问题
Calling on experts, gurus, and anybody to help read and parse a file in python.
On page 751 of 6th ed. or page 800 of 7th ed. of Superbible OpenGL there is Appendix B. The SBM File Format that seems to explain well the format to some extent.
I have tried to implement in python a reader of this file format.
OK, progress has been made. I have merged Rabbid76 amazing code to the source provided. Though I am attempting to make additional headway.
Update Jun 23, 2019 - major progress, fixed the error about glVertexAttribPointer(i, ... error.
Same day, fixed the Python cannot find the variable first error.
Same day, SUCCESS!!!! We have something that renders! Here is the final program sbmloader.py that reads, parses the SBM file format, created from this question.
Though the next question. Already answered, at part 2, creation of a ktxloader
- How to get the rendered object to appear as the torus/donut it is supposed to be? Perhaps there is something to do with loading the file here pattern1.ktx How do I load this to the variable tex_object variable? Simply assigning it doesn't seem to do anything. Ok, that's because ktx files are a different file format left for another project.
Update: June 24, 2019 The rendering issue has been fixed with perfect code by Rabbid76. I in wow shock, thank you very much!
The data to read, parse is here torus_nrms_tc.sbm
Any assistance, comments, or insight would be greatly appreciated. Here is what I have so far.
import sys
import time
import os
import time
import math
import ctypes
currentWDir = os.getcwd()
print( 'current working directory: {}'.format( str(currentWDir) ) )
fileDir = os.path.dirname(os.path.abspath(__file__)) # det the directory of this file
print( 'current location of self: {}'.format( str(fileDir) ) )
parentDir = os.path.abspath(os.path.join(fileDir, os.pardir)) # get the parent directory of this file
sys.path.insert(0, parentDir)
print( 'insert system directory: {}'.format( str(parentDir) ) )
os.chdir( fileDir )
baseWDir = os.getcwd()
print( 'changed current working directory: {}'.format( str(baseWDir) ) )
print ( '' )
fullscreen = True
import numpy.matlib
import numpy as np
try:
from OpenGL.GLUT import *
from OpenGL.GL import *
from OpenGL.GLU import *
#from OpenGL.raw.GL.ARB.vertex_array_object import glGenVertexArrays, glBindVertexArray
except:
print ('''
ERROR: PyOpenGL not installed properly.
''')
sys.exit()
def SB6M_FOURCC(a,b,c,d):
return ( (ord(a) << 0) | (ord(b) << 8) | (ord(c) << 16) | (ord(d) << 24) )
SB6M_MAGIC = SB6M_FOURCC('S','B','6','M')
SB6M_CHUNK_TYPE_INDEX_DATA = SB6M_FOURCC('I','N','D','X')
SB6M_CHUNK_TYPE_VERTEX_DATA = SB6M_FOURCC('V','R','T','X')
SB6M_CHUNK_TYPE_VERTEX_ATTRIBS = SB6M_FOURCC('A','T','R','B')
SB6M_CHUNK_TYPE_SUB_OBJECT_LIST = SB6M_FOURCC('O','L','S','T')
SB6M_CHUNK_TYPE_COMMENT = SB6M_FOURCC('C','M','N','T')
SB6M_CHUNK_TYPE_DATA = SB6M_FOURCC('D','A','T','A')
