Created minimal C library, true SDF sampling (WIP)

CMakeLists.txt

@@ -67,7 +67,7 @@ if(MSDFGEN_USE_VCPKG)
 endif()
 
 # Version is specified in vcpkg.json
-project(msdfgen VERSION ${MSDFGEN_VERSION} LANGUAGES CXX)
+project(msdfgen VERSION ${MSDFGEN_VERSION} LANGUAGES C CXX)
 
 if(MSDFGEN_DYNAMIC_RUNTIME)
     set(MSDFGEN_MSVC_RUNTIME "MultiThreaded$<$<CONFIG:Debug>:Debug>DLL")
@@ -87,11 +87,30 @@ if(MAX_WARNING_LEVEL)
     endif()
 endif()
 
+file(GLOB_RECURSE MSDFGEN_C_HEADERS RELATIVE ${CMAKE_CURRENT_SOURCE_DIR} "c/*.h")
+file(GLOB_RECURSE MSDFGEN_C_SOURCES RELATIVE ${CMAKE_CURRENT_SOURCE_DIR} "c/*.c")
 file(GLOB_RECURSE MSDFGEN_CORE_HEADERS RELATIVE ${CMAKE_CURRENT_SOURCE_DIR} "core/*.h" "core/*.hpp")
 file(GLOB_RECURSE MSDFGEN_CORE_SOURCES RELATIVE ${CMAKE_CURRENT_SOURCE_DIR} "core/*.cpp")
 file(GLOB_RECURSE MSDFGEN_EXT_HEADERS RELATIVE ${CMAKE_CURRENT_SOURCE_DIR} "ext/*.h" "ext/*.hpp")
 file(GLOB_RECURSE MSDFGEN_EXT_SOURCES RELATIVE ${CMAKE_CURRENT_SOURCE_DIR} "ext/*.cpp" "lib/*.cpp")
 
+# C library
+add_library(msdfgen-c ${MSDFGEN_C_HEADERS} ${MSDFGEN_C_SOURCES})
+add_library(msdfgen::msdfgen-c ALIAS msdfgen-c)
+set_target_properties(msdfgen-c PROPERTIES PUBLIC_HEADER "${MSDFGEN_C_HEADERS}")
+set_property(TARGET msdfgen-c PROPERTY MSVC_RUNTIME_LIBRARY "${MSDFGEN_MSVC_RUNTIME}")
+target_compile_definitions(msdfgen-c PUBLIC
+    MSDFGEN_VERSION=${MSDFGEN_VERSION}
+    MSDFGEN_VERSION_MAJOR=${MSDFGEN_VERSION_MAJOR}
+    MSDFGEN_VERSION_MINOR=${MSDFGEN_VERSION_MINOR}
+    MSDFGEN_VERSION_REVISION=${MSDFGEN_VERSION_REVISION}
+    MSDFGEN_COPYRIGHT_YEAR=${MSDFGEN_COPYRIGHT_YEAR}
+)
+target_include_directories(msdfgen-c INTERFACE
+    $<INSTALL_INTERFACE:include/msdfgen>
+    $<BUILD_INTERFACE:${CMAKE_CURRENT_SOURCE_DIR}/>
+)
+
 # Core library
 add_library(msdfgen-core "${CMAKE_CURRENT_SOURCE_DIR}/msdfgen.h" ${MSDFGEN_CORE_HEADERS} ${MSDFGEN_CORE_SOURCES})
 add_library(msdfgen::msdfgen-core ALIAS msdfgen-core)
@@ -166,8 +185,6 @@ if(NOT MSDFGEN_CORE_ONLY)
         PUBLIC
             $<INSTALL_INTERFACE:include/msdfgen>
             $<BUILD_INTERFACE:${CMAKE_CURRENT_SOURCE_DIR}>
-        PRIVATE
-            ${CMAKE_CURRENT_SOURCE_DIR}/include
     )
     set_property(DIRECTORY ${CMAKE_CURRENT_SOURCE_DIR} PROPERTY VS_STARTUP_PROJECT msdfgen-ext)
 

c/CompiledShape.c

@@ -0,0 +1,79 @@
+
+#include "CompiledShape.h"
+
+#include <math.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+static MSDFGEN_Vector2 computeCornerVec(MSDFGEN_Vector2 normalizedDirection, MSDFGEN_Vector2 adjacentEdgeDirection1) {
+    return MSDFGEN_Vector2_normalizeOrZero(MSDFGEN_Vector2_sum(normalizedDirection, MSDFGEN_Vector2_normalizeOrZero(adjacentEdgeDirection1)));
+}
+
+void MSDFGEN_compileLinearEdge(MSDFGEN_CompiledLinearEdge *dstEdgePtr, int colorMask, MSDFGEN_Vector2 point0, MSDFGEN_Vector2 point1, MSDFGEN_Vector2 prevEdgeDirection1, MSDFGEN_Vector2 nextEdgeDirection0) {
+    MSDFGEN_Vector2 p0p1 = MSDFGEN_Vector2_difference(point1, point0);
+    MSDFGEN_real p0p1SqLen = MSDFGEN_Vector2_squaredLength(p0p1);
+    dstEdgePtr->colorMask = colorMask;
+    dstEdgePtr->endpoint0 = point0;
+    dstEdgePtr->endpoint1 = point1;
+    dstEdgePtr->direction = MSDFGEN_Vector2_normalizeOrZero(p0p1);
+    dstEdgePtr->cornerVec0 = computeCornerVec(dstEdgePtr->direction, prevEdgeDirection1);
+    dstEdgePtr->cornerVec1 = computeCornerVec(dstEdgePtr->direction, nextEdgeDirection0);
+    dstEdgePtr->invDerivative.x = 0;
+    dstEdgePtr->invDerivative.y = 0;
+    if (p0p1SqLen != (MSDFGEN_real) 0) {
+        dstEdgePtr->invDerivative.x = -p0p1.x/p0p1SqLen;
+        dstEdgePtr->invDerivative.y = -p0p1.y/p0p1SqLen;
+    }
+}
+
+void MSDFGEN_compileQuadraticEdge(MSDFGEN_CompiledQuadraticEdge *dstEdgePtr, int colorMask, MSDFGEN_Vector2 point0, MSDFGEN_Vector2 point1, MSDFGEN_Vector2 point2, MSDFGEN_Vector2 prevEdgeDirection1, MSDFGEN_Vector2 nextEdgeDirection0) {
+    MSDFGEN_Vector2 p1p2 = MSDFGEN_Vector2_difference(point2, point1);
+    dstEdgePtr->colorMask = colorMask;
+    dstEdgePtr->endpoint0 = point0;
+    dstEdgePtr->endpoint1 = point2;
+    dstEdgePtr->derivative0 = MSDFGEN_Vector2_difference(point1, point0);
+    dstEdgePtr->derivative1 = MSDFGEN_Vector2_difference(p1p2, dstEdgePtr->derivative0);
+    dstEdgePtr->direction0 = dstEdgePtr->derivative0;
+    dstEdgePtr->direction1 = p1p2;
+    if (dstEdgePtr->direction0.x == (MSDFGEN_real) 0 && dstEdgePtr->direction0.y == (MSDFGEN_real) 0)
+        dstEdgePtr->direction0 = MSDFGEN_Vector2_difference(point2, point0);
+    if (dstEdgePtr->direction1.x == (MSDFGEN_real) 0 && dstEdgePtr->direction1.y == (MSDFGEN_real) 0)
+        dstEdgePtr->direction1 = MSDFGEN_Vector2_difference(point2, point0);
+    dstEdgePtr->direction0 = MSDFGEN_Vector2_normalizeOrZero(dstEdgePtr->direction0);
+    dstEdgePtr->direction1 = MSDFGEN_Vector2_normalizeOrZero(dstEdgePtr->direction1);
+    dstEdgePtr->cornerVec0 = computeCornerVec(dstEdgePtr->direction0, prevEdgeDirection1);
+    dstEdgePtr->cornerVec1 = computeCornerVec(dstEdgePtr->direction1, nextEdgeDirection0);
+}
+
+void MSDFGEN_compileCubicEdge(MSDFGEN_CompiledCubicEdge *dstEdgePtr, int colorMask, MSDFGEN_Vector2 point0, MSDFGEN_Vector2 point1, MSDFGEN_Vector2 point2, MSDFGEN_Vector2 point3, MSDFGEN_Vector2 prevEdgeDirection1, MSDFGEN_Vector2 nextEdgeDirection0) {
+    MSDFGEN_Vector2 p1p2 = MSDFGEN_Vector2_difference(point2, point1);
+    MSDFGEN_Vector2 p2p3 = MSDFGEN_Vector2_difference(point3, point2);
+    dstEdgePtr->colorMask = colorMask;
+    dstEdgePtr->endpoint0 = point0;
+    dstEdgePtr->endpoint1 = point3;
+    dstEdgePtr->derivative0 = MSDFGEN_Vector2_difference(point1, point0);
+    dstEdgePtr->derivative1 = MSDFGEN_Vector2_difference(p1p2, dstEdgePtr->derivative0);
+    dstEdgePtr->derivative2 = MSDFGEN_Vector2_difference(MSDFGEN_Vector2_difference(p2p3, p1p2), dstEdgePtr->derivative1);
+    dstEdgePtr->direction0 = dstEdgePtr->derivative0;
+    if (dstEdgePtr->direction0.x == (MSDFGEN_real) 0 && dstEdgePtr->direction0.y == (MSDFGEN_real) 0) {
+        dstEdgePtr->direction0 = MSDFGEN_Vector2_difference(point2, point0);
+        if (dstEdgePtr->direction0.x == (MSDFGEN_real) 0 && dstEdgePtr->direction0.y == (MSDFGEN_real) 0)
+            dstEdgePtr->direction0 = MSDFGEN_Vector2_difference(point3, point0);
+    }
+    dstEdgePtr->direction1 = p2p3;
+    if (dstEdgePtr->direction1.x == (MSDFGEN_real) 0 && dstEdgePtr->direction1.y == (MSDFGEN_real) 0) {
+        dstEdgePtr->direction1 = MSDFGEN_Vector2_difference(point3, point1);
+        if (dstEdgePtr->direction1.x == (MSDFGEN_real) 0 && dstEdgePtr->direction1.y == (MSDFGEN_real) 0)
+            dstEdgePtr->direction1 = MSDFGEN_Vector2_difference(point3, point0);
+    }
+    dstEdgePtr->direction0 = MSDFGEN_Vector2_normalizeOrZero(dstEdgePtr->direction0);
+    dstEdgePtr->direction1 = MSDFGEN_Vector2_normalizeOrZero(dstEdgePtr->direction1);
+    dstEdgePtr->cornerVec0 = computeCornerVec(dstEdgePtr->direction0, prevEdgeDirection1);
+    dstEdgePtr->cornerVec1 = computeCornerVec(dstEdgePtr->direction1, nextEdgeDirection0);
+}
+
+#ifdef __cplusplus
+}
+#endif

