在顶点和片段着色器之间添加几何着色器的链接错误

Question

当我尝试在工作顶点着色器和片段着色器之间添加几何着色器时，出现链接错误：

Fragment shader(s) failed to link,  vertex shader(s) failed to link. 
ERROR: error(#280) Not all shaders have valid object code
ERROR: error(#280) Not all shaders have valid object code

所有三个着色器都编译没有错误。我猜输入和输出不适合信息流管道。内置的细节让我很困惑，所以我无法发现错误。

着色器的来源：

vertex_source =
    "#version 330\n"
    "in vec3 Position;\n"
    "in vec2 TexCoord;\n"
    "out vec3 oColor;\n"
    "out vec2 oTexcoord;\n"
    "void main() {\n"
    "    oTexcoord = TexCoord;\n"
    "    gl_Position = gl_ModelViewProjectionMatrix*vec4(Position, 1.0);\n"
    "}\n";

geometry_source =
    "#version 330\n";
    "layout (triangles) in;\n";
    "layout (triangle_strip,  max_vertices=3) out;\n";
    "in vec3 Color;\n";
    "in vec2 TexCoord;\n";
    "out vec3 oColor;\n";
    "out vec2 oTexCoord;\n";
    "void main() {\n";
    "   oColor = Color;\n";
    "   oTexCoord = TexCoord;\n";
    "   gl_Position = gl_in[0].gl_Position;\n";
    "   EmitVertex();\n";
    "   gl_Position = gl_in[1].gl_Position;\n";
    "   EmitVertex();\n";
    "   gl_Position = gl_in[2].gl_Position;\n";
    "   EmitVertex();\n";
    "   EndPrimitive();\n";
    "}\n";

fragment_source =
    "#version 330\n"
    "in vec2 oTexcoord;\n"
    "out vec4 oColor;\n"
    "uniform sampler2D tex;\n"
    "uniform sampler2D tex_norm;\n"
    "uniform sampler2D tex_spec;\n"
    "void main() {\n"
    "   vec4 lightpos = normalize(-gl_ModelViewProjectionMatrix*vec4(1.0, -1.0, -1.5, 1.0));\n"
    "   vec3 tmpNorm  = normalize(texture2D(tex_norm, oTexcoord).rgb * 2.0 - 1.0);\n"
    "   float a       = dot(tmpNorm, lightpos.xyz);\n"
    "   float difuse  = max(a, 0.1);\n"
    "   float spec    = texture2D(tex_spec, oTexcoord).r * pow(a, 2.0);\n"
    "   vec3 tmpcolor = difuse * texture2D(tex, oTexcoord).rgb;\n"
    "   oColor        = vec4(tmpcolor+tmpcolor*spec, 1.0);\n"
    "}\n";

我在几何着色器中做错了什么？

我尝试跳过未使用的 oColor 并更改为几何着色器中的数组，如下所示：

#define GLSL(src) "#version 330 core\n" #src

vertex_source = GLSL(
    in vec3 Position;
    in vec2 TexCoord;
    out vec2 oTexcoord;
    void main() {
        gl_Position = gl_ModelViewProjectionMatrix*vec4(Position, 1.0);
        oTexcoord = TexCoord;
    }
);

geometry_source = GLSL(
    layout (triangles) in;
    layout (triangle_strip,  max_vertices=3) out;
    in vec2 gsTexCoord[];
    out vec2 gsoTexCoord;
    void main() {
        gsoTexCoord = gsTexCoord[0];
        gl_Position = gl_in[0].gl_Position;
        EmitVertex();
        gsoTexCoord = gsTexCoord[1];
        gl_Position = gl_in[1].gl_Position;
        EmitVertex();
        gsoTexCoord = gsTexCoord[2];
        gl_Position = gl_in[2].gl_Position;
        EmitVertex();
        EndPrimitive();
    }
);

fragment_source = GLSL(
    in vec2 oTexcoord;
    out vec4 oColor;
    uniform sampler2D tex;
    uniform sampler2D tex_norm;
    uniform sampler2D tex_spec;
    void main() {
       vec4 lightpos = normalize(-gl_ModelViewProjectionMatrix*vec4(1.0, -1.0, -1.5, 1.0));
        vec3 tmpNorm  = normalize(texture2D(tex_norm, oTexcoord).rgb * 2.0 - 1.0);
       float a       = dot(tmpNorm, lightpos.xyz);
       float difuse  = max(a, 0.1);
       float spec    = texture2D(tex_spec, oTexcoord).r * pow(a, 2.0);
       vec3 tmpcolor = difuse * texture2D(tex, oTexcoord).rgb;
       oColor        = vec4(tmpcolor+tmpcolor*spec, 1.0);
    }
);

这给了我以下链接错误：

Fragment shader(s) failed to link,  vertex shader(s) failed to link. 
ERROR: error(#277) Symbol 'gsTexCoord[0]' usage doesn't match between two stages
ERROR: error(#277) Symbol 'oTexcoord' usage doesn't match between two stages
ERROR: error(#277) Symbol 'gsTexCoord[0]' usage doesn't match between two stages
ERROR: error(#277) Symbol 'oTexcoord' usage doesn't match between two stages

Answer 1

您的几何着色器输入需要是数组值并与您的顶点着色器中的名称相匹配：

// existing vertex shader outputs:
out vec3 oColor;
out vec2 oTexcoord;

// wrong geometry shader inputs:
in vec3 Color;
in vec2 TexCoord;

// correct geometry shader inputs:
in vec3 oColor[];
in vec2 oTexCoord[];