Question

我正在尝试绘制一个简单的四边形以完美覆盖屏幕（一对一复制）。我正在使用渲染的纹理是使用framebuffer和glGetTexImage从先前的渲染中捕获的。这部分我很好。但是，当我再次加载并显示纹理时，在渲染中（左上角）会出现一些奇怪的伪像，到目前为止，我仍然无法摆脱它们。

为进行比较，这是当前的样子：

这应该是这样的：

这可能是由于纹理坐标，屏幕坐标，但是到目前为止我尝试过的所有方法都失败了。我应该如何改变/做些什么？

随后是渲染代码。

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);
    //...

Answer 1

我找到了答案，原来是我从窗户得到的窗户宽度和高度有问题。

我正在使用宽度和高度设置窗口大小，而我也使用glTexImage2D来获取纹理。

SetWindowPos(glWindow->hWnd, 0,
             0, 0, glWindow->width, glWindow->height,
             SWP_NOMOVE | SWP_NOZORDER);

但是，这设置了窗口大小，我需要设置的是客户区域大小，因为这是通过调用glTexImage2D收到的。要设置客户区域大小，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);
    //...

OpenGL，渲染纹理上的异常工件，渲染坐标？

1 个答案: