@@ -3608,109 +3608,164 @@ BoundingBox GetMeshBoundingBox(Mesh mesh)
36083608}
36093609
36103610// Compute mesh tangents
3611- // NOTE: To calculate mesh tangents and binormals we need mesh vertex positions and texture coordinates
3612- // Implementation based on: https://answers.unity.com/questions/7789/calculating-tangents-vector4.html
36133611void GenMeshTangents (Mesh * mesh )
36143612{
3615- if ((mesh -> vertices == NULL ) || (mesh -> texcoords == NULL ))
3613+ // Check if input mesh data is useful
3614+ if ((mesh == NULL ) || (mesh -> vertices == NULL ) || (mesh -> texcoords == NULL ) || (mesh -> normals == NULL ))
36163615 {
3617- TRACELOG (LOG_WARNING , "MESH: Tangents generation requires texcoord vertex attribute data" );
3616+ TRACELOG (LOG_WARNING , "MESH: Tangents generation requires vertices, texcoords and normals vertex attribute data" );
36183617 return ;
36193618 }
36203619
3620+ // Allocate or reallocate tangents data
36213621 if (mesh -> tangents == NULL ) mesh -> tangents = (float * )RL_MALLOC (mesh -> vertexCount * 4 * sizeof (float ));
36223622 else
36233623 {
36243624 RL_FREE (mesh -> tangents );
36253625 mesh -> tangents = (float * )RL_MALLOC (mesh -> vertexCount * 4 * sizeof (float ));
36263626 }
36273627
3628- Vector3 * tan1 = (Vector3 * )RL_MALLOC (mesh -> vertexCount * sizeof (Vector3 ));
3629- Vector3 * tan2 = (Vector3 * )RL_MALLOC (mesh -> vertexCount * sizeof (Vector3 ));
3628+ // Allocate temporary arrays for tangents calculation
3629+ Vector3 * tan1 = (Vector3 * )RL_CALLOC (mesh -> vertexCount , sizeof (Vector3 ));
3630+ Vector3 * tan2 = (Vector3 * )RL_CALLOC (mesh -> vertexCount , sizeof (Vector3 ));
36303631
3631- if (mesh -> vertexCount % 3 != 0 )
3632+ if (tan1 == NULL || tan2 == NULL )
36323633 {
3633- TRACELOG (LOG_WARNING , "MESH: vertexCount expected to be a multiple of 3. Expect uninitialized values." );
3634+ TRACELOG (LOG_WARNING , "MESH: Failed to allocate temporary memory for tangent calculation" );
3635+ if (tan1 ) RL_FREE (tan1 );
3636+ if (tan2 ) RL_FREE (tan2 );
3637+ return ;
36343638 }
36353639
3636- for (int i = 0 ; i <= mesh -> vertexCount - 3 ; i += 3 )
3640+ // Process all triangles of the mesh
3641+ // 'triangleCount' must be always valid
3642+ for (int t = 0 ; t < mesh -> triangleCount ; t ++ )
36373643 {
3638- // Get triangle vertices
3639- Vector3 v1 = { mesh -> vertices [(i + 0 )* 3 + 0 ], mesh -> vertices [(i + 0 )* 3 + 1 ], mesh -> vertices [(i + 0 )* 3 + 2 ] };
3640- Vector3 v2 = { mesh -> vertices [(i + 1 )* 3 + 0 ], mesh -> vertices [(i + 1 )* 3 + 1 ], mesh -> vertices [(i + 1 )* 3 + 2 ] };
3641- Vector3 v3 = { mesh -> vertices [(i + 2 )* 3 + 0 ], mesh -> vertices [(i + 2 )* 3 + 1 ], mesh -> vertices [(i + 2 )* 3 + 2 ] };
3644+ // Get triangle vertex indices
3645+ int i0 , i1 , i2 ;
3646+
3647+ if (mesh -> indices != NULL )
3648+ {
3649+ // Use indices if available
3650+ i0 = mesh -> indices [t * 3 + 0 ];
3651+ i1 = mesh -> indices [t * 3 + 1 ];
3652+ i2 = mesh -> indices [t * 3 + 2 ];
3653+ }
3654+ else
3655+ {
3656+ // Sequential access for non-indexed mesh
3657+ i0 = t * 3 + 0 ;