class SB6M_HEADER:
def __init__(self, data):
int_data = np.frombuffer(np.array(data[:16], dtype=np.byte), dtype=np.uint32)
self.magic, self.size, self.num_chunks, self.flags = int_data
print(self.magic, self.size, self.num_chunks, self.flags)
class SB6M_CHUNK_HEADER:
def __init__(self, data, offset):
int_data = np.frombuffer(np.array(data[offset:offset+8], dtype=np.byte), dtype=np.uint32)
self.type, self.size = int_data
class SB6M_CHUNK_INDEX_DATA(SB6M_CHUNK_HEADER):
def __init__(self, data, offset):
super().__init__(data, offset)
int_data = np.frombuffer(np.array(data[offset+8:offset+20], dtype=np.byte), dtype=np.uint32)
self.index_type, self.index_count, self.index_data_offset = int_data
class SB6M_CHUNK_VERTEX_DATA(SB6M_CHUNK_HEADER):
def __init__(self, data, offset):
super().__init__(data, offset)
int_data = np.frombuffer(np.array(data[offset+8:offset+20], dtype=np.byte), dtype=np.uint32)
self.data_size, self.data_offset, self.total_vertices = int_data
class SB6M_CHUNK_VERTEX_DATA(SB6M_CHUNK_HEADER):
def __init__(self, data, offset):
super().__init__(data, offset)
int_data = np.frombuffer(np.array(data[offset+8:offset+20], dtype=np.byte), dtype=np.uint32)
self.data_size, self.data_offset, self.total_vertices = int_data
SB6M_VERTEX_ATTRIB_FLAG_NORMALIZED = 0x00000001
SB6M_VERTEX_ATTRIB_FLAG_INTEGER = 0x00000002
class SB6M_VERTEX_ATTRIB_DECL:
def __init__(self, data, offset):
self.name = ''.join([chr(n) for n in data[offset:offset+64] if n > 30])
int_data = np.frombuffer(np.array(data[offset+64:offset+84], dtype=np.byte), dtype=np.uint32)
self.size, self.type, self.stride, self.flags, self.data_offset = int_data
class SB6M_VERTEX_ATTRIB_CHUNK(SB6M_CHUNK_HEADER):
def __init__(self, data, offset):
super().__init__(data, offset)
int_data = np.frombuffer(np.array(data[offset+8:offset+12], dtype=np.byte), dtype=np.uint32)
self.attrib_count = int_data[0]
self.attrib_data = []
for i in range(self.attrib_count):
self.attrib_data.append(SB6M_VERTEX_ATTRIB_DECL(data, offset+12+i*84))
class SB6M_DATA_CHUNK(SB6M_CHUNK_HEADER):
def __init__(self, data, offset):
super().__init__(data, offset)
int_data = np.frombuffer(np.array(data[offset+8:offset+20], dtype=np.byte), dtype=np.uint32)
self.encoding, self.data_offset, self.data_length = int_data
class SB6M_SUB_OBJECT_DECL:
def __init__(self, data, offset):
int_data = np.frombuffer(np.array(data[offset:offset+8], dtype=np.byte), dtype=np.uint32)
self.first, self.count = int_data
class SB6M_CHUNK_SUB_OBJECT_LIST(SB6M_CHUNK_HEADER):
def __init__(self, data, offset):
super().__init__(data, offset)
int_data = np.frombuffer(np.array(data[offset+8:offset+12], dtype=np.byte), dtype=np.uint32)
self.count = int_data[0]
self.sub_object = []
for i in range(self.count):
self.sub_object.append(SB6M_SUB_OBJECT_DECL(data, offset+12+i*8))
class SB6M_CHUNK_HEADER_:
chunk_type = 0
chunk_name = ''
size = 0
class SB6M_DATA_ENCODING:
SB6M_DATA_ENCODING_RAW = 0
class SB6M_CHUNK_COMMENT:
header = SB6M_CHUNK_HEADER_()
comment = []
comment.append('')
comment.append('')
# data_buffer = GLuint(0)
# vao = GLuint(0)
# index_type = GLuint(0)
index_offset = GLuint(0)
def get_sub_object_info(index, first, count):
if (index >= num_sub_objects):
first = 0
count = 0
else:
first = sub_object[index].first;
count = sub_object[index].count;
def render(instance_count = 1, base_instance = 0):
render_sub_object(0, instance_count, base_instance)
class SBMObject:
def __init__(self):
self.vao = GLuint(0)
def load(self, filename):
vertex_attrib_chunk = None
vertex_data_chunk = None
index_data_chunk = None
sub_object_chunk = None
data_chunk = None
#try:
data = numpy.fromfile(filename, dtype=np.byte)
filesize = data.size
header = SB6M_HEADER(data)
offset = header.size
for i in range(header.num_chunks):
chunk = SB6M_CHUNK_HEADER(data, offset)
if chunk.type == SB6M_CHUNK_TYPE_VERTEX_ATTRIBS:
vertex_attrib_chunk = SB6M_VERTEX_ATTRIB_CHUNK(data, offset)
elif chunk.type == SB6M_CHUNK_TYPE_VERTEX_DATA:
vertex_data_chunk = SB6M_CHUNK_VERTEX_DATA(data, offset)
elif chunk.type == SB6M_CHUNK_TYPE_INDEX_DATA:
index_data_chunk = SB6M_CHUNK_INDEX_DATA(data, offset)
elif chunk.type == SB6M_CHUNK_TYPE_SUB_OBJECT_LIST:
sub_object_chunk = SB6M_CHUNK_SUB_OBJECT_LIST(data, offset)
elif chunk.type == SB6M_CHUNK_TYPE_DATA:
data_chunk = SB6M_DATA_CHUNK(data, offset)
else:
raise
offset += chunk.size
#except:
# print("error reading file {}".format(filename))
print("finished reading")
if vertex_data_chunk and vertex_attrib_chunk:
start = vertex_data_chunk.data_offset
end = start + vertex_data_chunk.data_size
vertex_data = np.frombuffer(np.array(data[start:end], dtype=np.byte), dtype=np.float)
data_buffer = glGenBuffers(1)
glBindBuffer(GL_ARRAY_BUFFER, data_buffer)
glBufferData(GL_ARRAY_BUFFER, vertex_data, GL_STATIC_DRAW)
self.vertexcount = vertex_data_chunk.total_vertices
self.vao = glGenVertexArrays(1)
glBindVertexArray(self.vao)
for attrib_i, attrib in enumerate(vertex_attrib_chunk.attrib_data):
if attrib.name=='position' or attrib.name=='map1':
glVertexAttribPointer(attrib_i,
attrib.size, attrib.type,
GL_TRUE if (attrib.flags & SB6M_VERTEX_ATTRIB_FLAG_NORMALIZED) != 0 else GL_FALSE,
attrib.stride, ctypes.c_void_p(int(attrib.data_offset)))
glEnableVertexAttribArray(attrib_i)
def render(self):
glBindVertexArray(self.vao)
glDrawArrays(GL_TRIANGLES, 0, self.vertexcount)
# Vertex program
vs_source = '''
#version 420 core
uniform mat4 mv_matrix;
uniform mat4 proj_matrix;
layout (location = 0) in vec4 position;
layout (location = 4) in vec2 tc;
out VS_OUT
{
vec2 tc;
} vs_out;
void main(void)
{
vec4 pos_vs = mv_matrix * position;
vs_out.tc = tc;
gl_Position = proj_matrix * pos_vs;
}
'''
# Fragment program
fs_source = '''
#version 420 core
layout (binding = 0) uniform sampler2D tex_object;
in VS_OUT
{
vec2 tc;
} fs_in;
out vec4 color;
void main(void)
{
color = texture(tex_object, fs_in.tc * vec2(3.0, 1.0));
}
'''
identityMatrix = [1,0,0,0, 0,1,0,0, 0,0,1,0, 0,0,0,1]
render_prog = GLuint(0)
uniforms_mv_matrix = (GLfloat * 16)(*identityMatrix)
uniforms_proj_matrix = (GLfloat * 16)(*identityMatrix)
tex_index = 0
tex_object = []
M3D_PI = 3.14159265358979323846
M3D_PI_DIV_180 = M3D_PI / 180.0
M3D_INV_PI_DIV_180 = 57.2957795130823229
def m3dDegToRad(num):
return (num * M3D_PI_DIV_180)
def m3dRadToDeg(num):
return (num * M3D_INV_PI_DIV_180)
# Translate matrix. Only 4x4 matrices supported
def m3dTranslateMatrix44(m, x, y, z):
m[12] += x
m[13] += y
m[14] += z
# Creates a 4x4 rotation matrix, takes radians NOT degrees
def m3dRotationMatrix44(m, angle, x, y, z):
s = math.sin(angle)
c = math.cos(angle)
mag = float((x * x + y * y + z * z) ** 0.5)
if mag == 0.0:
m3dLoadIdentity(m)
return
x /= mag
y /= mag
z /= mag
xx = x * x
yy = y * y
zz = z * z
xy = x * y
yz = y * z
zx = z * x
xs = x * s
ys = y * s
zs = z * s
one_c = 1.0 - c
m[0] = (one_c * xx) + c
m[1] = (one_c * xy) - zs
m[2] = (one_c * zx) + ys
m[3] = 0.0
m[4] = (one_c * xy) + zs
m[5] = (one_c * yy) + c
m[6] = (one_c * yz) - xs
m[7] = 0.0
m[8] = (one_c * zx) - ys
m[9] = (one_c * yz) + xs
m[10] = (one_c * zz) + c
m[11] = 0.0
m[12] = 0.0
m[13] = 0.0
m[14] = 0.0
m[15] = 1.0
def m3dMultiply(A, B):
C = (GLfloat * 16)(*identityMatrix)
for k in range(0, 4):
for j in range(0, 4):
C[k*4+j] = A[0*4+j] * B[k*4+0] + A[1*4+j] * B[k*4+1] + \
A[2*4+j] * B[k*4+2] + A[3*4+j] * B[k*4+3]
return C
def m3dOrtho(l, r, t, b, n, f):
return (GLfloat * 16)(
2/(r-l), 0, 0, 0,
0, 2/(t-b), 0, 0,
0, 0, -2/(f-n), 0,
-(r+l)/(r-l), -(t+b)/(t-b), -(f+n)/(f-n), 1)
def m3dPerspective(fov_y, aspect, n, f):
a = aspect
ta = math.tan( fov_y / 2 )
return (GLfloat * 16)(
1/(ta*a), 0, 0, 0,
0, 1/ta, 0, 0,
0, 0, -(f+n)/(f-n), -1,
0, 0, -2*f*n/(f-n), 0)
def rotation_matrix(axis, theta):
"""
Return the rotation matrix associated with counterclockwise rotation about
the given axis by theta radians.
"""
axis = np.asarray(axis)
axis = axis / math.sqrt(np.dot(axis, axis))
a = math.cos(theta / 2.0)
b, c, d = -axis * math.sin(theta / 2.0)
aa, bb, cc, dd = a * a, b * b, c * c, d * d
bc, ad, ac, ab, bd, cd = b * c, a * d, a * c, a * b, b * d, c * d
return np.array([[aa + bb - cc - dd, 2 * (bc + ad), 2 * (bd - ac), 0],
[2 * (bc - ad), aa + cc - bb - dd, 2 * (cd + ab), 0],
[2 * (bd + ac), 2 * (cd - ab), aa + dd - bb - cc, 0],
[0,0,0,1]])
def translate(tx, ty, tz):
"""creates the matrix equivalent of glTranslate"""
return np.array([1.0, 0.0, 0.0, 0.0,
0.0, 1.0, 0.0, 0.0,
0.0, 0.0, 1.0, 0.0,
tx, ty, tz, 1.0], np.float32)
def load_shaders():
global render_prog
global uniforms_mv_matrix
global uniforms_proj_matrix
if (render_prog):
glDeleteProgram(render_prog);
fs = glCreateShader(GL_FRAGMENT_SHADER);
glShaderSource(fs, fs_source);
glCompileShader(fs);
vs = glCreateShader(GL_VERTEX_SHADER);
glShaderSource(vs, vs_source);
glCompileShader(vs);
render_prog = glCreateProgram();
glAttachShader(render_prog, vs);
glAttachShader(render_prog, fs);
glLinkProgram(render_prog);
glDeleteShader(vs);
glDeleteShader(fs);
uniforms_mv_matrix = glGetUniformLocation(render_prog, "mv_matrix");
uniforms_proj_matrix = glGetUniformLocation(render_prog, "proj_matrix");
class Scene:
def __init__(self, width, height):
self.width = width
self.height = height
B = (0x00, 0x00, 0x00, 0x00)
W = (0xFF, 0xFF, 0xFF, 0xFF)
tex_data = [
B, W, B, W, B, W, B, W, B, W, B, W, B, W, B, W,
W, B, W, B, W, B, W, B, W, B, W, B, W, B, W, B,
B, W, B, W, B, W, B, W, B, W, B, W, B, W, B, W,
W, B, W, B, W, B, W, B, W, B, W, B, W, B, W, B,
B, W, B, W, B, W, B, W, B, W, B, W, B, W, B, W,
W, B, W, B, W, B, W, B, W, B, W, B, W, B, W, B,
B, W, B, W, B, W, B, W, B, W, B, W, B, W, B, W,
W, B, W, B, W, B, W, B, W, B, W, B, W, B, W, B,
B, W, B, W, B, W, B, W, B, W, B, W, B, W, B, W,
W, B, W, B, W, B, W, B, W, B, W, B, W, B, W, B,
B, W, B, W, B, W, B, W, B, W, B, W, B, W, B, W,
W, B, W, B, W, B, W, B, W, B, W, B, W, B, W, B,
B, W, B, W, B, W, B, W, B, W, B, W, B, W, B, W,
W, B, W, B, W, B, W, B, W, B, W, B, W, B, W, B,
B, W, B, W, B, W, B, W, B, W, B, W, B, W, B, W,
W, B, W, B, W, B, W, B, W, B, W, B, W, B, W, B,
]
tex_object.append( glGenTextures(1) )
#glGenTextures(1, tex_object[0]);
glBindTexture(GL_TEXTURE_2D, tex_object[0]);
glTexStorage2D(GL_TEXTURE_2D, 1, GL_RGB8, 16, 16);
glTexSubImage2D(GL_TEXTURE_2D, 0, 0, 0, 16, 16, GL_RGBA, GL_UNSIGNED_BYTE, tex_data);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
tex_object.append ( glGenTextures(1) )
#tex_object[1] = sb7::ktx::file::load("pattern1.ktx");
myobject.load("torus_nrms_tc.sbm");
load_shaders();
glEnable(GL_DEPTH_TEST);
glDepthFunc(GL_LEQUAL);
def display(self):
global uniforms_mv_matrix
global uniforms_proj_matrix
currentTime = time.time()
gray = [ 0.2, 0.2, 0.2, 1.0 ];
ones = [ 1.0 ];
glClearBufferfv(GL_COLOR, 0, gray);
glClearBufferfv(GL_DEPTH, 0, ones);
glViewport(0, 0, self.width, self.height);
glBindTexture(GL_TEXTURE_2D, tex_object[tex_index]);
glUseProgram(render_prog);
T = (GLfloat * 16)(*identityMatrix)
RX = (GLfloat * 16)(*identityMatrix)
RY = (GLfloat * 16)(*identityMatrix)
R = (GLfloat * 16)(*identityMatrix)
# way # 1 - works
# T = translate(0.0, 0.0, -4.0).reshape(4,4)
# RX = np.array(rotation_matrix( [1.0, 0.0, 0.0], currentTime * m3dDegToRad(17.0)))
# RY = np.array(rotation_matrix( [0.0, 1.0, 0.0], currentTime * m3dDegToRad(13.0)))
# mv_matrix = np.matmul(np.matmul(RY, RX), T)
# way # 2 - works !!
m3dTranslateMatrix44(T, 0, 0, -4)
m3dRotationMatrix44(RX, currentTime * m3dDegToRad(17.0), 1.0, 0.0, 0.0)
m3dRotationMatrix44(RY, currentTime * m3dDegToRad(13.0), 0.0, 1.0, 0.0)
# way # 2 - option A works!
# Matrix multiplication is not commutative, order matters when multiplying matrices
R = m3dMultiply(RY, RX)
mv_matrix = m3dMultiply(T, R)
# way # 2 - option B works!
# T = np.matrix(T).reshape(4,4)
# mv_matrix = np.matmul(np.matmul(np.matrix(RY).reshape(4,4), np.matrix(RX).reshape(4,4)).reshape(4,4), T)
# way # 3 - works also
# T = np.matrix(translate(0.0, 0.0, -4.0)).reshape(4,4)
# RX = np.matrix(rotation_matrix( [1.0, 0.0, 0.0], currentTime * m3dDegToRad(17.0)))
# RY = np.matrix(rotation_matrix( [0.0, 1.0, 0.0], currentTime * m3dDegToRad(13.0)))
# mv_matrix = RX * RY * T
proj_matrix = (GLfloat * 16)(*identityMatrix)
proj_matrix = m3dPerspective(m3dDegToRad(60.0), float(self.width) / float(self.height), 0.1, 100.0);
glUniformMatrix4fv(uniforms_mv_matrix, 1, GL_FALSE, mv_matrix);
glUniformMatrix4fv(uniforms_proj_matrix, 1, GL_FALSE, proj_matrix);
myobject.render()
#gltDrawTorus(0.35, 0.15, 40, 20)
glutSwapBuffers()
def reshape(self, width, height):
self.width = width
self.height = height
def keyboard(self, key, x, y ):
global fullscreen
global tex_index
print ('key:' , key)
if key == b'\x1b': # ESC
sys.exit()
elif key == b'f' or key == b'F': #fullscreen toggle
if (fullscreen == True):
glutReshapeWindow(self.width, self.height)
glutPositionWindow(int((1360/2)-(512/2)), int((768/2)-(512/2)))
fullscreen = False
else:
glutFullScreen()
fullscreen = True
elif key == b'r' or key == b'R':
load_shaders()
elif key == b't' or key == b'T':
tex_index+=1
if (tex_index > 1):
tex_index = 0
print('done')
def init(self):
pass
def timer(self, blah):
glutPostRedisplay()
glutTimerFunc( int(1/60), self.timer, 0)
time.sleep(1/20.0)
myobject = SBMObject()
if __name__ == '__main__':
start = time.time()
glutInit()
glutInitDisplayMode(GLUT_RGBA | GLUT_DOUBLE | GLUT_DEPTH)
glutInitWindowSize(512, 512)
w1 = glutCreateWindow('OpenGL SuperBible - Texture Coordinates')
fullscreen = False
#glutFullScreen()
scene = Scene(512, 512)
glutReshapeFunc(scene.reshape)
glutDisplayFunc(scene.display)
glutKeyboardFunc(scene.keyboard)
glutIdleFunc(scene.display)
#glutTimerFunc( int(1/60), scene.timer, 0)
scene.init()
glutMainLoop()
Example of data structure of texture file - p.757 OpenGL Superbible 6th ed. or p.807 7th ed.
回答1:
Since you are already using NumPy, i'll give yuo an answer which uses NumPy to read the binary file. NumPy has some had functionality to reinterpret buffer data by different data type and that is exactly what is needed to interpret a binary file.
A binary file can be read toe a byte array by numpy.fromfile.e.g.:
data = numpy.fromfile(filename, dtype=np.byte)
Some bytes of the array can be interpreted as unsigned integer (unit32) by numpy.frombuffer. e.g.:
class SB6M_HEADER:
def __init__(self, data):
int_data = np.frombuffer(np.array(data[:16], dtype=np.byte), dtype=np.uint32)
self.magic, self.size, self.num_chunks, self.flags = int_data
print(self.magic, self.size, self.num_chunks, self.flags)
Porting the source code from sb6mfile.h respectively sb7object.cpp to python and reading and "*.sbm" file:
def SB6M_FOURCC(a,b,c,d):
return ( (ord(a) << 0) | (ord(b) << 8) | (ord(c) << 16) | (ord(d) << 24) )
SB6M_MAGIC = SB6M_FOURCC('S','B','6','M')
SB6M_CHUNK_TYPE_INDEX_DATA = SB6M_FOURCC('I','N','D','X')
SB6M_CHUNK_TYPE_VERTEX_DATA = SB6M_FOURCC('V','R','T','X')
SB6M_CHUNK_TYPE_VERTEX_ATTRIBS = SB6M_FOURCC('A','T','R','B')
SB6M_CHUNK_TYPE_SUB_OBJECT_LIST = SB6M_FOURCC('O','L','S','T')
SB6M_CHUNK_TYPE_COMMENT = SB6M_FOURCC('C','M','N','T')
SB6M_CHUNK_TYPE_DATA = SB6M_FOURCC('D','A','T','A')
class SB6M_HEADER:
def __init__(self, data):
int_data = np.frombuffer(np.array(data[:16], dtype=np.byte), dtype=np.uint32)
self.magic, self.size, self.num_chunks, self.flags = int_data
print(self.magic, self.size, self.num_chunks, self.flags)
class SB6M_CHUNK_HEADER:
def __init__(self, data, offset):
int_data = np.frombuffer(np.array(data[offset:offset+8], dtype=np.byte), dtype=np.uint32)
self.type, self.size = int_data
class SB6M_CHUNK_INDEX_DATA(SB6M_CHUNK_HEADER):
def __init__(self, data, offset):
super().__init__(data, offset)
int_data = np.frombuffer(np.array(data[offset+8:offset+20], dtype=np.byte), dtype=np.uint32)
self.index_type, self.index_count, self.index_data_offset = int_data
class SB6M_CHUNK_VERTEX_DATA(SB6M_CHUNK_HEADER):
def __init__(self, data, offset):
super().__init__(data, offset)
int_data = np.frombuffer(np.array(data[offset+8:offset+20], dtype=np.byte), dtype=np.uint32)
self.data_size, self.data_offset, self.total_vertices = int_data
class SB6M_CHUNK_VERTEX_DATA(SB6M_CHUNK_HEADER):
def __init__(self, data, offset):
super().__init__(data, offset)
int_data = np.frombuffer(np.array(data[offset+8:offset+20], dtype=np.byte), dtype=np.uint32)
self.data_size, self.data_offset, self.total_vertices = int_data
SB6M_VERTEX_ATTRIB_FLAG_NORMALIZED = 0x00000001
SB6M_VERTEX_ATTRIB_FLAG_INTEGER = 0x00000002
class SB6M_VERTEX_ATTRIB_DECL:
def __init__(self, data, offset):
self.name = ''.join([chr(n) for n in data[offset:offset+64] if n > 30])
int_data = np.frombuffer(np.array(data[offset+64:offset+84], dtype=np.byte), dtype=np.uint32)
self.size, self.type, self.stride, self.flags, self.data_offset = int_data
class SB6M_VERTEX_ATTRIB_CHUNK(SB6M_CHUNK_HEADER):
def __init__(self, data, offset):
super().__init__(data, offset)
int_data = np.frombuffer(np.array(data[offset+8:offset+12], dtype=np.byte), dtype=np.uint32)
self.attrib_count = int_data[0]
self.attrib_data = []
for i in range(self.attrib_count):
self.attrib_data.append(SB6M_VERTEX_ATTRIB_DECL(data, offset+12+i*84))
class SB6M_DATA_CHUNK(SB6M_CHUNK_HEADER):
def __init__(self, data, offset):
super().__init__(data, offset)
int_data = np.frombuffer(np.array(data[offset+8:offset+20], dtype=np.byte), dtype=np.uint32)
self.encoding, self.data_offset, self.data_length = int_data
class SB6M_SUB_OBJECT_DECL:
def __init__(self, data, offset):
int_data = np.frombuffer(np.array(data[offset:offset+8], dtype=np.byte), dtype=np.uint32)
self.first, self.count = int_data
class SB6M_CHUNK_SUB_OBJECT_LIST(SB6M_CHUNK_HEADER):
