
glTexCoord2f(50,0)
glVertex3f(200,20,200)
glEnd()

# parede
glBegin(GL_POLYGON)
glNormal3f(-1, 0, 0)
glTexCoord2f(0,0)
glVertex3f(-200,20,200)
glTexCoord2f(0,50)
glVertex3f(-200,20,-200)
glTexCoord2f(10,50)
glVertex3f(-200,-20,-200)
glTexCoord2f(10,0)
glVertex3f(-200,-20,200)
glEnd()

# parede
glBegin(GL_POLYGON)
glNormal3f(0, 0, 1)
glTexCoord2f(0,0)
glVertex3f(-200,-20,-200)
glTexCoord2f(0,50)
glVertex3f(200,-20,-200)
glTexCoord2f(10,50)
glVertex3f(200,20,-200)
glTexCoord2f(10,0)
glVertex3f(-200,20,-200)
glEnd()

# parede
glBegin(GL_POLYGON)
glNormal3f(-1, 0, 0)
glTexCoord2f(0,0)
glVertex3f(200,-20,-200)
glTexCoord2f(0,50)
glVertex3f(200,-20,200)
glTexCoord2f(10,50)
glVertex3f(200,20,200)
glTexCoord2f(10,0)
glVertex3f(200,20,-200)
glEnd()

# parede
glBegin(GL_POLYGON)
glNormal3f(0, 0, 1)
glTexCoord2f(0,0)
glVertex3f(-200,-20,200)
glTexCoord2f(0,50)
glVertex3f(200,-20,200)
glTexCoord2f(10,50)
glVertex3f(200,20,200)
glTexCoord2f(10,0)
glVertex3f(-200,20,200)
glEnd()

当灯光位置由glLightfv(GL_LIGHT0, GL_POSITION, pos)设置时，位置乘以当前模型视图矩阵。 这意味着如果在设置视图矩阵（gluLookAt）之前设置位置，则灯光位置相对于摄像机（视图空间位置）。 如果在设置视图矩阵后设置，则光位置必须在世界坐标中，因为它由视图矩阵变换。

如果您希望光源是摄像机位置，那么您需要在gluLookAt设置视图矩阵之前将光源设置到位置（0,0,0）。

glLightfv(GL_LIGHT0, GL_POSITION, (GLfloat*4)(0,0,0,1))
gluLookAt(pos[0], pos[1], pos[2], pos[0]+math.sin(math.pi*rotX/180), pos[1]+math.cos(math.pi*rotY/180), pos[2]+math.cos(math.pi*rotX/180), 0, 10, 0)

如果你想让聚光灯（或多或少）发挥作用，那么唯一的可能性就是使用一个非常小的GL_SHININESS参数（例如1）：

glLightfv(GL_LIGHT0, GL_POSITION, (GLfloat*4)(0,0,0,1))
glLightfv(GL_LIGHT0, GL_SPOT_DIRECTION, (GLfloat*3)(0, 0, -1))
glLightfv(GL_LIGHT0, GL_SPOT_CUTOFF, (GLfloat*1)(45))

gluLookAt(pos[0], pos[1], pos[2], pos[0]+math.sin(math.pi*rotX/180), pos[1]+math.cos(math.pi*rotY/180), pos[2]+math.cos(math.pi*rotX/180), 0, 10, 0)

glLightfv(GL_LIGHT0, GL_AMBIENT, (GLfloat*4)(0,0,0,1))
glLightfv(GL_LIGHT0, GL_DIFFUSE, (GLfloat*4)(0,0,0,1))
glLightfv(GL_LIGHT0, GL_SPECULAR, (GLfloat*4)(1,1,1,1))

# [...]

glMaterialfv(GL_FRONT_AND_BACK, GL_SHININESS, (GLfloat*1)(1))
glMaterialfv(GL_FRONT_AND_BACK, GL_SPECULAR, (GLfloat*4)(1,1,1,1))

另一种可能性是实现一个简单的Per Fragment Lighting着色器程序：

创建着色器程序源代码：

vert_code = b"""
varying vec3 N;
varying vec3 v;
varying vec2 uv;

void main(void)  
{     
    uv = gl_MultiTexCoord0.xy; 
    v = vec3(gl_ModelViewMatrix * gl_Vertex);       
    N = normalize(gl_NormalMatrix * gl_Normal);
    gl_Position = gl_ModelViewProjectionMatrix * gl_Vertex;  
}
"""

frag_code = b"""
varying vec3 N;
varying vec3 v; 
varying vec2 uv;  
uniform sampler2D u_texture;  
void main (void)  
{  
    vec3 L = normalize(gl_LightSource[0].position.xyz - v);   
    vec3 E = normalize(-v); // we are in Eye Coordinates, so EyePos is (0,0,0)  
    vec3 R = normalize(-reflect(L,N));  

    //calculate Ambient Term:  
    vec4 Iamb = gl_FrontLightProduct[0].ambient;    

    float spotCos = dot(gl_LightSource[0].spotDirection, -E);
    float sotCutOff = step(gl_LightSource[0].spotCosCutoff, spotCos);

    //calculate Diffuse Term:  
    vec4 Idiff = gl_FrontLightProduct[0].diffuse * max(dot(N,L), 0.0);
    Idiff = clamp(Idiff, 0.0, 1.0) * sotCutOff;     

    // calculate Specular Term:
    vec4 Ispec = gl_FrontLightProduct[0].specular 
                    * pow(max(dot(R,E),0.0),0.3*gl_FrontMaterial.shininess);
    Ispec = clamp(Ispec, 0.0, 1.0) * sotCutOff; 

    vec4 texColor = texture2D(u_texture, uv);  
    gl_FragColor = vec4(texColor.rgb * (Iamb + Idiff + Ispec), texColor.a);     
}
"""

编译并链接程序：

from ctypes import *

sh_code_list = [(GL_VERTEX_SHADER, vert_code), (GL_FRAGMENT_SHADER, frag_code)]

sh_objs = []
for sh_code in sh_code_list:
    sh_obj = glCreateShader(sh_code[0])
    src_buffer = create_string_buffer(sh_code[1])
    buf_pointer = cast(pointer(pointer(src_buffer)), POINTER(POINTER(c_char)))
    glShaderSource(sh_obj, 1, buf_pointer, None)
    glCompileShader(sh_obj)
    temp = c_int(0)
    glGetShaderiv(sh_obj, GL_COMPILE_STATUS, byref(temp))
    if not temp:
        glGetShaderiv(sh_obj, GL_INFO_LOG_LENGTH, byref(temp))
        buffer = create_string_buffer(temp.value)
        glGetShaderInfoLog(sh_obj, temp, None, buffer)
        print( 'compile error:' )
        print(buffer.value)
    sh_objs.append(sh_obj)

program = glCreateProgram()
for shObj in sh_objs: 
    glAttachShader(program, shObj)

glLinkProgram(program)
temp = c_int(0)
glGetProgramiv(program, GL_LINK_STATUS, byref(temp))
if not temp:
    glGetProgramiv(program, GL_INFO_LOG_LENGTH, byref(temp))
    buffer = create_string_buffer(temp.value)
    glGetProgramInfoLog(program, temp, None, buffer)
    print( 'link error:' )
    print(buffer.value)

在程序的主循环之前加载纹理：

glBindTexture(GL_TEXTURE_2D, chao.id)
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_MIRRORED_REPEAT)
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_MIRRORED_REPEAT)
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR)
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR)
glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, 256, 256, 0, GL_RGBA, GL_UNSIGNED_BYTE, Dchao)

glBindTexture(GL_TEXTURE_2D, parede.id)
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_MIRRORED_REPEAT)
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_MIRRORED_REPEAT)
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR)
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR)
glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, 1024, 1024, 0, GL_RGBA, GL_UNSIGNED_BYTE, Dparede)

绘制场景时使用该程序：

@tela.event
def on_draw():
    global pos, comando, rotX, rotY, parede, chao, Dchao, Dparede
    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT)
    if comando["w"] == 1:
        pos[2] += math.cos(math.pi*rotX/180)
        pos[0] += math.sin(math.pi*rotX/180)
    if comando["s"] == 1:
        pos[2] -= math.cos(math.pi*rotX/180)
        pos[0] -= math.sin(math.pi*rotX/180)
    if comando["d"] == 1:
        pos[2] += math.sin(math.pi*rotX/180)
        pos[0] -= math.cos(math.pi*rotX/180)
    if comando["a"] == 1:
        pos[2] -= math.sin(math.pi*rotX/180)
        pos[0] += math.cos(math.pi*rotX/180)

    glMatrixMode(GL_PROJECTION)
    glLoadIdentity()
    gluPerspective(45, 1, 0.1, 1000)
    glMatrixMode(GL_MODELVIEW)
    glLoadIdentity()
    if pos[0] < -188:
        pos[0] = -188
    if pos[2] < -188:
        pos[2] = -188
    if pos[0] > 188:
        pos[0] = 188
    if pos[2] > 188:
        pos[2] = 188

    glLightfv(GL_LIGHT0, GL_POSITION, (GLfloat*4)(0,0,0,1))
    glLightfv(GL_LIGHT0, GL_SPOT_DIRECTION, (GLfloat*3)(0, 0, -1))
    glLightfv(GL_LIGHT0, GL_SPOT_CUTOFF, (GLfloat*1)(45))

    gluLookAt(pos[0], pos[1], pos[2], pos[0]+math.sin(math.pi*rotX/180), pos[1]+math.cos(math.pi*rotY/180), pos[2]+math.cos(math.pi*rotX/180), 0, 10, 0)

    glLightfv(GL_LIGHT0, GL_AMBIENT, (GLfloat*4)(0.2,0.2,0.2,1))
    glLightfv(GL_LIGHT0, GL_DIFFUSE, (GLfloat*4)(0.8,0.8,0.8,1))
    glLightfv(GL_LIGHT0, GL_SPECULAR, (GLfloat*4)(1,1,1,1))
    glMaterialfv(GL_FRONT_AND_BACK, GL_SHININESS, (GLfloat*1)(100))
    glMaterialfv(GL_FRONT_AND_BACK, GL_SPECULAR, (GLfloat*4)(1,1,1,1))

    glBindTexture(GL_TEXTURE_2D, chao.id)

    glUseProgram(program)

    # chão
    glBegin(GL_POLYGON)
    glNormal3f(0, 1, 0)
    glTexCoord2f(0,0)
    glVertex3f(-200,-20,200)
    glTexCoord2f(0,10)
    glVertex3f(-200,-20,-200)
    glTexCoord2f(10,10)
    glVertex3f(200,-20,-200)
    glTexCoord2f(10,0)
    glVertex3f(200,-20,200)
    glEnd()

    glBindTexture(GL_TEXTURE_2D, parede.id)

    # teto
    glBegin(GL_POLYGON)
    glNormal3f(0, -1, 0)
    glTexCoord2f(0,0)
    glVertex3f(-200,20,200)
    glTexCoord2f(0,10)
    glVertex3f(-200,20,-200)
    glTexCoord2f(10,10)
    glVertex3f(200,20,-200)
    glTexCoord2f(10,0)
    glVertex3f(200,20,200)
    glEnd()

    # parede
    glBegin(GL_POLYGON)
    glNormal3f(-1, 0, 0)
    glTexCoord2f(0,0)
    glVertex3f(-200,20,200)
    glTexCoord2f(10,0)
    glVertex3f(-200,20,-200)
    glTexCoord2f(10,1)
    glVertex3f(-200,-20,-200)
    glTexCoord2f(0,1)
    glVertex3f(-200,-20,200)
    glEnd()

    # parede
    glBegin(GL_POLYGON)
    glNormal3f(0, 0, 1)
    glTexCoord2f(0,0)
    glVertex3f(-200,-20,-200)
    glTexCoord2f(10,0)
    glVertex3f(200,-20,-200)
    glTexCoord2f(10,1)
    glVertex3f(200,20,-200)
    glTexCoord2f(0,1)
    glVertex3f(-200,20,-200)
    glEnd()

    # parede
    glBegin(GL_POLYGON)
    glNormal3f(-1, 0, 0)
    glTexCoord2f(0,0)
    glVertex3f(200,-20,-200)
    glTexCoord2f(10,0)
    glVertex3f(200,-20,200)
    glTexCoord2f(10,1)
    glVertex3f(200,20,200)
    glTexCoord2f(0,1)
    glVertex3f(200,20,-200)
    glEnd()

    # parede
    glBegin(GL_POLYGON)
    glNormal3f(0, 0, 1)
    glTexCoord2f(0,0)
    glVertex3f(-200,-20,200)
    glTexCoord2f(10,0)
    glVertex3f(200,-20,200)
    glTexCoord2f(10,1)
    glVertex3f(200,20,200)
    glTexCoord2f(0,1)
    glVertex3f(-200,20,200)
    glEnd()

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