问OpenGL 3.1中不推荐使用glLineStipple

EN

#version 330

in vec4 vertex;

void main(void)
{
    // just a pass-through
    gl_Position = vertex;
}

#version 330

layout(lines) in;
layout(line_strip, max_vertices = 2) out;

uniform mat4 pvmMatrix;
uniform mat4 mMatrix;
uniform mat4 vMatrix;


out vec3 vPosition;  // passed to the fragment shader for plane clipping
out float texCoord;  // passed to the fragment shader for stipple pattern

void main(void)
{
    // to achieve uniform pattern density whatever the line orientation
    // the upper texture coordinate is made proportional to the line's length
    vec3 pos0 = gl_in[0].gl_Position.xyz;
    vec3 pos1 = gl_in[1].gl_Position.xyz;
    float max_u_texture = length(pos1 - pos0);

    // Line Start
    gl_Position = pvmMatrix * (gl_in[0].gl_Position);
    texCoord = 0.0;
    // depth position for clip plane
    vec4 vsPos0 = vMatrix * mMatrix * gl_Position;
    vPosition = vsPos0.xyz / vsPos0.w;
    EmitVertex();  // one down, one to go

    // Line End
    gl_Position = pvmMatrix * (gl_in[1].gl_Position);
    texCoord = max_u_texture;
    // depth position for clip plane
    vec4 vsPos1 = vMatrix * mMatrix * gl_Position;
    vPosition = vsPos0.xyz / vsPos0.w;
    EmitVertex();

    // done
    EndPrimitive();
}

#version 330

uniform int pattern;   // an integer between 0 and 0xFFFF representing the bitwise pattern
uniform int nPatterns; // the number of patterns/unit length of the viewport, typically 200-300 for good pattern density
uniform vec4 color;
uniform vec4 clipPlane0; // defined in view-space

in float texCoord;

in vec3 vPosition;

layout(location=0) out vec4 fragColor;

void main(void)
{
    // test vertex postion vs. clip plane position (optional)
    if (vPosition.z > clipPlane0.w) {
        discard;
        return;
    }

    // use 4 bytes for the masking pattern
    // map the texture coordinate to the interval [0,2*8[
    uint bitpos = uint(round(texCoord * nPatterns)) % 16U;
    // move a unit bit 1U to position bitpos so that
    // bit is an integer between 1 and 1000 0000 0000 0000 = 0x8000
    uint bit = (1U << bitpos);

    // test the bit against the masking pattern
    //  Line::SOLID:       pattern = 0xFFFF;  // = 1111 1111 1111 1111 = solid pattern
    //  Line::DASH:        pattern = 0x3F3F;  // = 0011 1111 0011 1111
    //  Line::DOT:         pattern = 0x6666;  // = 0110 0110 0110 0110
    //  Line::DASHDOT:     pattern = 0xFF18;  // = 1111 1111 0001 1000
    //  Line::DASHDOTDOT:  pattern = 0x7E66;  // = 0111 1110 0110 0110
    uint up = uint(pattern);

    // discard the bit if it doesn't match the masking pattern
    if ((up & bit) == 0U) discard;

    fragColor = color;
}