3658+ i1 = t * 3 + 1 ;
3659+ i2 = t * 3 + 2 ;
3660+ }
3661+
3662+ // Get triangle vertices position
3663+ Vector3 v1 = { mesh -> vertices [i0 * 3 + 0 ], mesh -> vertices [i0 * 3 + 1 ], mesh -> vertices [i0 * 3 + 2 ] };
3664+ Vector3 v2 = { mesh -> vertices [i1 * 3 + 0 ], mesh -> vertices [i1 * 3 + 1 ], mesh -> vertices [i1 * 3 + 2 ] };
3665+ Vector3 v3 = { mesh -> vertices [i2 * 3 + 0 ], mesh -> vertices [i2 * 3 + 1 ], mesh -> vertices [i2 * 3 + 2 ] };
36423666
36433667 // Get triangle texcoords
3644- Vector2 uv1 = { mesh -> texcoords [( i + 0 ) * 2 + 0 ], mesh -> texcoords [( i + 0 ) * 2 + 1 ] };
3645- Vector2 uv2 = { mesh -> texcoords [( i + 1 ) * 2 + 0 ], mesh -> texcoords [( i + 1 ) * 2 + 1 ] };
3646- Vector2 uv3 = { mesh -> texcoords [( i + 2 ) * 2 + 0 ], mesh -> texcoords [( i + 2 ) * 2 + 1 ] };
3668+ Vector2 uv1 = { mesh -> texcoords [i0 * 2 + 0 ], mesh -> texcoords [i0 * 2 + 1 ] };
3669+ Vector2 uv2 = { mesh -> texcoords [i1 * 2 + 0 ], mesh -> texcoords [i1 * 2 + 1 ] };
3670+ Vector2 uv3 = { mesh -> texcoords [i2 * 2 + 0 ], mesh -> texcoords [i2 * 2 + 1 ] };
36473671
3672+ // Calculate triangle edges
36483673 float x1 = v2 .x - v1 .x ;
36493674 float y1 = v2 .y - v1 .y ;
36503675 float z1 = v2 .z - v1 .z ;
36513676 float x2 = v3 .x - v1 .x ;
36523677 float y2 = v3 .y - v1 .y ;
36533678 float z2 = v3 .z - v1 .z ;
36543679
3680+ // Calculate texture coordinate differences
36553681 float s1 = uv2 .x - uv1 .x ;
36563682 float t1 = uv2 .y - uv1 .y ;
36573683 float s2 = uv3 .x - uv1 .x ;
36583684 float t2 = uv3 .y - uv1 .y ;
36593685
3686+ // Calculate denominator and check for degenerate UV
36603687 float div = s1 * t2 - s2 * t1 ;
3661- float r = (div == 0.0f )? 0.0f : 1.0f /div ;
3688+ float r = (fabsf ( div ) < 0.0001f )? 0.0f : 1.0f /div ;
36623689
3690+ // Calculate tangent and bitangent directions
36633691 Vector3 sdir = { (t2 * x1 - t1 * x2 )* r , (t2 * y1 - t1 * y2 )* r , (t2 * z1 - t1 * z2 )* r };
36643692 Vector3 tdir = { (s1 * x2 - s2 * x1 )* r , (s1 * y2 - s2 * y1 )* r , (s1 * z2 - s2 * z1 )* r };
36653693
3666- tan1 [i + 0 ] = sdir ;
3667- tan1 [i + 1 ] = sdir ;
3668- tan1 [i + 2 ] = sdir ;
3694+ // Accumulate tangents and bitangents for each vertex of the triangle
3695+ tan1 [i0 ] = Vector3Add (tan1 [i0 ], sdir );
3696+ tan1 [i1 ] = Vector3Add (tan1 [i1 ], sdir );
3697+ tan1 [i2 ] = Vector3Add (tan1 [i2 ], sdir );
36693698
3670- tan2 [i + 0 ] = tdir ;
3671- tan2 [i + 1 ] = tdir ;
3672- tan2 [i + 2 ] = tdir ;
3699+ tan2 [i0 ] = Vector3Add ( tan2 [ i0 ], tdir ) ;
3700+ tan2 [i1 ] = Vector3Add ( tan2 [ i1 ], tdir ) ;
3701+ tan2 [i2 ] = Vector3Add ( tan2 [ i2 ], tdir ) ;
36733702 }
36743703
3675- // Compute tangents considering normals
3704+ // Calculate final tangents for each vertex
36763705 for (int i = 0 ; i < mesh -> vertexCount ; i ++ )
36773706 {
36783707 Vector3 normal = { mesh -> normals [i * 3 + 0 ], mesh -> normals [i * 3 + 1 ], mesh -> normals [i * 3 + 2 ] };
36793708 Vector3 tangent = tan1 [i ];
36803709
3681- // TODO: Review, not sure if tangent computation is right, just used reference proposed maths...
3682- #if defined(COMPUTE_TANGENTS_METHOD_01 )
3683- Vector3 tmp = Vector3Subtract (tangent , Vector3Scale (normal , Vector3DotProduct (normal , tangent )));
3684- tmp = Vector3Normalize (tmp );
3685- mesh -> tangents [i * 4 + 0 ] = tmp .x ;
3686- mesh -> tangents [i * 4 + 1 ] = tmp .y ;
3687- mesh -> tangents [i * 4 + 2 ] = tmp .z ;
3688- mesh -> tangents [i * 4 + 3 ] = 1.0f ;
3689- #else
3690- Vector3OrthoNormalize (& normal , & tangent );
3691- mesh -> tangents [i * 4 + 0 ] = tangent .x ;
3692- mesh -> tangents [i * 4 + 1 ] = tangent .y ;
3693- mesh -> tangents [i * 4 + 2 ] = tangent .z ;
3694- mesh -> tangents [i * 4 + 3 ] = (Vector3DotProduct (Vector3CrossProduct (normal , tangent ), tan2 [i ]) < 0.0f )? -1.0f : 1.0f ;
3695- #endif
3710+ // Handle zero tangent (can happen with degenerate UVs)
3711+ if (Vector3Length (tangent ) < 0.0001f )
3712+ {
3713+ // Create a tangent perpendicular to the normal
3714+ if (fabsf (normal .z ) > 0.707f ) tangent = (Vector3 ){ 1.0f , 0.0f , 0.0f };
3715+ else tangent = Vector3Normalize ((Vector3 ){ - normal .y , normal .x , 0.0f });
3716+
3717+ mesh -> tangents [i * 4 + 0 ] = tangent .x ;
3718+ mesh -> tangents [i * 4 + 1 ] = tangent .y ;
3719+ mesh -> tangents [i * 4 + 2 ] = tangent .z ;
3720+ mesh -> tangents [i * 4 + 3 ] = 1.0f ;
3721+ continue ;
3722+ }
3723+
3724+ // Gram-Schmidt orthogonalization to make tangent orthogonal to normal
3725+ // T_prime = T - N * dot(N, T)
3726+ Vector3 orthogonalized = Vector3Subtract (tangent , Vector3Scale (normal , Vector3DotProduct (normal , tangent )));
3727+
3728+ // Handle cases where orthogonalized vector is too small
3729+ if (Vector3Length (orthogonalized ) < 0.0001f )
3730+ {
3731+ // Create a tangent perpendicular to the normal
3732+ if (fabsf (normal .z ) > 0.707f ) orthogonalized = (Vector3 ){ 1.0f , 0.0f , 0.0f };
3733+ else orthogonalized = Vector3Normalize ((Vector3 ){ - normal .y , normal .x , 0.0f });
3734+ }
3735+ else
3736+ {
3737+ // Normalize the orthogonalized tangent
3738+ orthogonalized = Vector3Normalize (orthogonalized );
3739+ }
3740+
3741+ // Store the calculated tangent
3742+ mesh -> tangents [i * 4 + 0 ] = orthogonalized .x ;
3743+ mesh -> tangents [i * 4 + 1 ] = orthogonalized .y ;
3744+ mesh -> tangents [i * 4 + 2 ] = orthogonalized .z ;
3745+
3746+ // Calculate the handedness (w component)
3747+ mesh -> tangents [i * 4 + 3 ] = (Vector3DotProduct (Vector3CrossProduct (normal , orthogonalized ), tan2 [i ]) < 0.0f )? -1.0f : 1.0f ;
36963748 }
36973749
3750+ // Free temporary arrays
36983751 RL_FREE (tan1 );
36993752 RL_FREE (tan2 );
37003753
3754+ // Update vertex buffers if available
37013755 if (mesh -> vboId != NULL )
37023756 {
37033757 if (mesh -> vboId [SHADER_LOC_VERTEX_TANGENT ] != 0 )
37043758 {
3705- // Update existing vertex buffer
3759+ // Update existing tangent vertex buffer
37063760 rlUpdateVertexBuffer (mesh -> vboId [SHADER_LOC_VERTEX_TANGENT ], mesh -> tangents , mesh -> vertexCount * 4 * sizeof (float ), 0 );
37073761 }
37083762 else
37093763 {
3710- // Load a new tangent attributes buffer
3764+ // Create new tangent vertex buffer
37113765 mesh -> vboId [SHADER_LOC_VERTEX_TANGENT ] = rlLoadVertexBuffer (mesh -> tangents , mesh -> vertexCount * 4 * sizeof (float ), false);
37123766 }
37133767
3768+ // Set up vertex attributes for shader
37143769 rlEnableVertexArray (mesh -> vaoId );
37153770 rlSetVertexAttribute (RL_DEFAULT_SHADER_ATTRIB_LOCATION_TANGENT , 4 , RL_FLOAT , 0 , 0 , 0 );
37163771 rlEnableVertexAttribute (RL_DEFAULT_SHADER_ATTRIB_LOCATION_TANGENT );
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