Support for more than 16 shapes in a collision object

totebo · June 6, 2020, 11:45am

WARNING:GAMESYS: Too many shapes in collision object. Up to 16 is supported (18). Discarding overflowing shapes.

See above. 18 collisions shapes are hardly excessive. Could this limit be configurable in game.project file?

Daniel_Widgren · June 6, 2020, 12:29pm

Maybe you could use tilesource for this and add collision there?

britzl · June 6, 2020, 12:52pm

Probably! Let’s have a look:

The error originates from this line of code:

github.com

defold/defold/blob/1.2.169/engine/gamesys/src/gamesys/resources/res_collision_object.cpp#L194


}


const dmPhysicsDDF::CollisionShape* embedded_shape = &resource->m_DDF->m_EmbeddedCollisionShape;
const dmPhysicsDDF::CollisionShape::Shape* shapes = embedded_shape->m_Shapes.m_Data;
if (shapes)
{
    // Create embedded convex shapes
    uint32_t count = embedded_shape->m_Shapes.m_Count;
    if (count > COLLISION_OBJECT_MAX_SHAPES)
    {
        dmLogWarning("Too many shapes in collision object. Up to %d is supported (%d). Discarding overflowing shapes.", COLLISION_OBJECT_MAX_SHAPES, count);
        count = COLLISION_OBJECT_MAX_SHAPES;
    }


    uint32_t current_shape_count = resource->m_ShapeCount;
    for (uint32_t i = 0; i < count; ++i)
    {
        if (physics_context->m_3D)
        {
            dmPhysics::HCollisionObject3D shape = Create3DShape(physics_context->m_Context3D, embedded_shape, i);
            if (shape)

Ok, so it uses the COLLISION_OBJECT_MAX_SHAPES constant. Where is it? Ah, here we go:

github.com

defold/defold/blob/1.2.169/engine/gamesys/src/gamesys/resources/res_collision_object.h#L16


#include <resource/resource.h>
#include <physics/physics.h>


#include "res_convex_shape.h"
#include "res_tilegrid.h"


#include "../proto/physics_ddf.h"


namespace dmGameSystem
{
    const uint32_t COLLISION_OBJECT_MAX_SHAPES = 16; // Number of shapes including shape from convex shape resource


    struct CollisionObjectResource
    {
        inline CollisionObjectResource()
        {
            memset(this, 0, sizeof(CollisionObjectResource));
        }


        uint64_t m_Mask[16];
        uint64_t m_Group;

So, in theory we should expose that value all the way from the game project config. The values are read here:

github.com

defold/defold/blob/1.2.169/engine/engine/src/engine.cpp#L853




dmPhysics::NewContextParams physics_params;
physics_params.m_WorldCount = dmConfigFile::GetInt(engine->m_Config, "physics.world_count", 4);
const char* physics_type = dmConfigFile::GetString(engine->m_Config, "physics.type", "2D");
physics_params.m_Gravity.setX(dmConfigFile::GetFloat(engine->m_Config, "physics.gravity_x", 0.0f));
physics_params.m_Gravity.setY(dmConfigFile::GetFloat(engine->m_Config, "physics.gravity_y", -10.0f));
physics_params.m_Gravity.setZ(dmConfigFile::GetFloat(engine->m_Config, "physics.gravity_z", 0.0f));
physics_params.m_Scale = dmConfigFile::GetFloat(engine->m_Config, "physics.scale", 1.0f);
physics_params.m_RayCastLimit2D = dmConfigFile::GetInt(engine->m_Config, "physics.ray_cast_limit_2d", 64);
physics_params.m_RayCastLimit3D = dmConfigFile::GetInt(engine->m_Config, "physics.ray_cast_limit_3d", 128);
physics_params.m_TriggerOverlapCapacity = dmConfigFile::GetInt(engine->m_Config, "physics.trigger_overlap_capacity", 16);
if (physics_params.m_Scale < dmPhysics::MIN_SCALE || physics_params.m_Scale > dmPhysics::MAX_SCALE)
{
    dmLogWarning("Physics scale must be in the range %.2f - %.2f and has been clamped.", dmPhysics::MIN_SCALE, dmPhysics::MAX_SCALE);
    if (physics_params.m_Scale < dmPhysics::MIN_SCALE)
        physics_params.m_Scale = dmPhysics::MIN_SCALE;
    if (physics_params.m_Scale > dmPhysics::MAX_SCALE)
        physics_params.m_Scale = dmPhysics::MAX_SCALE;
}
physics_params.m_ContactImpulseLimit = dmConfigFile::GetFloat(engine->m_Config, "physics.contact_impulse_limit", 0.0f);
if (dmStrCaseCmp(physics_type, "3D") == 0)

totebo · June 6, 2020, 12:56pm

Ha ha ha, you’re loving this new freedom Björn!

This is pretty amazing. Great to look at the exposed inner workings of Defold. I won’t be able to make this change myself, but hope someone might!