64 lines
2.0 KiB
GLSL
64 lines
2.0 KiB
GLSL
#version 450
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layout(location = 0) in vec3 fragColor;
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layout(location = 1) in vec3 fragSegmentStart;
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layout(location = 2) in vec3 fragSegmentEnd;
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layout(location = 3) in vec3 fragWorldPos;
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layout(location = 0) out vec4 outColor;
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layout(binding = 0) uniform UniformBufferObject {
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mat4 proj;
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mat4 model;
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mat4 view;
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} ubo;
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layout(binding = 1) uniform DashParameters {
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float dashSize;
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float gapSize;
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float dashOffset;
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float uAASize;
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int useWorldSpace;
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} dashParams;
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void main() {
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// 转换为NDC坐标
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vec3 ndcStart = fragSegmentStart / fragSegmentStart.z;
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vec3 ndcEnd = fragSegmentEnd / fragSegmentEnd.z;
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vec3 fragNDC = gl_FragCoord.xyz / gl_FragCoord.z;
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fragNDC = (fragNDC * 2.0) - 1.0;
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// 计算当前片元在线段上的投影
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vec2 lineDir = normalize(ndcEnd.xy - ndcStart.xy);
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vec2 startToFrag = fragNDC.xy - ndcStart.xy;
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float projection = dot(startToFrag, lineDir);
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// 计算线段在屏幕空间的长度（用于抗锯齿）
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float segmentLength = length(ndcEnd.xy - ndcStart.xy);
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// 应用虚线模式
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float dashPeriod = dashParams.dashSize + dashParams.gapSize;
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float currentPos = mod(projection + dashParams.dashOffset, dashPeriod);
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// 抗锯齿处理
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float alpha = 1.0;
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// 线段开始处的抗锯齿（避免线段起始处出现半截虚线）
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alpha *= smoothstep(0.0, dashParams.uAASize / segmentLength, projection);
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// 线段结束处的抗锯齿
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alpha *= 1.0 - smoothstep(segmentLength - dashParams.uAASize / segmentLength,
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segmentLength, projection);
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// 虚线模式抗锯齿
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alpha *= 1.0 - smoothstep(dashParams.dashSize,
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dashParams.dashSize + dashParams.uAASize / dashPeriod,
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currentPos);
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// 如果alpha接近0，直接丢弃片元
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if (alpha < 0.01) {
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discard;
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}
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outColor = vec4(fragColor, alpha);
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} |