How to make Shadow Mapping?
I was trying to understand how Shadow Mapping works on its own and describes this Python program to test Shadow Mapping, and this is as far as possible.
I searched for shadow mapping problems, but I haven't found what has already happened for something like this, so how do I color the normal rotating cube in front of the light and how do I correct the position of the shadow so that it appears and place it exactly on the surface ? I was just modifying the shader.
import pyglet, math, pyrr, ctypes
import numpy as np
from OpenGL.GL import *
from OpenGL.GL.shaders import *
app = pyglet.window.Window()
v = """
in layout(location=0) vec3 posicao;
uniform mat4 view;
uniform vec3 translate;
uniform float rot;
uniform float rot2;
uniform vec3 t2;
out vec3 outpos;
void main(){
vec3 p = posicao;
p = vec3(sin(rot)*p.x+cos(rot)*p.z,p.y,-sin(rot)*p.z+cos(rot)*p.x);
p = translate+p+t2;
p = vec3(p.x,sin(rot2)*p.z+cos(rot2)*p.y,-sin(rot2)*p.y+cos(rot2)*p.z);
outpos = p;
gl_Position = view*vec4(p,1);
}
"""
f = """
uniform vec3 cor;
uniform int modo;
uniform sampler2D shadow;
in vec3 outpos;
void main(){
if(modo==0){
float pi = 3.141592653589793;
vec3 o = outpos+vec3(0,-5,0);
o = vec3(o.x,sin(-30*pi/180)*o.z+cos(-30*pi/180)*o.y,-sin(-30*pi/180)*o.y+cos(-30*pi/180)*o.z);
o.z+=0.05;
float d = texture(shadow,vec2(.5)+o.xy/20).z;
float i = 1;
if(d<-o.z/20){
i = 0.5;
}
gl_FragColor = vec4(vec3(cor),1)*i;
//gl_FragColor = texture(shadow,outpos.xy);
}else{
gl_FragColor = vec4(vec3(-outpos.z/20),1);
}
}
"""
shader = compileProgram(compileShader(v,GL_VERTEX_SHADER),compileShader(f,GL_FRAGMENT_SHADER))
glUseProgram(shader)
tudo = [-200,-4,200,
200,-4,200,
200,-4,-200,
-200,-4,-200,
-2,-2,2,
-2,-2,-2,
2,-2,-2,
2,-2,2,
2,2,2,
2,2,-2,
-2,2,-2,
-2,2,2,
-2,2,2,
-2,2,-2,
-2,-2,-2,
-2,-2,2,
2,-2,2,
2,-2,-2,
2,2,-2,
2,2,2,
-2,2,-2,
2,2,-2,
2,-2,-2,
-2,-2,-2,
-2,-2,2,
2,-2,2,
2,2,2,
-2,2,2]
tudo = np.array(tudo, dtype=np.float32)
CUBO = glGenBuffers(1)
glBindBuffer(GL_ARRAY_BUFFER, CUBO)
glBufferData(GL_ARRAY_BUFFER, len(tudo)*4, tudo, GL_STREAM_DRAW)
glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 12, ctypes.c_void_p(0))
glEnableVertexAttribArray(0)
view = pyrr.matrix44.create_perspective_projection_matrix(60, app.width/app.height, .1, 10000)
p = glGetUniformLocation(shader, "view")
glUniformMatrix4fv(p, 1, GL_FALSE, view)
glEnable(GL_DEPTH_TEST)
# Tentativa de Shadow Mapping
glEnable(GL_TEXTURE_2D)
tf = glGenTextures(1)
glBindTexture(GL_TEXTURE_2D, tf)
glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, app.width, app.height, 0, GL_RGB, GL_UNSIGNED_BYTE, None)
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR)
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR)
f = glGenFramebuffers(1)
r = glGenRenderbuffers(1)
glBindFramebuffer(GL_FRAMEBUFFER, f)
glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, tf, 0)
glBindRenderbuffer(GL_RENDERBUFFER, r)
glRenderbufferStorage(GL_RENDERBUFFER, GL_DEPTH24_STENCIL8, app.width, app.height)
glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_DEPTH_ATTACHMENT, GL_RENDERBUFFER, r)
glBindRenderbuffer(GL_RENDERBUFFER, 0)
glBindFramebuffer(GL_FRAMEBUFFER, 0)
pos = [0,-10,0]
comando = {"a":0,"w":0,"s":0,"d":0,"q":0,"e":0}
girar = -1
@app.event
def on_draw():
global CUBO, shader, pos, comando, tudo, girar, f
glBindFramebuffer(GL_FRAMEBUFFER, f)
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT)
# Z-Buffer
p = glGetUniformLocation(shader, "modo")
glUniform1i(p, 1)
p = glGetUniformLocation(shader, "rot2")
glUniform1f(p, -30*math.pi/180)
p = glGetUniformLocation(shader, "t2")
glUniform3f(p, 0, -5, 0)
# Movimento
v = .04
if comando["a"] == 1:
pos[0]-=v
if comando["d"] == 1:
pos[0]+=v
if comando["w"] == 1:
pos[1]-=v
if comando["s"] == 1:
pos[1]+=v
if comando["q"] == 1:
pos[2]-=v
if comando["e"] == 1:
pos[2]+=v
# fundo vermelho
p = glGetUniformLocation(shader, "translate")
glUniform3f(p, 0, 0, 0)
p = glGetUniformLocation(shader, "rot")
glUniform1f(p, 0)
p = glGetUniformLocation(shader, "cor")
glUniform3f(p, 1, 0, 0)
glDrawArrays(GL_QUADS, 0, 4)
# objeto no meio
p = glGetUniformLocation(shader, "translate")
glUniform3f(p, -1, -5, -10)
p = glGetUniformLocation(shader, "rot")
glUniform1f(p, 0)
p = glGetUniformLocation(shader, "cor")
glUniform3f(p, 0, 0, 1)
glDrawArrays(GL_QUADS, 8, 4)
# objeto azul
p = glGetUniformLocation(shader, "translate")
glUniform3f(p, pos[0], pos[2], pos[1])
p = glGetUniformLocation(shader, "rot")
girar+=.4
glUniform1f(p, girar*math.pi/180)
p = glGetUniformLocation(shader, "cor")
glUniform3f(p, 0, 0, 1)
glDrawArrays(GL_QUADS, 4, 8)
p = glGetUniformLocation(shader, "cor")
glUniform3f(p, 0, 1, 0)
glDrawArrays(GL_QUADS, 12, 8)
p = glGetUniformLocation(shader, "cor")
glUniform3f(p, 1, 1, 0)
glDrawArrays(GL_QUADS, 20, 8)
# gravar o Framebuffer
glBindFramebuffer(GL_FRAMEBUFFER, 0)
# reset
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT)
# Z-Buffer tirando
p = glGetUniformLocation(shader, "modo")
glUniform1i(p, 0)
p = glGetUniformLocation(shader, "rot2")
glUniform1f(p, 0*math.pi/180)
p = glGetUniformLocation(shader, "t2")
glUniform3f(p, 0, 0, 0)
# fundo vermelho
p = glGetUniformLocation(shader, "translate")
glUniform3f(p, 0, 0, 0)
p = glGetUniformLocation(shader, "rot")
glUniform1f(p, 0)
p = glGetUniformLocation(shader, "cor")
glUniform3f(p, 1, 0, 0)
glDrawArrays(GL_QUADS, 0, 4)
# objeto no meio
p = glGetUniformLocation(shader, "translate")
glUniform3f(p, -1, -5, -10)
p = glGetUniformLocation(shader, "rot")
glUniform1f(p, 0)
p = glGetUniformLocation(shader, "cor")
glUniform3f(p, 0, 0, 1)
glDrawArrays(GL_QUADS, 8, 4)
# objeto azul
p = glGetUniformLocation(shader, "translate")
glUniform3f(p, pos[0], pos[2], pos[1])
p = glGetUniformLocation(shader, "rot")
glUniform1f(p, girar*math.pi/180)
p = glGetUniformLocation(shader, "cor")
glUniform3f(p, 0, 0, 1)
glDrawArrays(GL_QUADS, 4, 8)
p = glGetUniformLocation(shader, "cor")
glUniform3f(p, 0, 1, 0)
glDrawArrays(GL_QUADS, 12, 8)
p = glGetUniformLocation(shader, "cor")
glUniform3f(p, 1, 1, 0)
glDrawArrays(GL_QUADS, 20, 8)
@app.event
def on_key_press(k,m):
global comando, grandeG
if k == pyglet.window.key.A:
comando["a"] = 1