c/CompiledShape.h

@@ -0,0 +1,61 @@
+
+#pragma once
+
+#include <stddef.h>
+#include "Vector2.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/*typedef struct {
+    void *userPtr;
+    void *(*reallocPtr)(void *userPtr, void *memoryPtr, size_t memorySize);
+    void *(*freePtr)(void *userPtr, void *memoryPtr);
+} MSDFGEN_Allocator;*/
+
+typedef struct {
+    int colorMask;
+    MSDFGEN_Vector2 endpoint0, endpoint1;
+    MSDFGEN_Vector2 cornerVec0, cornerVec1;
+    MSDFGEN_Vector2 direction;
+    MSDFGEN_Vector2 invDerivative;
+} MSDFGEN_CompiledLinearEdge;
+
+typedef struct {
+    int colorMask;
+    MSDFGEN_Vector2 endpoint0, endpoint1;
+    MSDFGEN_Vector2 cornerVec0, cornerVec1;
+    MSDFGEN_Vector2 direction0, direction1;
+    MSDFGEN_Vector2 derivative0, derivative1;
+} MSDFGEN_CompiledQuadraticEdge;
+
+typedef struct {
+    int colorMask;
+    MSDFGEN_Vector2 endpoint0, endpoint1;
+    MSDFGEN_Vector2 cornerVec0, cornerVec1;
+    MSDFGEN_Vector2 direction0, direction1;
+    MSDFGEN_Vector2 derivative0, derivative1, derivative2;
+} MSDFGEN_CompiledCubicEdge;
+
+typedef struct {
+    MSDFGEN_CompiledLinearEdge *linearEdges;
+    MSDFGEN_CompiledQuadraticEdge *quadraticEdges;
+    MSDFGEN_CompiledCubicEdge *cubicEdges;
+    size_t nLinearEdges, nQuadraticEdges, nCubicEdges;
+} MSDFGEN_CompiledShape;
+
+/*void MSDFGEN_Shape_initialize(MSDFGEN_Shape *shapePtr);
+void MSDFGEN_Shape_clear(MSDFGEN_Shape *shapePtr, MSDFGEN_Allocator allocator);*/
+
+void MSDFGEN_compileLinearEdge(MSDFGEN_CompiledLinearEdge *dstEdgePtr, int colorMask, MSDFGEN_Vector2 point0, MSDFGEN_Vector2 point1, MSDFGEN_Vector2 prevEdgeDirection1, MSDFGEN_Vector2 nextEdgeDirection0);
+void MSDFGEN_compileQuadraticEdge(MSDFGEN_CompiledQuadraticEdge *dstEdgePtr, int colorMask, MSDFGEN_Vector2 point0, MSDFGEN_Vector2 point1, MSDFGEN_Vector2 point2, MSDFGEN_Vector2 prevEdgeDirection1, MSDFGEN_Vector2 nextEdgeDirection0);
+void MSDFGEN_compileCubicEdge(MSDFGEN_CompiledCubicEdge *dstEdgePtr, int colorMask, MSDFGEN_Vector2 point0, MSDFGEN_Vector2 point1, MSDFGEN_Vector2 point2, MSDFGEN_Vector2 point3, MSDFGEN_Vector2 prevEdgeDirection1, MSDFGEN_Vector2 nextEdgeDirection0);
+
+/*void MSDFGEN_Shape_addLinearEdge(MSDFGEN_Shape *shapePtr, const MSDFGEN_Shape::LinearEdge *edgePtr, MSDFGEN_Allocator allocator);
+void MSDFGEN_Shape_addQuadraticEdge(MSDFGEN_Shape *shapePtr, const MSDFGEN_Shape::QuadraticEdge *edgePtr, MSDFGEN_Allocator allocator);
+void MSDFGEN_Shape_addCubicEdge(MSDFGEN_Shape *shapePtr, const MSDFGEN_Shape::CubicEdge *edgePtr, MSDFGEN_Allocator allocator);*/
+
+#ifdef __cplusplus
+}
+#endif

c/Vector2.h

@@ -0,0 +1,59 @@
+
+#pragma once
+
+#include <math.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+typedef double MSDFGEN_real;
+
+typedef struct {
+    MSDFGEN_real x, y;
+} MSDFGEN_Vector2;
+
+inline MSDFGEN_real MSDFGEN_Vector2_squaredLength(MSDFGEN_Vector2 v) {
+    return v.x*v.x+v.y*v.y;
+}
+
+inline MSDFGEN_real MSDFGEN_Vector2_dot(MSDFGEN_Vector2 a, MSDFGEN_Vector2 b) {
+    return a.x*b.x+a.y*b.y;
+}
+
+inline MSDFGEN_real MSDFGEN_Vector2_cross(MSDFGEN_Vector2 a, MSDFGEN_Vector2 b) {
+    return a.x*b.y-a.y*b.x;
+}
+
+inline MSDFGEN_Vector2 MSDFGEN_Vector2_scale(MSDFGEN_real s, MSDFGEN_Vector2 v) {
+    v.x *= s;
+    v.y *= s;
+    return v;
+}
+
+inline MSDFGEN_Vector2 MSDFGEN_Vector2_sum(MSDFGEN_Vector2 a, MSDFGEN_Vector2 b) {
+    MSDFGEN_Vector2 result;
+    result.x = a.x+b.x;
+    result.y = a.y+b.y;
+    return result;
+}
+
+inline MSDFGEN_Vector2 MSDFGEN_Vector2_difference(MSDFGEN_Vector2 a, MSDFGEN_Vector2 b) {
+    MSDFGEN_Vector2 result;
+    result.x = a.x-b.x;
+    result.y = a.y-b.y;
+    return result;
+}
+
+inline MSDFGEN_Vector2 MSDFGEN_Vector2_normalizeOrZero(MSDFGEN_Vector2 v) {
+    MSDFGEN_real length = sqrt(MSDFGEN_Vector2_squaredLength(v));
+    if (length != (MSDFGEN_real) 0) {
+        v.x /= length;
+        v.y /= length;
+    }
+    return v;
+}
+
+#ifdef __cplusplus
+}
+#endif

c/equation-solver.c

@@ -0,0 +1,76 @@
+
+#include "equation-solver.h"
+
+#define _USE_MATH_DEFINES
+#include <math.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+int MSDFGEN_solveQuadratic(double x[2], double a, double b, double c) {
+    // a == 0 -> linear equation
+    if (a == 0 || fabs(b) > 1e12*fabs(a)) {
+        // a == 0, b == 0 -> no solution
+        if (b == 0) {
+            if (c == 0)
+                return -1; // 0 == 0
+            return 0;
+        }
+        x[0] = -c/b;
+        return 1;
+    }
+    double dscr = b*b-4*a*c;
+    if (dscr > 0) {
+        dscr = sqrt(dscr);
+        x[0] = (-b+dscr)/(2*a);
+        x[1] = (-b-dscr)/(2*a);
+        return 2;
+    } else if (dscr == 0) {
+        x[0] = -b/(2*a);
+        return 1;
+    } else
+        return 0;
+}
+
+static int solveCubicNormed(double x[3], double a, double b, double c) {
+    double a2 = a*a;
+    double q = 1/9.*(a2-3*b);
+    double r = 1/54.*(a*(2*a2-9*b)+27*c);
+    double r2 = r*r;
+    double q3 = q*q*q;
+    a *= 1/3.;
+    if (r2 < q3) {
+        double t = r/sqrt(q3);
+        if (t < -1) t = -1;
+        if (t > 1) t = 1;
+        t = acos(t);
+        q = -2*sqrt(q);
+        x[0] = q*cos(1/3.*t)-a;
+        x[1] = q*cos(1/3.*(t+2*M_PI))-a;
+        x[2] = q*cos(1/3.*(t-2*M_PI))-a;
+        return 3;
+    } else {
+        double u = (r < 0 ? 1 : -1)*pow(fabs(r)+sqrt(r2-q3), 1/3.);
+        double v = u == 0 ? 0 : q/u;
+        x[0] = (u+v)-a;
+        if (u == v || fabs(u-v) < 1e-12*fabs(u+v)) {
+            x[1] = -.5*(u+v)-a;
+            return 2;
+        }
+        return 1;
+    }
+}
+
+int MSDFGEN_solveCubic(double x[3], double a, double b, double c, double d) {
+    if (a != 0) {
+        double bn = b/a;
+        if (fabs(bn) < 1e6) // Above this ratio, the numerical error gets larger than if we treated a as zero
+            return solveCubicNormed(x, bn, c/a, d/a);
+    }
+    return MSDFGEN_solveQuadratic(x, b, c, d);
+}
+
+#ifdef __cplusplus
+}
+#endif

c/equation-solver.h

@@ -0,0 +1,16 @@
+
+#pragma once
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+// ax^2 + bx + c = 0
+int MSDFGEN_solveQuadratic(double x[2], double a, double b, double c);
+
+// ax^3 + bx^2 + cx + d = 0
+int MSDFGEN_solveCubic(double x[3], double a, double b, double c, double d);
+
+#ifdef __cplusplus
+}
+#endif

