Java Opengl:丢弃带有着色器的纹理背景 [英] Java Opengl: Discarding Texture Background with Shaders

问题描述

我正在尝试按照本教程操作，以使用着色器删除纹理的背景色. https://www.opengl.org/sdk/docs/tutorials/ClockworkCoders /discard.php

I'm trying to follow this tutorial to remove the background color of texture with a shader. https://www.opengl.org/sdk/docs/tutorials/ClockworkCoders/discard.php

一切运行正常，我直接从教程中复制了着色器代码，但是片段着色器引发了多个错误.

Everything is running correctly, I copied the shader code directly from the tutorial, however the fragment shader is throwing several errors.

sampler2D myTexture;
           varying vec2 vTexCoord;
void main (void) 
{  
   vec4 color = texture2D(myTexture, vTexCoord); 

    if (color.rgb == vec3(1.0,0.0,0.0))
      discard; 

   gl_FragColor = color;
}

错误:0:3:"sampler2D":采样器必须统一
错误:0:7:"myTexture":未声明的标识符
错误:0:7:"vTexCoord":未声明的标识符
错误:0:7:'texture2D':找不到匹配的重载函数(使用隐式转换)
错误:0:7:"=":无法从常量浮点数"转换为浮点数的4分量矢量"

ERROR: 0:3: 'sampler2D' : samplers must be uniform
ERROR: 0:7: 'myTexture' : undeclared identifier
ERROR: 0:7: 'vTexCoord' : undeclared identifier
ERROR: 0:7: 'texture2D' : no matching overloaded function found (using implicit conversion)
ERROR: 0:7: '=' : cannot convert from 'const float' to '4-component vector of float'

我用纹理和Vec2替换了未声明的标识符，但是它们仍然未被识别.我猜他们必须以某种方式加载.

I replaced the undeclared identifiers with my texture and Vec2, but they remain unidentified. I'm guessing they have to be loaded in somehow.

这可能是引发"...没有匹配的过载..."错误的原因.我不理解的另外两个，代码直接来自教程，因此从理论上讲应该不会出现此类问题.

This is probably what is then throwing the "...no matching overloaded..." error. The other two I don't understand, the code is directly from the tutorial so there shouldn't be such problems, in theory.

我的lwjgl版本是2.9.1

My lwjgl version is 2.9.1

以下是相关来源:

    shaderProgram = glCreateProgram();
    vertexShader  = glCreateShader(GL_VERTEX_SHADER);
    fragmentShader = glCreateShader(GL_FRAGMENT_SHADER);

    StringBuilder vertexShaderSource   = new StringBuilder();
    StringBuilder fragmentShaderSource = new StringBuilder();

    try{
        BufferedReader reader = new BufferedReader(new FileReader("src/shader.vert"));
        String line;
        line = reader.readLine();

        while(line != null){
            line = reader.readLine();

            if(line != null){
                vertexShaderSource.append(line).append('\n');
            }
        }
        reader.close();


    } catch (IOException e) {
        System.err.println("Vertex no load.");
        Display.destroy();
        System.exit(1);
    }

    try{
        BufferedReader reader = new BufferedReader(new FileReader("src/shader.frag"));
        String line;
        //line = reader.readLine();

        while(true){
            line = reader.readLine();

            if(line == null){
                break;
            }

            fragmentShaderSource.append(line).append('\n');
        }
        reader.close();


    } catch (IOException e) {
        System.err.println("Frag no load.");
        Display.destroy();
        System.exit(1);
    }
    System.out.println(fragmentShaderSource);

    glShaderSource(vertexShader, vertexShaderSource);
    glCompileShader(vertexShader);
    if(glGetShader(vertexShader, GL_COMPILE_STATUS) == GL_FALSE){
        System.err.println("Vertex no compile");
    }
    glShaderSource(fragmentShader, fragmentShaderSource);
    glCompileShader(fragmentShader);
    if(glGetShader(fragmentShader, GL_COMPILE_STATUS) == GL_FALSE){
        System.err.println("frag no compile");
    }

    System.out.println("Shader.frag Error Log\n" + glGetShaderInfoLog(fragmentShader, 1024));

    glAttachShader(shaderProgram, vertexShader);
    glAttachShader(shaderProgram, fragmentShader);
    glLinkProgram(shaderProgram);
    glValidateProgram(shaderProgram);

推荐答案

GLSL中的统一变量必须以uniform关键字开头.因此，要修复所有问题，请将第一行替换为

Uniform variables in GLSL have to start with the uniform keyword. So to fix everything, replace the first line with

uniform sampler2D myTexture;

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