Files
MapLibreParticleLab/shaders/drawable.line_pattern.fragment.glsl
Stefan Karschti 8f6bab98c1 Line Layer (#1142)
Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>
Co-authored-by: Tim Sylvester <tim@wetdogweather.com>
Co-authored-by: mwilsnd <mwilsnd@gmail.com>
2023-08-31 15:36:19 +02:00

106 lines
3.6 KiB
GLSL

layout (std140) uniform LinePatternUBO {
highp mat4 u_matrix;
mediump vec4 u_scale;
highp vec2 u_texsize;
highp vec2 u_units_to_pixels;
mediump float u_ratio;
lowp float u_device_pixel_ratio;
highp float u_fade;
highp float pad1;
};
layout (std140) uniform LinePatternPropertiesUBO {
lowp float u_blur;
lowp float u_opacity;
lowp float u_offset;
mediump float u_gapwidth;
mediump float u_width;
highp float pad2;
highp vec2 pad3;
};
layout (std140) uniform LinePatternTilePropertiesUBO {
lowp vec4 u_pattern_from;
lowp vec4 u_pattern_to;
};
layout (std140) uniform LinePatternInterpolationUBO {
lowp float u_blur_t;
lowp float u_opacity_t;
lowp float u_offset_t;
lowp float u_gapwidth_t;
lowp float u_width_t;
lowp float u_pattern_from_t;
lowp float u_pattern_to_t;
highp float pad4;
};
uniform sampler2D u_image;
in vec2 v_normal;
in vec2 v_width2;
in float v_linesofar;
in float v_gamma_scale;
#pragma mapbox: define lowp vec4 pattern_from
#pragma mapbox: define lowp vec4 pattern_to
#pragma mapbox: define lowp float blur
#pragma mapbox: define lowp float opacity
void main() {
#pragma mapbox: initialize mediump vec4 pattern_from
#pragma mapbox: initialize mediump vec4 pattern_to
#pragma mapbox: initialize lowp float blur
#pragma mapbox: initialize lowp float opacity
vec2 pattern_tl_a = pattern_from.xy;
vec2 pattern_br_a = pattern_from.zw;
vec2 pattern_tl_b = pattern_to.xy;
vec2 pattern_br_b = pattern_to.zw;
float pixelRatio = u_scale.x;
float tileZoomRatio = u_scale.y;
float fromScale = u_scale.z;
float toScale = u_scale.w;
vec2 display_size_a = vec2((pattern_br_a.x - pattern_tl_a.x) / pixelRatio, (pattern_br_a.y - pattern_tl_a.y) / pixelRatio);
vec2 display_size_b = vec2((pattern_br_b.x - pattern_tl_b.x) / pixelRatio, (pattern_br_b.y - pattern_tl_b.y) / pixelRatio);
vec2 pattern_size_a = vec2(display_size_a.x * fromScale / tileZoomRatio, display_size_a.y);
vec2 pattern_size_b = vec2(display_size_b.x * toScale / tileZoomRatio, display_size_b.y);
// Calculate the distance of the pixel from the line in pixels.
float dist = length(v_normal) * v_width2.s;
// Calculate the antialiasing fade factor. This is either when fading in
// the line in case of an offset line (v_width2.t) or when fading out
// (v_width2.s)
float blur2 = (blur + 1.0 / u_device_pixel_ratio) * v_gamma_scale;
float alpha = clamp(min(dist - (v_width2.t - blur2), v_width2.s - dist) / blur2, 0.0, 1.0);
float x_a = mod(v_linesofar / pattern_size_a.x, 1.0);
float x_b = mod(v_linesofar / pattern_size_b.x, 1.0);
// v_normal.y is 0 at the midpoint of the line, -1 at the lower edge, 1 at the upper edge
// we clamp the line width outset to be between 0 and half the pattern height plus padding (2.0)
// to ensure we don't sample outside the designated symbol on the sprite sheet.
// 0.5 is added to shift the component to be bounded between 0 and 1 for interpolation of
// the texture coordinate
float y_a = 0.5 + (v_normal.y * clamp(v_width2.s, 0.0, (pattern_size_a.y + 2.0) / 2.0) / pattern_size_a.y);
float y_b = 0.5 + (v_normal.y * clamp(v_width2.s, 0.0, (pattern_size_b.y + 2.0) / 2.0) / pattern_size_b.y);
vec2 pos_a = mix(pattern_tl_a / u_texsize, pattern_br_a / u_texsize, vec2(x_a, y_a));
vec2 pos_b = mix(pattern_tl_b / u_texsize, pattern_br_b / u_texsize, vec2(x_b, y_b));
vec4 color = mix(texture(u_image, pos_a), texture(u_image, pos_b), u_fade);
fragColor = color * alpha * opacity;
#ifdef OVERDRAW_INSPECTOR
fragColor = vec4(1.0);
#endif
}