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2.1 KiB
GLSL

#ifdef GL_OES_standard_derivatives
#extension GL_OES_standard_derivatives : enable
#endif
uniform vec4 color;
uniform float cellAlpha;
uniform vec2 lineCount;
uniform vec2 lineThickness;
uniform vec2 lineOffset;
czm_material czm_getMaterial(czm_materialInput materialInput)
{
czm_material material = czm_getDefaultMaterial(materialInput);
vec2 st = materialInput.st;
float scaledWidth = fract(lineCount.s * st.s - lineOffset.s);
scaledWidth = abs(scaledWidth - floor(scaledWidth + 0.5));
float scaledHeight = fract(lineCount.t * st.t - lineOffset.t);
scaledHeight = abs(scaledHeight - floor(scaledHeight + 0.5));
float value;
#ifdef GL_OES_standard_derivatives
// Fuzz Factor - Controls blurriness of lines
const float fuzz = 1.2;
vec2 thickness = (lineThickness * czm_pixelRatio) - 1.0;
// From "3D Engine Design for Virtual Globes" by Cozzi and Ring, Listing 4.13.
vec2 dx = abs(dFdx(st));
vec2 dy = abs(dFdy(st));
vec2 dF = vec2(max(dx.s, dy.s), max(dx.t, dy.t)) * lineCount;
value = min(
smoothstep(dF.s * thickness.s, dF.s * (fuzz + thickness.s), scaledWidth),
smoothstep(dF.t * thickness.t, dF.t * (fuzz + thickness.t), scaledHeight));
#else
// Fuzz Factor - Controls blurriness of lines
const float fuzz = 0.05;
vec2 range = 0.5 - (lineThickness * 0.05);
value = min(
1.0 - smoothstep(range.s, range.s + fuzz, scaledWidth),
1.0 - smoothstep(range.t, range.t + fuzz, scaledHeight));
#endif
// Edges taken from RimLightingMaterial.glsl
// See http://www.fundza.com/rman_shaders/surface/fake_rim/fake_rim1.html
float dRim = 1.0 - abs(dot(materialInput.normalEC, normalize(materialInput.positionToEyeEC)));
float sRim = smoothstep(0.8, 1.0, dRim);
value *= (1.0 - sRim);
vec4 halfColor;
halfColor.rgb = color.rgb * 0.5;
halfColor.a = color.a * (1.0 - ((1.0 - cellAlpha) * value));
halfColor = czm_gammaCorrect(halfColor);
material.diffuse = halfColor.rgb;
material.emission = halfColor.rgb;
material.alpha = halfColor.a;
return material;
}