OpenGL,渲染纹理上的异常伪影,渲染坐标? [关闭]
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【中文标题】OpenGL,渲染纹理上的异常伪影,渲染坐标? [关闭]【英文标题】:OpenGL, unusual artifacts on rendered texture, render co-ordinates? [closed] 【发布时间】:2019-05-24 20:52:35 【问题描述】:我正在尝试渲染一个简单的四边形以完美覆盖屏幕(一对一复制)。我用来渲染的纹理是从使用帧缓冲区和glGetTexImage
的先前渲染中捕获的。这部分我很好。但是,当我再次加载并显示纹理时,我在渲染中(左上角)得到了一些奇怪的伪影,到目前为止我一直无法摆脱它们。
为了比较,这是它目前的样子:
它应该是这样的:
这可能是由于纹理坐标、屏幕坐标造成的,但到目前为止我所尝试的一切都失败了。我应该改变/做些什么?
渲染代码如下。
void setWidthHeightRender(GLsizei width, GLsizei height)
if(height == 0)
height = 1;
glViewport(0, 0, width, height);
glMatrixMode(GL_PROJECTION);
glLoadIdentity();
//GLdouble left, GLdouble right, GLdouble bottom, GLdouble top, GLdouble zNear, GLdouble zFar
glOrtho(0.0, width, height, 0.0, -1.0, 1.0);
glMatrixMode(GL_MODELVIEW);
glLoadIdentity();
unsigned createGLTexture(unsigned width, unsigned height, const uint8_t* data)
// the texture we're going to render
GLuint renderedTexture;
glGenTextures(1, &renderedTexture);
// bind the newly created texture
glBindTexture(GL_TEXTURE_2D, renderedTexture);
// give the image to opengl
glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, width, height, 0, GL_RGB, GL_UNSIGNED_BYTE, data);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
glBindTexture(GL_TEXTURE_2D, 0);
return renderedTexture;
void drawImage(unsigned glTxt, float tx, float ty, float bx, float by, float z)
//glEnable(GL_BLEND);
//glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
glEnable(GL_TEXTURE_2D);
glBindTexture(GL_TEXTURE_2D, glTxt);
glBegin(GL_TRIANGLE_FAN);
glTexCoord2f(0, 1);
glVertex3f(tx, ty, z);
glTexCoord2f(0, 0);
glVertex3f(tx, by, z);
glTexCoord2f(1, 0);
glVertex3f(bx, by, z);
glTexCoord2f(1, 1);
glVertex3f(bx, ty, z);
glEnd();
glDisable(GL_TEXTURE_2D);
glDisable(GL_BLEND);
//...
wglMakeCurrent(it->second->hDC, it->second->hRC);
//create the texture + load the texture
unsigned glTxt = createGLTexture((right - left), (bottom - top), &bfr[0]);
//render the texture to the correct screen positions
setWidthHeightRender((right - left), (bottom - top));
glClearColor(0.0f, 0.0f, 0.0f, 0.0f);
glClear(GL_COLOR_BUFFER_BIT|GL_DEPTH_BUFFER_BIT);
drawImage(glTxt, 0.0, 0.0, (right - left), (bottom - top), 0.0f);
//swap the buffers
SwapBuffers(it->second->hDC);
//unload the texture
glDeleteTextures(1, &glTxt);
//...
【问题讨论】:
一个可能的原因可能是纹理图像的行必须对齐到 4。可能是您为完整图像分配/读取/存储的数据太少。 (请注意,OpenGL 纹理使用从上到下的图像。因此,伪影出现在顶部是有道理的。)但是,这些伪影也可能是由任何其他越界访问引起的。 【参考方案1】:我找到了答案,原来是我从窗户获得的窗户宽度和高度有问题。
我使用宽度和高度来设置窗口大小,我也使用glTexImage2D
来获取纹理。
SetWindowPos(glWindow->hWnd, 0,
0, 0, glWindow->width, glWindow->height,
SWP_NOMOVE | SWP_NOZORDER);
然而,这设置了窗口大小,我需要设置的是客户区大小,因为这是通过调用glTexImage2D
收到的。要设置客户区大小,您应该改用:
RECT Rect;
Rect.left = (long)glWindow->x_pos; // Set Left Value To x_pos
Rect.right = (long)glWindow->x_pos+glWindow->width; // Set Right Value To x_pos+width
Rect.top = (long)glWindow->y_pos; // Set Top Value To y_pos
Rect.bottom = (long)glWindow->y_pos+glWindow->height; // Set Bottom Value To y_pos+height
AdjustWindowRectEx(&Rect, glWindow->dwStyle, FALSE, glWindow->dwExStyle);
SetWindowPos(glWindow->hWnd, 0,
0, 0, Rect.right-Rect.left, Rect.bottom-Rect.top,
SWP_NOMOVE | SWP_NOZORDER);
//...
//bind the texture for modification
glBindTexture(GL_TEXTURE_2D, glWindow->renderedTexture);
//Now correct width and height used here (and else where) matching client area.
glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, glWindow->width, glWindow->height, 0, GL_RGB, GL_UNSIGNED_BYTE, 0);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
//...
【讨论】:
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