渲染到屏幕外缓冲区然后渲染到纹理时如何使用深度测试 [英] How to use depth testing when rendering to an offscreen buffer then onto texture

问题描述

我将场景渲染为纹理。这工作正常，但深度测试不起作用。如果渲染到离屏纹理，我如何启用深度测试？我正在使用FrameBuffer类 http://www.opengl.org/news/comments/framebuffer_object_fbo_c_class_available_with_example_application /

I'm rendering my scene to a texture. This works fine except that depth testing does not work. How do I enable depth testing if rendering to an offscreen texture? I'm using the FrameBuffer class 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);

推荐答案

您需要附加渲染缓冲区或纹理除了颜色附件之外，还有 GL_DEPTH_ATTACHMENT 。这里有一个很好的教程，让你开始：

You need to attach a render buffer or a texture to the GL_DEPTH_ATTACHMENT in addition to the color attachment. Here's a good tutorial to get you started:

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

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