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我将可移动的 3d 对象和不可移动的 3d 分开。我可以为不可移动物体生成 2 个纹理：背景颜色纹理和背景深度纹理。我没有问题。两者的值都可以。我用灰色渐变纹理检查深度值。

我想用这些纹理在opengl中写入/填充颜色缓冲区和深度缓冲区，但深度不起作用（屏幕上的颜色缓冲区很好）。

我的目标是在相机不移动时永远不要重新计算不可移动的 3d 对象。

（rem：深度缓冲区位大小始终为 16 位）

这是我生成深度纹理的代码：

U16 m_backgroundDepthBuffer[4096 * 4096]; // it's a member of my class

glReadPixels(0,0, width(), height(), GL_DEPTH_COMPONENT, GL_UNSIGNED_SHORT, (void*)m_backgroundDepthBuffer);

// Allocate GPU-memory for the depth-texture.
glDeleteTextures(1, &m_backgroundDepthTextureId);
glGenTextures(1, &m_backgroundDepthTextureId);
glBindTexture(GL_TEXTURE_2D, m_backgroundDepthTextureId);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
glTexImage2D(GL_TEXTURE_2D, 0, GL_DEPTH_COMPONENT16,
            width(), height(), 0, GL_DEPTH_COMPONENT, GL_UNSIGNED_SHORT, m_backgroundDepthBuffer);

这是我填充颜色缓冲区的代码：

void Application::Render()
{
    glEnable(GL_DEPTH_TEST);
    glDepthFunc(GL_LESS);

    glClear(GL_DEPTH_BUFFER_BIT|GL_COLOR_BUFFER_BIT);


    // render background
    Render::RenderImage(m_backgroundTextureId, 0,0, width(), height());

    // for debug
    // Render::RenderImage(m_backgroundDepthGrayTextureId, 0,0, width(), height());


    // This is how I fill the depth buffer : it's work but slow
    glDrawPixels(width(), height(), GL_DEPTH_COMPONENT, GL_UNSIGNED_SHORT, (GLvoid*) m_backgroundDepthBuffer); // 

    // doesn't work
    // Render::RenderDepth(m_backgroundDepthTextureId, 0,0, width(), height());

}

这是我的 Render::RenderImage() ：它有效

void Render::RenderImage(U32 tex, int x, int y, int w, int h, float anchorX, float anchorY)
{
    glClear(GL_DEPTH_BUFFER_BIT);

    GLboolean depth = glIsEnabled(GL_DEPTH_TEST);
    if (depth)
        glDisable(GL_DEPTH_TEST);

    glMatrixMode(GL_PROJECTION);
    glPushMatrix();
    glLoadIdentity();
    gluOrtho2D(0, s_width, s_height, 0);

    glMatrixMode(GL_MODELVIEW);
    glPushMatrix();
    glLoadIdentity();

    glColor3ub(255, 255, 255);

    glEnable(GL_TEXTURE_2D);
    glBindTexture(GL_TEXTURE_2D, tex);

    glEnableClientState(GL_VERTEX_ARRAY);
    glEnableClientState(GL_TEXTURE_COORD_ARRAY);
    glDisableClientState(GL_COLOR_ARRAY);

    x -= (int)(anchorX * w);
    y -= (int)(anchorY * h);

    gVertices[0] = VECTOR3F(x, y, 0);
    gVertices[1] = VECTOR3F(x + w - 1, y, 0);
    gVertices[2] = VECTOR3F(x + w - 1, y + h - 1, 0);
    gVertices[3] = VECTOR3F(x, y + h - 1, 0);

    gTexCoords[0] = VECTOR2F(0, 1);
    gTexCoords[1] = VECTOR2F(1, 1);
    gTexCoords[2] = VECTOR2F(1, 0);
    gTexCoords[3] = VECTOR2F(0, 0);

    gIndexes[0] = 2;
    gIndexes[1] = 1;
    gIndexes[2] = 0;

    gIndexes[3] = 0;
    gIndexes[4] = 3;
    gIndexes[5] = 2;

    glVertexPointer(3, GL_FLOAT, 0, gVertices); 
    glTexCoordPointer(2, GL_FLOAT, 0, gTexCoords);
    glDrawElements(GL_TRIANGLES, 3 * 2, GL_UNSIGNED_SHORT, gIndexes);

    glDisable(GL_TEXTURE_2D);


    glPopMatrix();

    glMatrixMode(GL_PROJECTION);
    glPopMatrix();
    glMatrixMode(GL_MODELVIEW);

    if (depth)
        glEnable(GL_DEPTH_TEST);
}

这是我的 Render::RenderDepth() ：它不起作用/我有一个深度 = 0.0f 的纹理，而不是使用每个纹素的深度。我只想更改深度缓冲区而不对颜色缓冲区执行任何操作 Render::RenderDepth() 类似于 Render::RenderImage() ：我渲染 2 个三角形

void Render::RenderDepth(U32 tex, int x, int y, int w, int h, float anchorX, float anchorY)
{
    glClear(GL_DEPTH_BUFFER_BIT);


    /*glTexParameteri(GL_TEXTURE_2D_ARRAY, GL_TEXTURE_COMPARE_MODE, GL_COMPARE_REF_DEPTH_TO_TEXTURE_EXT);
    glTexParameteri(GL_TEXTURE_2D_ARRAY, GL_TEXTURE_COMPARE_FUNC, GL_ALWAYS);
    glTexParameteri(GL_TEXTURE_2D_ARRAY, GL_DEPTH_TEXTURE_MODE, GL_ALPHA);
*/
    GLboolean depth = glIsEnabled(GL_DEPTH_TEST);
    //if (depth)
    glEnable(GL_DEPTH_TEST);

    glMatrixMode(GL_PROJECTION);
    glPushMatrix();
    glLoadIdentity();
    gluOrtho2D(0, s_width, s_height, 0);

    glMatrixMode(GL_MODELVIEW);
    glPushMatrix();
    glLoadIdentity();

    glColor3ub(255, 255, 255);

    glEnable(GL_TEXTURE_2D);
    glBindTexture(GL_TEXTURE_2D, tex);

    glEnableClientState(GL_VERTEX_ARRAY);
    glEnableClientState(GL_TEXTURE_COORD_ARRAY);
    glDisableClientState(GL_COLOR_ARRAY);

    x -= (int)(anchorX * w);
    y -= (int)(anchorY * h);

    gVertices[0] = VECTOR3F(x, y, 0.0);
    gVertices[1] = VECTOR3F(x + w - 1, y, 0.0);
    gVertices[2] = VECTOR3F(x + w - 1, y + h - 1, 0.0);
    gVertices[3] = VECTOR3F(x, y + h - 1, 0.0);

    gTexCoords[0] = VECTOR2F(0, 1);
    gTexCoords[1] = VECTOR2F(1, 1);
    gTexCoords[2] = VECTOR2F(1, 0);
    gTexCoords[3] = VECTOR2F(0, 0);

    gIndexes[0] = 2;
    gIndexes[1] = 1;
    gIndexes[2] = 0;

    gIndexes[3] = 0;
    gIndexes[4] = 3;
    gIndexes[5] = 2;

    glVertexPointer(3, GL_FLOAT, 0, gVertices);
    glTexCoordPointer(2, GL_FLOAT, 0, gTexCoords);
    glDrawElements(GL_TRIANGLES, 3 * 2, GL_UNSIGNED_SHORT, gIndexes);

    glDisable(GL_TEXTURE_2D);


    glPopMatrix();

    glMatrixMode(GL_PROJECTION);
    glPopMatrix();
    glMatrixMode(GL_MODELVIEW);

}
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