def __init__(self, data, offset):
super().__init__(data, offset)
int_data = np.frombuffer(np.array(data[offset+8:offset+12], dtype=np.byte), dtype=np.uint32)
self.count = int_data[0]
self.sub_object = []
for i in range(self.count):
self.sub_object.append(SB6M_SUB_OBJECT_DECL(data, offset+12+i*8))
def load(filename):
vertex_attrib_chunk = None
vertex_data_chunk = None
index_data_chunk = None
sub_object_chunk = None
data_chunk = None
try:
data = numpy.fromfile(filename, dtype=np.byte)
filesize = data.size
header = SB6M_HEADER(data)
offset = header.size
for i in range(header.num_chunks):
chunk = SB6M_CHUNK_HEADER(data, offset)
if chunk.type == SB6M_CHUNK_TYPE_VERTEX_ATTRIBS:
vertex_attrib_chunk = SB6M_VERTEX_ATTRIB_CHUNK(data, offset)
elif chunk.type == SB6M_CHUNK_TYPE_VERTEX_DATA:
vertex_data_chunk = SB6M_CHUNK_VERTEX_DATA(data, offset)
elif chunk.type == SB6M_CHUNK_TYPE_INDEX_DATA:
index_data_chunk = SB6M_CHUNK_INDEX_DATA(data, offset)
elif chunk.type == SB6M_CHUNK_TYPE_SUB_OBJECT_LIST:
sub_object_chunk = SB6M_CHUNK_SUB_OBJECT_LIST(data, offset)
elif chunk.type == SB6M_CHUNK_TYPE_DATA:
data_chunk = SB6M_DATA_CHUNK(data, offset)
else:
raise
offset += chunk.size
except:
print("error reading file {}".format(filename))
Finally the floating point vertex data can be read:
if vertex_data_chunk and vertex_attrib_chunk:
start = vertex_data_chunk.data_offset
end = start + vertex_data_chunk.data_size
vertex_data = np.frombuffer(np.array(data[start:end], dtype=np.byte), dtype=np.float)
data_buffer = glGenBuffers(1)
glBindBuffer(GL_ARRAY_BUFFER, data_buffer)
glBufferData(GL_ARRAY_BUFFER, vertex_data, GL_STATIC_DRAW)
vertexcount = vertex_data_chunk.total_vertices
vao = glGenVertexArrays(1)
glBindVertexArray(self.vao)
for attrib_i, attrib in enumerate(vertex_attrib_chunk.attrib_data):
if attrib.name=='position' or attrib.name=='map1':
glVertexAttribPointer(attrib_i,
attrib.size, attrib.type,
GL_TRUE if (attrib.flags & SB6M_VERTEX_ATTRIB_FLAG_NORMALIZED) != 0 else GL_FALSE,
attrib.stride, ctypes.c_void_p(int(attrib.data_offset)))
glEnableVertexAttribArray(attrib_i)
Finally draw the mesh:
glBindVertexArray(vao)
glDrawArrays(GL_TRIANGLES, 0, vertexcount)
回答2:
The next step has to be similar to what happens in the C code:
SB6M_HEADER * header = (SB6M_HEADER *)ptr;
ptr += header->size;
You need to advance the pointer by a known size.
You have that attribute in your header class. Do you set it correctly?
But I would suggest a different approach: do not use raw Pyhon for this at all.
Instead create a wrapper using the original C code found in sb6mfile.h
and a part of the function to read the file found in sb7object.cpp
Then access this code using Python's CFFI. You pass the C header with the SBM types to the files and can use them in Python.
Once this works you can get the data back and put it in a numpy array. Usually this is a bit of work but once it works it is really robust.
Here are some links to get you started:
buffer_size = np_arr.size*np_arr.dtype.itemsize
c_buffer = ffi.buffer(cffi_arr,buffer_size)
np_arr2 = np.frombuffer(c_buffer, dtype=np_arr.dtype)
(https://ammous88.wordpress.com/2014/12/30/numpy-array-with-cffi-c-function/)
https://docs.scipy.org/doc/numpy/reference/generated/numpy.frombuffer.html
How to pass a Numpy array into a cffi function and how to get one back out?
numpy.frombuffer(ffi.buffer(p, size))https://bitbucket.org/cffi/cffi/issues/292/cant-copy-data-to-a-numpy-array#comment-31752678
来源：https://stackoverflow.com/questions/56711138/how-to-read-parse-the-sbm-file-format-from-superbible-opengl