Algorithm 在GLSL中将浮点数转换为十进制数字
，GLSL缺少任何类型的printf调试 但有时我真的希望在调试着色器时检查数值 我一直在尝试创建一个可视化调试工具。 我发现，如果使用Algorithm 在GLSL中将浮点数转换为十进制数字,algorithm,opengl,printf,glsl,shader,Algorithm,Opengl,Printf,Glsl,Shader,，GLSL缺少任何类型的printf调试 但有时我真的希望在调试着色器时检查数值 我一直在尝试创建一个可视化调试工具。 我发现，如果使用sampler2D，其中数字0123456789已在monospace中渲染，则可以在着色器中相当轻松地渲染任意数字序列。基本上，你只需要改变你的x坐标 现在，要使用它来检查浮点数，我需要一个算法来将float转换为十进制数字序列，就像您在任何printf实现中可以找到的那样 不幸的是，这些算法似乎需要表示 更高精度格式的浮点数，我不知道会是什么样子 可能在GL
sampler2D0123456789floatprintffloatrenderecimal（1.0）1.09999702renderecimal（2.5）2.599999246RenderDecimal（2.6）2.6999992801.02.6renderecimal（2.5）50.099…2.599000022pythonpython2.x数字。pngvertexShaderSource = """\
varying vec2 vFragCoordinate;
void main(void)
{
vFragCoordinate = gl_Vertex.xy;
gl_Position = gl_ModelViewProjectionMatrix * gl_Vertex;
}
"""
fragmentShaderSource = """\
varying vec2 vFragCoordinate;
uniform vec2 uTextureSize;
uniform sampler2D uTextureSlotNumber;
float OrderOfMagnitude( float x )
{
return x == 0.0 ? 0.0 : floor( log( abs( x ) ) / log( 10.0 ) );
}
void RenderDecimal( float value )
{
// Assume that the texture to which uTextureSlotNumber refers contains
// a rendering of the digits '0123456789' packed together, such that
const vec2 startOfDigitsInTexture = vec2( 0, 0 ); // the lower-left corner of the first digit starts here and
const vec2 sizeOfDigit = vec2( 100, 125 ); // each digit spans this many pixels
const float nSpaces = 10.0; // assume we have this many digits' worth of space to render in
value = abs( value );
vec2 pos = vFragCoordinate - startOfDigitsInTexture;
float dpstart = max( 0.0, OrderOfMagnitude( value ) );
float decimal_position = dpstart - floor( pos.x / sizeOfDigit.x );
float remainder = mod( pos.x, sizeOfDigit.x );
if( pos.x >= 0 && pos.x < sizeOfDigit.x * nSpaces && pos.y >= 0 && pos.y < sizeOfDigit.y )
{
float digit_value;
// Version B
float dp, running_value = value;
for( dp = dpstart; dp >= decimal_position; dp -= 1.0 )
{
float base = pow( 10.0, dp );
digit_value = mod( floor( running_value / base ), 10.0 );
running_value -= digit_value * base;
}
// Version A
//digit_value = mod( floor( value * pow( 10.0, -decimal_position ) ), 10.0 );
vec2 textureSourcePosition = vec2( startOfDigitsInTexture.x + remainder + digit_value * sizeOfDigit.x, startOfDigitsInTexture.y + pos.y );
gl_FragColor = texture2D( uTextureSlotNumber, textureSourcePosition / uTextureSize );
}
// Render the decimal point
if( ( decimal_position == -1.0 && remainder / sizeOfDigit.x < 0.1 && abs( pos.y ) / sizeOfDigit.y < 0.1 ) ||
( decimal_position == 0.0 && remainder / sizeOfDigit.x > 0.9 && abs( pos.y ) / sizeOfDigit.y < 0.1 ) )
{
gl_FragColor = texture2D( uTextureSlotNumber, ( startOfDigitsInTexture + sizeOfDigit * vec2( 1.5, 0.5 ) ) / uTextureSize );
}
}
void main(void)
{
gl_FragColor = texture2D( uTextureSlotNumber, vFragCoordinate / uTextureSize );
