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python - 如何使 OpenGL 镜面光工作？

问题描述

如何使 OpenGL 中的镜面光照正常工作？我使用python，我一直在尝试学习它是如何工作的，我已经能够制作纹理、深度、创建基本游戏玩法，但现在我试图让镜面光照像手电筒一样工作，所以我不断地将它的位置更改为与玩家相同的位置以及玩家正在寻找的方向，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()

我已经尝试更改 glMaterial，或更改照明中的不同内容，但没有任何效果，我只是希望照明像手电筒一样工作，请用代码给出答案

标签： pythonpython-3.xopenglglslpyglet

解决方案

由于固定功能光模型的gouraud 着色，您想要做的事情是不可能的。另请参阅纹理平面上的 OpenGL Lighting is not working，这是一个关于类似问题的问题。您必须将表面（墙壁和地板）细分为较小的瓷砖，因为仅针对顶点坐标计算光线并在表面上进行插值。表面中间的镜面高光不会出现。

我知道那不会满足你。但请注意，按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。请参阅固定功能管道和旧版 OpenGL。阅读有关顶点规范和着色器的信息，了解最先进的渲染方式。

如果你想“看到”任何东西，你必须跳过聚光灯，因为它不适用于你的几何：

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

但激活环境漫射光：

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)

对于光的计算，需要表面的法线向量。

激活灯光模型GL_LIGHT_MODEL_TWO_SIDE侧：

glLightModeli(GL_LIGHT_MODEL_TWO_SIDE, GL_TRUE)

通过 设置法线向量glNormal3f：

# 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 设置时glLightfv(GL_LIGHT0, GL_POSITION, pos)，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之前设置位置 ( gluLookAt)，那么灯光位置是相对于相机的（视图空间位置）。
如果它是在设置视图矩阵之后设置的，那么灯光位置必须在世界坐标中，因为它是由视图矩阵变换的。

如果您希望光源是相机位置，那么您必须在视图矩阵设置之前gluLookAt将灯光设置为 (0, 0, 0) 位置。 

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）起作用，那么唯一的可能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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