if k == pyglet.window.key.W:
comando["w"] = 1
if k == pyglet.window.key.S:
comando["s"] = 1
if k == pyglet.window.key.D:
comando["d"] = 1
if k == pyglet.window.key.Q:
comando["q"] = 1
if k == pyglet.window.key.E:
comando["e"] = 1
@app.event
def on_key_release(k,m):
global comando
if k == pyglet.window.key.A:
comando["a"] = 0
if k == pyglet.window.key.W:
comando["w"] = 0
if k == pyglet.window.key.S:
comando["s"] = 0
if k == pyglet.window.key.D:
comando["d"] = 0
if k == pyglet.window.key.Q:
comando["q"] = 0
if k == pyglet.window.key.E:
comando["e"] = 0
def SRO(dt):
on_draw()
pyglet.clock.schedule(SRO)
pyglet.app.run()
Solution
The issue is caused by the limited accuracy of the shadow depth buffer. Since only 1 channel per fragment needs to be stored in the shadow buffer, I recommend to use the floating point internal texture format GL_R16F (or GL_R32F):
glTexImage2D(GL_TEXTURE_2D, 0, GL_R16F, app.width, app.height, 0, GL_RED, GL_UNSIGNED_BYTE, None)
Note the (shadow) depth is now stored in the red color channel, thus you have to read the value from the red (x) channel rather than the blue (z) channel in the fragment shader:
floaz d = texture(shadow,vec2(.5)+o.xy/20).z;
float d = texture(shadow,vec2(.5)+o.xy/20).x;
- WSGIServerException: [Errno 8] nodename nor servname provided, or not known
- Python/Flask Login form throws 500 error on IIS
- Matplotlib plt.show() isn't showing graph
- How to avoid duplicate processing in python API server?
- Extract points/coordinates from a polygon in Shapely
- How do I detect collision in pygame?
- Typehint a method that returns new instance using a superclass classmethod
- How to process requests from multiiple users using ML model and FastAPI?
- How can I clear the interpreter console?
- What are the reasons for the differences in output results when using the groupby function in the Python pandas package?
- How to antialias picture to get rid of the jerkiness in the image
- Is there any difference between list(array) and array.tolist() in Python?
- How to move x-axis on top of the plot in plotnine?
- Pulling Zillow Rent Data from Zillow API
- Safest way to incrementally append to a file?
- Unable to install mysqlclient package on EC2 instance
- FastAPI - How to get app instance inside a router?
- SQLAlchemy: engine, connection and session difference
- Generating binary arrays with alternating values based on change indices in NumPy
- How can i solve this error: ValueError: The feature names should match those that were passed
- 'super' object has no attribute '__sklearn_tags__'
- Python: How to copy all attibutes from base class to derived one
- mitm proxy is closed, but the port is still occupied
- How to find pg_config path
- Why does "pip install" inside Python raise a SyntaxError?
- Plotting a matplotlib pie chart using 2 columns
- ImportError: No module named langchain.llms
- How do I disable the security certificate check in Python requests
- How can I import Psycopg2 into a Lambda Function on AWS?
- Django built in Logout view `Method Not Allowed (GET): /users/logout/`