RenderDecimal( 2.5 ); // for current demonstration purposes, just a constant
}
"""
# Python (PyOpenGL) code to demonstrate the above
# (Note: the same OpenGL calls could be made from any language)
import os, sys, time
import OpenGL
from OpenGL.GL import *
from OpenGL.GLU import *
import pygame, pygame.locals # just for getting a canvas to draw on
try: from PIL import Image # PIL.Image module for loading image from disk
except ImportError: import Image # old PIL didn't package its submodules on the path
import numpy # for manipulating pixel values on the Python side
def CompileShader( type, source ):
shader = glCreateShader( type )
glShaderSource( shader, source )
glCompileShader( shader )
result = glGetShaderiv( shader, GL_COMPILE_STATUS )
if result != 1:
raise Exception( "Shader compilation failed:\n" + glGetShaderInfoLog( shader ) )
return shader
class World:
def __init__( self, width, height ):
self.window = pygame.display.set_mode( ( width, height ), pygame.OPENGL | pygame.DOUBLEBUF )
# compile shaders
vertexShader = CompileShader( GL_VERTEX_SHADER, vertexShaderSource )
fragmentShader = CompileShader( GL_FRAGMENT_SHADER, fragmentShaderSource )
# build shader program
self.program = glCreateProgram()
glAttachShader( self.program, vertexShader )
glAttachShader( self.program, fragmentShader )
glLinkProgram( self.program )
# try to activate/enable shader program, handling errors wisely
try:
glUseProgram( self.program )
except OpenGL.error.GLError:
print( glGetProgramInfoLog( self.program ) )
raise
# enable alpha blending
glTexEnvf( GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_MODULATE )
glEnable( GL_DEPTH_TEST )
glEnable( GL_BLEND )
glBlendEquation( GL_FUNC_ADD )
glBlendFunc( GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA )
# set projection and background color
gluOrtho2D( 0, width, 0, height )
glClearColor( 0.0, 0.0, 0.0, 1.0 )
self.uTextureSlotNumber_addr = glGetUniformLocation( self.program, 'uTextureSlotNumber' )
self.uTextureSize_addr = glGetUniformLocation( self.program, 'uTextureSize' )
def RenderFrame( self, *textures ):
glClear( GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT )
for t in textures: t.Draw( world=self )
pygame.display.flip()
def Close( self ):
pygame.display.quit()
def Capture( self ):
w, h = self.window.get_size()
rawRGB = glReadPixels( 0, 0, w, h, GL_RGB, GL_UNSIGNED_BYTE )
return Image.frombuffer( 'RGB', ( w, h ), rawRGB, 'raw', 'RGB', 0, 1 ).transpose( Image.FLIP_TOP_BOTTOM )
class Texture:
def __init__( self, source, slot=0, position=(0,0,0) ):
# wrangle array
source = numpy.array( source )
if source.dtype.type not in [ numpy.float32, numpy.float64 ]: source = source.astype( float ) / 255.0
while source.ndim < 3: source = numpy.expand_dims( source, -1 )
if source.shape[ 2 ] == 1: source = source[ :, :, [ 0, 0, 0 ] ] # LUMINANCE -> RGB
