我无法从片段着色器写入 FBO 中的颜色缓冲区。这个想法是绘制到这个纹理,然后把这个纹理绘制成一个四边形。问题是,着色器在绘制到默认窗口缓冲区时起作用,因为如果我删除 FBO,则会显示场景。并且四边形的纹理也有效,我用导入的纹理尝试了它,它显示了。我得到的只是黑屏。可能出了什么问题?:(
创建 FBO 的代码:
glGenFramebuffers(1, &fbo);
glBindFramebuffer(GL_FRAMEBUFFER, fbo);
glGenRenderbuffers(1, &depthbuff); //Add a depth renderbuffer for depth testing
glBindRenderbuffer(GL_RENDERBUFFER, depthbuff);
glRenderbufferStorage(GL_RENDERBUFFER, GL_DEPTH_COMPONENT, width, height);
glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_DEPTH_ATTACHMENT, GL_RENDERBUFFER, depthbuff);
//Add the buffer to be drawn to and the buffer for the picking information
glGenTextures(1, &drawbuff);
glBindTexture(GL_TEXTURE_2D, drawbuff);
glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA8, width, height, 0, GL_RGBA, GL_UNSIGNED_BYTE, 0);
glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, drawbuff, 0);
glGenTextures(1, &pickingbuff);
glBindTexture(GL_TEXTURE_2D, pickingbuff);
glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA8, width, height, 0, GL_RGBA, GL_UNSIGNED_BYTE, 0);
glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT1, GL_TEXTURE_2D, pickingbuff, 0);
渲染代码:
glBindFramebuffer(GL_FRAMEBUFFER, fbo);
GLenum buffers[] = { GL_COLOR_ATTACHMENT0, GL_COLOR_ATTACHMENT1 };
glDrawBuffers(2, buffers);
shader->bind(); //If the three lines above are removed, it draws correctly to the window
drawStuff();
四边形代码:
quadshader->bind();
glEnable(GL_TEXTURE_2D);
int drawTexID = quadshader->uniformLocation("drawTex");
glActiveTexture(GL_TEXTURE0);
//glBindTexture(GL_TEXTURE_2D, anotherTexture); //This works. A texture imported from a TGA
glBindTexture(GL_TEXTURE_2D, drawbuff);
glUniform1i(drawTexID, 0);
drawQuad();
最后,片段着色器,我只是将其设置为将所有内容绘制为纯色:
void main(void) {
gl_FragData[0] = vec4(1.0, 1.0, 0.0, 1.0);
gl_FragData[1] = vec4(0.0, 1.0, 1.0, 1.0);
}
编辑:如果有任何帮助,整个事情都在 Qt GLWidget 中。