c/msdfgen-c.h

@@ -0,0 +1,85 @@
+
+#pragma once
+
+#include <stddef.h>
+#include "Vector2.h"
+#include "CompiledShape.h"
+
+#define MSDFGEN_CUBIC_SEARCH_STARTS 4
+#define MSDFGEN_CUBIC_SEARCH_STEPS 4
+
+#define MSDFGEN_ABTEST_ALT_CACHE 0
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+typedef struct {
+#if MSDFGEN_ABTEST_ALT_CACHE
+    MSDFGEN_Vector2 origin;
+#endif
+    MSDFGEN_real edgeDistance;
+} MSDFGEN_TrueDistanceEdgeCache;
+
+typedef struct {
+    MSDFGEN_Vector2 origin;
+    MSDFGEN_real minDistance;
+    MSDFGEN_TrueDistanceEdgeCache edgeData[1];
+} MSDFGEN_TrueDistanceCache;
+
+typedef struct {
+    MSDFGEN_Vector2 origin;
+    struct EdgeData {
+        MSDFGEN_real absDistance;
+        MSDFGEN_real domainDistance0, domainDistance1;
+        MSDFGEN_real perpendicularDistance0, perpendicularDistance1;
+    } edgeData[1];
+} MSDFGEN_PerpendicularDistanceCache;
+
+typedef struct {
+    struct {
+        MSDFGEN_real scale, translate;
+    } distanceMapping;
+    struct {
+        MSDFGEN_Vector2 scale, translate;
+    } projection;
+} MSDFGEN_SDFTransformation;
+
+typedef struct {
+    enum Mode {
+        DISABLED,
+        INDISCRIMINATE,
+        EDGE_PRIORITY,
+        EDGE_ONLY
+    } mode;
+    enum DistanceCheckMode {
+        DO_NOT_CHECK_DISTANCE,
+        CHECK_DISTANCE_AT_EDGE,
+        ALWAYS_CHECK_DISTANCE
+    } distanceCheckMode;
+    MSDFGEN_real minDeviationRatio;
+    MSDFGEN_real minImproveRatio;
+    void *buffer;
+} MSDFGEN_ErrorCorrectionSettings;
+
+size_t MSDFGEN_TrueDistanceCache_size(const MSDFGEN_CompiledShape *shapePtr);
+size_t MSDFGEN_PerpendicularDistanceCache_size(const MSDFGEN_CompiledShape *shapePtr);
+
+void MSDFGEN_TrueDistanceCache_initialize(MSDFGEN_TrueDistanceCache *cachePtr, const MSDFGEN_CompiledShape *shapePtr);
+void MSDFGEN_PerpendicularDistanceCache_initialize(MSDFGEN_PerpendicularDistanceCache *cachePtr, const MSDFGEN_CompiledShape *shapePtr);
+
+MSDFGEN_real MSDFGEN_signedDistance(const MSDFGEN_CompiledShape *shapePtr, MSDFGEN_Vector2 origin, MSDFGEN_TrueDistanceCache *cachePtr);
+MSDFGEN_real MSDFGEN_perpendicularSignedDistance(const MSDFGEN_CompiledShape *shapePtr, MSDFGEN_Vector2 origin, MSDFGEN_PerpendicularDistanceCache *cachePtr);
+MSDFGEN_real MSDFGEN_multiSignedDistance(MSDFGEN_real dstMultiDistance[3], const MSDFGEN_CompiledShape *shapePtr, MSDFGEN_Vector2 origin, MSDFGEN_PerpendicularDistanceCache *cachePtr);
+
+void MSDFGEN_generateSDF(float *dstPixels, int width, int height, size_t rowStride, const MSDFGEN_CompiledShape *shapePtr, MSDFGEN_SDFTransformation transformation, MSDFGEN_TrueDistanceCache *cachePtr);
+void MSDFGEN_generatePSDF(float *dstPixels, int width, int height, size_t rowStride, const MSDFGEN_CompiledShape *shapePtr, MSDFGEN_SDFTransformation transformation, MSDFGEN_PerpendicularDistanceCache *cachePtr);
+void MSDFGEN_generateMSDF(float *dstPixels, int width, int height, size_t rowStride, const MSDFGEN_CompiledShape *shapePtr, MSDFGEN_SDFTransformation transformation, MSDFGEN_PerpendicularDistanceCache *cachePtr);
+void MSDFGEN_generateMTSDF(float *dstPixels, int width, int height, size_t rowStride, const MSDFGEN_CompiledShape *shapePtr, MSDFGEN_SDFTransformation transformation, MSDFGEN_PerpendicularDistanceCache *cachePtr);
+
+void MSDFGEN_errorCorrectionMSDF(MSDFGEN_ErrorCorrectionSettings settings, float *pixels, int width, int height, size_t rowStride, const MSDFGEN_CompiledShape *shapePtr, MSDFGEN_SDFTransformation transformation, MSDFGEN_PerpendicularDistanceCache *cachePtr);
+void MSDFGEN_errorCorrectionMTSDF(MSDFGEN_ErrorCorrectionSettings settings, float *pixels, int width, int height, size_t rowStride, const MSDFGEN_CompiledShape *shapePtr, MSDFGEN_SDFTransformation transformation, MSDFGEN_PerpendicularDistanceCache *cachePtr);
+
+#ifdef __cplusplus
+}
+#endif

c/msdfgen.c

@@ -0,0 +1,273 @@
+
+#include "msdfgen-c.h"
+
+#include <math.h>
+#include <float.h>
+#include "equation-solver.h"
+
+#define DISTANCE_DELTA_FACTOR 1.001
+
+//#define MSDFGEN_IF_CACHE_AND(...) // disable cache
+#define MSDFGEN_IF_CACHE_AND if
+
+extern long long MSDFGEN_PERFSTATS_CACHE_TESTS;
+extern long long MSDFGEN_PERFSTATS_CACHE_MISSES;
+
+long long MSDFGEN_PERFSTATS_CACHE_TESTS = 0;
+long long MSDFGEN_PERFSTATS_CACHE_MISSES = 0;
+
+#define MSDFGEN_PERFSTATS_CACHE_TEST() (++MSDFGEN_PERFSTATS_CACHE_TESTS)
+#define MSDFGEN_PERFSTATS_CACHE_MISS() (++MSDFGEN_PERFSTATS_CACHE_MISSES)
+
+//#define NO_CACHE_AND_SQUARE_DISTANCE
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+static int nonZeroSign(MSDFGEN_real x) {
+    return x > (MSDFGEN_real) 0 ? 1 : -1;
+}
+
+static int crossNonZeroSign(MSDFGEN_Vector2 a, MSDFGEN_Vector2 b) {
+    return a.x*b.y > b.x*a.y ? 1 : -1;
+}
+
+size_t MSDFGEN_TrueDistanceCache_size(const MSDFGEN_CompiledShape *shapePtr) {
+    return sizeof(MSDFGEN_TrueDistanceCache) + (shapePtr->nLinearEdges+shapePtr->nQuadraticEdges+shapePtr->nCubicEdges)*sizeof(MSDFGEN_TrueDistanceEdgeCache);
+}
+
+void MSDFGEN_TrueDistanceCache_initialize(MSDFGEN_TrueDistanceCache *cachePtr, const MSDFGEN_CompiledShape *shapePtr) {
+    MSDFGEN_TrueDistanceEdgeCache *cur, *end;
+    cachePtr->origin.x = 0;
+    cachePtr->origin.y = 0;
+    cachePtr->minDistance = .0625f*FLT_MAX;
+    for (cur = cachePtr->edgeData, end = cachePtr->edgeData+(shapePtr->nLinearEdges+shapePtr->nQuadraticEdges+shapePtr->nCubicEdges); cur < end; ++cur) {
+        #if MSDFGEN_ABTEST_ALT_CACHE
+            cur->origin.x = 0;
+            cur->origin.y = 0;
+        #else
+            cur->edgeDistance = 0;
+        #endif
+    }
+}
+
+#ifdef NO_CACHE_AND_SQUARE_DISTANCE
+
+// INCOMPLETE !!!!
+
+MSDFGEN_real MSDFGEN_signedDistance(const MSDFGEN_CompiledShape *shapePtr, MSDFGEN_Vector2 origin, MSDFGEN_TrueDistanceCache *cachePtr) {
+    int sign = -1;
+    MSDFGEN_real sqd = FLT_MAX;
+    size_t i;
+
+    for (i = 0; i < shapePtr->nLinearEdges; ++i) {
+        MSDFGEN_Vector2 originP0 = MSDFGEN_Vector2_difference(shapePtr->linearEdges[i].endpoint0, origin);
+        MSDFGEN_real originP0SqD = MSDFGEN_Vector2_squaredLength(originP0);
+        MSDFGEN_real t = MSDFGEN_Vector2_dot(originP0, shapePtr->linearEdges[i].invDerivative);
+        if (originP0SqD < sqd) {
+            sqd = originP0SqD;
+            sign = crossNonZeroSign(shapePtr->linearEdges[i].cornerVec0, MSDFGEN_Vector2_sum(shapePtr->linearEdges[i].direction, originP0));
+        }
+        if (t > (MSDFGEN_real) 0 && t < (MSDFGEN_real) 1) {
+            MSDFGEN_real pd = MSDFGEN_Vector2_cross(shapePtr->linearEdges[i].direction, originP0);
+            MSDFGEN_real sqpd = pd*pd;
+            if (sqpd < sqd) {
+                sqd = sqpd;
+                sign = nonZeroSign(pd);
+            }
+        }
+    }
+
+    for (i = 0; i < shapePtr->nQuadraticEdges; ++i) {
+        MSDFGEN_Vector2 originP0 = MSDFGEN_Vector2_difference(shapePtr->quadraticEdges[i].endpoint0, origin);
+        MSDFGEN_real originP0SqD = MSDFGEN_Vector2_squaredLength(originP0);
+        MSDFGEN_real a = MSDFGEN_Vector2_squaredLength(shapePtr->quadraticEdges[i].derivative1);
+        MSDFGEN_real b = (MSDFGEN_real) 3*MSDFGEN_Vector2_dot(shapePtr->quadraticEdges[i].derivative0, shapePtr->quadraticEdges[i].derivative1);
+        MSDFGEN_real c = (MSDFGEN_real) 2*MSDFGEN_Vector2_squaredLength(shapePtr->quadraticEdges[i].derivative0) + MSDFGEN_Vector2_dot(originP0, shapePtr->quadraticEdges[i].derivative1);
+        MSDFGEN_real d = MSDFGEN_Vector2_dot(originP0, shapePtr->quadraticEdges[i].derivative0);
+        double t[3];
+        int solutions = MSDFGEN_solveCubic(t, a, b, c, d);
+        if (originP0SqD < sqd) {
+            sqd = originP0SqD;
+            sign = crossNonZeroSign(shapePtr->quadraticEdges[i].cornerVec0, MSDFGEN_Vector2_sum(shapePtr->quadraticEdges[i].direction0, originP0));
+        }
+        #define MSDFGEN_SD_RESOLVE_QUADRATIC_SOLUTION(t) if (t > 0 && t < 1) { \
+            MSDFGEN_Vector2 originP = MSDFGEN_Vector2_sum(MSDFGEN_Vector2_sum(originP0, MSDFGEN_Vector2_scale((MSDFGEN_real) (2*t), shapePtr->quadraticEdges[i].derivative0)), MSDFGEN_Vector2_scale((MSDFGEN_real) (t*t), shapePtr->quadraticEdges[i].derivative1)); \
+            MSDFGEN_real originPSqD = MSDFGEN_Vector2_squaredLength(originP); \
+            if (originPSqD < sqd) { \
+                MSDFGEN_Vector2 direction = MSDFGEN_Vector2_sum(shapePtr->quadraticEdges[i].derivative0, MSDFGEN_Vector2_scale(t, shapePtr->quadraticEdges[i].derivative1)); \
+                sqd = originPSqD; \
+                sign = crossNonZeroSign(direction, originP); \
+            } \
+        }
+        if (solutions > 0) {
+            MSDFGEN_SD_RESOLVE_QUADRATIC_SOLUTION(t[0]);
+            if (solutions > 1) {
+                MSDFGEN_SD_RESOLVE_QUADRATIC_SOLUTION(t[1]);
+                if (solutions > 2)
+                    MSDFGEN_SD_RESOLVE_QUADRATIC_SOLUTION(t[2]);
+            }
+        }
+    }
+
+    return (MSDFGEN_real) sign*sqrt(sqd);
+}
+
+#else
+
+#if MSDFGEN_ABTEST_ALT_CACHE
+#define MSDFGEN_IF_TRUE_DISTANCE_UNCACHED MSDFGEN_PERFSTATS_CACHE_TEST(); MSDFGEN_IF_CACHE_AND(++edgeCache, edgeCache[-1].edgeDistance-DISTANCE_DELTA_FACTOR*sqrt(MSDFGEN_Vector2_squaredLength(MSDFGEN_Vector2_difference(origin, edgeCache[-1].origin))) <= minDistance)
+#else
+#define MSDFGEN_IF_TRUE_DISTANCE_UNCACHED MSDFGEN_PERFSTATS_CACHE_TEST(); MSDFGEN_IF_CACHE_AND((edgeCache++->edgeDistance -= cacheDelta) <= minDistance)
+#endif
+
+MSDFGEN_real MSDFGEN_signedDistance(const MSDFGEN_CompiledShape *shapePtr, MSDFGEN_Vector2 origin, MSDFGEN_TrueDistanceCache *cachePtr) {
+
+    MSDFGEN_real cacheDelta = DISTANCE_DELTA_FACTOR*sqrt(MSDFGEN_Vector2_squaredLength(MSDFGEN_Vector2_difference(origin, cachePtr->origin)));
+    MSDFGEN_real minDistance = cachePtr->minDistance+cacheDelta;
+    int distanceSign = -1;
+    MSDFGEN_TrueDistanceEdgeCache *edgeCache = cachePtr->edgeData;
+    size_t i;
+
+    for (i = 0; i < shapePtr->nLinearEdges; ++i) {
+        MSDFGEN_IF_TRUE_DISTANCE_UNCACHED {
+            MSDFGEN_Vector2 originP0 = MSDFGEN_Vector2_difference(shapePtr->linearEdges[i].endpoint0, origin);
+            MSDFGEN_real originP0Dist = sqrt(MSDFGEN_Vector2_squaredLength(originP0));
+            MSDFGEN_real t = MSDFGEN_Vector2_dot(originP0, shapePtr->linearEdges[i].invDerivative);
+            if (originP0Dist < minDistance) {
+                minDistance = originP0Dist;
+                distanceSign = crossNonZeroSign(shapePtr->linearEdges[i].cornerVec0, MSDFGEN_Vector2_sum(shapePtr->linearEdges[i].direction, originP0));
+            }
+            edgeCache[-1].edgeDistance = originP0Dist;
+            if (t > (MSDFGEN_real) 0 && t < (MSDFGEN_real) 1) {
+                MSDFGEN_real psd = MSDFGEN_Vector2_cross(shapePtr->linearEdges[i].direction, originP0);
+                MSDFGEN_real pd = fabs(psd);
+                if (pd < minDistance) {
+                    minDistance = pd;
+                    distanceSign = nonZeroSign(psd);
+                }
+                edgeCache[-1].edgeDistance = pd;
+            } else {
+                MSDFGEN_real originP1Dist = sqrt(MSDFGEN_Vector2_squaredLength(MSDFGEN_Vector2_difference(shapePtr->linearEdges[i].endpoint1, origin)));
+                if (originP1Dist < edgeCache[-1].edgeDistance)
+                    edgeCache[-1].edgeDistance = originP1Dist;
+            }
+            MSDFGEN_PERFSTATS_CACHE_MISS();
+            #if MSDFGEN_ABTEST_ALT_CACHE
+                edgeCache[-1].origin = origin;
+            #endif
+        }
+    }
+
+    for (i = 0; i < shapePtr->nQuadraticEdges; ++i) {
+        MSDFGEN_IF_TRUE_DISTANCE_UNCACHED {
+            MSDFGEN_Vector2 originP0 = MSDFGEN_Vector2_difference(shapePtr->quadraticEdges[i].endpoint0, origin);
+            MSDFGEN_real originP0Dist = sqrt(MSDFGEN_Vector2_squaredLength(originP0));
+            MSDFGEN_real originP1Dist = sqrt(MSDFGEN_Vector2_squaredLength(MSDFGEN_Vector2_difference(shapePtr->quadraticEdges[i].endpoint1, origin)));
+            MSDFGEN_real a = MSDFGEN_Vector2_squaredLength(shapePtr->quadraticEdges[i].derivative1);
+            MSDFGEN_real b = (MSDFGEN_real) 3*MSDFGEN_Vector2_dot(shapePtr->quadraticEdges[i].derivative0, shapePtr->quadraticEdges[i].derivative1);
+            MSDFGEN_real c = (MSDFGEN_real) 2*MSDFGEN_Vector2_squaredLength(shapePtr->quadraticEdges[i].derivative0) + MSDFGEN_Vector2_dot(originP0, shapePtr->quadraticEdges[i].derivative1);
+            MSDFGEN_real d = MSDFGEN_Vector2_dot(originP0, shapePtr->quadraticEdges[i].derivative0);
+            double t[3];
+            int solutions = MSDFGEN_solveCubic(t, a, b, c, d);
+            if (originP0Dist < minDistance) {
+                minDistance = originP0Dist;
+                distanceSign = crossNonZeroSign(shapePtr->quadraticEdges[i].cornerVec0, MSDFGEN_Vector2_sum(shapePtr->quadraticEdges[i].direction0, originP0));
+            }
+            edgeCache[-1].edgeDistance = originP0Dist;
+            if (originP1Dist < edgeCache[-1].edgeDistance)
+                edgeCache[-1].edgeDistance = originP1Dist;
+            #define MSDFGEN_SD_RESOLVE_QUADRATIC_SOLUTION(t) if (t > 0 && t < 1) { \
+                MSDFGEN_Vector2 originP = MSDFGEN_Vector2_sum(MSDFGEN_Vector2_sum(originP0, MSDFGEN_Vector2_scale((MSDFGEN_real) (2*t), shapePtr->quadraticEdges[i].derivative0)), MSDFGEN_Vector2_scale((MSDFGEN_real) (t*t), shapePtr->quadraticEdges[i].derivative1)); \
+                MSDFGEN_real originPDist = sqrt(MSDFGEN_Vector2_squaredLength(originP)); \
+                if (originPDist < minDistance) { \
+                    MSDFGEN_Vector2 direction = MSDFGEN_Vector2_sum(shapePtr->quadraticEdges[i].derivative0, MSDFGEN_Vector2_scale(t, shapePtr->quadraticEdges[i].derivative1)); \
+                    minDistance = originPDist; \
+                    distanceSign = crossNonZeroSign(direction, originP); \
+                } \
+                if (originPDist < edgeCache[-1].edgeDistance) \
+                    edgeCache[-1].edgeDistance = originPDist; \
+            }
+            if (solutions > 0) {
+                MSDFGEN_SD_RESOLVE_QUADRATIC_SOLUTION(t[0]);
+                if (solutions > 1) {
+                    MSDFGEN_SD_RESOLVE_QUADRATIC_SOLUTION(t[1]);
+                    if (solutions > 2)
+                        MSDFGEN_SD_RESOLVE_QUADRATIC_SOLUTION(t[2]);
+                }
+            }
+            MSDFGEN_PERFSTATS_CACHE_MISS();
+            #if MSDFGEN_ABTEST_ALT_CACHE
+                edgeCache[-1].origin = origin;
+            #endif
+        }
+    }
+
+    for (i = 0; i < shapePtr->nCubicEdges; ++i) {
+        MSDFGEN_IF_TRUE_DISTANCE_UNCACHED {
+            int start, step;
+            MSDFGEN_Vector2 originP0 = MSDFGEN_Vector2_difference(shapePtr->cubicEdges[i].endpoint0, origin);
+            MSDFGEN_real originP0Dist = sqrt(MSDFGEN_Vector2_squaredLength(originP0));
+            MSDFGEN_real originP1Dist = sqrt(MSDFGEN_Vector2_squaredLength(MSDFGEN_Vector2_difference(shapePtr->cubicEdges[i].endpoint1, origin)));
+            if (originP0Dist < minDistance) {
+                minDistance = originP0Dist;
+                distanceSign = crossNonZeroSign(shapePtr->cubicEdges[i].cornerVec0, MSDFGEN_Vector2_sum(shapePtr->cubicEdges[i].direction0, originP0));
+            }
+            edgeCache[-1].edgeDistance = originP0Dist;
+            if (originP1Dist < edgeCache[-1].edgeDistance)
+                edgeCache[-1].edgeDistance = originP1Dist;
+            for (start = 0; start <= MSDFGEN_CUBIC_SEARCH_STARTS; ++start) {
+                MSDFGEN_real t = (MSDFGEN_real) 1/(MSDFGEN_real) MSDFGEN_CUBIC_SEARCH_STARTS*(MSDFGEN_real) start;
+                MSDFGEN_Vector2 originP = MSDFGEN_Vector2_sum(
+                    MSDFGEN_Vector2_sum(
+                        MSDFGEN_Vector2_sum(originP0, MSDFGEN_Vector2_scale((MSDFGEN_real) 3*t, shapePtr->cubicEdges[i].derivative0)),
+                        MSDFGEN_Vector2_scale((MSDFGEN_real) 3*(t*t), shapePtr->cubicEdges[i].derivative1)
+                    ), MSDFGEN_Vector2_scale(t*t*t, shapePtr->cubicEdges[i].derivative2)
+                );
+                for (step = 0; step < MSDFGEN_CUBIC_SEARCH_STEPS; ++step) {
+                    MSDFGEN_Vector2 derivative0 = MSDFGEN_Vector2_sum(
+                        MSDFGEN_Vector2_sum(
+                            MSDFGEN_Vector2_scale((MSDFGEN_real) 3, shapePtr->cubicEdges[i].derivative0),
+                            MSDFGEN_Vector2_scale((MSDFGEN_real) 6*t, shapePtr->cubicEdges[i].derivative1)
+                        ), MSDFGEN_Vector2_scale((MSDFGEN_real) 3*(t*t), shapePtr->cubicEdges[i].derivative2)
+                    );
+                    MSDFGEN_Vector2 derivative1 = MSDFGEN_Vector2_sum(
+                        MSDFGEN_Vector2_scale((MSDFGEN_real) 6, shapePtr->cubicEdges[i].derivative1),
+                        MSDFGEN_Vector2_scale((MSDFGEN_real) 6*t, shapePtr->cubicEdges[i].derivative2)
+                    );
+                    t -= MSDFGEN_Vector2_dot(originP, derivative0)/(MSDFGEN_Vector2_squaredLength(derivative0)+MSDFGEN_Vector2_dot(originP, derivative1));
+                    if (t <= (MSDFGEN_real) 0 || t >= (MSDFGEN_real) 1)
+                        break;
+                    originP = MSDFGEN_Vector2_sum(
+                        MSDFGEN_Vector2_sum(
+                            MSDFGEN_Vector2_sum(originP0, MSDFGEN_Vector2_scale((MSDFGEN_real) 3*t, shapePtr->cubicEdges[i].derivative0)),
+                            MSDFGEN_Vector2_scale((MSDFGEN_real) 3*(t*t), shapePtr->cubicEdges[i].derivative1)
+                        ), MSDFGEN_Vector2_scale(t*t*t, shapePtr->cubicEdges[i].derivative2)
+                    );
+                    MSDFGEN_real originPDist = sqrt(MSDFGEN_Vector2_squaredLength(originP));
+                    if (originPDist < minDistance) {
+                        minDistance = originPDist;
+                        distanceSign = crossNonZeroSign(derivative0, originP);
+                    }
+                    if (originPDist < edgeCache[-1].edgeDistance)
+                        edgeCache[-1].edgeDistance = originPDist;
+                }
+            }
+            MSDFGEN_PERFSTATS_CACHE_MISS();
+            #if MSDFGEN_ABTEST_ALT_CACHE
+                edgeCache[-1].origin = origin;
+            #endif
+        }
+    }
+
+    cachePtr->origin = origin;
+    cachePtr->minDistance = minDistance;
+    return (MSDFGEN_real) distanceSign*minDistance;
+}
+
+#endif
+
+#ifdef __cplusplus
+}
+#endif