问题描述
我最近下载了一个使用pyOpenGl和pygame的批处理渲染程序。我想编辑绘制功能，以便在绘制纹理时可以翻转纹理。这是批处理渲染程序的代码。
import numpy
from OpenGL import GL
from OpenGL.GL import shaders
import ctypes
def setup_shaders(vpMatrix):
global shaderProgram,vshader,fshader
global texCoordAttribute,positionAttribute
vshader = shaders.compileShader('''#version 440
layout (location = 0) uniform mat4 vpMatrix;
layout (location = 0) in vec2 vPosition;
layout (location = 1) in vec2 vTexCoord0;
//layout (location = 2) in vec4 vVertColor;
out vec2 texCoord0;
//out vec4 vertColor;
void main(void) {
gl_Position = vpMatrix * vec4(vPosition,0.0,1.0);
texCoord0 = vTexCoord0;
}''',GL.GL_VERTEX_SHADER)
fshader = shaders.compileShader('''#version 440
in vec2 texCoord0;
//in vec4 vertColor;
layout (location = 1) uniform sampler2D u_texture0;
void main(void) {
gl_FragColor = texture2D(u_texture0,texCoord0);
}''',GL.GL_FRAGMENT_SHADER)
shaderProgram = shaders.compileProgram(vshader,fshader)
texCoordAttribute = GL.glGetAttribLocation(shaderProgram,'vTexCoord0')
positionAttribute = GL.glGetAttribLocation(shaderProgram,'vPosition')
texUniform = GL.glGetUniformlocation(shaderProgram,'u_texture0')
GL.glEnabLevertexAttribArray(positionAttribute)
GL.glEnabLevertexAttribArray(texCoordAttribute)
GL.gluseProgram(shaderProgram)
GL.gluniformMatrix4fv(
GL.glGetUniformlocation(shaderProgram,'vpMatrix'),1,False,vpMatrix,)
GL.gluniform1i(texUniform,0)
# Todo: cleanup (delete shaders)
class GLTexture:
def __init__(self,textureId,width,height):
self.texture = textureId
self.width,self.height = width,height
def delete(self):
GL.glDeleteTextures([self.texture])
class GLTextureRegion:
def __init__(self,glTexture,subX,subY,subWidth,subHeight):
self.texture = glTexture
#self.tx,self.ty = subX,subY
self.tw,self.th = subWidth,subHeight
self.normalizedCoords = (
subX / glTexture.width,subY / glTexture.height,(subX + subWidth) / glTexture.width,subX / glTexture.width,(subY + subHeight) / glTexture.height,)
def write_tex_coords(self,aj):
nc = self.normalizedCoords
aj[4 * 0 + 2] = nc[0]
aj[4 * 0 + 3] = nc[1]
aj[4 * 1 + 2] = nc[2]
aj[4 * 1 + 3] = nc[3]
aj[4 * 2 + 2] = nc[4]
aj[4 * 2 + 3] = nc[5]
aj[4 * 3 + 2] = nc[6]
aj[4 * 3 + 3] = nc[7]
def write_vertices(self,aj,x,y):
aj[4 * 0 + 0] = x
aj[4 * 0 + 1] = y
aj[4 * 1 + 0] = x + self.tw
aj[4 * 1 + 1] = y
aj[4 * 2 + 0] = x
aj[4 * 2 + 1] = y + self.th
aj[4 * 3 + 0] = x + self.tw
aj[4 * 3 + 1] = y + self.th
def update_array(self,vboData,arrayIndex,y):
aj = vboData[arrayIndex]
self.write_vertices(aj,y)
self.write_tex_coords(aj)
def delete(self):
'''deletes the underlying texture'''
self.texture.delete()
class Batch:
def __init__(self,maxQuads = 10000):
self.maxQuads = maxQuads
self.vboIndices = GL.glGenBuffers(1)
GL.glBindBuffer(GL.GL_ELEMENT_ARRAY_BUFFER,self.vboIndices)
vidA = []
for i in range(maxQuads):
vidA.extend([
4 * i + 0,4 * i + 2,4 * i + 1,4 * i + 3
])
self.vboIndexData = numpy.array(vidA,numpy.ushort)
del vidA
GL.glBufferData(
GL.GL_ELEMENT_ARRAY_BUFFER,self.vboIndexData,GL.GL_STATIC_DRAW,)
self.vbo = GL.glGenBuffers(1) # texture coords & vertices
GL.glBindBuffer(GL.GL_ARRAY_BUFFER,self.vbo)
self.vboData = numpy.zeros((maxQuads,4 * 4),numpy.float32)
GL.glBufferData(
GL.GL_ARRAY_BUFFER,self.vboData,GL.GL_DYNAMIC_DRAW
)
self.currentTexture = None
self.objectIndex = 0
def begin(self):
GL.glBindBuffer(
GL.GL_ARRAY_BUFFER,self.vbo,)
if self.currentTexture:
GL.glBindTexture(
GL.GL_TEXTURE_2D,self.currentTexture.texture,)
GL.glEnable(GL.GL_TEXTURE_2D)
GL.glActiveTexture(GL.GL_TEXTURE0)
def draw(self,textureRegion,y,flip = False):
if self.currentTexture != textureRegion.texture:
self.flush()
self.currentTexture = textureRegion.texture
GL.glBindTexture(
GL.GL_TEXTURE_2D,textureRegion.texture.texture,)
elif self.objectIndex >= self.maxQuads:
self.flush()
textureRegion.update_array(
self.vboData,self.objectIndex,y
)
self.objectIndex += 1
def end(self):
self.flush()
def flush(self):
if not self.objectIndex:
return
GL.glVertexAttribPointer(
texCoordAttribute,2,GL.GL_FLOAT,GL.GL_TRUE,4 * self.vboData.itemsize,ctypes.c_void_p(2 * self.vboData.itemsize)
)
GL.glVertexAttribPointer(
positionAttribute,GL.GL_FALSE,ctypes.c_void_p(0)
)
GL.glBufferSubData(
GL.GL_ARRAY_BUFFER,16 * self.objectIndex * self.vboData.itemsize,)
GL.glDrawElements(
GL.GL_TRIANGLES,6 * self.objectIndex,GL.GL_UNSIGNED_SHORT,ctypes.c_void_p(0),)
self.objectIndex = 0
def delete(self):
GL.glDeleteBuffers(1,[self.vbo])
GL.glDeleteBuffers(1,[self.vboIndices])
到目前为止，我已经尝试了一些涉及glscalef的事情（正如我在网上找到的答案所建议的那样），但是我无法使它对纹理产生任何影响。有没有办法在draw函数中使这项工作有效？还是我必须完全尝试另一种方法？
解决方法
您可以在顶点着色器中“翻转”纹理坐标的y分量：
void main(void) {
// [...]
texCoord0 = vec2(vTexCoord0.x,1.0 - vTexCoord0.y);
}
如果要“翻转”单个纹理，则可以翻转纹理坐标属性。将True或False传递给参数flipY：
class GLTextureRegion:
# [...]
def write_tex_coords(self,aj,flipY):
nc = self.normalizedCoords
for i in range(4):
aj[i*4 + 2] = nc[i*2]
aj[i*4 + 3] = 1-nc[i*2 + 1] if flipY else nc[i*2 + 1]
# [...]
def update_array(self,vboData,arrayIndex,x,y,flipY):
aj = vboData[arrayIndex]
self.write_vertices(aj,y)
self.write_tex_coords(aj,flipY)
或者，您可以在顶点着色器中通过统一缩放纹理坐标。初始化制服
layout (location = 0) uniform mat4 vpMatrix;
layout (location = 1) uniform vec2 uTexCoordScale;
layout (location = 0) in vec2 vPosition;
layout (location = 1) in vec2 vTexCoord0;
out vec2 texCoord0;
void main(void)
{
gl_Position = vpMatrix * vec4(vPosition,0.0,1.0);
texCoord0 = uTexCoordScale * vTexCoord0;
}
如果要“翻转”纹理，请通过（1.0，1.0）初始化统一uTexCoordScale并将其更改为（1.0，-1.0）。