GLSL MRT 将相同的数据写入所有颜色附件
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【中文标题】GLSL MRT 将相同的数据写入所有颜色附件【英文标题】：GLSL MRT writes same data to all color attachments 【发布时间】：2014-09-23 12:12:57 【问题描述】：我正在编写延迟着色代码。 我有一个带有 4 个颜色附件（纹理）和一个深度附件（渲染缓冲区）的 FBO。 我使用着色器渲染我的场景，该着色器会写入这 4 个颜色附件。 问题是，第 0 个颜色附件的数据也被写入其他附件。
下面是我的代码：
Renderer_Deferred.java
public class Renderer_Deferred
private final int FBO;
private final int depthbuffer;
public final int positiontexture, diffusetexture, normaltexture, bumpmap;
Renderer_Deferred()
System.out.println("Setting up the deferrer..");
positiontexture = GL11.glGenTextures();
diffusetexture = GL11.glGenTextures();
normaltexture = GL11.glGenTextures();
bumpmap = GL11.glGenTextures();
FBO = glGenFramebuffers();
glBindFramebuffer(GL_FRAMEBUFFER, FBO);
GL11.glBindTexture(ARBTextureRectangle.GL_TEXTURE_RECTANGLE_ARB, positiontexture);
GL11.glTexParameterf(ARBTextureRectangle.GL_TEXTURE_RECTANGLE_ARB, GL11.GL_TEXTURE_MIN_FILTER, GL11.GL_LINEAR);
GL11.glTexParameterf(ARBTextureRectangle.GL_TEXTURE_RECTANGLE_ARB, GL11.GL_TEXTURE_MAG_FILTER, GL11.GL_NEAREST);
GL11.glTexImage2D(ARBTextureRectangle.GL_TEXTURE_RECTANGLE_ARB, 0, GL30.GL_RGB32F, Configuration.displayWidth, Configuration.displayheight, 0, GL11.GL_RGBA, GL11.GL_UNSIGNED_BYTE, (java.nio.ByteBuffer) null);
GL11.glBindTexture(ARBTextureRectangle.GL_TEXTURE_RECTANGLE_ARB, 0);
GL11.glBindTexture(ARBTextureRectangle.GL_TEXTURE_RECTANGLE_ARB, diffusetexture);
GL11.glTexParameterf(ARBTextureRectangle.GL_TEXTURE_RECTANGLE_ARB, GL11.GL_TEXTURE_MIN_FILTER, GL11.GL_LINEAR);
GL11.glTexParameterf(ARBTextureRectangle.GL_TEXTURE_RECTANGLE_ARB, GL11.GL_TEXTURE_MAG_FILTER, GL11.GL_NEAREST);
GL11.glTexImage2D(ARBTextureRectangle.GL_TEXTURE_RECTANGLE_ARB, 0, GL11.GL_RGBA, Configuration.displayWidth, Configuration.displayheight, 0, GL11.GL_RGBA, GL11.GL_UNSIGNED_BYTE, (java.nio.ByteBuffer) null);
GL11.glBindTexture(ARBTextureRectangle.GL_TEXTURE_RECTANGLE_ARB, 0);
GL11.glBindTexture(ARBTextureRectangle.GL_TEXTURE_RECTANGLE_ARB, normaltexture);
GL11.glTexParameterf(ARBTextureRectangle.GL_TEXTURE_RECTANGLE_ARB, GL11.GL_TEXTURE_MIN_FILTER, GL11.GL_LINEAR);
GL11.glTexParameterf(ARBTextureRectangle.GL_TEXTURE_RECTANGLE_ARB, GL11.GL_TEXTURE_MAG_FILTER, GL11.GL_NEAREST);
GL11.glTexImage2D(ARBTextureRectangle.GL_TEXTURE_RECTANGLE_ARB, 0, GL30.GL_RGB16F, Configuration.displayWidth, Configuration.displayheight, 0, GL11.GL_RGBA, GL11.GL_UNSIGNED_BYTE, (java.nio.ByteBuffer) null);
GL11.glBindTexture(ARBTextureRectangle.GL_TEXTURE_RECTANGLE_ARB, 0);
GL11.glBindTexture(ARBTextureRectangle.GL_TEXTURE_RECTANGLE_ARB, bumpmap);
GL11.glTexParameterf(ARBTextureRectangle.GL_TEXTURE_RECTANGLE_ARB, GL11.GL_TEXTURE_MIN_FILTER, GL11.GL_LINEAR);
GL11.glTexParameterf(ARBTextureRectangle.GL_TEXTURE_RECTANGLE_ARB, GL11.GL_TEXTURE_MAG_FILTER, GL11.GL_NEAREST);
GL11.glTexImage2D(ARBTextureRectangle.GL_TEXTURE_RECTANGLE_ARB, 0, GL11.GL_RGBA, Configuration.displayWidth, Configuration.displayheight, 0, GL11.GL_RGBA, GL11.GL_UNSIGNED_BYTE, (java.nio.ByteBuffer) null);
GL11.glBindTexture(ARBTextureRectangle.GL_TEXTURE_RECTANGLE_ARB, 0);
GL11.glViewport(0, 0, Configuration.displayWidth, Configuration.displayheight);
glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, ARBTextureRectangle.GL_TEXTURE_RECTANGLE_ARB, positiontexture, 0);
glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT1, ARBTextureRectangle.GL_TEXTURE_RECTANGLE_ARB, diffusetexture, 0);
glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT2, ARBTextureRectangle.GL_TEXTURE_RECTANGLE_ARB, normaltexture, 0);
glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT3, ARBTextureRectangle.GL_TEXTURE_RECTANGLE_ARB, bumpmap, 0);
depthbuffer = glGenRenderbuffers();
glBindRenderbuffer(GL_RENDERBUFFER, depthbuffer);
glRenderbufferStorage(GL_RENDERBUFFER, GL14.GL_DEPTH_COMPONENT24, Configuration.displayWidth, Configuration.displayheight);
glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_DEPTH_ATTACHMENT, GL_RENDERBUFFER, depthbuffer);
glBindRenderbuffer(GL_RENDERBUFFER, 0);
if(glCheckFramebufferStatus(GL_FRAMEBUFFER) != GL_FRAMEBUFFER_COMPLETE)
System.err.println("Generating the deferred FBO failed!");
System.exit(5321);
glBindFramebuffer(GL_FRAMEBUFFER, 0); ////////////////////////////////////////////////////////
public void startRendering()
// CLEAR AND HOOK UP TEXTURES
glBindFramebuffer(GL_FRAMEBUFFER, FBO);
IntBuffer buf = BufferUtils.createIntBuffer(4);
buf.put(GL_COLOR_ATTACHMENT0);
buf.put(GL_COLOR_ATTACHMENT1);
buf.put(GL_COLOR_ATTACHMENT2);
buf.put(GL_COLOR_ATTACHMENT3);
buf.flip();
GL20.glDrawBuffers(buf);
if(glCheckFramebufferStatus(GL_FRAMEBUFFER) != GL_FRAMEBUFFER_COMPLETE)
System.err.println("Deferred renderer failed to setup correctly!");
GL11.glEnable(GL11.GL_DEPTH_TEST);
GL11.glDepthFunc(GL11.GL_LEQUAL);
GL11.glViewport(0, 0, Configuration.displayWidth, Configuration.displayheight);
GL11.glClearColor(SimpleCraft.world.skycolor.x, SimpleCraft.world.skycolor.y, SimpleCraft.world.skycolor.z, 0f);
GL11.glClear(GL11.GL_COLOR_BUFFER_BIT | GL11.GL_DEPTH_BUFFER_BIT);
public void stopRendering()
glBindFramebuffer(GL_FRAMEBUFFER, 0);
上面是我的代码，用于激活和停用延迟渲染器。 完成后，后处理器激活：
public class Renderer_Postprocessor
PostprocessingObject postprocessor;
public static int loc_pos, loc_diffuse, loc_normal, loc_bump, loc_ambient;
public static int loc_viewingdistance, loc_modelviewmatrix;
Renderer_Postprocessor()
postprocessor = new PostprocessingObject();
public void postprocess(int pos, int diffuse, int normal, int bump)
GL11.glClear(GL11.GL_COLOR_BUFFER_BIT);
GL11.glDisable(GL11.GL_DEPTH_TEST);
GL20.glUseProgram(Shaders.PROGRAM_POSTPROCESSOR);
GL20.glDrawBuffers(GL11.GL_BACK);
GL13.glActiveTexture(GL13.GL_TEXTURE0);
GL11.glBindTexture(ARBTextureRectangle.GL_TEXTURE_RECTANGLE_ARB, pos);
GL13.glActiveTexture(GL13.GL_TEXTURE1);
GL11.glBindTexture(ARBTextureRectangle.GL_TEXTURE_RECTANGLE_ARB, diffuse);
GL13.glActiveTexture(GL13.GL_TEXTURE2);
GL11.glBindTexture(ARBTextureRectangle.GL_TEXTURE_RECTANGLE_ARB, normal);
GL13.glActiveTexture(GL13.GL_TEXTURE3);
GL11.glBindTexture(ARBTextureRectangle.GL_TEXTURE_RECTANGLE_ARB, bump);
GLUtility.uploadToShader(Configuration.viewDistanceInBlocks, loc_viewingdistance);
GLUtility.uploadToShader(Camera.getModelViewMatrix(new Matrix4f(), Camera.getViewMatrix()), loc_modelviewmatrix);
GL30.glBindVertexArray(postprocessor.getVAO());
GL11.glDrawArrays(GL11.GL_TRIANGLES, 0, 6);
GL30.glBindVertexArray(0);
GL20.glUseProgram(0);
GL13.glActiveTexture(GL13.GL_TEXTURE0);
GL11.glBindTexture(ARBTextureRectangle.GL_TEXTURE_RECTANGLE_ARB, 0);
GL13.glActiveTexture(GL13.GL_TEXTURE1);
GL11.glBindTexture(ARBTextureRectangle.GL_TEXTURE_RECTANGLE_ARB, 0);
GL13.glActiveTexture(GL13.GL_TEXTURE2);
GL11.glBindTexture(ARBTextureRectangle.GL_TEXTURE_RECTANGLE_ARB, 0);
GL13.glActiveTexture(GL13.GL_TEXTURE3);
GL11.glBindTexture(ARBTextureRectangle.GL_TEXTURE_RECTANGLE_ARB, 0);
GL11.glEnable(GL11.GL_DEPTH_TEST);
以下是我的延迟器和后处理器的片段着色器：
Deferred_Fragment.frag
#version 330 core
#extension GL_ARB_explicit_uniform_location : require
layout(location=0) uniform sampler2DArray texture_diffuse;
layout(location=1) uniform sampler2DArray texture_normal;
uniform vec3 pass_EyeVector;
in vec4 pass_Position;
in vec3 pass_TextureCoord;
in vec3 pass_Normal;
layout(location = 0) out vec4 pos;
layout(location = 1) out vec4 dif;
layout(location = 2) out vec4 nor;
layout(location = 3) out vec4 bum;
void main(void)
pos = texture(texture_diffuse, pass_TextureCoord); // Transform from -1 / 1 to 0 / 1
dif = pass_Position;
nor = vec4(pass_Normal, 1.0);
bum = texture(texture_normal, pass_TextureCoord);
还有 postprocessor.frag
#version 330 core
#extension GL_ARB_explicit_uniform_location : require
layout(location=0) uniform sampler2DRect positiontexture;
layout(location=1) uniform sampler2DRect diffusetexture;
layout(location=2) uniform sampler2DRect normaltexture;
layout(location=3) uniform sampler2DRect bumpmap;
in vec2 pass_TextureCoord;
out vec4 out_Color;
void main(void)
out_Color = texture(diffusetexture, pass_TextureCoord);
【问题讨论】：
出于好奇，为什么在 GL 3.3 中使用矩形纹理？您应该能够使用texelFetch (...) 完成同样的事情。
我从一个星期以来就遇到了这个问题，我感到很沮丧，循环浏览我发现的任何关于延迟着色的教程。一个使用矩形纹理，所以我也尝试过。之前没用过texelFetch()，现在试试，写下结果。
【参考方案1】：
您正在尝试将 location 布局限定符用于统一变量：
layout(location=0) uniform sampler2DArray texture_diffuse;
layout(location=1) uniform sampler2DArray texture_normal;
layout(location=0) uniform sampler2DRect positiontexture;
layout(location=1) uniform sampler2DRect diffusetexture;
layout(location=2) uniform sampler2DRect normaltexture;
layout(location=3) uniform sampler2DRect bumpmap;
我在 GLSL 规范中找不到任何表明支持此功能的内容。至少在 330 中，仅列出了顶点着色器输入和片段着色器输出以支持location。在以后的版本中，似乎也支持in/out其他着色器阶段的变量，但我仍然没有看到任何关于制服的提及。
您可能打算使用此限定符设置采样器的纹理单元。有一个binding 限定符，如下所示：
layout(binding=0) uniform sampler2DArray texture_diffuse;
layout(binding=1) uniform sampler2DArray texture_normal;
不过，这仅在 OpenGL 4.2（GLSL 版本 420）及更高版本中受支持。如果您想坚持使用 GLSL 330，则需要以老式方式设置采样器制服的纹理单元，使用 glGetUniformLocaction() 和 glUniform1i()。
【讨论】：
感谢您的回答！制服的布局（位置）由扩展启用。我将尝试再次以老式方式上传纹理并发布结果。我明确地发现，我的错误很可能出现在延迟渲染器中，因为我尝试了带有预加载纹理的后处理器，它工作正常。 啊，好吧，我应该在着色器代码中看到这一点。顾名思义，它定义了统一的 location，对吗？所以这使得glGetUniformLocation() 调用变得不必要了，但您仍然需要调用glUniform1i() 来设置值？
很有可能。我已经删除了所有布局（位置）并回到了老式的方式。现在一切正常，尽管我并没有真正理解我的错误。感谢您的帮助！【参考方案2】：
您应该使用布局绑定而不是布局位置来绑定采样器。 您可能还应该重新检查您的绑定点，因为您有多个采样器绑定到同一位置。如果将纹理绑定到 TEXTURE0，请将其指定为 binding=0。
尝试将其更改为：
layout(binding=0) uniform sampler2DArray texture_diffuse;
layout(binding=1) uniform sampler2DArray texture_normal;
layout(binding=0) uniform sampler2DRect positiontexture;
layout(binding=1) uniform sampler2DRect diffusetexture;
layout(binding=2) uniform sampler2DRect normaltexture;
layout(binding=3) uniform sampler2DRect bumpmap;
【讨论】：
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