Add basic github actions build

.github/workflows/build.yml

@@ -0,0 +1,82 @@
+# This starter workflow is for a CMake project running on multiple platforms. There is a different starter workflow if you just want a single platform.
+# See: https://github.com/actions/starter-workflows/blob/main/ci/cmake-single-platform.yml
+name: CMake on multiple platforms
+
+on:
+  push:
+    branches: master
+  pull_request:
+    branches: master
+
+jobs:
+  build:
+    runs-on: ${{ matrix.os }}
+
+    strategy:
+      # Set fail-fast to false to ensure that feedback is delivered for all matrix combinations. Consider changing this to true when your workflow is stable.
+      fail-fast: false
+
+      # Set up a matrix to run the following 3 configurations:
+      # 1. <Windows, Release, latest MSVC compiler toolchain on the default runner image, default generator>
+      # 2. <Linux, Release, latest GCC compiler toolchain on the default runner image, default generator>
+      # 3. <Linux, Release, latest Clang compiler toolchain on the default runner image, default generator>
+      #
+      # To add more build types (Release, Debug, RelWithDebInfo, etc.) customize the build_type list.
+      matrix:
+        os: [ubuntu-latest, windows-latest]
+        build_type: [Release]
+        c_compiler: [gcc, clang, cl]
+        include:
+          - os: windows-latest
+            c_compiler: cl
+            cpp_compiler: cl
+          - os: ubuntu-latest
+            c_compiler: gcc
+            cpp_compiler: g++
+          - os: ubuntu-latest
+            c_compiler: clang
+            cpp_compiler: clang++
+        exclude:
+          - os: windows-latest
+            c_compiler: gcc
+          - os: windows-latest
+            c_compiler: clang
+          - os: ubuntu-latest
+            c_compiler: cl
+
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Set reusable strings
+        # Turn repeated input strings (such as the build output directory) into step outputs. These step outputs can be used throughout the workflow file.
+        id: strings
+        shell: bash
+        run: |
+          echo "build-output-dir=${{ github.workspace }}/build" >> "$GITHUB_OUTPUT"
+
+      - name: Update packages
+        run: sudo apt-get update
+
+      - name: Install packages
+        run: sudo apt-get install --fix-missing libgl1-mesa-dev
+
+      - name: Configure CMake
+        # Configure CMake in a 'build' subdirectory. `CMAKE_BUILD_TYPE` is only required if you are using a single-configuration generator such as make.
+        # See https://cmake.org/cmake/help/latest/variable/CMAKE_BUILD_TYPE.html?highlight=cmake_build_type
+        run: >
+          cmake -B ${{ steps.strings.outputs.build-output-dir }}
+          -DCMAKE_CXX_COMPILER=${{ matrix.cpp_compiler }} -DCMAKE_C_COMPILER=${{
+          matrix.c_compiler }} -DCMAKE_BUILD_TYPE=${{ matrix.build_type }} -S
+          ${{ github.workspace }}
+
+      - name: Build
+        # Build your program with the given configuration. Note that --config is needed because the default Windows generator is a multi-config generator (Visual Studio generator).
+        run:
+          cmake --build ${{ steps.strings.outputs.build-output-dir }} --config
+          ${{ matrix.build_type }}
+
+      #- name: Test
+      #  working-directory: ${{ steps.strings.outputs.build-output-dir }}
+      # Execute tests defined by the CMake configuration. Note that --build-config is needed because the default Windows generator is a multi-config generator (Visual Studio generator).
+      # See https://cmake.org/cmake/help/latest/manual/ctest.1.html for more detail
+      #  run: ctest --build-config ${{ matrix.build_type }}

CMakeLists.txt

@@ -1,4 +1,4 @@
-cmake_minimum_required(VERSION 3.7)
+cmake_minimum_required(VERSION 3.10)
 
 project(chipmunk)
 

README.textile

@@ -1,5 +1,24 @@
 !http://files.slembcke.net/chipmunk/logo/logo1_med.png!
 
+h2. FORK INFO - START HERE
+
+This is a fork of the original "Chipmunk2D":https://github.com/slembcke/Chipmunk2D 
+
+The main purpose of this fork is to be a compainion for the Python 2D physics library "Pymunk":https://www.pymunk.org which is built on Chipmunk2D. Given the slow pace of development of Chipmunk2D, and some unique requirements and oppurtunitites of Pymunk this is something that have grown over a long time. What really made me consider to make it more formal was the discussion "here":https://github.com/slembcke/Chipmunk2D/issues/237 with Slembcke, the creator of Chipmunk2D. 
+
+I do not forsee that I have the time, motivation or skills to really revive Chipmunk2D. However, I hope to incorporate minor new features, and a bunch of fixes. Any changes are driven by what make sense from the Pymunk use case. However, I do think many of these changes are useful also to users outside of Pymunk, and you are of course free to use the fork for other projects / languages as well.
+
+At the moment I dont have any formal release of this fork, but I plan to make some kind of rename and a release if/when enough changes are accumulated.
+
+h3. Differeces:
+
+* This fork will have ABI breaking changes. For Pymunk it does not matter, a Pymunk verison is always compiled against a specific Chipmunk2D version.
+* This fork might have API breaking changes. Since Pymunk wraps Chipmunk2D in a Python friendly API, end users of Pymunk wont be affected.
+* Some additional minor features, useful from Pymunk 
+* Fixes to various issues, mainly those affecting Pymunk
+
+---
+
 h2. NEW IN CHIPMUNK 7
 
 Chipmunk 7 is complete and now includes the ARM NEON optimizations, the autogeometry code, and the mulithreaded solver. 

VERSION.txt

@@ -1,3 +1,24 @@
+What's new in NEXT:
+* API: Now possible to to override cpMessage by defining CP_OVERRIDE_MESSAGE 
+* API: The maxForce property now have effect on DampedSpring and DampedRotarySpring
+* API: Reset velocity and constraint jAcc when body type changes to DYNAMIC
+* API: Add transform property to cpSpaceDebugDrawOptions 
+* API: Use CGFloat as the float type if CP_USE_CGTYPES is set.
+* BUG: Fixed total impulse calculation of DampedRotarySpring
+* BUG: Fix for compiling cpPolyline with MSVC 
+* BUG: Fix FFI symbols not exported on windows under mingw 
+* BUG: Fix a potential divide by zero in ClosestT
+* BUG: Fix division by zero in cpPolyShapeSegmentQuery() function.
+* BUG: Fix planetmath url (by ccgargantua)
+* BUG: Optimized memory allocation of cpPolylineSet (by richardgroves)
+* BUG: Fix cast between incompatible function type to reduce warnings (by aganm)
+* BUG: Rename body local variable to fix shadow warning (by aganm)
+* BUG: Fixes bug in cpSpaceShapeQuery to not miss collisions (by alanmillard)
+* BUG: Fix for cpSpaceShapeQuery using cpSegmentShape with null body (by maniek2332)
+* MISC: Fix spelling of positive (by skitt)
+
+
+
 What's new in 7.0.3:
 * MISC: Replacing GLFW with Sokol in the demo application. No need to push GLFW binaries and has a nice x-platform renderer to build on.
 * MISC: Fixed some 'const' warnings for MSCV.

demo/ChipmunkDemo.c

@@ -189,6 +189,7 @@ ChipmunkDemoDefaultDrawImpl(cpSpace *space)
 		ColorForShape,
 		{0.0f, 0.75f, 0.0f, 1.0f}, // Constraint color
 		{1.0f, 0.0f, 0.0f, 1.0f}, // Collision point color
+		cpTransformIdentity,
 		NULL,
 	};
 

include/chipmunk/chipmunk_structs.h

@@ -239,12 +239,14 @@ typedef void (*cpConstraintPreStepImpl)(cpConstraint *constraint, cpFloat dt);
 typedef void (*cpConstraintApplyCachedImpulseImpl)(cpConstraint *constraint, cpFloat dt_coef);
 typedef void (*cpConstraintApplyImpulseImpl)(cpConstraint *constraint, cpFloat dt);
 typedef cpFloat (*cpConstraintGetImpulseImpl)(cpConstraint *constraint);
+typedef void (*cpConstraintResetAccImpl)(cpConstraint *constraint);
 
 typedef struct cpConstraintClass {
 	cpConstraintPreStepImpl preStep;
 	cpConstraintApplyCachedImpulseImpl applyCachedImpulse;
 	cpConstraintApplyImpulseImpl applyImpulse;
 	cpConstraintGetImpulseImpl getImpulse;
+	cpConstraintResetAccImpl resetAcc;
 } cpConstraintClass;
 
 struct cpConstraint {

include/chipmunk/cpMarch.h

@@ -1,6 +1,10 @@
 // Copyright 2013 Howling Moon Software. All rights reserved.
 // See http://chipmunk2d.net/legal.php for more information.
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 /// Function type used as a callback from the marching squares algorithm to sample an image function.
 /// It passes you the point to sample and your context pointer, and you return the density.
 typedef cpFloat (*cpMarchSampleFunc)(cpVect point, void *data);
@@ -26,3 +30,7 @@ CP_EXPORT void cpMarchHard(
   cpMarchSegmentFunc segment, void *segment_data,
   cpMarchSampleFunc sample, void *sample_data
 );
+
+#ifdef __cplusplus
+}
+#endif

include/chipmunk/cpPolyline.h

@@ -1,6 +1,10 @@
 // Copyright 2013 Howling Moon Software. All rights reserved.
 // See http://chipmunk2d.net/legal.php for more information.
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 // Polylines are just arrays of vertexes.
 // They are looped if the first vertex is equal to the last.
 // cpPolyline structs are intended to be passed by value and destroyed when you are done with them.
@@ -68,3 +72,7 @@ CP_EXPORT void cpPolylineSetCollectSegment(cpVect v0, cpVect v1, cpPolylineSet *
 CP_EXPORT cpPolylineSet *cpPolylineConvexDecomposition(cpPolyline *line, cpFloat tol);
 
 #define cpPolylineConvexDecomposition_BETA cpPolylineConvexDecomposition
+
+#ifdef __cplusplus
+}
+#endif

src/chipmunk.c

@@ -17,7 +17,7 @@
  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
  * SOFTWARE.
- */
+ */ 
 
 #include <stdio.h>
 #include <string.h>
@@ -28,6 +28,7 @@
 
 #include "chipmunk/chipmunk_private.h"
 
+#ifndef CP_OVERRIDE_MESSAGE
 void
 cpMessage(const char *condition, const char *file, int line, int isError, int isHardError, const char *message, ...)
 {
@@ -52,6 +53,8 @@ cpMessage(const char *condition, const char *file, int line, int isError, int is
 	fprintf(stderr, "\tSource:%s:%d\n", file, line);
 #endif
 }
+#endif 
+
 
 #define STR(s) #s
 #define XSTR(s) STR(s)

src/cpBBTree.c

@@ -544,7 +544,7 @@ cpBBTreeAlloc(void)
 	return (cpBBTree *)cpcalloc(1, sizeof(cpBBTree));
 }
 
-static int
+static cpBool
 leafSetEql(void *obj, Node *node)
 {
 	return (obj == node->obj);

src/cpBody.c

@@ -103,9 +103,9 @@ cpBodyFree(cpBody *body)
 #ifdef NDEBUG
 	#define	cpAssertSaneBody(body)
 #else
-	static void cpv_assert_nan(cpVect v, char *message){cpAssertHard(v.x == v.x && v.y == v.y, message);}
-	static void cpv_assert_infinite(cpVect v, char *message){cpAssertHard(cpfabs(v.x) != INFINITY && cpfabs(v.y) != INFINITY, message);}
-	static void cpv_assert_sane(cpVect v, char *message){cpv_assert_nan(v, message); cpv_assert_infinite(v, message);}
+	static void cpv_assert_nan(cpVect v, const char *message){cpAssertHard(v.x == v.x && v.y == v.y, message);}
+	static void cpv_assert_infinite(cpVect v, const char *message){cpAssertHard(cpfabs(v.x) != INFINITY && cpfabs(v.y) != INFINITY, message);}
+	static void cpv_assert_sane(cpVect v, const char *message){cpv_assert_nan(v, message); cpv_assert_infinite(v, message);}
 
 	static void
 	cpBodySanityCheck(const cpBody *body)
@@ -160,6 +160,23 @@ cpBodySetType(cpBody *body, cpBodyType type)
 		body->m_inv = body->i_inv = INFINITY;
 
 		cpBodyAccumulateMassFromShapes(body);
+
+        // Check any constraints, and if there are
+        // constraints with another non-DYNAMIC body:
+        // Reset any accumulated force in constraints attached to the body.
+        // Reset velocity of the body. These will be NaN or Inf otherwise.
+        cpConstraint* constraint = body->constraintList;
+        while (constraint) {
+            constraint->klass->resetAcc(constraint);
+            cpBody* a = cpConstraintGetBodyA(constraint);
+            a->v = cpvzero;
+            a->w = 0.0f;
+            cpBody* b = cpConstraintGetBodyB(constraint);
+            b->v = cpvzero;
+            b->w = 0.0f;
+
+            constraint = cpConstraintNext(constraint, body);
+        }
 	} else {
 		body->m = body->i = INFINITY;
 		body->m_inv = body->i_inv = 0.0f;

src/cpCollision.c

@@ -559,7 +559,7 @@ CircleToSegment(const cpCircleShape *circle, const cpSegmentShape *segment, stru
 		cpVect n = info->n = (dist ? cpvmult(delta, 1.0f/dist) : segment->tn);
 
 		// Reject endcap collisions if tangents are provided.
-		cpVect rot = cpBodyGetRotation(segment->shape.body);
+		cpVect rot = segment->shape.body ? cpBodyGetRotation(segment->shape.body) : cpv(1.0f, 0.0f);
 		if(
 			(closest_t != 0.0f || cpvdot(n, cpvrotate(segment->a_tangent, rot)) >= 0.0) &&
 			(closest_t != 1.0f || cpvdot(n, cpvrotate(segment->b_tangent, rot)) >= 0.0)
@@ -587,8 +587,8 @@ SegmentToSegment(const cpSegmentShape *seg1, const cpSegmentShape *seg2, struct
 #endif
 
 	cpVect n = points.n;
-	cpVect rot1 = cpBodyGetRotation(seg1->shape.body);
-	cpVect rot2 = cpBodyGetRotation(seg2->shape.body);
+	cpVect rot1 = seg1->shape.body ? cpBodyGetRotation(seg1->shape.body) : cpv(1.0f, 0.0f);
+	cpVect rot2 = seg2->shape.body ? cpBodyGetRotation(seg2->shape.body) : cpv(1.0f, 0.0f);
 
 	// If the closest points are nearer than the sum of the radii...
 	if(
@@ -645,7 +645,7 @@ SegmentToPoly(const cpSegmentShape *seg, const cpPolyShape *poly, struct cpColli
 #endif
 
 	cpVect n = points.n;
-	cpVect rot = cpBodyGetRotation(seg->shape.body);
+	cpVect rot = seg->shape.body ? cpBodyGetRotation(seg->shape.body) : cpv(1.0f, 0.0f);
 
 	if(
 		// If the closest points are nearer than the sum of the radii...

src/cpDampedRotarySpring.c

@@ -20,7 +20,7 @@
  */
 
 #include "chipmunk/chipmunk_private.h"
-
+#include <stdio.h>
 static cpFloat
 defaultSpringTorque(cpDampedRotarySpring *spring, cpFloat relativeAngle){
 	return (relativeAngle - spring->restAngle)*spring->stiffness;
@@ -40,7 +40,10 @@ preStep(cpDampedRotarySpring *spring, cpFloat dt)
 	spring->target_wrn = 0.0f;
 
 	// apply spring torque
-	cpFloat j_spring = spring->springTorqueFunc((cpConstraint *)spring, a->a - b->a)*dt;
+	cpFloat t_spring = spring->springTorqueFunc((cpConstraint *)spring, a->a - b->a);
+	t_spring = cpfclamp(t_spring, -spring->constraint.maxForce, spring->constraint.maxForce);
+
+	cpFloat j_spring = t_spring*dt;
 	spring->jAcc = j_spring;
 
 	a->w -= j_spring*a->i_inv;
@@ -65,8 +68,12 @@ applyImpulse(cpDampedRotarySpring *spring, cpFloat dt)
 
 	//apply_impulses(a, b, spring->r1, spring->r2, cpvmult(spring->n, v_damp*spring->nMass));
 	cpFloat j_damp = w_damp*spring->iSum;
-	spring->jAcc += j_damp;
+	cpFloat maxImpulse = spring->constraint.maxForce*dt;
 
+	cpFloat jAccClamped = cpfclamp(spring->jAcc-j_damp, -maxImpulse, maxImpulse);
+	j_damp = spring->jAcc - jAccClamped;
+
+	spring->jAcc -= j_damp;
 	a->w += j_damp*a->i_inv;
 	b->w -= j_damp*b->i_inv;
 }
@@ -77,11 +84,18 @@ getImpulse(cpDampedRotarySpring *spring)
 	return spring->jAcc;
 }
 
+static void
+resetAcc(cpDampedRotarySpring *spring) 
+{
+	spring->jAcc = 0.0f;
+}
+
 static const cpConstraintClass klass = {
 	(cpConstraintPreStepImpl)preStep,
 	(cpConstraintApplyCachedImpulseImpl)applyCachedImpulse,
 	(cpConstraintApplyImpulseImpl)applyImpulse,
 	(cpConstraintGetImpulseImpl)getImpulse,
+	(cpConstraintResetAccImpl)resetAcc,
 };
 
 cpDampedRotarySpring *