我正在尝试在 JOGL 2.0 中实现简单的阴影映射技术,并且我在将深度值渲染到纹理中时遇到了困难。也许我做错了,但奇怪的是,用彩色渲染场景可以正常工作。我在stackoverflow上也发现了一个类似的问题,在这里被问到:Render the depth buffer into a texture using a frame buffer
问题通过调用解决
gl.glDrawBuffer(GL2.GL_NONE);
gl.glReadBuffer(GL2.GL_NONE);
但是,这对我没有帮助。当我像往常一样用颜色渲染场景时,功能正常工作。结果如下:
但是,在尝试渲染深度值之后,它只会渲染白色(以及与场景完全不对应的东西)
---- 更新的代码,现在可以正常工作:
private void initializeFBO3(GL2 gl) {
//Create frame buffer
gl.glGenFramebuffers(1, frameBufferID, 0);
gl.glBindFramebuffer(GL2.GL_FRAMEBUFFER, frameBufferID[0]);
// ------------- Depth buffer texture --------------
gl.glGenTextures(1,depthBufferID,0);
gl.glBindTexture(GL2.GL_TEXTURE_2D, depthBufferID[0]);
gl.glTexImage2D(GL2.GL_TEXTURE_2D, // target texture type
0, // mipmap LOD level
GL2.GL_DEPTH_COMPONENT, // internal pixel format
//GL2.GL_DEPTH_COMPONENT
shadowMapWidth, // width of generated image
shadowMapHeight, // height of generated image
0, // border of image
GL2.GL_DEPTH_COMPONENT, // external pixel format
GL2.GL_UNSIGNED_INT, // datatype for each value
null); // buffer to store the texture in memory
//Some parameters
gl.glTexParameteri(GL2.GL_TEXTURE_2D, GL2.GL_TEXTURE_MIN_FILTER, GL2.GL_NEAREST);
gl.glTexParameteri(GL2.GL_TEXTURE_2D, GL2.GL_TEXTURE_MAG_FILTER, GL2.GL_NEAREST);
gl.glTexParameteri(GL2.GL_TEXTURE_2D, GL2.GL_TEXTURE_WRAP_S, GL2.GL_CLAMP_TO_EDGE);
gl.glTexParameteri(GL2.GL_TEXTURE_2D, GL2.GL_TEXTURE_WRAP_T, GL2.GL_CLAMP_TO_EDGE);
//Attach 2D texture to this FBO
gl.glFramebufferTexture2D(GL2.GL_FRAMEBUFFER,
GL2.GL_DEPTH_ATTACHMENT,
GL2.GL_TEXTURE_2D,
depthBufferID[0],0);
gl.glBindTexture(GL2.GL_TEXTURE_2D, 0);
//Disable color buffer
//https://stackoverflow.com/questions/12546368/render-the-depth-buffer-into-a-texture-using-a-frame-buffer
gl.glDrawBuffer(GL2.GL_NONE);
gl.glReadBuffer(GL2.GL_NONE);
//Set pixels ((width*2)* (height*2))
//It has to have twice the size of shadowmap size
pixels = GLBuffers.newDirectByteBuffer(shadowMapWidth*shadowMapHeight*4);
//Set default frame buffer before doing the check
//http://www.opengl.org/wiki/FBO#Completeness_Rules
gl.glBindFramebuffer(GL2.GL_FRAMEBUFFER, 0);
int status = gl.glCheckFramebufferStatus(GL2.GL_FRAMEBUFFER);
// Always check that our framebuffer is ok
if(gl.glCheckFramebufferStatus(GL2.GL_FRAMEBUFFER) != GL2.GL_FRAMEBUFFER_COMPLETE)
{
System.err.println("Can not use FBO! Status error:" + status);
}
}
public void display(GLAutoDrawable drawable) {
GL2 gl = drawable.getGL().getGL2(); // get the OpenGL graphics context
gl.glClear(GL2.GL_COLOR_BUFFER_BIT | GL2.GL_DEPTH_BUFFER_BIT);
gl.glLoadIdentity(); // reset the model-view matrix
//Render scene into Frame buffer first
gl.glBindFramebuffer(GL2.GL_FRAMEBUFFER, frameBufferID[0]);
renderSmallScene(gl);
//Read pixels from buffer
gl.glBindFramebuffer(GL2.GL_READ_FRAMEBUFFER, frameBufferID[0]);
//Read pixels
gl.glReadPixels(0, 0, shadowMapWidth, shadowMapHeight, GL2.GL_DEPTH_COMPONENT , GL2.GL_UNSIGNED_BYTE, pixels);
//Switch back to default FBO
gl.glBindFramebuffer(GL2.GL_FRAMEBUFFER, 0);
drawSceneObjects(gl);
//Draw pixels, format has to have only one
gl.glDrawPixels(shadowMapWidth, shadowMapHeight, GL2.GL_LUMINANCE , GL2.GL_UNSIGNED_BYTE, pixels);
}
工作结果: