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#include "util.h"
AxisAngle AxisAngleIdentity() {
return (AxisAngle){Vector3Zero(), 0.0};
}
float signum(float n) {
if (n > 0.0)
return 1.0;
else if (n < 0.0)
return -1.0;
else
return 0.0;
}
void printVector3(Vector3 v) {
printf("%f %f %f\n", v.x, v.y, v.z);
}
void printVector2(Vector2 v) {
printf("%f %f\n", v.x, v.y);
}
// Warning. Mostly chatgpt written.
static void projectTriangleOntoAxis(const Triangle3D triangle, const Vector3 axis, float* min, float* max) {
float dot1 = Vector3DotProduct(triangle[0], axis);
float dot2 = Vector3DotProduct(triangle[1], axis);
float dot3 = Vector3DotProduct(triangle[2], axis);
*min = fminf(fminf(dot1, dot2), dot3);
*max = fmaxf(fmaxf(dot1, dot2), dot3);
}
static bool trianglesIntersectOnAxis(const Triangle3D triangleA, const Triangle3D triangleB, Vector3 axis) {
float minA, maxA;
float minB, maxB;
projectTriangleOntoAxis(triangleA, axis, &minA, &maxA);
projectTriangleOntoAxis(triangleB, axis, &minB, &maxB);
return (minA <= maxB && maxA >= minB);
}
bool checkTriangleCollision3D(const Triangle3D triangleA, const Triangle3D triangleB, Vector3 normalA, Vector3 normalB) {
// Test triangle normals
if (!trianglesIntersectOnAxis(triangleA, triangleB, normalA))
return false;
if (!trianglesIntersectOnAxis(triangleA, triangleB, normalB))
return false;
// Test cross products of triangle edges
Vector3 edgesA[3] = {
Vector3Subtract(triangleA[1], triangleA[0]),
Vector3Subtract(triangleA[2], triangleA[1]),
Vector3Subtract(triangleA[0], triangleA[2])
};
Vector3 edgesB[3] = {
Vector3Subtract(triangleB[1], triangleB[0]),
Vector3Subtract(triangleB[2], triangleB[1]),
Vector3Subtract(triangleB[0], triangleB[2])
};
for (int i = 0; i < 3; i++) {
Vector3 axis = Vector3CrossProduct(normalA, edgesA[i]);
if (!trianglesIntersectOnAxis(triangleA, triangleB, axis))
return false;
axis = Vector3CrossProduct(normalB, edgesB[i]);
if (!trianglesIntersectOnAxis(triangleA, triangleB, axis))
return false;
}
return true;
}
void copyTriangle3D(Triangle3D a, const Triangle3D b) {
a[0] = b[0];
a[1] = b[1];
a[2] = b[2];
}
Vector3 getVertexAt(Mesh mesh, int vertexNum) {
return (Vector3){
mesh.vertices[vertexNum * 3],
mesh.vertices[vertexNum * 3 + 1],
mesh.vertices[vertexNum * 3 + 2]
};
}
void drawModelWireframe(Model model, Vector3 position, Quaternion rotation, Color color) {
// DrawModelWires doesn't work on the version of opengl that web assembly uses.
// Instead I use this stupid peice of shit.
#ifdef PLATFORM_WEB
for (int i = 0; i < model.meshCount; ++i) {
Mesh mesh = model.meshes[i];
// Loop through the triangles.
for (int triangleNum = 0; triangleNum < mesh.triangleCount; ++triangleNum) {
Triangle3D triangle = {
getVertexAt(mesh, triangleNum * 3),
getVertexAt(mesh, triangleNum * 3 + 1),
getVertexAt(mesh, triangleNum * 3 + 2)
};
// Rotation and transform.
for (int vertexNum = 0; vertexNum < 3; ++vertexNum) {
triangle[vertexNum] = Vector3RotateByQuaternion(triangle[vertexNum], rotation);
triangle[vertexNum] = Vector3Add(triangle[vertexNum], position);
}
// Draw.
DrawLine3D(triangle[0], triangle[1], color);
DrawLine3D(triangle[1], triangle[2], color);
DrawLine3D(triangle[2], triangle[0], color);
}
}
#else
model.transform = QuaternionToMatrix(rotation);
DrawModelWires(model, position, 1.0, color);
#endif
}
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