Question

我正在编写一个延迟着色器，作为第一步，熟悉GLSL并使用着色器和帧缓冲区我试图通过着色器更改网格的颜色。我通过调用glDrawBuffers与一个包含附件的数组然后将纹理绑定到我的帧缓冲区来链接到其中一个缓冲区：

    glReadBuffer(GL_NONE);
    GLint color_loc = glGetFragDataLocation(pass_prog,"out_Color");
    GLenum draws [1];
    draws[color_loc] = GL_COLOR_ATTACHMENT0;
    glDrawBuffers(1, draws);

    glBindTexture(GL_TEXTURE_2D, diffuseTexture);    
    glFramebufferTexture(GL_FRAMEBUFFER, draws[color_loc], diffuseTexture, 0);

我的片段着色器中有一个out_Color变量（否则它甚至不会编译），但我无法通过在着色器中设置该变量来改变网格的颜色。有没有人知道为什么，可以向我解释一下？

由于

编辑：我的着色器：顶点着色器

    #version 330


uniform mat4x4 u_Model;
uniform mat4x4 u_View;
uniform mat4x4 u_Persp;
uniform mat4x4 u_InvTrans;

in  vec3 Position;
in  vec3 Normal;

out vec3 fs_Normal;
out vec4 fs_Position;

void main(void) {
    fs_Normal = (u_InvTrans*vec4(Normal,0.0f)).xyz;
    vec4 world = u_Model * vec4(Position, 1.0);
    vec4 camera = u_View * world;
    fs_Position = camera;
    gl_Position = u_Persp * camera;
}

片段着色器

    #version 330

uniform float u_Far;

in vec3 fs_Normal;
in vec4 fs_Position;

out vec4 out_Normal;
out vec4 out_Position;
out vec4 out_Color;

void main(void)
{
    out_Normal = vec4(normalize(fs_Normal),0.0f);
    out_Position = vec4(fs_Position.xyz,1.0f); //Tuck position into 0 1 range
    out_Color = vec4(1.0f, 0.0f, 0.0f, 1.0f);//first three diffuse, last specular
}

我没有做延迟着色器以学习GLSL。我正在学习GLSL 延迟着色器。 =）

设置纹理的更多源代码：

glActiveTexture(GL_TEXTURE0);

glGenTextures(1, &depthTexture);
glGenTextures(1, &normalTexture);
glGenTextures(1, &positionTexture);
glGenTextures(1, &diffuseTexture);

//DEPTH TEXTURE
glBindTexture(GL_TEXTURE_2D, depthTexture);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP);
glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP);
glTexParameteri(GL_TEXTURE_2D, GL_DEPTH_TEXTURE_MODE, GL_INTENSITY);
glTexImage2D( GL_TEXTURE_2D, 0, GL_DEPTH_COMPONENT, w, h, 0, GL_DEPTH_COMPONENT, GL_FLOAT, 0);

//NORMAL TEXTURE
glBindTexture(GL_TEXTURE_2D, normalTexture);    
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);   
glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP);
glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP);        
glTexImage2D( GL_TEXTURE_2D, 0, GL_RGB32F , w, h, 0, GL_RGBA, GL_FLOAT,0);

//POSITION TEXTURE
glBindTexture(GL_TEXTURE_2D, positionTexture);  
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);   
glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP);
glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP);        
glTexImage2D( GL_TEXTURE_2D, 0, GL_RGB32F , w, h, 0, GL_RGBA, GL_FLOAT,0);

//DIFFUSE TEXTURE
glBindTexture(GL_TEXTURE_2D, diffuseTexture);   
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);   
glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP);
glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP);        
glTexImage2D( GL_TEXTURE_2D, 0, GL_RGB32F , w, h, 0, GL_RGBA, GL_FLOAT,0);

 //create a framebuffer object
glGenFramebuffers(1, &FBO);
glBindFramebuffer(GL_FRAMEBUFFER, FBO);

 //Instruct openGL that we won't bind a color texture with the currently binded FBO
glReadBuffer(GL_NONE);
GLint normal_loc = glGetFragDataLocation(pass_prog,"out_Normal");
GLint position_loc = glGetFragDataLocation(pass_prog,"out_Position");
GLint color_loc = glGetFragDataLocation(pass_prog,"out_Color");
GLenum draws [3];
draws[normal_loc] = GL_COLOR_ATTACHMENT0;
draws[position_loc] = GL_COLOR_ATTACHMENT1;
draws[color_loc] = GL_COLOR_ATTACHMENT2;
glDrawBuffers(3, draws);

glBindTexture(GL_TEXTURE_2D, depthTexture); 
glFramebufferTexture(GL_FRAMEBUFFER, GL_DEPTH_ATTACHMENT, depthTexture, 0);
glBindTexture(GL_TEXTURE_2D, normalTexture);    
glFramebufferTexture(GL_FRAMEBUFFER, draws[normal_loc], normalTexture, 0);
glBindTexture(GL_TEXTURE_2D, positionTexture);    
glFramebufferTexture(GL_FRAMEBUFFER, draws[position_loc], positionTexture, 0);
glBindTexture(GL_TEXTURE_2D, diffuseTexture);    
glFramebufferTexture(GL_FRAMEBUFFER, draws[color_loc], diffuseTexture, 0);


 check FBO status
FBOstatus = glCheckFramebufferStatus(GL_FRAMEBUFFER);
if(FBOstatus != GL_FRAMEBUFFER_COMPLETE) {
    printf("GL_FRAMEBUFFER_COMPLETE failed, CANNOT use FBO\n");
    checkFramebufferStatus(FBOstatus);
}


 switch back to window-system-provided framebuffer
glClear(GL_DEPTH_BUFFER_BIT|GL_DEPTH_BUFFER_BIT);
glBindFramebuffer(GL_FRAMEBUFFER, 0);
glBindTexture(GL_TEXTURE_2D, 0);

编辑：我解决了感谢。

Answer 1

你应该做这样的事情。我假设out_color被声明为out vec4 out_Color：

Compile shaders and attach them to the program.
glBindFragDataLocation(program, 0, "out_Color");
glLinkProgram(program);
glUseProgram(program);

GLenum drawBuffers[1] = { GL_COLOR_ATTACHMENT0 }
glDrawBuffers(1, drawBuffers);

Setup FBO.

它应该工作，如果没有，发布你的片段着色器和更多的源代码。顺便说一下，我还应该说创建一个延迟渲染器来学习GLSL并不是一个好主意。有更简单的方法来学习GLSL。

使用着色器更改颜色

1 个答案: