2a8ebc4906
Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>
115 lines
3.6 KiB
C++
115 lines
3.6 KiB
C++
// Generated code, do not modify this file!
|
|
#pragma once
|
|
#include <mln/shaders/shader_source.hpp>
|
|
|
|
namespace mln {
|
|
namespace shaders {
|
|
|
|
template <>
|
|
struct ShaderSource<BuiltIn::HillshadePrepareShader, gfx::Backend::Type::OpenGL> {
|
|
static constexpr const char* name = "HillshadePrepareShader";
|
|
static constexpr const char* vertex = R"(layout (location = 0) in vec2 a_pos;
|
|
layout (location = 1) in vec2 a_texture_pos;
|
|
|
|
layout (std140) uniform HillshadePrepareDrawableUBO {
|
|
highp mat4 u_matrix;
|
|
};
|
|
|
|
layout (std140) uniform HillshadePrepareTilePropsUBO {
|
|
highp vec4 u_unpack;
|
|
highp vec2 u_dimension;
|
|
highp float u_zoom;
|
|
highp float u_maxzoom;
|
|
};
|
|
|
|
out vec2 v_pos;
|
|
|
|
void main() {
|
|
gl_Position = u_matrix * vec4(a_pos, 0, 1);
|
|
|
|
highp vec2 epsilon = 1.0 / u_dimension;
|
|
float scale = (u_dimension.x - 2.0) / u_dimension.x;
|
|
v_pos = (a_texture_pos / 8192.0) * scale + epsilon;
|
|
}
|
|
)";
|
|
static constexpr const char* fragment = R"(#ifdef GL_ES
|
|
precision highp float;
|
|
#endif
|
|
|
|
in vec2 v_pos;
|
|
uniform sampler2D u_image;
|
|
layout (std140) uniform HillshadePrepareTilePropsUBO {
|
|
highp vec4 u_unpack;
|
|
highp vec2 u_dimension;
|
|
highp float u_zoom;
|
|
highp float u_maxzoom;
|
|
};
|
|
|
|
float getElevation(vec2 coord, float bias) {
|
|
// Convert encoded elevation value to meters
|
|
vec4 data = texture(u_image, coord) * 255.0;
|
|
data.a = -1.0;
|
|
return dot(data, u_unpack);
|
|
}
|
|
|
|
void main() {
|
|
vec2 epsilon = 1.0 / u_dimension;
|
|
float tileSize = u_dimension.x - 2.0;
|
|
|
|
// queried pixels (using Sobel operator kernel):
|
|
// +-----------+
|
|
// | | | |
|
|
// | a | b | c |
|
|
// | | | |
|
|
// +-----------+
|
|
// | | | |
|
|
// | d | e | f |
|
|
// | | | |
|
|
// +-----------+
|
|
// | | | |
|
|
// | g | h | i |
|
|
// | | | |
|
|
// +-----------+
|
|
|
|
float a = getElevation(v_pos + vec2(-epsilon.x, -epsilon.y), 0.0);
|
|
float b = getElevation(v_pos + vec2(0, -epsilon.y), 0.0);
|
|
float c = getElevation(v_pos + vec2(epsilon.x, -epsilon.y), 0.0);
|
|
float d = getElevation(v_pos + vec2(-epsilon.x, 0), 0.0);
|
|
//float e = getElevation(v_pos, 0.0);
|
|
float f = getElevation(v_pos + vec2(epsilon.x, 0), 0.0);
|
|
float g = getElevation(v_pos + vec2(-epsilon.x, epsilon.y), 0.0);
|
|
float h = getElevation(v_pos + vec2(0, epsilon.y), 0.0);
|
|
float i = getElevation(v_pos + vec2(epsilon.x, epsilon.y), 0.0);
|
|
|
|
// Convert the raw pixel-space derivative (slope) into world-space slope.
|
|
// The conversion factor is: tileSize / (8 * meters_per_pixel).
|
|
// meters_per_pixel is calculated as pow(2.0, 28.2562 - u_zoom).
|
|
// The exaggeration factor is applied to scale the effect at lower zooms.
|
|
// See nickidlugash's awesome breakdown for more info
|
|
// https://github.com/mapbox/mapbox-gl-js/pull/5286#discussion_r148419556
|
|
float exaggerationFactor = u_zoom < 2.0 ? 0.4 : u_zoom < 4.5 ? 0.35 : 0.3;
|
|
float exaggeration = u_zoom < 15.0 ? (u_zoom - 15.0) * exaggerationFactor : 0.0;
|
|
|
|
vec2 deriv = vec2(
|
|
(c + f + f + i) - (a + d + d + g),
|
|
(g + h + h + i) - (a + b + b + c)
|
|
) * tileSize / pow(2.0, exaggeration + (28.2562 - u_zoom));
|
|
|
|
// Encode the derivative into the color channels (r and g)
|
|
// The derivative is scaled from world-space slope to the range [0, 1] for texture storage.
|
|
// The maximum possible world-space derivative is assumed to be 4 (hence division by 8.0).
|
|
fragColor = clamp(vec4(
|
|
deriv.x / 8.0 + 0.5,
|
|
deriv.y / 8.0 + 0.5,
|
|
1.0,
|
|
1.0), 0.0, 1.0);
|
|
#ifdef OVERDRAW_INSPECTOR
|
|
fragColor = vec4(1.0);
|
|
#endif
|
|
}
|
|
)";
|
|
};
|
|
|
|
} // namespace shaders
|
|
} // namespace mln
|