Files
MapLibreParticleLab/include/mbgl/shaders/mtl/common.hpp
2024-05-17 07:30:55 -07:00

385 lines
11 KiB
C++

#pragma once
namespace mbgl {
namespace shaders {
constexpr auto prelude = R"(
#include <metal_stdlib>
using namespace metal;
// The maximum allowed miter limit is 2.0 at the moment. the extrude normal is stored
// in a byte (-128..127). We scale regular normals up to length 63, but there are also
// "special" normals that have a bigger length (of up to 126 in this case).
#define LINE_NORMAL_SCALE (1.0 / (127 / 2))
// The attribute conveying progress along a line is scaled to [0, 2^15).
#define MAX_LINE_DISTANCE 32767.0
#define SDF_PX 8.0
// OpenGL `mod` is `x-y*floor(x/y)` where `floor` rounds down.
// Metal `fmod` is `x-y*trunc(x/y)` where `trunc` rounds toward zero.
// This function provides GL-compatible modulus for porting GLSL shaders.
template <typename T1, typename T2>
inline auto glMod(T1 x, T2 y) { return x - y * metal::floor(x/y); }
float radians(float degrees) {
return M_PI_F * degrees / 180.0;
}
// Unpack a pair of values that have been packed into a single float.
// The packed values are assumed to be 8-bit unsigned integers, and are
// packed like so: packedValue = floor(input[0]) * 256 + input[1],
float2 unpack_float(const float packedValue) {
const int packedIntValue = int(packedValue);
const int v0 = packedIntValue / 256;
return float2(v0, packedIntValue - v0 * 256);
}
float2 unpack_opacity(const float packedOpacity) {
return float2(float(int(packedOpacity) / 2) / 127.0, glMod(packedOpacity, 2.0));
}
// To minimize the number of attributes needed, we encode a 4-component
// color into a pair of floats (i.e. a vec2) as follows:
// [ floor(color.r * 255) * 256 + color.g * 255, floor(color.b * 255) * 256 + color.g * 255 ]
float4 decode_color(const float2 encoded) {
return float4(unpack_float(encoded[0]) / 255, unpack_float(encoded[1]) / 255);
}
// Unpack a pair of paint values and interpolate between them.
float unpack_mix_float(const float2 packedValue, const float t) {
return mix(packedValue[0], packedValue[1], t);
}
// Unpack a pair of paint values and interpolate between them.
float4 unpack_mix_color(const float4 packedColors, const float t) {
return mix(decode_color(float2(packedColors[0], packedColors[1])),
decode_color(float2(packedColors[2], packedColors[3])), t);
}
template<class ForwardIt, class T>
ForwardIt upper_bound(ForwardIt first, ForwardIt last, thread const T& value)
{
size_t count = last - first;
while (count > 0)
{
ForwardIt it = first;
const size_t step = count / 2;
it += step;
if (!(value < *it))
{
first = ++it;
count -= step + 1;
}
else {
count = step;
}
}
return first;
}
float interpolationFactor(float base, float rangeMin, float rangeMax, float z) {
const float zoomDiff = rangeMax - rangeMin;
const float zoomProgress = z - rangeMin;
if (zoomDiff == 0) {
return 0;
} else if (base == 1.0f) {
return zoomProgress / zoomDiff;
} else {
return (pow(base, zoomProgress) - 1) / (pow(base, zoomDiff) - 1);
}
}
enum class GPUInterpType : uint16_t {
Step,
Linear,
Exponential,
Bezier
};
enum class GPUOutputType : uint16_t {
Float,
Color,
};
enum class GPUOptions : uint16_t {
None = 0,
IntegerZoom = 1 << 0,
Transitioning = 1 << 1,
};
bool operator&(GPUOptions a, GPUOptions b) { return (uint16_t)a & (uint16_t)b; }
constant const int maxExprStops = 16;
struct alignas(16) GPUExpression {
GPUOutputType outputType;
uint16_t stopCount;
GPUOptions options;
GPUInterpType interpolation;
union InterpOptions {
struct Exponential {
float base;
} exponential;
struct Bezier {
float x1;
float y1;
float x2;
float y2;
} bezier;
} interpOptions;
float inputs[maxExprStops];
union Stops {
float floats[maxExprStops];
float2 colors[maxExprStops];
} stops;
float eval(float zoom) device const {
const auto effectiveZoom = (options & GPUOptions::IntegerZoom) ? floor(zoom) : zoom;
const auto index = find(effectiveZoom);
if (index == 0) {
return stops.floats[0];
} else if (index == stopCount) {
return stops.floats[stopCount - 1];
}
switch (interpolation) {
case GPUInterpType::Step: return stops.floats[index - 1];
default: assert(false);
[[fallthrough]];
case GPUInterpType::Linear: assert(interpOptions.exponential.base == 1.0f);
[[fallthrough]];
case GPUInterpType::Exponential: {
const float rangeBeg = inputs[index - 1];
const float rangeEnd = inputs[index];
const auto t = interpolationFactor(interpOptions.exponential.base, rangeBeg, rangeEnd, effectiveZoom);
return mix(stops.floats[index - 1], stops.floats[index], t);
}
case GPUInterpType::Bezier:
assert(false);
return stops.floats[0];
}
}
float4 evalColor(float zoom) device const {
const auto effectiveZoom = (options & GPUOptions::IntegerZoom) ? floor(zoom) : zoom;
const auto index = find(effectiveZoom);
if (index == 0) {
return getColor(0);
} else if (index == stopCount) {
return getColor(stopCount - 1);
}
switch (interpolation) {
case GPUInterpType::Step:
return getColor(index - 1);
default:
assert(false);
[[fallthrough]];
case GPUInterpType::Linear:
assert(interpOptions.exponential.base == 1.0f);
[[fallthrough]];
case GPUInterpType::Exponential: {
const float rangeBeg = inputs[index - 1];
const float rangeEnd = inputs[index];
const auto t = interpolationFactor(interpOptions.exponential.base, rangeBeg, rangeEnd, effectiveZoom);
return mix(getColor(index - 1), getColor(index), clamp(t, 0.0, 1.0));
}
case GPUInterpType::Bezier:
assert(false);
return getColor(0);
}
}
/// Get the index of the entry to use from the zoom level
size_t find(float zoom) device const {
return upper_bound(&inputs[0], &inputs[stopCount], zoom) - &inputs[0];
}
float4 getColor(size_t index) device const { return decode_color(stops.colors[index]); }
};
static_assert(sizeof(GPUExpression) == 32 + (4 + 8) * maxExprStops, "wrong alignment");
static_assert(sizeof(GPUExpression) % 16 == 0, "wrong alignment");
enum {
idGlobalPaintParamsUBO,
globalUBOCount
};
enum {
idLineDrawableUBO = globalUBOCount,
idLineInterpolationUBO,
idLineTilePropertiesUBO,
idLineEvaluatedPropsUBO,
idLineExpressionUBO,
lineUBOCount
};
enum class LineExpressionMask : uint32_t {
None = 0,
Color = 1 << 0,
Opacity = 1 << 1,
Blur = 1 << 2,
Width = 1 << 3,
GapWidth = 1 << 4,
FloorWidth = 1 << 5,
Offset = 1 << 6,
};
bool operator&(LineExpressionMask a, LineExpressionMask b) { return (uint32_t)a & (uint32_t)b; }
struct alignas(16) LineExpressionUBO {
GPUExpression color;
GPUExpression blur;
GPUExpression opacity;
GPUExpression gapwidth;
GPUExpression offset;
GPUExpression width;
GPUExpression floorwidth;
};
static_assert(sizeof(LineExpressionUBO) % 16 == 0, "wrong alignment");
struct alignas(16) GlobalPaintParamsUBO {
/* 0 */ float2 pattern_atlas_texsize;
/* 8 */ float2 units_to_pixels;
/* 16 */ float2 world_size;
/* 24 */ float camera_to_center_distance;
/* 28 */ float symbol_fade_change;
/* 32 */ float aspect_ratio;
/* 36 */ float pixel_ratio;
/* 40 */ float zoom;
/* 44 */ float pad1;
/* 48 */
};
static_assert(sizeof(GlobalPaintParamsUBO) == 3 * 16, "unexpected padding");
struct alignas(16) FillEvaluatedPropsUBO {
float4 color;
float4 outline_color;
float opacity;
float fade;
float from_scale;
float to_scale;
};
struct alignas(16) FillExtrusionDrawableUBO {
/* 0 */ float4x4 matrix;
/* 64 */ float2 texsize;
/* 72 */ float2 pixel_coord_upper;
/* 80 */ float2 pixel_coord_lower;
/* 88 */ float height_factor;
/* 92 */ float tile_ratio;
/* 96 */
};
static_assert(sizeof(FillExtrusionDrawableUBO) == 6 * 16, "unexpected padding");
struct alignas(16) FillExtrusionPropsUBO {
/* 0 */ float4 color;
/* 16 */ float4 light_color_pad;
/* 32 */ float4 light_position_base;
/* 48 */ float height;
/* 52 */ float light_intensity;
/* 56 */ float vertical_gradient;
/* 60 */ float opacity;
/* 64 */ float fade;
/* 68 */ float from_scale;
/* 72 */ float to_scale;
/* 76 */ float pad2;
/* 80 */
};
static_assert(sizeof(FillExtrusionPropsUBO) == 5 * 16, "unexpected padding");
struct alignas(16) FillExtrusionTilePropsUBO {
/* 0 */ float4 pattern_from;
/* 16 */ float4 pattern_to;
/* 32 */
};
static_assert(sizeof(FillExtrusionTilePropsUBO) == 2 * 16, "unexpected padding");
struct alignas(16) FillExtrusionInterpolateUBO {
/* 0 */ float base_t;
/* 4 */ float height_t;
/* 8 */ float color_t;
/* 12 */ float pattern_from_t;
/* 16 */ float pattern_to_t;
/* 20 */ float pad1, pad2, pad3;
/* 32 */
};
static_assert(sizeof(FillExtrusionInterpolateUBO) == 2 * 16, "unexpected padding");
struct alignas(16) LineEvaluatedPropsUBO {
float4 color;
float blur;
float opacity;
float gapwidth;
float offset;
float width;
float floorwidth;
LineExpressionMask expressionMask;
float pad1;
};
struct alignas(16) SymbolDrawableUBO {
float4x4 matrix;
float4x4 label_plane_matrix;
float4x4 coord_matrix;
float2 texsize;
float2 texsize_icon;
float gamma_scale;
/*bool*/ int rotate_symbol;
float2 pad;
};
static_assert(sizeof(SymbolDrawableUBO) == 14 * 16, "unexpected padding");
struct alignas(16) SymbolTilePropsUBO {
/*bool*/ int is_text;
/*bool*/ int is_halo;
/*bool*/ int pitch_with_map;
/*bool*/ int is_size_zoom_constant;
/*bool*/ int is_size_feature_constant;
float size_t;
float size;
float padding;
};
static_assert(sizeof(SymbolTilePropsUBO) == 2 * 16, "unexpected padding");
struct alignas(16) SymbolInterpolateUBO {
float fill_color_t;
float halo_color_t;
float opacity_t;
float halo_width_t;
float halo_blur_t;
float pad1, pad2, pad3;
};
static_assert(sizeof(SymbolInterpolateUBO) == 32, "unexpected padding");
struct alignas(16) SymbolEvaluatedPropsUBO {
float4 text_fill_color;
float4 text_halo_color;
float text_opacity;
float text_halo_width;
float text_halo_blur;
float pad1;
float4 icon_fill_color;
float4 icon_halo_color;
float icon_opacity;
float icon_halo_width;
float icon_halo_blur;
float pad2;
};
static_assert(sizeof(SymbolEvaluatedPropsUBO) == 6 * 16, "unexpected padding");
// unpack pattern position
inline float2 get_pattern_pos(const float2 pixel_coord_upper, const float2 pixel_coord_lower,
const float2 pattern_size, const float tile_units_to_pixels, const float2 pos) {
const float2 offset = glMod(glMod(glMod(pixel_coord_upper, pattern_size) * 256.0, pattern_size) * 256.0 + pixel_coord_lower, pattern_size);
return (tile_units_to_pixels * pos + offset) / pattern_size;
}
)";
}
} // namespace mbgl