if source.shape[ 2 ] == 2: source = source[ :, :, [ 0, 0, 0, 1 ] ] # LUMINANCE_ALPHA -> RGBA
if source.shape[ 2 ] == 3: source = source[ :, :, [ 0, 1, 2, 2 ] ]; source[ :, :, 3 ] = 1.0 # RGB -> RGBA
# now it can be transferred as GL_RGBA and GL_FLOAT
# housekeeping
self.textureSize = [ source.shape[ 1 ], source.shape[ 0 ] ]
self.textureSlotNumber = slot
self.textureSlotCode = getattr( OpenGL.GL, 'GL_TEXTURE%d' % slot )
self.listNumber = slot + 1
self.position = list( position )
# transfer texture content
glActiveTexture( self.textureSlotCode )
self.textureID = glGenTextures( 1 )
glBindTexture( GL_TEXTURE_2D, self.textureID )
glEnable( GL_TEXTURE_2D )
glTexImage2D( GL_TEXTURE_2D, 0, GL_RGBA32F, self.textureSize[ 0 ], self.textureSize[ 1 ], 0, GL_RGBA, GL_FLOAT, source[ ::-1 ] )
glTexParameterf( GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST )
glTexParameterf( GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST )
# define surface
w, h = self.textureSize
glNewList( self.listNumber, GL_COMPILE )
glBegin( GL_QUADS )
glColor3f( 1, 1, 1 )
glNormal3f( 0, 0, 1 )
glVertex3f( 0, h, 0 )
glVertex3f( w, h, 0 )
glVertex3f( w, 0, 0 )
glVertex3f( 0, 0, 0 )
glEnd()
glEndList()
def Draw( self, world ):
glPushMatrix()
glTranslate( *self.position )
glUniform1i( world.uTextureSlotNumber_addr, self.textureSlotNumber )
glUniform2f( world.uTextureSize_addr, *self.textureSize )
glCallList( self.listNumber )
glPopMatrix()
world = World( 1000, 800 )
digits = Texture( Image.open( 'digits.png' ) )
done = False
while not done:
world.RenderFrame( digits )
for event in pygame.event.get():
# Press 'q' to quit or 's' to save a timestamped snapshot
if event.type == pygame.locals.QUIT: done = True
elif event.type == pygame.locals.KEYUP and event.key in [ ord( 'q' ), 27 ]: done = True
elif event.type == pygame.locals.KEYUP and event.key in [ ord( 's' ) ]:
world.Capture().save( time.strftime( 'snapshot-%Y%m%d-%H%M%S.png' ) )
world.Close()
vertexShaderSource=”“”\
可变矢量2坐标；
真空总管（真空）
{
vFragCoordinate=gl_Vertex.xy；
gl_位置=gl_模型视图投影矩阵*gl_顶点；
}
"""
fragmentShaderSource=“”\
可变矢量2坐标；
统一的vec2文本大小；
均匀取样器2D uTextureSlotNumber；
浮点数量级（浮点x）
{
返回x==0.0？0.0:floor（log（abs（x））/log（10.0））；
}
void renderCIMAL（浮动值）
{
//假设uTextureSlotNumber引用的纹理包含
//压缩在一起的数字“0123456789”的呈现，以便
const vec2 startofdigitintexture=vec2（0，0）；//第一个数字的左下角从这里开始，然后
const vec2 sizeOfDigit=vec2（100125）；//每个数字跨越这么多像素
const float nSpaces=10.0；//假设我们有这么多数字的空间来渲染
值=abs（值）；
vec2 pos=vFragCoordinate-开始数字集成；
浮点dpstart=max（0.0，数量级（值））；
浮点十进制位置=dpstart-地板（位置x/sizeOfDigit.x）；
浮动余数=模（位置x，尺寸F数字x）；
如果（pos.x>=0&&pos.x=0&&pos.y=十进制位置；dp-=1.0）
{
浮动底座=功率（10.0，dp）；
数字_值=mod（地板（运行_值/基础），10.0）；
运行_值-=数字_值*基数；
}
//版本A
//数字值=模（地板（值*功率（10.0，-十进制位置）），10.0）；
vec2 textureSourcePosition=vec2（StartToDigitIntexture.x+余数+位数值*sizeOfDigit.x，StartToDigitIntexture.y+位置y）；
gl_FragColor=纹理2d（uTextureSlotNumber，纹理资源位置/uTextureSize）；
}
//渲染小数点
if（（十进制位置==-1.0和余数/sizeOfDigit.x<0.1和abs（pos.y）/sizeOfDigit.y<0.1）||
（十进制位置==0.0和余数/sizeOfDigit.x>0.9和abs（pos.y）/sizeOfDigit.y<0.1））
{
gl_FragColor=texture2D（uTextureSlotNumber，（startoDigiitsIntexture+sizeOfDigit*vec2（1.5,0.5））/uTextureSize；
}
}
真空总管（真空）
{
gl_FragColor=纹理2d（uTextureSlotNumber，vFragCoordinate/uTextureSize）；
renderCIMAL（2.5）；//对于当前的演示，只需一个常量
}
"""
#Python（PyOpenGL）代码来演示上述内容
#（注意：任何语言都可以进行相同的OpenGL调用）
导入操作系统、系统、时间
导入OpenGL
从OpenGL.GL导入*
从OpenGL.GLU导入*
导入pygame，pygame.locals#只是为了得到一张画布来画画
try:from PIL import Image#PIL.Image模块用于从磁盘加载映像
除了ImportError:import Image#old PIL没有在路径上打包其子模块
导入numpy#用于在Python端操纵像素值
def编译头（类型、源）：
着色器=glCreateShader（类型）
glShaderSource（着色器，源）
glCompileShader（着色器）
结果=glGetShaderiv（着色器，GL\u编译\u状态）
如果有结果！=1:
引发异常（“着色器编译失败：\n”+glGetShaderInfoLog（着色器））
重新
// Assume that the texture to which uTextureSlotNumber refers contains
// a rendering of the digits '0123456789' packed together, such that
const vec2 startOfDigitsInTexture = vec2( 100, 125 ); // the lower-left corner of the first digit starts here and
const vec2 sizeOfDigit = vec2( 0.1, 0.2 ); // each digit spans this many pixels
const float nSpaces = 10.0; // assume we have this many digits' worth of space to render in
void RenderDigit( int strPos, int digit, vec2 pos )
{
float testStrPos = pos.x / sizeOfDigit.x;
if ( testStrPos >= float(strPos) && testStrPos < float(strPos+1) )
{
float start = sizeOfDigit.x * float(digit);
vec2 textureSourcePosition = vec2( startOfDigitsInTexture.x + start + mod( pos.x, sizeOfDigit.x ), startOfDigitsInTexture.y + pos.y );
gl_FragColor = texture2D( uTextureSlotNumber, textureSourcePosition / uTextureSize );
}
}
const int MAX_DIGITS = 32;
int digits[MAX_DIGITS];
int noOfDigits = 0;
int posOfComma = 0;
void Reverse( int start, int end )
{
for ( ; start < end; ++ start, -- end )
{
int digit = digits[start];
digits[start] = digits[end];
digits[end] = digit;
}
}
void ValueToDigits( float value )
{
const float base = 10.0;
int start = noOfDigits;
value = abs( value );
float frac = value; value = floor(value); frac -= value;
// integral digits
for ( ; value > 0.0 && noOfDigits < MAX_DIGITS; ++ noOfDigits )
{
float newValue = floor( value / base );
digits[noOfDigits] = int( value - base * newValue );
value = newValue;
}
Reverse( start, noOfDigits-1 );
posOfComma = noOfDigits;
// fractional digits
for ( ; frac > 0.0 && noOfDigits < MAX_DIGITS; ++ noOfDigits )
{
frac *= base;
float digit = floor( frac );
frac -= digit;
digits[noOfDigits] = int( digit );
}
}
void RenderDecimal( float value )
{
// fill the array of digits with the floating point value
ValueToDigits( value );
// Render the digits
vec2 pos = vFragCoordinate.xy - startOfDigitsInTexture;
if( pos.x >= 0 && pos.x < sizeOfDigit.x * nSpaces && pos.y >= 0 && pos.y < sizeOfDigit.y )
{
// render the digits
for ( int strPos = 0; strPos < noOfDigits; ++ strPos )
