如何在渲染到離屏緩衝區然後渲染到紋理時使用深度測試

Question

我正在將我的場景渲染到紋理。這工作正常，但深度測試不起作用。如果渲染到離屏紋理，我如何啓用深度測試？我使用framebuffer類http://www.opengl.org/news/comments/framebuffer_object_fbo_c_class_available_with_example_application/

glGetIntegerv(GL_DRAW_BUFFER, &drawBuffer); 
frameBuffer->Bind(); 
glDrawBuffer(GL_COLOR_ATTACHMENT0_EXT); 
rAngle += 0.3f; 
glUseProgram(0); 
drawSpinningTeapot(); 
FramebufferObject::Disable(); 

glDrawBuffer(drawBuffer); 
glViewport(0, 0, WINDOW_WIDTH,WINDOW_HEIGHT); 
glClear(GL_COLOR_BUFFER_BIT); 

glUseProgram(g_program); 
glEnable(GL_DEPTH_TEST); 
glEnable(GL_TEXTURE_2D); 
glBindTexture(GL_TEXTURE_2D,tex1); 
texSampler = glGetUniformLocation(g_program,"texture"); 
glUniform1f(texSampler, 0); 
glActiveTexture(GL_TEXTURE0); 
glBegin(GL_QUADS); 
{ 
    glTexCoord2f(0, 0); glVertex3f(-1, -1, -0.5f); 
    glTexCoord2f(1, 0); glVertex3f(1, -1, -0.5f); 
    glTexCoord2f(1, 1); glVertex3f(1, 1, -0.5f); 
    glTexCoord2f(0, 1); glVertex3f(-1, 1, -0.5f); 
} 
glEnd(); 
glDisable(GL_TEXTURE_2D); 

Answer 1

您需要附上渲染緩衝器或除附色紋理的GL_DEPTH_ATTACHMENT。這裏有一個很好的教程，讓你開始：

http://www.songho.ca/opengl/gl_fbo.html