glsl - 片段着色器（模糊）->黑屏

Question

在过去的几天里，我一直在努力让它发挥作用，但我真的开始变得绝望了。对于您可能提出的建议，我将非常感激。

我一直在尝试做的事情：

• 将场景渲染到 FBO
• 模糊使用 glsl 着色器附加的纹理
• 将生成的纹理渲染到屏幕对齐的四边形

问题：

如果我启用片段着色器（水平模糊），我确实会得到模糊的图像在第一帧左右渲染到我的四边形，之后它就全黑了。

我怀疑我将纹理传递给着色器的方式有问题：

    horizontalBlurVertex.enable();

    horizontalBlurFragment.enable();

    glActiveTexture(GL_TEXTURE0);
    glBindTexture(GL_TEXTURE_2D, fboTexture);
    glUniform1i(glGetUniformLocation(horizontalBlurFragment.program, "RTScene"), 0);

编辑： 另外一条信息： 如果我删除 glUniform1i(glGetUniformLocation(horizo​​ntalBlurFragment.program, "RTScene"), 0);我得到完全相同的结果。我猜这表明我的着色器永远不会获取任何纹理数据。

来源：

vertex-shader：

varying vec2 vTexCoord;

void main(void)
{
   gl_FrontColor = gl_Color;
   gl_Position = ftransform();

   vec2 Pos;
   Pos = sign(gl_Vertex.xy);

   gl_Position = vec4(Pos, 0.0, 1.0);

   vTexCoord = Pos * 0.5 + 0.5;
}

fragment-shader：

uniform sampler2D RTScene;
varying vec2 vTexCoord;

const float blurSize = 1.0/800.0;
const float weightSum = 70.0 + 2.0 * (1.0 + 8.0 + 28.0 + 56.0);

void main(void)
{
   vec4 sum = vec4(0.0);

   sum += texture2D(RTScene, vec2(vTexCoord.x - 4.0*blurSize, vTexCoord.y)) * 1.0 / weightSum;
   sum += texture2D(RTScene, vec2(vTexCoord.x - 3.0*blurSize, vTexCoord.y)) * 8.0 / weightSum;
   sum += texture2D(RTScene, vec2(vTexCoord.x - 2.0*blurSize, vTexCoord.y)) * 28.0 / weightSum;
   sum += texture2D(RTScene, vec2(vTexCoord.x - blurSize, vTexCoord.y)) * 56.0 / weightSum;
   sum += texture2D(RTScene, vec2(vTexCoord.x, vTexCoord.y)) * 70.0 / weightSum;
   sum += texture2D(RTScene, vec2(vTexCoord.x + blurSize, vTexCoord.y)) * 56.0 / weightSum;
   sum += texture2D(RTScene, vec2(vTexCoord.x + 2.0*blurSize, vTexCoord.y)) * 28.0 / weightSum;
   sum += texture2D(RTScene, vec2(vTexCoord.x + 3.0*blurSize, vTexCoord.y)) * 8.0 / weightSum;
   sum += texture2D(RTScene, vec2(vTexCoord.x + 4.0*blurSize, vTexCoord.y)) * 1.0 / weightSum;

   gl_FragColor = sum;
}

渲染到fbo：（

//handels
    GLuint fbo, fboTexture, fboDepthbuffer;

    // generate namespace for the frame buffer, colorbuffer and depthbuffer
    glGenFramebuffersEXT(1, &fbo);
    glGenTextures(1, &fboTexture);
    glGenRenderbuffersEXT(1, &fboDepthbuffer);

    //switch to our fbo so we can bind stuff to it
    glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, fbo);

    //create the colorbuffer texture and attach it to the frame buffer
    glGenTextures(1, &fboTexture);
    glBindTexture(GL_TEXTURE_2D, fboTexture);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
    glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
    glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, width, height, 0, GL_RGBA, GL_UNSIGNED_BYTE, NULL);
    glFramebufferTexture2DEXT(GL_FRAMEBUFFER_EXT,GL_COLOR_ATTACHMENT0_EXT, GL_TEXTURE_2D, fboTexture, 0);

    // create a render buffer as our depthbuffer and attach it
    glBindRenderbufferEXT(GL_RENDERBUFFER_EXT, fboDepthbuffer);
    glRenderbufferStorageEXT(GL_RENDERBUFFER_EXT, GL_DEPTH_COMPONENT24, width, height);
    glFramebufferRenderbufferEXT(GL_FRAMEBUFFER_EXT, GL_DEPTH_ATTACHMENT_EXT, GL_RENDERBUFFER_EXT, fboDepthbuffer);

    // Go back to regular frame buffer rendering
    glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, 0);

    glBindTexture(GL_TEXTURE_2D, 0);
    glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, fbo);
        glPushAttrib(GL_VIEWPORT_BIT);
            glViewport(0, 0, width, height);
            glPushMatrix();
                glBegin(GL_QUADS);
                    glNormal3f(0.0, 0.0, 1.0);

                    glColor3f(1.0f, 1.0f, 0.0f);
                    glVertex3f(-0.1, 0.1, -1.0);

                    glColor3f(1.0f, 0.0f, 0.0f);
                    glVertex3f(0.1, 0.1, -1.0);

                    glColor3f(0.0f, 1.0f, 0.0f);
                    glVertex3f(0.1, -0.1, -1.0);

                    glColor3f(0.0f, 0.0f, 1.0f);
                    glVertex3f(-0.1, -0.1, -1.0);
                glEnd();
            glPopMatrix();
        glPopAttrib();
    glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, 0);

不在这里发布我的ShaderLoader源代码，因为使用更简单的着色器（切换颜色等）效果很好）

如果您认为错误出在其他地方我很乐意发布一些额外的代码。

Answer 1

问题解决了！

结果我愚蠢地在每一帧创建了我的固定基地台......现在工作得很好。