RenderDigit( strPos, digits[strPos], pos );
}
// Render the decimal point
float testStrPos = pos.x / sizeOfDigit.x;
float remainder = mod( pos.x, sizeOfDigit.x );
if( ( testStrPos >= float(posOfComma) && testStrPos < float(posOfComma+1) && remainder / sizeOfDigit.x < 0.1 && abs( pos.y ) / sizeOfDigit.y < 0.1 ) ||
( testStrPos >= float(posOfComma-1) && testStrPos < float(posOfComma) && remainder / sizeOfDigit.x > 0.9 && abs( pos.y ) / sizeOfDigit.y < 0.1 ) )
{
gl_FragColor = texture2D( uTextureSlotNumber, ( startOfDigitsInTexture + sizeOfDigit * vec2( 1.5, 0.5 ) ) / uTextureSize );
}
}
varying vec2 vFragCoordinate;
uniform vec2 uTextureSize;
uniform sampler2D uTextureSlotNumber;
float Digit( float x, int position, float base )
{
int i;
float digit;
if( position < 0 )
{
x = fract( x );
for( i = -1; i >= position; i-- )
{
if( x <= 0.0 ) { digit = 0.0; break; }
x *= base;
digit = floor( x );
x -= digit;
}
}
else
{
x = floor( x );
float prevx;
for( i = 0; i <= position; i++ )
{
if( x <= 0.0 ) { digit = 0.0; break; }
prevx = x;
x = floor( x / base );
digit = prevx - base * x;
}
}
return digit;
}
float OrderOfMagnitude( float x )
{
return x == 0.0 ? 0.0 : floor( log( abs( x ) ) / log( 10.0 ) );
}
void RenderDecimal( float value )
{
// Assume that the texture to which uTextureSlotNumber refers contains
// a rendering of the digits '0123456789' packed together, such that
const vec2 startOfDigitsInTexture = vec2( 0, 0 ); // the lower-left corner of the first digit starts here and
const vec2 sizeOfDigit = vec2( 100, 125 ); // each digit spans this many pixels
const float nSpaces = 10.0; // assume we have this many digits' worth of space to render in
value = abs( value );
vec2 pos = vFragCoordinate - startOfDigitsInTexture;
float dpstart = max( 0.0, OrderOfMagnitude( value ) );
int decimal_position = int( dpstart - floor( pos.x / sizeOfDigit.x ) );
float remainder = mod( pos.x, sizeOfDigit.x );
if( pos.x >= 0.0 && pos.x < sizeOfDigit.x * nSpaces && pos.y >= 0.0 && pos.y < sizeOfDigit.y )
{
float digit_value = Digit( value, decimal_position, 10.0 );
vec2 textureSourcePosition = vec2( startOfDigitsInTexture.x + remainder + digit_value * sizeOfDigit.x, startOfDigitsInTexture.y + pos.y );
gl_FragColor = texture2D( uTextureSlotNumber, textureSourcePosition / uTextureSize );
}
// Render the decimal point
if( ( decimal_position == -1 && remainder / sizeOfDigit.x < 0.1 && abs( pos.y ) / sizeOfDigit.y < 0.1 ) ||
( decimal_position == 0 && remainder / sizeOfDigit.x > 0.9 && abs( pos.y ) / sizeOfDigit.y < 0.1 ) )
{
gl_FragColor = texture2D( uTextureSlotNumber, ( startOfDigitsInTexture + sizeOfDigit * vec2( 1.5, 0.5 ) ) / uTextureSize );
}
}
void main(void)
{
gl_FragColor = texture2D( uTextureSlotNumber, vFragCoordinate / uTextureSize );
RenderDecimal( 2.5 ); // for current demonstration purposes, just a constant
}